posted on June 23, 2011 18:36
|Every tube was designed in Solid Works and the cage was pre assembled and rendered which made the actual cage construction very fast. The cage would also be really easy to duplicate.
The car was constructed at APD Team Headquarters, 42 Autosports, in Concord, NC. (Located in the heart of NASCAR/Grand Am country, which provided the team with some unique resources.) Project leader and chief mechanic, James Longhurst an ASE/Acura Certified Master Technician was in charge of the build. The 3318 Lb car was completely gutted and a roll cage was fabricated to Grand am spec by a NASCAR fabricator utilizing Solid Works software to shorten workflow. Design and cage construction took only 3 days! When finished the build up the car in race trim with driver and ½ tank of fuel weighed in at 2840 Lbs on the MotoIQ scales at Cal Speedway.
|It is amazing that this cage was built in only 3 days!
|The cage was mig welded. There is nothing wrong with good mig welding for a mild steel cage.
|The finished cage is a masterpiece! Sign us up for a 3 day wonder like this!
The stock engine output was base lined at 42 Autosports sister shop by John Earl of Six Sigma Dyno Services on a Dyno Dynamics unit and produced 148hp and 119tq before modification. After mods, on the Six Sigma dyno it produced 173hp and 148tq an increase of 25hp and 29tq. On Road Race Engineering’s Dynopack Hub Dyno for MotoIQ Certification, at California Speedway, the mods yielded 201hp and 164tq.
|The cage completely ties the unibody of the car together.
Stock k24A2 engine spec:
Displacement: 2,354 cc (143.6 cu in)
Power: 200 PS (150 kW; 200 hp) @ 6800 rpm
Torque: 232 N·m (171 lb·ft) @ 4500 rpm (166 lbft @ 4500 rpm U.S.)
Bore: 87 mm
Stroke: 99 mm
|The team saw impressive power gains just from freshening up the engine, blueprinting it, header, exhaust, air intake and getting a good tune with a Hondata ECU. Just a typical K motor. We feel that the K motor is the best 4 cylinder engine on the market.
|Our official impound dyno chart shows impressive power. To meet the TU requirements, the team is going to continue to develop the engine.
Friday, June 24, 2011 3:04 AM
Avid Motoiq reader first time commenting. Why did they remove the front anti-roll bar if the car is exibiting excessive roll? Looks like the car is really leaning on that front left! Thanks
Friday, June 24, 2011 6:58 AM
Usually you would do that in an extreme case of curing understeer. Removing the front bar softens the front and gives it more grip. I thought most good FWD cars picked up the inside wheel? I guess the Grand-Am/SCCA guys found a better way?
Friday, June 24, 2011 7:00 AM
Forgot to add, the cage is great and the brakes are ingenious. I wonder what other cars those will fit? Obviously the Accord, but I wonder if you can get those on a Civic or Integra. Or an S2000 for that matter. New idea for Project S2k maybe?
Friday, June 24, 2011 9:22 AM
@8695, I'm very content with the StopTechs on the S2k and this setup would be a downgrade due to rotor sizing. However, it is a damn badass budget setup they've come up with and ingenious!
Jonathan, always carry spare rotors! S2ks crack rotors like potato chips; typically every 4-6 track days. Ducting helps them last longer.
Amazing on the cage. Just goes to show what can be done by the professional racing industry that has access to the more advanced tools for designing.
Friday, June 24, 2011 9:32 AM
@Khiem: Jonathan and crew already learned that S2000 rotors crack like potato chips. They had both front rotors severely crack at CA Speedway, with the driver's front cracked all the way through to the hub!
And yes, SolidWorks FTW! Only $99 if you're a student... :)
Friday, June 24, 2011 10:08 AM
A lot of FWD racers don't use front bars. Advocates say that it helps forward traction on corner exit. A lot of successful and smart people do this. I personally don't agree with it and use significantly big front bars on FWD race cars, especially those with McPherson struts.
Friday, June 24, 2011 11:03 AM
I got a warm smile on my face as I read this! It's nice to see a competitor open up and walk you through their build. It's not like your hiding ANYTHING from fellow competitors Mike. The only problem with the TSX I ever found, was the difficulty to find a manual tranny version. It was on my list of potential suitors for my endeavors and maybe found one (but 165k was too many miles to start with) in 2 months of looking! I guess it's only a problem if you're interested in getting one.
Did APD mention any sort of cam work in the future? Does anyone even make a sportier/race cam for the K24?
Friday, June 24, 2011 11:27 AM
Thanks for the article! Always interested to see what other FWD pros are using.
Mike: I was under the impression that FWD racers don't use (or use small) front bars to make the car oversteer and rotate better? How would you setup sway bars on a car with McPherson struts? For example, same sized front/rear, larger rear, etc...?
Friday, June 24, 2011 11:36 AM
On my 2003 Focus, I disconnected the front bar some time ago. I like how the car handles without the bar.. compared to how it handled with the bar.
I'm running a BIG 25mm Eibach rear bar and KW Variant 3's all the way around.
I'm going to keep the front bar off for now.. and when budget allows, have KW re-work my setup with new spring rates, after I lighten the car a bit more (shifting the corner weight around...)
Fingers crossed I'll be able to race with you guys at Auto Club Speedway in October! :-)
Friday, June 24, 2011 11:45 AM
Eric L - Mike covered most of that in his Ultimate guide to suspension and handling found in the "Tech" section of the site. I think part 1 or 2 :/
Nikolas - Time to uncross those fingers and remember the infamous words of Rob Schneider "You can do it"!
Friday, June 24, 2011 12:12 PM
Hi guys, Thank you all very much for the compliments and comments on the car, components, and the build!
To answer some of the questions posed here:
a) Front Sway Bar: At the spring rates we are currently running, removing the front bar to uncouple the left and right sides front end was the best solution at this point to obtain maximum grip, the down side is excessive body roll in the front end! Once we upgrade to substantially stiffer springs on both ends of the car we can then experiment with front bars of varying stiffness to fine tune the front end. Suspension set up is always a compromise of elements, and we chose what we thought was the best compromise within our current parameters.
Mike I am very interested to speak with you about the large front bar concept!
b) Brakes: The car currently will stand on it's nose with this set up, we can brake super late and deep and no brake fade, but as Martin identified we are cracking front rotors like potato chips lol:)
This is caused by a combination of factors: Aftermarket inexpensive rotors, aggressive brake pads and lack of brake ducting. For the next event we are going to be testing a set of rotors and special compound brake pads supplied by HPD through the Racing Line and our standard Hawk pads with specially designed rotors from APM racing that incorporate an ingenious cooling design.
We also have plans and the parts on hand to instal brake ducting, just did not have time to finish it for the first event!
In relation to this set up working on other Honda cars: YES, the calipers will potentially bolt up to various knuckles and others will/may require adapter plates, the other issue is picking the appropriate rotor hat height, it just requires a little research and thought but is fairly easy to sort out.
(Anybody that needs help or info, please feel free to PM me.)
c) Our goal with this build is 3 fold: To introduce folks to the Honda Racing Line Parts and support program from HPD through the build and refinement of this car, to build the most competitive race package possible highlighting quality products and technology on a modest budget, with complete transparency to our fellow racers and followers and to highlight the MotoIQ series of racing, which is very accessible to the average racer or builder and
a fantastic place to compete thanks to Mike and his organization!
Friday, June 24, 2011 12:13 PM
Nick, you got two weeks, bring the Focus to Willow!
On a McStrut FF car I run a decent front bar and a big rear bar. Bars help on transients and FF econoboxes usually have such lame suspension geometry you don't want them to roll much as the loose camber. The TSX has a lot of camber gain though but the APD car has tons of body roll due to its street car like spring rates.
I think it would be better off with the stock front bar and a stiffer rear bar or lacking that stiller rear springs. Usually on most cars its more efficient to stiffen the bar to limit roll rather than up the spring rate. More spring rate means less mechanical grip.
You want the softest springs that keeps the car off the bumpstops, then balance with bars. At least thats the way I do it. Plenty of smart and successful guys do it differently though.
Friday, June 24, 2011 12:18 PM
I forgot to note that at the end of the article, the team plans to add crower cams. The car will get tons faster. Its super easy to make 250 whp on a k24 with just bolt ons and the car is way under it's weight limit. I suggest looking at IPS cams or perhaps Skunk2. i have opinions about crower that I will keep to my self.
HAR, have you look to Pro Parts? They can revalve Koni's to get you the damping you need for the spring rates you want. I suggest getting a digressive curve in those Konis.
Friday, June 24, 2011 12:32 PM
Thanks Mike! We do have cam plans:) Just sorting out a few supporting issues right now - header primaries are a little small, so we are working on a header solution.
Re valving has been just an issue of timing (having it available:)
Talking with an "unamed shcok company" you know who:) about double adjustables... Also Compass360 has offered us some spare Motons or Koni 2800's at a great price... just trying to put together the most economical deal! We are working with a severly limited budget!
Friday, June 24, 2011 12:57 PM
PS: Mike do you want me to see if I can get you some Tegris? Milliken is right down the mountain from me:)
Friday, June 24, 2011 1:01 PM
with the high cost of pads and rotors for OEM applications i'm surprised you didn't custom mount a caliper like the forged superlights from wilwood,
Friday, June 24, 2011 1:06 PM
@ Skullworks, (race) pads and rotors for this set up actually are fairly inexspensive:)
Friday, June 24, 2011 3:36 PM
Thanks for the replys! I too believe in as soft springs as possible then tuning roll resistance with the appropriate anti-roll bar. It just makes sense! although your springs contribute to overall roll stiffness if you have an independent roll stiffness adjustment it makes sense to use it!
Friday, June 24, 2011 4:30 PM
S2000 front brakes rotors are pretty damn cheap which is why many of those guys are very stubborn about not wanting to upgrade to a big brake it; you can get front set for ~$60-$80.
I'm very curious to see what these APD rotors look like. If the price is reasonable, I imagine they would sell well to the S2k crowd.
Can HPD's website be improved? For example, I'm looking for parts for the S2k. So you select the 'All Honda' option and you get pages of parts. The problem is, I have no freakin clue as to what car those parts are for! Civic? S2k? Accord? CR-V? You have to click on the part to find out what it fits. It would be much nicer if there were one more option to select your vehicle type.
Friday, June 24, 2011 4:40 PM
I'm glad I read this article, as it can help some with explaining the six-speed tranny problems many RSX, TSX and 8th gen Si owners (me included) have had with it. However, many have had 2nd and 3rd issues with OEM Honda fluid and have switched to Amsoil or Redline MTF. I tried blending Amsoil and Motul Gear FF 75W140 in equal parts but find that Redline and 10% Gear FF seems to work well without the cold weather stiffness. Still has occasional stiffness/reticence in engaging 2nd, but I feel that is engine movement (since it does it low or high RPMs) and the Ingalls dampener is on the list.
It is too bad the new Acuras and Civic Si , with their crappy styling and decontented K-series engines, lacking exhaust VTEC and with cast-in-head exhaust manifold are such a let-down that they make baby Jesus cry. Honda has peaked and the decline isn't pretty.
Friday, June 24, 2011 8:39 PM
Sorry to say it Mike, but those Weds TC105N wheels are not forged, they're cast.
Have they thought about switching the skunk2 upper control arm around. The left one goes to the right and the right one goes to the left? If they do so, they gain 2 degree of caster, just a thought.
Friday, June 24, 2011 8:41 PM
@8695: yes, those TL Type S Brembo brakes do fit the S2000.
Friday, June 24, 2011 9:24 PM
@ JDMized Thanks for pointing this out! here is a link to the actual "AMF" manufacturing process for the wheels: http://www.wedsna.com/amf.html
Interesting statement on the upper control arms - we will take a look at this.
Friday, June 24, 2011 9:47 PM
JDM, it is a form of cold working and forging. It is the same as the Enkei MAT process.
Saturday, June 25, 2011 1:25 PM
@Mike, so it's semi-forging then? SSR likes to call it that way (or MAT for the Enkei and AME). Not a true forging like Volk does though.
@HAR, yes, if you swap the Skunk2 upper control around you will gain two degree of caster. A friend of mine (Graham Downey, 3 times Honda Challenge National Champion) show me that.
Saturday, June 25, 2011 2:14 PM
Thank You JDMized - We will look at this:)
Saturday, June 25, 2011 3:44 PM
Great article! I have one thing to comment on, that oem mtf will surely cause the trans gears to wear quickly. Having run a tsx and civic in world challenge I have fond memories of replacing 4th gear at many tracks in the middle of a race weekend. Lightweight shockproof will make the gears last way longer and a fresh set of synchros will shift through the fluid just fine. Keep up the good work, car must be a blast!
Saturday, June 25, 2011 4:19 PM
Billy reported that Compass 360 WPC treated the tranny and it solved all the problems.
Saturday, June 25, 2011 4:35 PM
I can see the life of the gears being extended but the oem fluid is still too thin and breaks down quickly under heat and stress of racing. I even find unacceptable wear in these on stock street cars like the 06+ si. Again, just my experience not trying to preach or anything here.
Saturday, June 25, 2011 9:37 PM
First time posting. Wanted to say thank you for the great article, I visit the site frequently and love everything you guys do.
Being an SR20VE owner I do envy the K24, solid engine.
Interesting information on the suspension for FWD owners. I am not super smart with suspension but have gone to the track a couple of times in my B13 and have what I think are severe oversteer issues, the back end rotates very very easily. I'll have to try some of the things you guys discussed to see if I can balance things out.
I will be watching for future updates on the car :).
Sunday, June 26, 2011 8:16 AM
Source for the CoT support rods? :)
Sunday, June 26, 2011 8:41 AM
All of the bits came from a friends Nascar shop:)
Sunday, June 26, 2011 11:47 AM
Follow-up on the front sway bar discussion: If you're running 1 more race before getting the new double-adjustable whoziwhatzits, put the front bar back on and do some testing. If it turns out to be a bad move, you can simply remove on end link to disengage the bar and run the rest of the weekend that way.
On the weak transmission, I'm surprised to see you guys running an unsprung clutch disc. If the transmission is weak and you have a 2.4-liter engine spinning 7600 rpm, you're gonna have some wicked torsional vibrations coming into it. A sprung hub can really knock down the vibrational abuse the transmission sees. Peter Cunningham was having issues blowing up SE-R 6-speeds with a 7500+ rpm QR25 and I believe a sprung hub is what finally solved the problem. He may have done something similar with the Acuras he was also running, but i can't recall for sure.
Sunday, June 26, 2011 12:26 PM
@ Dave Coleman, Thanks for the input Dave!
We are very happy with the car where it is right now based on what we decidied to go with for the 1st stage of the car build.
We have actually tested with and without the front bar extensively, at our current spring rates, we happen to find the car better for us without the front bar. Things may change once get the "whoizwhatsit's" on the car and test again:)
In regard to the transmission:
We have had NO problems at all "yet" with the transmission, as it says in the article we went through it completely during the build and made a conscious choice on the clutch package and it works very well for us. The choice regarding MTF was made after testing 3 different fluids and we happen to like the way Honda MTF functioned in relation to the other 2 tested. (We do change it out regularly:) and there are plans to WPC treat the gear set at a later date.
For those who do not know the story of the cars first outing:
We took this car straight out of the box 480lbs heavier and 35 horsepower down from the limit in relation to our 2 closest competitors Dai and Mike:) and put it in P3 in qualifying at Cal Speedway, then proceeded to move into P1 at the start and to lead the race for a short while before being overcome by Dai in the Nissan and the Nissan's great midrange tourque and lighter weight:)
We then kept the car in P2 until the point Mike got us:) and finished in a very comfortable P3!
The only issues we had all weekend were cracking inexpensive aftermarket brake rotors (We finished the race with the drivers side cracked all the way through to the hub with some extremely bad vibration:) We have found the solution for this and will be testing it at Willow Springs.
All in all we are pretty darn pleased with the car, it's components and what we have acomplished to date and look forward to refining from here:)
Sunday, June 26, 2011 12:35 PM
For those of you that have not seen yet Mike, Dai and the MotoIQ guys put together a great race video with in car cameras from the Cal Speedway event:
Watch the Acura at work until Dai get's us:)
Sunday, June 26, 2011 7:25 PM
There are successful racers out there who don't use any sway bars because the bars transfer weight from the inside wheels to the outside wheels and therefore decrease mechanical grip. I'd really love to talk with Mike about this, actually.
Sunday, June 26, 2011 10:37 PM
What people don't understand is sure a sway bar causes weight transfer to the outside wheels but it is no more that any other means of changing roll stiffness to the same extent to balance the chassis.
Sometimes if the suspension geometry can accomodate it, you can get more grip by allowing the car to roll. In a statics environment, roll does not cause much difference it weight transfer so you might be able to justify that. Dynamicaly though excessive roll can cause enough weight transfer to upset things though so there is a limit to this.
When walking that line it is important to look at data and some of the drivers feedback so you don't go overboard. Excessive anything is usually not good on a race car and sometimes things are not always intuitive. Common mistake most chassis guys do is to limit things too much and uses too much bar, too much spring and too much damping. Too much can fool drivers too as too much sometimes feels pretty good and easy to drive. It usually makes you slow though hence it is important to have data if you can afford it.
The only disadvantage a bar has is that it can take away from some of the independent nature of IRS suspension which can result in more tire shock and less mechanical grip under some conditions. I have found this to be the case only when going vastly overboard with bars.
Where bars work magic is on transients. A car with swaybars feels much better and more secure to the driver as it takes less of a set and there is much faster transient response. Bars can also allow for softer springs and overall more mechanical grip while allowing softer springs and damper settings to maintain good transient response.
Lastly in the context of lower dollar racing, adjustable bars really help in setting up a car for different racks and drivers. A low bucks team has a smaller or no crew, and little to no test time.
It usually takes at least an hour for even a crack crew to effect a spring change but even a lone one man driver and crew can change a bar setting in a few minutes. Lets face it more of us fall into the latter most of the time.
Usually if set up in the zone I prefer of balanced spring to bar roll resistance, one hole on the sway bar is about the same as 150-250 lbs on the springs. I think for most people having adjustable bars is the way to go, even on FWD cars.
The only type of car where I might not run significant bars are offroad racing, rally and rallycross depending on how groomed the course and how much tarmac. I would run some bar though.
Remember, the bar is the best friend of the club racer and the guys with a small crew and not much money!
Sunday, June 26, 2011 10:49 PM
In short, HAR I think you should put that stock front bar on, cut the ends off and weld on a plate with some holes and use some Whiteline end links to make it adjustable. Do the same thing to the rear bar. That way you can have more rear bar if you want. I have had that done on plenty of stock bars and it works awesome.
Go up at least 200 in/lbs in the rear, more like 300, I am pretty sure the konis can handle it without valving. You gotta remember that most of the difference in those is in the last part of the adjustment.
I bet the car gets tons better and the three wheel motion gets cut down and you hardly spent any money!
There is no way a Sentra with wheelbarrow suspension with worse tires than what you have, built with no money should be able to outcorner you. A Sentra has some of the poorest suspension I have ever seen on a car, probably because Nissan insists on using the same spindle geometry that they have used since the 70's and they don't care about rack placement either. Come to think about it they place everything for the most possible bump steer, worst roll center, worst camber curve etc. It could be that they design that line of car to do nothing but horrible understeer and when people try to tune it out, it turns into a reall tsail whippy monster.
Next race if you let me see your tire temp data and stuff I should be able to think of a few more things.
Sunday, June 26, 2011 10:53 PM
It doesn't increase weight transfer more than just a spring? I don't think so and here's why.
During cornering a swaybar counteracts roll by "transferring" rate from the inside spring (which it is attempting to compress) to the outside spring (which it is trying to stretch).
If you have equal rate springs with no bars, this "rate transfer" cannot occur.
The other disadvantages, less independent movement, more weight, are probably not big deals.
I completely agree with you on the ease of setup, but there is a way to tune similarly with a spring only setup - roll centers. On my McStruts I can lower the front (which causes the roll couple to expand) and raise the rear (which causes the roll couple to contract) if I want more oversteer or do the opposite if I want more understeer. You can do that with just coilover sleeves.
Also, as a side note, you can run a lot more power without a limited slip if you don't have swaybars on the axle getting power. Since the swaybar is transferring weight to the outside wheel, the amount of grip available to the inside wheel decreases the greater the stiffness of the swaybar.
Although that said, if you have an AWD vehicle and an agressive limited slip in the rear, that effect could be useful as a kind of ghetto yaw control.
Sunday, June 26, 2011 10:57 PM
I should probably put some math here on the rate transfer stuff.
If you have 500 lb/inch springs and a swaybar that needs 100 lb/inch to compress, during a corner with 1 inch of body roll you effectively have a 600lb spring on the outside wheel and a 400 lb spring on the inside wheel. This increases the load on the outside wheel compared to a purely sprung setup.
Sunday, June 26, 2011 10:59 PM
sure it does but to get the same slip angle you would have to go to a 600 in/lb spring which is something people conveniently forget.
Sunday, June 26, 2011 11:02 PM
And I also agree with you as far as transitions. I'm running a pure spring setup right now on my project. Previously I've run huge swaybar setups.
The advantages I've seen without bars are as follows:
1. Better tire wear.
2. Better grip in long corners especially.
3. Better steering feel.
4. Better consistency.
The advantages I've seen with huge bars are as follows:
1. A little easier to tune.
2. Better transitional responses.
3. Better ride.
Sunday, June 26, 2011 11:06 PM
Yah, you definitely need stiffer springs to get the slip angle, but you can get rid of extra load transfer this way. I'm not saying it's a cornecopia, but it does have benefits.
Here are some interesting links about the theory from a guy who is way smarter than me.
Sunday, June 26, 2011 11:07 PM
You are wrong when you talk about absolutes. I can show you where you can get more corner exit traction with a rear bar. I also don't recommend chassis tuning by attempting to alter roll centers and roll axis unless you really know what you are doing and have a lot of experience and don't get carried away with it. There are many difficult to diagnose handling problems that can happen if you fall in love with doing something like that.
I think there was an article about sway bars and weight transfer in Race Car Engineering a few months ago I think. I was mostly explaining the trend of preloaded bars in circle track but it had some good basic info.
Sunday, June 26, 2011 11:08 PM
Mike, I love your insight on how crappy Nissan suspension geometry is, I've noticed that people with Z31 300ZXs especially have some major issues with bump steer and roll center. What cars do you consider to be the hands down best in terms of factory suspension geometry? I'm especially curious about cars out of the early 90s.
Sunday, June 26, 2011 11:12 PM
I also don't agree with running huge bars although I don't know exactly what huge bar means to you. To me huge means more than 60% of the overall roll resistance coming from the bar.
Even 60% is kinda off most cars sweet spot although I have had a lot of success going past this amount lately on a car whose rules set prohibited me from doing other things to get away from having to run so much rear bar.
BTW that car has excellent, class leading forward bite and corner exit traction with a HUGE rear bar.
Sunday, June 26, 2011 11:17 PM
I'm not trying to speak in absolutes. If you have a ton of roll, for example, and the suspension geometry goes whack whenever you go around a corner then yes, a swaybar will probably help. If the springs are too stiff and the car is bouncing, then softer springs and swaybars will probably help.
But if you don't have those problems, the bar probably hurts you.
I'm curious which problems you've run into changing roll centers. If nothing else it will give me a list of things to watch out for this year when I'm goofing around. My car is pretty close to neutral at max ride height and I run bumpy tracks, but I want to try a little more understeer for the faster of the two tracks I run and a little more oversteer for the slower of the two.
Sunday, June 26, 2011 11:25 PM
I think the Nissan S chassis has one of the best geometries for a McStrut front suspension.
Weird that they got it so right with that and so wrong with some of the others.
E36 BMW's too.
EG and EK Honda's except the short links can make them sorta lame if you are not careful.
Lotus stuff except it is made like crap.
Nissan's of that era did weird multi link geometry, in fact all Japanese multilink stuff out of that era is weird. I can go on a rant about it it sometimes makes me so mad. I think a lot of that is from the culture of engineers that take a train to work and are textbook smart.
Like R32 and Z32 front suspension. Forward canted upper link is to have variable camber curve, faster when turned, slower when straight, supposedly for better straight line tracking due to less sideways wheel displacement when going over bumps.
The Japanese guys just forgot about all other aspects of design and optimized for this obscure trait. Worst offense with this design, super close sideways instant center so the front of the car jacks under the load of good tires or has an out of control instant center that really moves dynamically. It's one of the reasons why we could never get the XS R32 to reach its full potential and what Eric and I were gonna fix to make it beyond what I think is probably the fastest time attack R32 ever built.
This is just part of what pisses me off about that cars suspension. Belive me you don't want to get me started.
Or the stupid Mazda FC extra links to make a stupid semi trailing arm suspension not toe out thing resulting in something more complicated than making a proper suspension.
The list goes on and on. Don't get me started.
Sunday, June 26, 2011 11:32 PM
Too high of a roll center usualy makes the car have a weird nibbling hop and twichyness at the limit of traction. The driver feesl this as unstableness and a lack of overall grip. Screwing with the shocks has little effect and the problem seems insenstive to your attempts of adjusting it out.
Extremly bad and the car will suddenly loose traction on the odd end and be hard to recover it. Really bad, the car flips over :) Some poorly designed lift kits for trucks are like this.
Sunday, June 26, 2011 11:35 PM
I had assumed that the S chassis had among if not the best Nissan suspension, either that or the drift crowd brainwashed us.
I know I'll never understand multilink so I'm glad you're somewhat excluding it.
I'll try to leave it at that. I am curious how the Miata stacks up against the S chassis and the MX-3 against the EG if you don't mind a quick answer to that one.
Sunday, June 26, 2011 11:38 PM
I also feel that a bar almost never hurts you and most cars except those that I mentioned can do better with a bar. I have never done anything but make cars go faster by adding them and I have never made a car slower or had a client that was not absolutely stoked with how I set up his car except the client I briefly had that would try outsmart me by talking to half the "experts" he knew and make other adjustment without telling me and fiddled on the car on his own without me knowing it to "test" me while I was trying to dial his car in. I politely quit after a couple of test sessions. Other than that I have had nothing but excellent results and satisfied customers.
Sunday, June 26, 2011 11:45 PM
I never looked at those Mazda products closely so I don't have an opinion.
The rear of the S chassis has a few issues. I think it has too much negative camber gain, a decent toe curve, ok roll center.
The S13 has way too much anti squat, it's better in the S14 and even better in the S15. Still pretty good though, its one of my favorite cars.
I HATE Sentras. The reason I race them is that they are super cheap to race. Nothing is cheaper except perhaps a Lemons car. Nissan has an excellent racer support program. The fact that Nissan sold them to me for a dollar helps too.
If it were not for that I would be racing a EG or EK.
Monday, June 27, 2011 12:55 AM
I know people get good results with sway bars, but the guy I linked to went 8 years between losses, so you can clearly get good results without them as well.
I'm primarily interested in the physics of why or why not you should use swaybars.
Monday, June 27, 2011 8:26 AM
I just listed the reasons why. As far as physics, calculate how much roll resistance you get from springs and how much the bars contribute to it and you have the actual numbers.
The links in your post don't work unless you are registered to that forum. I find it difficult to believe that anyone actually racing in any sort of competitive class could not loose in 8 years of racing. That would have to be some sort of record.
Monday, June 27, 2011 8:35 AM
Sixcylinders - Steve Rockwood helped me understand multi-link SO much better by relating to my off-roading/4wd background. Google "five-link suspension" and try to find a very clear view of one on a sandrail/sandcar, now compare that picture to a multi-link diagram. Although pieces may look a lot different in shape, mounting location, etc, they still serve the same function, which in turn helped me understand adjustability a LOT better. Hopefully that may offer a little more insight (shoulder shrug).
Mike - Unfortunately most poorly designed lift kits don't reveal themselves to most people until it's too late for the owner: first time off road, hard braking or worst during an emergency on-road manuever!
Daewoo - I think the physics have been pretty well covered but let me ask you a simple question. Of all the shows you've seen and magazines you've read, how many slalom times stayed the same or got worse after larger or adjustable sway bars were added? In my work that's known as evidence based!
Monday, June 27, 2011 9:10 AM
On a completely off topic subject - How do you change your avatar here?
Monday, June 27, 2011 9:24 AM
Go to the upper right search bar, type in "gravatar" and get the article titled "how to customize your avatar" which should be the first article of your search. I'm guessing something Honda oriented :)
Monday, June 27, 2011 9:46 AM
Thank You Der Bruce:) and you would be correct:)
Monday, June 27, 2011 10:29 AM
BTW, my project TDI has similarly balky synchros, and I've had excellent luck with Redline's Ultra Lightweight Shockproof (seems to be new, as I only recall light and heavy before). Not sure if you've tried it, but it's worked for me.
Monday, June 27, 2011 10:54 AM
Isnt shockproof not for syncros? Although I use it for syncro boxes all the time in racing, perhaps it might be detrimental to them for long term street use?
Monday, June 27, 2011 11:51 AM
It may not be, but looking at Redline's site, only the Heavy Shockproof specifically says not recommended for most synchro applications.
I do know I've heavy in my SE-R for about 60k miles with no ill effects (other than shredding gears, but resused synchros almost every time), my brother's turbo SE-R (~60k miles, no trans issues at all), my street G20 back in the day (~60k miles) and now the Jetta.
I may try MT90, as when I bought this, the local shop only had the ultralight, or GL-5 stuff, which I know eats brass synchros.
Monday, June 27, 2011 11:51 AM
Even the T5 in my CJ called for ATF, some guys were recomending Redline as a synthetic alternative. I wouldn't have been shocked had ze Germans asked for gear oil. They love their Euro blends!
Monday, June 27, 2011 12:43 PM
Ze Germansss spec sum veird gear oil wiz very specific specsss available only zrough ze VW outletssss, which iss typical for every damned fluid in ze car.
Monday, June 27, 2011 1:34 PM
Steve - When I had my GTI, I tried NAPA, Walmart and finally Autozone before I could find a full synthetic and not pay the ridiculous stealership fees. I think Royal Purple and Mobil 1 makes a full synthetic of the GL-4 variety at your next change. Oh, and excellent accent! It's a good thing I'm fluent in Deutsch :)
HAR - I was half expecting a pic of the TSX or HPDs CR-Z! I forgot to ask if you guys were planning a battery relocation kit along with some possible more CF bits up front for better weight distribution?
Monday, June 27, 2011 2:25 PM
@ Der Bruce, you are a mind reader:) Yes the light weight CF battery is on the way from Braille, to be mounted in the rear passenger compartment, CF Hood and Trunk in the near future and full rear lexan in the fall:)
Monday, June 27, 2011 4:12 PM
I've noticed my 07 SI can be a little notchy going into 3rd gear at times. Better change out that ultra thin factory gear oil soon before a long term problem develops. I've been pretty happy with Redline MTL in mild street cars. Great reading here!
Monday, June 27, 2011 8:52 PM
The guy was Steve Hoelscher in a Fiat X19 in D-prepared. He won the SOLO nationals 8 years in a row. I can copy and paste it here but it's long. It would probably be best to message you if anybody is interested.
Like I said, 8 years between losses.
I will include the physics reasons for avoiding swaybars though, as quoted from the article.
This is why getting rid of the bar entirely has benefits:
"... (we're shooting for a combined rate of 550 lbs/inch) 550 lbs/in target rate – 200 lbs/in bar = 350 lbs/in springs.
Easy enough. But we have a problem here. Swaybars are not the dynamic equivalent of springs. A swaybar transfers load from the inside tire to the outside tire and thus reduce mechanical grip as they add spring rate. And the effect is not linear. The stiffer the bar in comparison to the springs, the greater the effect (loss of mechanical grip). To give an example of the effect, if we set our proposed STS2 car up using the target data we have assumed above using the target spring rates without any swaybar, the car should have good balance. However, if we achieved that same target spring rate using a front swaybar, the car would tend to understeer more than if we used only springs and no swaybar. And the greater percentage of the total front spring rate the bar accounted for, the more the car would understeer. I noted as much early in the thread.
"We now must choose how much bar we want to use for our final setup. As the reader may know, I don’t use swaybars on my DP car. Nor did I use swaybars on my previous racecar, a DSP X1/9. For me it is far easier to manage the setup of the car without swaybars. I also prefer the feel of the car without swaybars. It has long been my thought that; because a swaybar reduces mechanical grip, why would you want to put anything on the car that reduces mechanical grip?
Monday, June 27, 2011 11:08 PM
Oh autocross, I thought you were talking about racing....
It is interesting though I wonder if we should start a thread on the forum.
Of course a swaybar will reduce mechnical grip, so will a stiffer spring. Of course the target rates will be different with both.
A bar is less linear than a spring. which is the main difference. I feel that if you follow my 50% or less rule a car will be faster with bars.
Monday, June 27, 2011 11:30 PM
Haha, I did start a thread on the forum. Not a bad idea to start another though.
Same guy has setup SCCA runoff cars too, done pretty well.
Let's just say I disagree that a stiffer spring reduces grip.
Monday, June 27, 2011 11:53 PM
Going to a stiffer spring has to reduce mechanical grip. More weight transfer, more slip angle and less mechanical grip! You can't balance the chassis without this!
Tuesday, June 28, 2011 1:09 AM
You misunderstand me. You are talking about making one end of the car stiffer relative to the other, ie, transfer from one axle to the other due to interactions with roll centers/springs/bars/etc. I am talking about weight transfer across a single axle.
For the purposes of our exercise here, let's assume the vehicle in question is a Segway. Only two wheels aligned like this TIRE axle TIRE and a suspension controlling each "TIRE." This way we can discuss the weight transferring effect unique to swaybars.
First let's imagine that our Segway suspension is a pure spring setup. The sole weight transfer in this setup is determined by the cornering G vs. the COG height. I assume we agree on this. Okay, a tiny bit come from role but we can ignore that.
Now let's imagine our Segway has springs and a swaybar. When this Segway corners we have the same COG vs cornering G weight transfer but we also have the additional weight transfer from the sway bar resisting roll. This means that the outside tire does more work relative to the inside tire with swaybars, hence the decrease in mechanical grip.
All that energy that goes into resisting roll goes from the inside tire to the outside tire with a bar. Without a bar, there is no such effect.
Tuesday, June 28, 2011 9:50 AM
@ Der Bruce: yeah, Redline MTL is GL-4, and I love Redline products. When I was doing the clutch swap and realized I had forgotten the gear oil, I went down to the Wal-Mart, couldn't find anything GL-4, then went to the local dune buggy shop that always has Redline stuff. Once I got there, there was a bare shelf with MTL listed under it, and a stocked shelf with Ultralight. I went Ultralight. It's worked so far, but I will probably swap it out for MTL. Luckily the VW trans only uses 2 quarts.
@ Daewoo: Does our imaginary car have gyroscopic balance control as well? ;-p
The main problem I see with your statements is you're simplifying matters too much. Yes, the outside tire does end up with a larger share of the work, but it's not entirely about maximum mechanical grip on a track. A skidpad, sure, but not on the track. What about transitions, bumps, curbing, braking, accelerating, etc?
Now, as for the DP champ, that's a specific case where the driver didn't like the way swaybars felt. He did say he logged decrease mechanical grip, and I don't disagree, but does that mean that swaybars should be ditched by all? When roadracing, a comfortable driver is a fast driver. If he/she doesn't feel "right" in the car, he/she is gonna suck.
That being said, I think the next race I'm going to experiment with no swaybar, since I feel the car understeers too much for what I want it to do, and Martin feels it's a little looser than he wants. Oh the joys of multi-driver cars... ;-p
Tuesday, June 28, 2011 10:18 AM
Balance is balance and once you develop the amount of slip angle needed to balance the chassis it doesn't matter how you do it.
Of course adding a bar is going to decrease grip, it's how chassis tuning works. If you make the overall outer tire slip angle the same between the two examples to where the chassis balance is the same, the overall grip of both system will be pretty close the same.
By taking slip angle out of the inside tire, it has more overall grip and how you use it depends on the dynamics of the system which there are a lot of variables.
It's hard to say exactly because there are a lot of other things going on but mostly.
Go on a slid pad and see. Sometimes if you balance the car in steady state cornering using only sway bars the car will sometimes pull more lateral G's than if you used only springs. It certainly will not pull a lot less. I did this for a term paper in school.
I have fixed rear traction problem by going to really soft rear springs and using a really big rear bar. The car is winning and generates a lot of lateral G. If a big rear bar killed mechanical grip disproportionately, this should not happen. It should just spin the outside wheel and not go anywhere. The car actualy comes close to doing a wheelie on corner exit.
Tuesday, June 28, 2011 5:02 PM
@ Mike: Balance is balance? Not really. You could balance a pig of a car, say a stock Corolla, by putting really little tires on the back. It would still not be as good as using a better suspension system.
Swaybars are like smaller tires. They decrease the total grip available to the system by transferring extra weight to the outside tires and away from the inside tires.
Once again, I'm not saying this is a cornecopia, but swaybars are almost always a compromise, and a compromise I prefer to avoid. Since I don't know what the car in question is and I don't know the setup, I'm not going to question your decision. Maybe the suspension geometry needs a lot of squat to work. Maybe the soft springs are preventing tire shock. I don't know. However, that big bar IS transferring load from the inside rear tire to the outside rear tire.
As for your term paper, did you equalize the roll rates between the swaybar setup and the spring only setup? I'm guessing not.
I agree it's not for everyone. If, for example, I had a car with huge roll couples that I couldn't fix and ran on a bumpy track, I would use swaybars. If I had a FWD car I simply could not make turn, I would use a swaybar to weaken the rear.
I'm also not trying to deny the complexity of the system. There are times when you will need a bar. The point I'm trying to make is that in an ideal world (and a lot of not ideal worlds too), the swaybar sacrifices grip compared to a pure spring setup. You may have to sacrifice maximum mechanical grip to get some other goal, but you probably should start off making sacrifices unless you have to.
I didn't post the whole thing from the autocross champ, but suffice to say it wasn't just about feel. He got significantly faster because he had more grip. I had a similar experience as regards both performance and feel, although I required a significantly less aggressively spring rate than Hoelscher because my car has relatively close roll couples.
Tuesday, June 28, 2011 5:21 PM
A swaybar is going to transfer more weight at less overall roll stiffness but that does not always equate to less mechanical grip. This is one of the reasons why it can often give more mechanical grip depending on the setup and the conditions! Remember more weight transfer at less overall roll stiffness! I think we are both saying the same thing but differently with a different understanding of what that means in the end.
That is a gross oversimplification that is dangerous to preach as a universal solution. It's proven wrong all the time. I mean a lot of F1 and Formula cars have sway bars and if they lost grip because of it as a universal rule, then all the engineers would simply not ever try them! If you are going to live by that, then you should not try to engineer suspensions for a living.
I don't know for sure but I suspect you are a well read and very intelligent hobbyist. That is very commendable. I do this as a large part of my living and have a bunch of real world experience on a variety of cars, from GT cars to drift cars, FWD, AWD, and RWD all of them tended to handle very well as long as the client left me in total charge of the set up.
I have never hurt a car buy putting a bar on it only improved it as long as there was time and money to tune around it. Of course I never just put a bar on anything, changes to spring rates and other things have to go along with it.
You don't have to believe me but it would be a shame for you to not gain experience because you believe something you read on the internet.
Tuesday, June 28, 2011 7:53 PM
Interesting side note on swaybars and F1 cars in particular.
If you have a roll center above the COG in conjunction with a roll bar, it will actually transfer weight from the outside tire to the inside tire. Looking at the front of an F1 car, I suspect this is the case.
Anyway, you are certainly more experienced than I am and I am not saying you cannot tune a car to handle well with sway bars. Actually, that's why I'm quoting Mr. Hoelscher. I'm just presenting an outside the box idea that has a record of success and has worked well for me on my particular project.
I suspect it works for my car because I have relatively close roll couples and therefore don't need an extreme spring rate and all the bouncing/tire shock that goes with it. And yes, I have a very oddball car, though I suspect the principal applies to many other cars.
Also, if I'm correct, most big bucks racecars use cockpit adjustable swaybars as trim for changing fuel loads/tire conditions. Ie, where the bar has very little stiffness relative to the spring. If I had a bunch of money and could afford cockpit adjustable bars to trim in that much detail, I would do it too.
Tuesday, June 28, 2011 8:17 PM
F1 cars do not have the roll center above the CoG.
You can tune a car with no bars but it usually isn't the best way to do things and to state otherwise is misleading the majority of the people in most cases-ie bad general advice.
It doesn't mean that it isn't good to experiment if you can afford to and have the time. Most of us don't.
Remember that the most common mistake that people make in suspension tuning is using too much. Too much roll resistance, too much damping, too much negative camber. Its human nature to go bigger.
Usually extremes of things don't work the best except in certain cases.
What sort of suspension does your car have? McStrut usually has a large roll couple.
Tuesday, June 28, 2011 9:28 PM
Usually isn't the best way? I'm not aware of many people who have tried it. If you have, I'd be very interested in your results.
I'm pretty sure modern F1 cars run very high roll centers, at least in the front, although that's for aero reasons and not because it's ideal geometry. Here's a picture.
I completely agree with you on the extremes thing. I'm running 1.5 degrees negative camber in the front (getting camber plates made for Daewoos is a custom job, predictably), zero camber in the back, knock off Bilsteins and 9kg/mm coils at all four corners. Hardly extreme. I operate on the theory that the smallest changes to get the desired results are often the best, and that simple is preferable to complex all else equal.
My car is 4 wheel McStrut. I haven't modeled it yet, but eyeballing the geometry and making imaginary lines with sticks puts the rear roll center about three quarters the way up the bumper in the back and somewhere in the oil pan in the front. The car is pretty low and I don't get very much roll.
Here's a video of the car pulling max G in a trail throttle situation. http://www.youtube.com/watch?v=sS8Vvx3fhPs&feature=youtube_gdata
Tuesday, June 28, 2011 10:07 PM
I was watching your in car video and your car looks and sounds like it understeers heavily and rolls a lot. The track looks pretty fun and the guys that you are racing against are horrible drivers! Your lines are much better.
I think you need more negative camber in the front, stiffer rear springs and.... Sway bars! I would run something like 25mm front and rear with a 12 kg rear spring. If you drive the car a lot on the street, you can go as much as 2.5 degrees negative and not kill your tires too bad. 1/8" toe out in front and zero rear toe as well.
This is assuming your typical econobox sort of motion ratios for the bars and struts. Weirdness in design will change some of this. I guarantee your car will be much faster unless there are weird things with the motion ratios.
Tuesday, June 28, 2011 10:10 PM
If you send me some measurements I can guess much closer and I think I could get you 1.5-2 seconds a lap faster on that course.
Tuesday, June 28, 2011 11:23 PM
I definitely need more front camber. That said, I was actually counter steering through the fast corners every time. If you watch my hands, you can see me catching small slides at least once a lap. Do you set up your FWDs to oversteer more than mine?
This is the first car I've designed and chosen suspension parts for from the ground up, and I was actually thinking the car was too loose!
What sort of roll angle do you shoot for, btw? I'm at about 2.5 degrees right now.
And thanks for the offer. What measurements would you need?
Tuesday, June 28, 2011 11:24 PM
BTW, that's Taebaek Racing Park in South Korea. It's a nice facility. I'm building this car with a bunch of middle school students and we're going to eventually compete in the 2.0 liter and under time attack series. I'm speaking slowly and using small words for their benefit, btw. ;)
Wednesday, June 29, 2011 8:30 AM
In the video, it really looks like heavy understeer, the front wheels are turned in a lot and are howling. It might be oversteering under lift throttle. I set up FWD cars to oversteer on trail braking or left foot braking and slight oversteer on lift throttle.
My race cars roll at around 1.5 degrees per G, at least on paper. I don't try to actualy measure what it is.
I need your corner weights , track width, wheelbase, roof height and motion ratios of your bars and coilovers
Wednesday, June 29, 2011 8:45 AM
@ Daewoo: I agree with Mike's assessment on understeer: I see a lot of slip angle entering that first corner, and the the braking/left-right transition combo going into the second corner would result in a Scandinavian Flick in a more neutral car. You'd certainly be catching more than small slides if you did that in the Dog Car, or Project G20! ;-p
Of course, everyone's idea of understeer is different. For me, I want the car loose as a TJ hooker going into the corner, and will tolerate only the slightest push at WOT after the apex. Martin, in the same car, prefers more stability entering the corner, so he'll tolerate the push after the apex. While looser is usually faster in the FWD world, if the driver isn't comfortable with the way it handles, he's going to be slow.
Someone wise once said: "oversteer scares passengers. Understeer scares the driver."
Wednesday, June 29, 2011 1:21 PM
I tried to find APD's website with no luck in order to email them some info in regards to their setup.
I recommend Wilwood calipers since there are kits out there that bolt up that are both lighter and utilize larger piston sizing. Also I highly recommend using RL rotors/NSX 300mm rotors with curved vanes.
Otherwise did a damn good job.
Lets see the TSX kick some a$$!
Wednesday, June 29, 2011 2:11 PM
@ Swiftlegend: Thank you for your input!
Best way to contact us is via PM here!
As our goal stated in the article and since we are sponsored by Honda Performnace Development, was utilizing OEM available parts to create our front brake package - These calipers are made by Brembo and piston size is perfect for the bias we wanted to achieve on this car.
Yes Willwood's would have been lighter but actually we prefer Brembo product:) and this is a race tested solution developed by some Honda Research West folks and tested on a factory Civic Si at the 25hrs of Thunderhill (Car finished 2nd in class only due to a broken seat slider mount that took a few minutes in the pit to fix.)
Rotor suggestion is good but the hat heights are not correct for our application - We have some new aftermarket rotors with enhanced cooling from APM we are going to test shortly!
Thank you for the compliment we did finish 3rd first time out of the box with this car,and watch our results at the Buttonwillow MotoIQ event after we bring our horsepower up to our weight limit and make a few minor suspension adjustments:)
Thank you again for the support and have a great 4th of July weekend!
Wednesday, June 29, 2011 5:06 PM
@Mike: I'll get those numbers for you soon. Thanks again. (BTW, my free editing offer stands.)
@Rockwood: Oversteer or understeer felt like a function of speed more than anything. Maybe this is the universe telling me I have huge moments of inertia.
In the two hairpins I was definitely getting push. In the long sweeper going onto the back straight, even at WOT it was moving in the back. In the decreasing radius turn two leading into the second hairpin I usually went through the corner with no lock or slightly opposite lock. It happened after I ran out of batteries, but on many of the "fuck it, super aggressive" laps I ran later, I was catching big slides in that corner, which is pretty exciting with the wall that close!
Thursday, June 30, 2011 10:46 AM
How big are your stock bars?
Saturday, July 02, 2011 12:43 PM
From the Team at Apd - Hope your all having a great 4th of July weekend! and let us know if you have any more questions or would like to share your input on the build with us!~
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