posted on August 20, 2010 05:00
Part 3: Attack of the Weight Weenie
by Dave Coleman
Project Miatabusa's theoretical claim to Awesomeness doesn't come from power alone, but from the unique combination of power, lightness, and soul ripping sound. Power, by itself, will be entertaining but far from impressive. At 173 hp stock, the Hayabusa engine is only making the kind of power you would expect from a mild turbo kit on a stock Miata engine. Add in the roughly 170-pound weight savings from the engine itself, though, and multiply by the wail of 11,000 rpm, and its a spine quivering equation. (And of course, just wait until we turbocharge it...)
To make this swap really pay off, though, we need to add as much lightness as possible. Lightness is the fuel that feeds nimbleness, responsiveness, and raw performance in all four directions, not just the direction you travel a quarter mile at a time. There is nothing more effective at improving the overall performance of a car than a good diet.
A Miata seems like a tough candidate for a diet, though. Inspired by the Lotus Elan, lightness was designed in from the start, with extravagances like a featherweight aluminum hood already built in. And the design team's much touted "gram strategy" focused on shedding weight--even tiny amounts of it--from even the most mundane parts of the car, on the theory that if you add together enough inconsequential little details they'll add up to something meaningful. This suggests that they probably didn't leave that many weight savings opportunities on the table.
I have access, with my day job, to some of the earliest Miatas in existence. Cars #13 and #15 reside in Mazda R&D's basement, and I recently put #15 on a scale. It was 2163 pounds with a full tank of gas.
As with most cars, though, the purity of purpose that defined the original was watered down as the years went on. Bigger engines, more airbags, bigger brakes. The refinements that differentiate this 1996 Miata from the 1989 original each seem a perfectly reasonable compromise in isolation, but added together they reveal a 156-pound bloating. The day after I bought it, project Miatabusa tipped the scales at 2,319 pounds.
We still don't know exactly how much weight the Hayabusa engine swap will save. We do know the stock 1.8, with alternator and power steering pump, but without the flywheel, weighed 296 pounds. We also know the Hayabusa engine, without gearbox or header, weighed 135 pounds. So on the surface, it looks like we should have 161 pounds shaved right off the bat. We still haven't accounted for the added weight of the new flywheel shaft and bearings we're adding to the Hayabusa engine, the weight of the new engine mounts, or the weight savings from our unfinished tubular subframe, though, so its premature to put an exact number there.
That 161 pound savings will only bring us back to approximately where the original 1.6 Miatas were. Some of the difference between that original Miata and our 1996 are parts we plan to keep, like the bigger, stronger diff, bigger brakes and more serious door bars, but there are still plenty of pounds on the table.
As a start, we've managed to save another 73 pounds just by discarding the parts of the car that are really only required by the kinds of people who wouldn't put a Hayabusa engine in their Miata in the first place. The following is the result of a simple afternoon's work. Consider this a warmup, both for us and for you. Check out our progress and then put your brain to work. Where else can we shave pounds? Drop your suggestions in the comments, below.
License Plates - 2 lbs
The first pound saved was simple. The previous owner was a USC alum, and somehow felt the need to inform the world of this fact with a depleted uranium license plate frame. Seriously, this cast pot-metal license plate frame weighed a full pound. Unacceptable. It nearly tore a hole in the garbage bag on the way to the curb.
Another pound was found on the front plate, but it wasn't as easy.
The factory front license plate mount is a crappy piece cobbled together from some weak steel bar stock. Ours was bent and barely attached via some loose, rusty nuts.
As with almost every Miata front plate, the mounting bolts were installed with the long, pointy bolt shaft pointed at the nose of the car. At least they had the decency to use lightweight plastic hardware...
The inevitable result of this sloppy mounting is the park-by-braille crowd denting your front bumper. It's virtually impossible to find an NA Miata that's free of these license plate dents. If you remove the front bumper to access the back of these dents, you can do a decent 80% fix with nothing but a heat gun, your fingers, and some gloves.
Ok, there really isn't much weight in the license plate itself, but there is wasted space. The Miata's radiator intake is relatively small, and filling it with license plate is not a good way to keep it cool. Normally I'd just leave the damn thing off, but with the rampant proliferation of red light cameras comes the militant enforcement of front plate laws. Not running one is just begging for trouble.
It could be argued that doing this to your front plate is also begging for trouble, but to any clear-thinking person, this is a reasonable compromise. The plate is now small enough to fit the Miata's bumper, and still clearly shows the tax collectors what they need to know. Sadly, clear-thinking people seldom sign up for jobs that require bullet-proof vests. Only time will tell how well we can get away with this one.
The plate is mounted with lightweight plastic fasteners like the ones holding the fender liners in place. This required drilling holes directly into the bumper, a practice I'm normally violently opposed to, but this bumper is far from pristine and seemed ready for a little experimentation.
I'm not entirely thrilled with the way the size and location of the plate makes it look like a little numerical Hitler stache, but the whole drilling-into-the-bumper thing makes this a pretty hard one to change your mind on. If you've got any better suggestions, bring 'em on.
All together, the mounting hardware and discarded plate parts took another pound off the extreme end of the car.
Monday, August 02, 2010 10:13 PM
You guys did a project miata in Sport Compact Car Magazine. Just read your own article and do all that stuff again.
You had lightweight composite panels as I recall, and a flyin miata(?) fixed headlight conversion. If you don't have a copy of your own magazine laying around I'll find it when I go home and post it for you.
Monday, August 02, 2010 10:30 PM
Isn't that Miata that ab0z is talking about the same Miata that Matt Andrews drives in the Red Line Time Attack Series?
I might be wrong, but it sounds like Dave is on a tight budget, and adding a bunch of dry carbon to the mix would require a bunch of dinero.
Hey Dave, how about moving the fuse box that sits in the engine bay and relocate it in one single panel under the dash, that way you can cut the amount of wiring.
Monday, August 02, 2010 10:38 PM
What about ditching all the instruments for one little digital one that can serve multiple purposes and a tachometer? Or the single screen unit a Hyabusa would use anyways? How about shortening the exhaust so that it's header, into cat (if it will have one) into a skinny little muffler (Glasspack?) and have it terminate with a turn down under the car about mid-ship? (Would also save weight hanging off past the rear axle). Has a smaller radiator been mentioned? Perhaps mounted further back even?
Monday, August 02, 2010 11:06 PM
I think most the basics have already been stated. What about removing the soft-top? Installing a fuel cell? Most bikes rarely have more than a couple gallons of gas on them, so it would be reasonable to install a smaller than stock cell as it also acts as an insurance policy. Depending on one's level of dedication, you could remove the window winders and related parts, installing a lexan/plexiglass window with the type of "fresh air vent" found on light aircraft. If made removable, it's perfectly reasonable to leave them attached the whole time and remove them in heavy traffic or for a top-down cruise.
Monday, August 02, 2010 11:13 PM
I love the idea behind the licence plate. But being a California resident too, I don't know how legal is that front plate.
How about keeping it all stock (too late now) and have it located right under the blinker....on the side. That was the radiator cools off, the cops keep eating their doughnuts and you're safe.
How about using some zip-ties to keep that licence plate on the bumper. Hey more holes in the bumper for those zip-ties, the lighter the bumper gets.
Keep it up Dave.
Tuesday, August 03, 2010 12:12 AM
I'm assuming you're gonna use either a stock aluminium roof, or an aftermarket fiberglass roof. In which case, you could eliminate the insulation.
How about the rear windshield? Lexan? how about the front?
How about the headlights? Do you need them? Are you planning to drive Miatabusa at night?
Power steering? Who needs that?
How about side mirrors? Are you gonna replace them with some aero ARP?
You don't need windshield wipers either....if the windshield is dirty, stop at the local gas station.
If you retain the stock hood, cut the webbing underneath.
Instead of using the hood latch with its cable and hook mechanism, eliminate that, and use a simple bungee cord.
Tuesday, August 03, 2010 2:09 AM
Are there light weight bumpers for the Miata? I know there are light weight bumpers available for the USDM STi's. The stock bumper on the STi weighs 26lbs while the aftermarket one weighs 8lbs. Something like that would prove to be quite useful as its all the way at the tip end of the car. Perhaps sourcing some JDM parts since their bumpers always seem smaller/lighter. I don't know how much that would cost though and if it would fit inside your budget.
Tuesday, August 03, 2010 3:34 AM
Check the glove box door. Some cars have extra weight added to it so it doesn't feel like the cheap plastic it is, same with the center console lid. Does the trunk have a liner? Like JDMized said, get rid of the hood hardware and use pins and ditch the power steering pump and lines.
I'm perplexed that no one mentioned the stereo. There is at least 10 pounds of amp and driver magnets. Wait, what? You want to listen to tunes, and miss out on the 10k rpms? Sacrilege.
Tuesday, August 03, 2010 3:38 AM
Wouldn't a custom fixed-beam conversion save a few more pounds by eliminating those flip-up headlights? (Plus, the flip-up headlights cause a lot of drag.)
Yank out the current headlights. Buy two sets of projectors (cheap fog lamps might work), install them in the hole where the original lights were, then cover it up with a sheet of lexan or plexiglass.
Tuesday, August 03, 2010 4:15 AM
Make the shifter a short throw shifter, if you are going after weight spare nothing, what about the area that seperates the trunk could you not cut it out and make an x-brace that would be structually stronger anyways? The stock seats, rims and brakes.
Tuesday, August 03, 2010 4:35 AM
rsgriff, I think Dave has a plan to do the same thing the radiator/planned intercooler as he did with the S13 and move it as far back as possible. Though I expect this will be again for throttle response primarily and the weight loss of the potentially extra charge piping will just be a convenient by-product.
Then there's the 949Racing 6UL wheel that is what I think a cost-effective alternative to SSR's now discontinued 7 lbs 14" wheel for less rotational inertia. Plus the 6UL will fit almost any planned brake upgrade with a 15" or 17" wheel. Though TR Motorsport's C1 is an even cheaper wide 15" wheel that I am using and loving despite a 10 year old set of shocks and open diff.
Tuesday, August 03, 2010 4:38 AM
As a like-minded aging import enthusiast, I share your common-sense approach to weight-savings. Here's an idea I've been kicking around lately for my S14.
What about some sort of ipod/iPhone DIN-sized dock hooked only to a center channel speaker (like the DIN-sized z32 speaker) If you could dremmel out that enclosure and swap in some nicer, less rotted drivers - a couple of Mac laptop speaker perhaps?, it would probably be more than adequate for listening to NPR or fighting the boredom in traffic. The factory head unit + door speakers would shave a few pounds - and you could still stream radio from the internet on the phone.
Wunderradio is awesome. I listen to radio from all over the country (including local radio.)
Tuesday, August 03, 2010 5:09 AM
@jdmized, I have noticed more than one rich Orange County eurosnob with "european" front plates that are actually reproduction plates with their california number on them. That doesn't mean they actually get away with it, but I have seen it...
Now your ideas:
The factory hardtop is fiberglass, and yes, I'll be using one. There is no insulation to remove, though. Maybe a lexan window, but that ain't free!
Headlights: yes, I need them, but you're right, there's something like 15 pounds to be saved there. The best canyon driving is at night, though, so whatever solution I come up with has to have better-than-stock performance, and so far, I haven't found any off-the-shelf solutions that are.
Mirrors: I'll at least downgrade from power to manual.
Wipers: I do need wipers. I'm a windshield squirting fool. I squirt my windshield like 8 times a day. I don't know why...
Hood: I like the spirit of your bungee idea, but I have to be able to leave the car parked unattended, and a stock hood latch is great for that.
Keep the ideas coming!
Tuesday, August 03, 2010 5:10 AM
For the license plate I would have bolted it to the bumper over where the Mazda logo used to be. The space seems large enough and it's still visible.
For more weight, remove the brake booster. Sub 1-ton cars with disc brakes don't need the help. Just step up the MC a bit to get some extra pressure. Also remove the sound deadener under the carpet and put the carpet back on top. The carpet more than anything keeps the sound down, and the deadener is heavy. Since you're a So Cal boy, why don't you strip the undercoating and paint the underbody. No salt in the desert right? How about plastic fasteners for useless things like the fenders, bumpers, etc. ad titanium for everything else (there's an ad to the upper right for titanium fasteners). Then of course go for carbon or fiberglass bits wherever you can on the body.
For my first Intgera I had a $5 boom box with a cassette adapter for an Ipod. Removable weight, just like the spare. Don't forget the Odyssey battery if you ever figure out the electric starter (have you thought about a hand crank yet? That would certainly save some weight).
Tuesday, August 03, 2010 5:12 AM
I've been toying with an iPod idea where I could ditch the head unit and just run an iPod directly to a small amp. Some of the smaller iPods come with an FM receiver. Problem is, the smallest amps I can find (~4.5 pounds) weigh more than a cheap head unit (~2.7 pounds), so all I gain is a little in-dash storage space.
I'm not much of an audio guy, but I do like to have something to keep me from being bored on the way to the track. Anybody have any lightweight audio ideas? Like actual components that don't weigh much?
Tuesday, August 03, 2010 5:23 AM
Nothing like standing on your wheel at 1:30 in the morning trying to use a rock to beat it straight enough for the fix-a-flat to hold long enough to get you down the mountain.
Tuesday, August 03, 2010 5:34 AM
Lightweight audio = iPod + headphones. Beyond that, anything removable as mentioned previously. I have a pair of tiny speakers made by iHome that were $40 and do a decent job. http://www.ihomeaudio.com/iHM77
Tuesday, August 03, 2010 6:01 AM
You could get rid of that lingering stench and weight at the same time! http://www.miata.net/skidmarks/images/Trunk.jpg
Also: iPod+headrest speakers.
Tuesday, August 03, 2010 6:02 AM
Single Din stereo (or iPod) + something like this:
It would be really trick if you could build it all into a some sort of removable cage (quick disconnects at the back, fold up handle on top) and take it out at the track.
Tuesday, August 03, 2010 6:05 AM
There are very small T-Amplifiers out there, such as this one: http://www.amphony.com/products/a100.htm. However, it is a 24V amplifier that is for home use.
I am assuming that the Miata is mainly metal. I have heard of people 'acid dipping' panels to save weight since it literally removes some metal (heard, not for sure).
If you have removed the A/C, why not remove all the ducting
for the ventilation system too, or at least the ducting for through the dash and keep the defroster and floorboard going for cold days. You could also get rid of the entire cabin heating system (Including cage fan, baffles, heater core....) and just install heated seats and dress warm!
What about the windshield washer system?
Tuesday, August 03, 2010 6:09 AM
Howdy Mr. Coleman!
First things first, you're my freaking hero. I love the look on peoples faces (smart people no less) when I throw out the term "the Dave Point."
Anyways, on to weight savings. I'm not sure what the bumpers are made out of, but there might be some room for weigh savings there. I know that the FC3S has some really lightweight composite style bumpers, so if the Miata is rocking some big hunks of steel, you might be able to shave 10 pounds there by a trip to the local junkyard.
I'm also behind the idea for tossing the brake booster. A mix between a smaller master cylinder or calipers with bigger pistons could keep pedal effort within an acceptable range (I aint smart enough to figure that combination out, but I have no doubt that you can, haha).
What about streamlining the heater? I mean with no AC, it seems to me like you've got a lot of flaps, motors and ducts that won't be needed anymore. Maybe with some flexible ducting, a light weight electric motor and one flap (to switch between defrost and face/foot) you could save a few pounds there. You could also simply the controls for it too. Have a simple 4 position switch for off, low, med, and high and one 2 position switch for the defroster and foot/face selection. You can also get rid of the flap and selector for selecting temperature. This might also give the chance to kill some more wiring.
Also, can't remember if you mentioned anything about the battery, but since you're going to be running full bike electronics with only a few added systems (heater, cheap radio) why not run a motorcycle battery. Those things weigh like a third as much as the lightest car batteries.
For the audio setup you could head to the local PC shop and find the lightest cheapest set of PC speakers that have a built in amp (I have a Sony set that weighs about 1 pound) and takes batteries. Figure out the input voltage and run a simple voltage regulator (that adds like 2 grams worth of weight), ditch the speakers, feed the left and right channels into each other (protecting them with resistors and making them mono) then run your new mono signal into one speaker mounted centrally. Then you can run your iPod straight into the amp. The total weight, including the speaker should be about the same as a standard head unit minus the speakers. If you need to charge the iPod at the same time you can buy a cheap charge cable at Radio shack and feed it off the speakers if they run on 5v or just get another voltage regulator and feed it from that. I just did something pretty similar to this to the ancient radio in my LT23 Mitsubishi 360.
Alright, not sure if any of these ideas are valid but maybe they'll give you some ideas of your own!
Hope I helped!
Tuesday, August 03, 2010 6:27 AM
What about seats? A Kirkey Intermediate bolted to the passenger floor and a harness will keep any unwitting passengers safe enough, and far enough out of reach of the airbag as to warrant it's removal (saving you that 10 lbs, lol). A thin race seat will probably help your gangly ass fit in a Mazda microcar better anyway.
As for headlights, the aftermarket solutions (that don't suck) almost exclusively use Hella 90mm high and low beam modules that can be had from Susquehanna Motorsports (rallylights.com) for very reasonable money. Hella also has HID and Bi-halogen 90mm modules and some 60mm and 50mm modules that might save a few lbs, and will definitely fit the Miata's shallow headlight hole better. Depending on how hood you feel, I bet you could nab a few of the 90mm modules and mounting brackets from Susquehanna and heat form some Lexan lenses from Home depot storm door replacement panels over the stock Miata headlight doors and have a very effective, very light headlight package for under $300
You could also do a Lotus-esque interior if you're hard. The JDM, y0 Clubroadster dorks have kind of made an art of pulling the interiors out of their street cars, and have actually managed to make it look pretty passable, if you can deal with the noise/ discomfort/ snivel factor of not having carpet.
Also, will you be running a roll bar? I guess they're not required by most track day orgs, but driving a tin can Miata without one gives ME the willies.
Tuesday, August 03, 2010 7:05 AM
Jeff, why is "by Dave Coleman" written in rainbow colors in the lead photo?
Tuesday, August 03, 2010 7:40 AM
The good news is that your hero worship of Dave is not misplaced. I had the privilege of meeting Dave when a friend and I flew out to pick up SCC's Project SE-R that my friend had bought on eBay from Dave. He's just as friendly, humorous, and entertaining in person!
Tuesday, August 03, 2010 7:45 AM
Because it's a Miata...
Tuesday, August 03, 2010 7:47 AM
hahah...I didn't even think about that.
Tuesday, August 03, 2010 8:19 AM
....I am surprised nobody has mentioned it before. I am hoping that Dave keeps all the stuff he's removing from the car and later on sells it either on ebay or craigstlist. The money made would of course go toward buying lightweight parts for the Miata.
Also, I am running a Odyssey PC650 battery in my project car. As far as I know, there is another smaller battery (also by Odyssey) called PC454.....or something like that. Although I heard that the PC454 is strictly for bike and won't have much cranking power for a car. You probably know better Dave.
Braille also make those new carbon fiber battery that supposedly are light weight. I would look into that.
As far as wheels, I would say Enkei RPF1 are your ticket.....fairly light and strong (for being cast), and affordable.
Like mentioned above, remove the sound deadening/ tar inside the cabin (and if you want to keep the carpet, keep it)....remove the tar also under the car, and if you're worry about rust; use some Rustoleum for the certain spots.
Remove the e-brake. E-brakes are for drifters. Remove it along with all the lines. If you have to park your car on a hill, point the wheels toward the curb and put it into 1st.....it won't go anywhere.
Remove the horn ! If someone cuts you off, flip the middle finger, it always work.
Get rid of the brake light in the rear.....wiring and all. Much like your front licence plate.....it's a gray area.....
Remove also the white lights in the rear that light up your rear license plate.....they're mandatory by law.....but.....
If you really want to keep a speaker in the car, just keep one, maybe locate it down low on the tranny-hump in front of the shifter....
Remove the OE seat belt and keep only 4-5 point harness. (in California you must keep the OE seatbelt and use them on public roads at all time). Using 4-5 point harness on public roads is consider illegal....but I can tell you how many times I got pulled over, and the officer never point that out.
Tuesday, August 03, 2010 8:25 AM
Oh another thing: Instead of using the OE bracket and lever to open the car (from the inside). Go buy a steel brake-cable for mountain bikes, loop it around the mechanism inside the door and use it to open the car from the inside (that's what I did with my project car).....simple and it works great.
Also, cut 3" holes in the front bumper to allow air into the radiator/ air intake....that way you'll also save some weight.
Tuesday, August 03, 2010 11:47 PM
Haha, i was just wondering if Dave was trying to tell us "something" w/ the rainbow and miata. Uguys beat me to it!
What about replacing the stock bumpers w/ something lighter? Thick alum channel, or some DOM tubing. I have no idea about the construction of a yata, works on S chassis tho. May shave a few lbs + strengthen the front/rear.
Depending on how, umm, "hardcore" ^^you are ;[... I sprayed a thin layer of Rhino Lining on my bare floor, sans the carpet and heavy crap... This in in a top-less S13 tho... I'm also w/ the re-wiring idea.]
Wednesday, August 04, 2010 12:07 AM
^LOL at the Miata driver in boots^
-How about scooter mirrors for the stock one that you need by law
-Getting rid of the hood/trunk props (if they are gutted they can stay open by themselves).
-RainX trumps the wiper system if you ask me, all that crap is like 30lbs.
-When you turbo you should go DIY water meth with an old Walbro and Home Depot fittings. Squirt pre compressor and again just before the throttle plates. No need for heavy intercooler and pipe and reduced cooling and countless boost leaks. You could tune past Lambda for max torque and all kinds of other cool stuff.
Wednesday, August 04, 2010 5:08 AM
There are numerous threads on Miata.net and ClubRoadster.net on weight savings in a Miata (to various extremes). Regarding the hood - I would think Aerocatch latches would be a nice addition and would eliminate the hood prop, stock latch and cable.
Replace the steering wheel with a non-airbag unit.
Replace the entire dash assembly with one from an NA6 car.
Ditch the airbags and all related wiring and sensors. Modern airbags work, but how much faith do you have in the 14 year old burlap sacks filled with gunpowder in that Miata?
Remove the center armrest/console (replace with an Autokonexion "shorty" console or DIY).
There are mini-amps (made for motorcycles?) that are lighter than a headunit and have the connections to hook up to an iPod, drive two speakers and power the USB.
Lighter seats (Elise seats are $$$ but a great fit for the Miata).
Remove the soft top completely and add a hardtop (probably not much, if any, of a net weight loss).
Wednesday, August 04, 2010 8:48 AM
haha! Dave makes his own covers... I had nothing to do with that!
Thursday, August 05, 2010 4:17 AM
+1 on the idea of ditching the stock fuse panel altogether. Get a smaller fuse panel from Painless Wiring or even the electrical aisle at Rice Boys. (Sorry, I meant Pep Boys.)
Thursday, August 05, 2010 5:29 AM
"Power, by itself, will be entertaining but far from impressive. At 173 hp stock, the Hayabusa engine is only making the kind of power you would expect from a mild turbo kit on a stock Miata engine."
1.8 liters, 173 hp stock - how is that "far" from impressive? Beats the snot out of the BP I-4 motor NA, unless I am missing something big here, by about 50-60 peak hp.
Glass half empty Dave, plenty of people would be very happy to have that power NA in such a small package. But I recognize OCD when I see it ;)
Thursday, August 05, 2010 9:22 AM
In Jamaica we used to cut the front plates on turbo cars due to the intercooler until the police started issuing crazy tickets.
In the UK, the gov't only issues the plate numbers and private companies build the plates. I've seen some cars with stickers instead of front plates.
Friday, August 06, 2010 5:44 AM
I was thinking about places to shave weight again and remembered that on the FC they use a really light weight brake and clutch pedal assembly. Again, not sure what the Miata uses, but if it's rocking something steel and heavy there's a few pounds that can be shaved there for relatively cheap.
Anyways, cant wait for the next installment!
Saturday, August 07, 2010 2:58 AM
how much does Dave weigh? I suggest a low-carb diet and do some p90x while you're not building the Miata.
Sunday, August 08, 2010 6:50 AM
Random idea that probobly will backfire, but i stole it from some woodworking stuff: The first big picture under the "liscence plate" subheading- looking at the edges of the bumper it looks really thick. Is the whole bumper that thick or is it just doubled up around the edges/bolt locations? If it is that thick all over, there is a way to accurately thin it- take a drill press and set it so that it stops a few millimeters short of going all the way through, then get to work driling nearly through in close intervals.
the wood working way i've seen to thin the rest using these guide holes is to use hand gauges and then thumb planes etc... but I think a dremel tool should work for you. Again, shot in the dark, but it could remove some weight. if not for the front bumper, maybe it'll work elsewhere? This way you won't have to buy lighter parts and it would still look the same from the outside.
Friday, August 13, 2010 4:49 AM
Dave, for lightweight audio components, look at some early 2000's Kenwood eXcelon Dual Mags, they use neodymium magnets and are far lighter than even the crappiest stock speakers, with the added bonus of better sound
Monday, September 06, 2010 5:20 AM
I found the anti Miatabusa at IDRC. An RB25DET powered Miata.
Friday, September 24, 2010 10:29 AM
I would have left the state portion of the license plate in tact to avoid any issues with the front plate, but that's me.
As for weight savings, my one suggestion that hasn't been mentioned yet is the plastic wheel arch protectors. I only assume the car came with some? Ditch those if you feel like it.
Oh, and one guy I know went over every single bolt/stud and cut off the extra threads sticking out past the nut (leave one or two threads left if you feel like it). Dozens of grams saved! ;)
Okay last suggestion. The engine mounts and thick cast steel items you find on many cars (maybe the Miatabusa doesn't have any) can be lightened with a drill press and big drill bits quite well and will retain strength if done properly.
Thursday, March 10, 2011 7:20 PM
Seen a few suggestions, thought I'd comment:
Bumpers, already very light, so unless you throw out the plastic crash beams there's not much to gain here.
HVAC could be simplified by removing the entire ventilation system, and I recall seeing vented side glass(in front of the DS window) with a vent built into them available some time back.
Battery, definitely run something smaller and lighter. A local autoX guy uses a jet-ski battery or something similar in his 94R Miata, and uses a jump box to boost the current for starts. You could run something A LITTLE bigger and do without the jump box I imagine.
I applaud skipping the gutted interior, but some trimming of interior parts/panels is still possible. I know there's plenty in the guts of the dash that can be hacked out prior to reinstallation, and it won't look unduly juvenile from the outside. Likewise, remove tar mats under carpet and add Dynamat. Quieter than stock sound proofing and lighter. Can remove crash beams from doors, but that falls under the bumper crash beams heading, good stuff to have for a streetable car.
Do not overlook wheel weight. I know I'm preaching to the choir telling Dave Coleman and this gang about unsprung weight, but it is huge on a Miata. The factory wheels are already fairly light, but 13" wheels have been a hot ticket in certain AutoX classes for Miatas for a long time. Tire weight applies too.
Remembering Mazda's gram strategy pays dividends with the Miata. You may not save a lot of weight cutting unneeded plastic out of the back of the dash, but a couple of pounds here and there adds up. I've heard of all sorts of foolishness ranging from a guy that cut unneeded threaded portions off of every bolt and screw in the Miata(OCD much?) to a CSP autocrosser who cut the stock brake discs up(1.6L brakes, already lighter than 1.8L), bolted them to custom aluminum hats, then drilled the Hell out of them to save weight. He commented that the brakes would just start to fade after a 55 second autocross run.
Lots of weight can be saved affordably, but if 24 Hours of Lemons has taught us anything, you substitute time for money(labor is still free afterall).