Project V8 RX-7: Part 3- Inside the GM LS3 Cylinder Head

Project V8 RX-7: Part 3 - Inside the GM LS3 Cylinder Head
By Mike Kojima

In the last edition of Project V8 RX-7 we looked into the bottom end of our EROD LS3 engine to find that the modern Chevy V8 is a far cry from the old small block Chevy of years past.  Lately on some forums that cater to import performance, there has been a huge backlash against the LS swap, particularly into Nissan S chassis and RX-7’s.  All sorts of bleating noise from uninformed sheep decry putting “NASCAR” engines and the like into the S chassis. Purists claim that putting in a domestic engine somehow is making their favorite cars all the same and causes them to lose their soul and other things not defined by logic.  Such is the garbage cluttering the net these days.  Like many FFF facts on the interwebz, their are many fundamental inaccuracies to these statements.

Read more about Project V8 RX-7!

Project V8 RX-7: Part 3- Inside the GM LS3 Cylinder Head
This is a NASCAR SB2 engine.  It is very closely related to a small block Chevy. Many of the parts will interchange except it has a few major differences.  The distributor is in front instead of in back for less spark scatter at high RPM. The heads are actually pretty sweet and have canted splayed valves with ah high quench and turbulence combustion chamber. The camshaft is much higher in the block for crank clearance with big lobes and for shorter less flexy and lighter pushrods and everything is beefed up and more suitable for racing.  It has an iron short skirt block.  It is not even close in design to an LS motor.

One, the LS engine is not a NASCAR engine or anything close.  NASCAR engines have evolved from the venerable small block Chevy and do not share any parts or engineering with the LS other than bore center dimensions.   Although they are not really small block Chevys anymore with different block castings--with relocated camshafts and way different main web dimensions, cylinder and deck thicknesses--they are at least recognizable close relatives.  The LS is very different from these engines, if you were to simply look at the bottom end you might think it was a European or Japanese design.

Project V8 RX-7: Part 3- Inside the GM LS3 Cylinder Head
This is not a NASCAR motor.  The only things the same between an LS and a small block Chevy are the bore spacing and the fact that they are both V8's and have push rods.  Examining the cutaway diagrams closely should show that there are no similarities in architecture between the two engines at all.

Two, LS motors are are not all the same, they are many variants of the LS engine and there are more LS tuning options than any import engine.  In fact, tuning an LS is probably more intellectually stimulating that figuring out many power solutions to popular imports.  It's typical youth trying to make a statement in non conformity by conforming to a youth norm!

Project V8 RX-7: Part 3- Inside the GM LS3 Cylinder Head
Lighter than a Nissan KA24, almost as light as a  13B-REW or SR20DET with way more power than any of them makes the LS a good swap choice.  GM Performance's EROD swap kit can make it all smog legal as well!


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Monday, April 25, 2011 1:29 AM
Good article there!
The problem why people hate the LS swap, in my opinion, is that the people who do swap the LS into a japanese car tend to hate on the ones that don't and its not always the engine that causes trouble, but the people around them. I wouldn't mind having LS3 in my s13, but for european market it is not affordable and there is always that fun of david vs. goliath, until turbos and stuff starts to break. It would be much nicer to read these articles if they written without hate or love, just neutral, bringing out the good and bad. Cheers
Monday, April 25, 2011 1:48 AM
Mike, would you go into more detail on getting higher rpms out of a pushrod engine? With the older SBCs I think it required solid lifters. Do the LS motors also need to make that switch?
Monday, April 25, 2011 4:33 AM
I wish GM would make an LS version of the 4.3 V6.

(I just like V6's. The whole slap a V8 in it just seems too easy but, I respect the reasoning behind it)
Mike Kojima
Mike Kojimalink
Monday, April 25, 2011 6:14 AM
For higher revs, solid lifters, adjustable shaft mounted roller rockers, stffer and lighter pushrods maybe and careful spring selection. For really high rpm a dry sump is a must.

For a SBC, add guide plates and cam thust control bearings as well as re engineering the whole motor (see NASCAR motor).

As far as good and bad about the LS swap. In an FD or S chassis, I can't see anything bad about doing a swap other than the cost and that if you hate pushrods, its a pushrod engine. If you really like turbos maybe its boring.

In the US LS motors are cheap and easy to find in junkyards. Matt Powers found his LS7 in a junkyard and bought it for $6000. With the drysump, cam manifold and headers he ended up spending around $14,000. Not bad for what the results were.

If you wanted an older LS the costs could be as low as $5000 for an LS, T56 and swap kit. About what a SR swap might cost if you did a FMIC.
Der Bruce
Der Brucelink
Monday, April 25, 2011 7:07 AM
I wonder if you could put the top end of the erod on the LS2 and still get CARB compliance? From what I've read, your original LS1 would've been too much work to make the LS3 heads work.
Mike Kojima
Mike Kojimalink
Monday, April 25, 2011 7:33 AM
All LS heads interchange.
Monday, April 25, 2011 7:39 AM
I understand and agree with the LS swaps in theory. But why not make all motors 2 valve pushrod engines? If it's so great, then why do we have DOHC motors? For many swaps, the pushrod design allows for a lot of compactness. But is the design that superior that it makes more sense? If it is superior, then I can't wait to see some pushrod I-4 motors roll out of Detroit.
And you said 20mpg highway on the LS was better than turbo 4's? (maybe you meant turbos in general) My little 4G63T gets 30+mpg all day long. I bet I could get over 40+mpg on a long flat highway. Maybe I just love turbos too much :D
Der Bruce
Der Brucelink
Monday, April 25, 2011 8:03 AM
Mike - from what I understand, the cylinder bore of the ls1 makes it so the ls3 valves won't clear. But the ls2 clears JUST barely.

Jeff - The pushrod works for the V8 because of it's compact nature in a V8 layout. 4 cylinders don't really apply. Now, the lightest cars the LS motors come in, outside the Corvette, are typically 3700+lbs curb weight. I would bet a bone stock LS1 in an S chassis could push the 30mpg mark. I love turbo 4s as well, but not all turbo 4s are as efficient as they could be. What's your 4g63t in that gets 30+mpg? If you say EVO, I'm calling my initials!
Monday, April 25, 2011 8:11 AM
I-4 engines are pretty compact to begin with whereas a V8 is close to twice as big. And a pushrod setup doesn't package nicely in an I-4. Where would you put the cam? and the rods? It doesn't make sense, you'd have to stick it off to the side and add mass. In a V-8 you're also using 1 cam + pushrods instead of 4 cams where in an I configuration it's 1 cam plus pushrods instead of 2 cams (not really much of a savings).

Also, my completely stock WRX got mid to high 20 mpgs at 183 hp. Crank it up to 430 hp and you can probly cut that in half and have worse drivablility. I would jump at the chance to get nearly equal economy in an engine with over double the horsepower.
Monday, April 25, 2011 8:19 AM

A push-rod I-4 does come out of Detroit just google a Mopar A4 engine. Not saying its better or anything just that it does exist and no vehicle was ever sold publicly featuring this engine but its still kinda cool.

The engine is used in midget racing and is able to accept a single wedge or hemi cylinder head. In Hemi trim i believe the engine pumps out 350hp naturally aspirated. It is still a relatively small engine and is extremely strong.
Mike Kojima
Mike Kojimalink
Monday, April 25, 2011 8:40 AM
Jeffballs, My 4G63 struggles to get 20 mpg even with the extensive part throttle tuning I did to get better fuel economy. I got something like 16 mpg stock and I have gotten as low as 12. This is for mixed driving. The best I have ever gotten is 24 with almost all highway driving.

I don't drive that fast on the street. I don't know how you get 30 mpg all day long I wish I did. Is your car a fwd DSM? Lighter weight, better aero and less drivetrain drag than an EVO could do it I guess. If you have an EVO I would say, yeah right.... Teach me how to do it!

The LS is probably the best engineered and most refined SI pushrod engine out there. GM considered doing a DOHC but the numbers kept looking better for the OHV engine considering the performance envelope. For very high revs like purpose built race engines and bikes, the DOHC is markedly superior due to its potentialy much lower valvetrain mass. The DOHC can have less valvetrain friction in production car applications as well. For below 8000 rpm considering overall weight and packaging it is hard to beat an LS though.

Bruce, they sell kits to put late heads on LS1's. The LS1 and LS2 have the same size valves I am pretty sure.
Dusty Duster
Dusty Dusterlink
Monday, April 25, 2011 9:46 AM
Um, what does "FFF" mean?
Jeff Naeyaert
Jeff Naeyaertlink
Monday, April 25, 2011 11:04 AM
type it into the search bar above.. it's abbreviated for good reason :)
Monday, April 25, 2011 11:16 AM
Another thing that factors in, especially with all of the LS heads available, is the valve angle relative to the cylinder axis. From 15 to 11 degrees, the shallower the angle, the less shrouding of the valve occurs at a narrower bore. Probably what makes big-block Chevy and Ford Cleveland and yates style heads so popular for making power is valve angle and valve cant off centerline.
Monday, April 25, 2011 1:41 PM
The LS1,3,7 is a really good engine. Light weight, all aluminum. Lots of support. Found in a ton of cars over the years, in lots of cars. As the iron block version, in lots of trucks, and even cheaper.

Its a typical American Hot Rod route. Just go back to the 50's and 60's and the small block Chevy was always a popular swap into everything. Tons of Chevy engines in Fords. Simpler, more widespread, I get it.

I don't particularly like cross manufacturer engine swaps, but it floats some guys boats. Just check out some of the crazy stuff in Australia, Europe, Asia. Guys are going to use engines they are familiar with, ones that it is easy to get parts for.

Since I take this as a little jab, I will respond to it. I am a GM guy. GMC Syclone, GMC Typhoon, Buick Grand National. All turbo 6 stuff. Making the 6 work in those cars, can get costly, and a decent amount of guys swap in V-8's. The Sy/Ty guys use the iron blocks, twin turbo, and make big power and torque. Use the later 4L80 trans to handle the power. I like the 8's in the cars, but I still prefer my cars to have the V-6's.

The "NASCAR" jab has nothing to do with the engine. Not at all. Its the conformity of the cars that I am taking issue with. Its the "every car has an LS series engine" in professional drifting that I have an issue with. Its a great engine, I get it. However, if the diversity is the headlight and grill stickers, then there is really no diversity. I even actually enjoy the tech of NASCAR, what they do with a 358 cubic inch engine, for 500 race miles, turning 9500 rpms in a pushrod engine. Its impressive. However, the conformity of the cars is boring. Explain to me the excitement in watching a spec series?

So what you are saying is that it requires a LS series engine to win at drifting? The only good swap is an LS series engine? Jump off the bandwagon.
Mike Kojima
Mike Kojimalink
Monday, April 25, 2011 2:40 PM
Drift cars are pretty diverse. At Long Beach a Ford won 2 and 3 were LS powered. In the top 10 there were 5 chevy powered cars, 4 LS engines and 1 small block chevy. There was one V8 Nissan, a turbo V6, a turbo rotary, A turbo I4 and a V8 Ford Coyote. Of the LS engines Two were LS7's, one was based on an LS2 and I am not sure about the other. I am pretty sure it's an exotic aluminum tall deck big cubic inch LSX varient. So six of the 10 engines were different. There were only two pairs of simular engines.

The LS is not the only good swap or the only engine that can win at drifting but it is one of the cheaper ways to be competitive.
Monday, April 25, 2011 3:03 PM
For Formula Drift Long Beach:

40% of the top 10 cars were LS powered.
50% of the top 10 cars were Chevy V-8 powered
70% of the cars were V-8 powered

Seems like you need a V-8 to be at the top of the field, and that if its an LS series engine, you are in the majority rather than minority

In NASCAR, 100% of the cars are V-8 powered, and I think about 0% of the real cars are V-8 powered. Makes it entertaining, but not necessarily relevant. Ford, Toyota, Dodge, Chevy, all the same. Not interesting. Drifting is going to turn into this. Already you have 40% of the cars running the same engine. Give it another season or two, and you will have 80%.

Again, not saying the LS is a bad engine, but I think its bad for pro drifting.

Monday, April 25, 2011 3:29 PM
good read. thanks for the info. im considering this engine for my dream project. whats the overall hp goals for this engine/car combo?
Monday, April 25, 2011 3:33 PM
I dont think Formula D will turn into a NASCAR. Honestly, i see it going back to a grassroots ruleset in the next couple of years if anything. I think you can relax.
Mike Kojima
Mike Kojimalink
Monday, April 25, 2011 9:11 PM
If V8 motors are banned I would probably end up running VQ engines in everything and get just as good results but end up spending more.

I told the guys at XDC to ban V8's so they could be different than Formula D and cater to the traditional Import Performance market. I think it owuld be a good move for them to do so.
Tuesday, April 26, 2011 3:24 AM
Everyone here is forgetting the most popular pushrod engine of all time! It's numbers put the SBC, or the LS engine to shame----and it's a 4 cylinder to boot.

The air cooled vw flat 4!
Tuesday, April 26, 2011 3:52 AM
Mike, my 4G63 is a 1st gen 6-bolt (7.8:1 compression) and is only pulling around about 2500lbs in FWD trim. I have an original 1989 Dodge Colt GT turbo that I swapped over. The aero is terrible, but with the lack of weight and the FWD efficiency, I get great gas mileage. The EVO is completely different, although completely the same. Stupid.
I understand the "cheap" route of swapping in an LS and the power potential. My issues stem with everything else. Why is an LS cheap if the suspension costs more than the motor? Yes, it's all important and we save money where we can. I guess I still think the V8 thing is a cop out like when Honduhs were beating 5.0L Mustangs back in the day. The V8 is a great platform for Drifting, but it takes away from the "uniqueness" of each vehicle. Tyndago makes very good points.
Mike Kojima
Mike Kojimalink
Tuesday, April 26, 2011 6:29 AM
Jeffballs, no wonder you can get decent mileage. I like the 4G63 for a lot of things but it doesn't have the best port or combustion chamber layout. On an EVO it breaks out of closed loop super easy due to the responsive turbo and drinks gas. I extended the closed loop operating range, moved it so it loops on the leaner side of 14.7, tuned the MIVEC and spark maps for best manifold vacuum at part throttle. All of this helped to the tune of about 4 mpg but it's still bad.

Sean, I am an engineer and I look at an engine for a race car with no sentiment or emotional attachment. I simply try to get the best performance for the budget I am given by the client. Winning is the game. Cost vs benefit is calculated. If I can get target performance and power density and reliability with a cheaper powerplant, then thats what I do. It allows money to be spent on other areas to build a more well rounded race car.

In the case of the car I work on, it enables us to build an S13 with almost 50/50 weight distribution with a non fiddly engine that can last the entire season without touching it. It enables us to beat cars costing 2 to 3 times as much and enables us to put more money in chassis development to where we still have the best handling car in the series even though the rules have been against us for this year. Winning with what you are given is more interesting to me than being original. In our overall car, there is plenty of differentness and innovation, just not in sexy areas like the engine.

Being able to be original for the sake of doing it l is a rare luxury for an engineer. That's fun too but perhaps the only time I have gotten to do that was working for a manufacture where you had to make their product competitive.

The VW flat 4 is a piece of crap in anything other than a super light car like a sand rail or buggy for a very narrow type of use, like drag racing in one of the aforementioned chassis or closed course offroad racing in a class that dictates its use. It had been surpassed in most other forms of racing by other designs.

This is just my opinion though.
Tuesday, April 26, 2011 7:05 AM
I love all the children with the sentimental attachments to an engine class (I4).

Like mike said, you really can't argue with the weight:hp, volume:hp, or area under the curve:money,

I can only assume these are the type of people that would rather buy their bigmac fries and drink separate just so they weren't conforming to the menu numbers, either solve with logic or you're a woman (no offense intended towards women with logic capabilities) the motor works, fits, is cheaper, is more reliable at ANY given power level (assuming you want >200hp) and the torque curve looks like a table not a cliff.

BTW I have 3 sr20's 1 KA24, a QR25, a v-twin (90 not 72) a 5.4 modular ford and 1SBC (267 cu in) I am not a pushrod fan but arguing against solid reasoning puts you in the lot with religious zealots and the like.

Motors are intended to produce TQ, this one happens to do the job with less space and weight and just happens to be the best answer, if you don't like the answer, ask a different question, like what motor will let me avoid the wife the most by breaking constantly, answer: rotary, see there you go now rotary is the answer!
Eric Hsu
Eric Hsulink
Tuesday, April 26, 2011 7:23 AM
I dig the LS3 cylinder head and I like how GM made some drastic changes in the cylinder head to evolve it. There's a certain amount of passion and a whole lot of demand from the US aftermarket that drives GM to do this. Too bad the Japanese OEMs only give a shit about sales numbers (death to accountants and MBAs), but then again the Japanese design superior cylinder heads from the get go. Its almost as if the Americans rush to get their shit out and figure it out along the way.

Its important to remember that the GM LSes only get 20+ MPG because the stock ECUs drop cylinders during cruise. They are actually only running on 4 cylinders on the highway. Put in your aftermarket ECU without a cylinder drop strategy and you'd be hard pressed to get 20 MPG on the highway with an LS in a 3500 lb car. I'm not saying it's impossible. It just isn't likely.
Mike Kojima
Mike Kojimalink
Tuesday, April 26, 2011 7:40 AM
Eric, I don't think all of the LS engines do, only certain ones. I know Jeff as getting mid to high 20's in the FD before with the LS1 and the LS3 is even more efficient.

I think a lot of it is due to the LS having a very good fast burning chamber with a lot of tumble and swirl. It's hard to get swirl in a 4 valve design. The LS chamber also has a lot of quench and is very shallow so it has a low surface to volume ratio, all good for thermal efficiency.

The LS has real good BSFC numbers. I think Japanese tend not to exploit the squish potential of their chambers and piston domes for reasons I don't understand why. It could be the balance of NOX vs HC's and sometimes they are surprisingly bassackwards in some areas. Like the smart guy did the head, but the piston guy didn't look at the quench pads and some morons did the engine management calibration.
Jeff Naeyaert
Jeff Naeyaertlink
Tuesday, April 26, 2011 8:18 AM
yeah Active Fuel Management was only used in the L99--which is a variant of the LS3. it uses a solenoid that deactivates the lifters on half the cylinders during cruise. Some of the 2010 automatic Camaros have it I think.

as for the mpg's, don't forget the .5:1 6th gear ratio.. Cruising 80mph the engine was only spinning 1800rpm with the old LS1 (with a 3.90 rear end).

Der Bruce
Der Brucelink
Tuesday, April 26, 2011 9:51 AM
So I take most people's MPG and HP claims with a grain of salt because faith works for religion but cars are science and I like to see the data. You can quote me on that last part, just made it up. Anyway, when I had my LS1 GTO for the short time I had it, my best tank combined was 23mpg. I never got to take it on any highway only trips. You can take it with a grain of salt if you like but GM provided that nice 6th gear ratio that Jeff mentioned, and they designed a 1st-4th gear shift, as described in the owner's manual, to help the fuel economy for economical driving conditions. 23mpg is not great combined but certainly not bad for a 3700lb+driver car outing out 350hp.

A big fact that hasn't been mentioned is that GM designed the LS1, LSJ and most of their engines to put down their horsepower numbers on 89 octane pee water. That is one of GM's most amazing distinctions in all of this.
Eric Hsu
Eric Hsulink
Tuesday, April 26, 2011 3:59 PM
Ahhh yes, the .5 6th gear will get you the rockin MPG. I think there's a fuel and ignition cut strategy that goes with the solenoid/lifter deactivation strategy as well.

Yeah the japanese can definitely be bassackwards, but for pure airflow the modern Japanese heads can flow ridiculous numbers. In an oem application, the Japanese are probably super conservative too. They probably need to write 1500 reports to get a head designed.

The LS has massive quench. I guess that's the benefit of having a massive cylinder and only two valves. I am getting more and more interested in the LS3/7s.
Jeff Naeyaert
Jeff Naeyaertlink
Tuesday, April 26, 2011 4:24 PM
sweet! I don't plan to do any internal engine stuff for a while, so that should give Cosworth plenty of time to R&D some bitchin' LS stuff :) ....I knew you'd come around!
Daewoo Of Death
Daewoo Of Deathlink
Tuesday, April 26, 2011 4:57 PM
I realize this is completely leaving behind the whole "affordable" thing, but the only production engine family I can think of that seems to match the efficiency/reliability/packaging/power density is the Porsche flat 6s. That's pretty good company for a truck engine.
Eric Hsu
Eric Hsulink
Tuesday, April 26, 2011 5:13 PM
Hahah I never hated LS engines. I just don't think they belong in an import chassis. Call me a purist to some degree.
Eric Hsu
Eric Hsulink
Tuesday, April 26, 2011 5:21 PM
But yeah for sure, you'll be the first to know if we develop anything. Now I have to see if the others are down. I had this discussion with Mike and Martin at lunch last week and I asked them, "outside of the corvette, camaro, cts-v, and gto, what other performance car comes with an LS?"
Tuesday, April 26, 2011 6:31 PM
Jeff Naeyaert
Jeff Naeyaertlink
Tuesday, April 26, 2011 7:27 PM
don't forget the Ultima GTR!
Tuesday, April 26, 2011 11:52 PM
And the Bertone Mantide!
Wednesday, April 27, 2011 8:30 AM
"All LS heads interchange." "...they sell kits to put late heads on LS1's." Is this true? Can you point me to where I can purchase an adapter kit to fit unmodified rectangular port heads (LS3/L92/LS7) to a 99mm bore block (LS1)? I am aware of Mast Motorsport selling a version of the LS3 style head for LS1 applications, but the adapter kit sounds like it may be a cheaper alternative.
Mike Kojima
Mike Kojimalink
Wednesday, April 27, 2011 1:04 PM
My mistake, they sell kits for the LS2. The LS1 has too small of a bore.
Wednesday, April 27, 2011 4:31 PM
Interesting. It's nice to see GM has stepped out of the stone age. Now they just need to put this engine in everything they produce so I can buy one from the junkyard in 15 years for $90.
Wednesday, April 27, 2011 7:19 PM
The 5.0 modular is actually lighter than the LS engines and a fair bit smaller than the DOHC 4.6(it's even smaller than the SOHC modulars) so it might be closer to the LS but they're definitely still smaller.
Der Bruce
Der Brucelink
Wednesday, April 27, 2011 7:52 PM
Shin - 5.0 motors - 525-575lbs depending on who you ask
LS1 - 390-400lbs depending on who you ask
Mike Kojima
Mike Kojimalink
Wednesday, April 27, 2011 7:59 PM
I think Eric wrote an article here someplace last year about how bad that ford head is.
Wednesday, April 27, 2011 8:08 PM
5.0 Coyote motors are no where near 500lbs
444lbs packaged see what it comes with in the link http://www.fordracingparts.com/parts/part_details.asp?PartKeyField=11829

The LS1 was officially recorded @ 430lbs
Eric Hsu
Eric Hsulink
Wednesday, April 27, 2011 8:17 PM
No I was clowning the 4.6L SOHC heads. I believe the 5.0 DOHC heads are all new.
Eric Hsu
Eric Hsulink
Wednesday, April 27, 2011 8:20 PM
Oh snap, Shin is right. Now we need a Ford 5.0 modular Coyote vs LS3 story ASAP.
Jeff Naeyaert
Jeff Naeyaertlink
Wednesday, April 27, 2011 8:24 PM
yeah but the cg of the LS is prolly quite a bit lower... so THERE!
Mike Kojima
Mike Kojimalink
Wednesday, April 27, 2011 9:14 PM
The Coyote is a huge sucker though.
Thursday, April 28, 2011 7:07 AM
@ Jeff the Coyote is shorter though so it can be pushed back more for better weight distribution ;)

@ Mike the coyote is smaller than the older DOHCs and might be closer in dimensions to the LS1.

Friday, April 29, 2011 7:14 AM
Gotta say, I agree that switching to the now ubiquitous Chevy LS does rob the RX-7 of some of it's character. The rotary is such a down-right cool engine, it is almost a shame to replace it with something less interesting... almost.

After having one's 13B drop it's third apex seal in as many months, the coolness factor starts to go WAY DOWN! lol.
Friday, April 29, 2011 3:15 PM
Putting an american engine in a japanese cars is blasphemous, sacrilegious, treason. Its conceding that big V8's are better and their not. people have been fixing them up for over 50yrs, why keep doing the same thing? why not go with the new so in the future their IS SOMETHING new to mod? if you keep reliving the past you end up going in a circle, WHY DO THAT? and i hate Ls1's because of the owners, not the engines...
btw, how is 497lbs barely heavier than low-mid to even high 300's?????
One more thing, a ls1 rx7 will never handle the same or as good as one with a rotary, its weight, size and placement WILL NOT ALLOW IT! hang up saying it will, owners of them have CONFIRMED they do not.... stop it... it doesn't...
Jeff Naeyaert
Jeff Naeyaertlink
Friday, April 29, 2011 3:30 PM
Friday, April 29, 2011 4:07 PM
From SCC Sept. '06, which featured an RX7 LS1 swap story:

13B-REW 425 Lbs
LS1 487 Lbs

That's 62 pounds difference. Relocate the battery and you'd recoup half the change in weight distribution. Are you saying the 13B is the latest and greatest thing to hit the aftermarket? Just so you know, the LS series wasn't even in production at the time RX7's stopped being sold in the states. Hardly old technology. Oh, and there's a lot more to tuning bench racing comparisons of weight distribution.

Quit being a fanboi.
Friday, April 29, 2011 8:30 PM
Yeh! What killamane said!!!! Go with the the super high tech invention which is the four cylinder engine! It's like no other engine that has come before it! lol.

- Alfa Romeo Twin Cam engine was the first mass produced twin cam engines, produced from 1954.

- The Oldsmobile Rocket V8 was the first OHV V8, in 1949.

- The NSU Spider in 1964 was the first car with a Wankel.

Yup. That twin-cam four and rotary are totally brand new and revolutionary!
Mike Kojima
Mike Kojimalink
Friday, April 29, 2011 9:28 PM
Fiat, Peugeot, Alfa Romeo and others made some of the first DOHC twin cam 4 valve pentroof motors from 1913-1920 so a twin cam 4 valve is hardly new technology.
Saturday, April 30, 2011 7:53 PM
Apparently the guys calling the LS engine low tech and old are idiots. Its obvious they dont know how refined the LS engines are and what new technology goes into them. Fool killamane probably from Zilvia.
Scott Helmer
Scott Helmerlink
Saturday, April 30, 2011 9:07 PM
I suspect Killamane is actually from an RX-7 forum, but yeah. At least Dorkspeed's bringin' that sarcasm that really shuts F-Cubes up.

I'm just waiting for somebody to say that an RB26 or a 2JZ swap is clearly superior in every way, especially when it comes to weight distribution; that's when the real fun will start. What saddens me is that there was once a day in which I might have been one of those people. I will say, however, that it's too bad Mazda doesn't really have a good high performance/low stress/low weight alternative from IRL/some sort of slightly upmarket luxury brand such as a couple of other marques that I know of, but that's primarily because not unlike Eric, I consider myself to be somewhat of a purist. I say keep a Mazda a Mazda, a Nissan a Nissan, and a Chevy a Chevy (GMC/Pontiac/Olds/etc). However I also suspect this (among other things I imagine) will keep me from being competitive in top level drifting; gotta give to be able to take.
Sunday, May 01, 2011 9:02 AM
Thanks Scott!

Don't get me wrong, I like to keep BMW engines in BMWs and Mazda engines in Mazdas. It's just part of what keeps each car unique and interesting. It has nothing to do with what makes the most sense from a performance stand point. I mean, let's face it: if it were just a matter of what made the most performance sense, 99% of the cars out there would be running LS swaps... and the enthusiast world would be a much more boring place for it.

Let's look at the facts: the LS2 is about 450 lbs, puts out an easy 400 HP, is dead reliable, has tons of aftermarket support, is nice and compact, and can be had for pretty cheep to boot! It's a pretty hard engine to beat. And this is coming from a Euro-snob!

Any way, long story made short, if I had an FD RX-7, I would keep it 13B powered... until about the third time it blows up! Then I thing I would go ahead and switch to an LS! lol.

Thursday, May 19, 2011 5:05 PM
it doesn't matter if it's the best engine in the world, putting the same engine in everything is quite pointless.

It's like having a FormulaD running all the same cars.
for eg. if the mustang chassis is is the best for drifting, then we all gonna use that chassis?
Would you be interested in a competition like that?

It's the difference of different cars that makes motorsports interesting.
Thursday, May 19, 2011 5:12 PM
At that point it would come down to driver skill... reference spec miata.
John Rogers
John Rogerslink
Wednesday, June 01, 2011 10:52 PM
I would also love to read a comparison of the new 5.0 Coyote and the LS3. I am a Ford technician so I am familiar with the 5.0's guts, however, I would love to read a comparison of each engines "potential" from an engineer's perspective.
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