Why did GM go with the LSA rather than the 427 if the original ZL-1's had it?

[Sven59]

Originally Posted by mclark10

Dave Barton of Barton Shifters dad has a supercharged Z06. 640 at the wheels.

Someone told me that the compression was too high in the 427 for a supercharger?

[FINALLYSATISFIED]

Originally Posted by DrkPhx

Both good points. I think it came down to what I call revisionist marketing where GM is trying to rewrite it's heritage through clever maketing of a storied name like the ZL1. It's interesting how GM insisted on sticking to the "true heritage" of the Z/28 (which is fine) but completely went away from the heritage of the ZL1 which a true purpose built drag car. Not too long GM was calling the ZL1 a barely legal track car (road course at that) and now it's being marketed as a "GT" car after the release of the Z/28. lol. The argument that the current COPO is it's replacement is invalid because it's not a street legal car unlike the real ZL1. My .02

Exactly I was thinking! Just was waiting for someone to say it. Maybe fbodfather came chime in with a better understanding of it all. Just was slightly confused when I seem the '69 ZL-1 with the 427 but they mentioned going back to the heritage for the Z/28 which is technically wrong. Maybe it's not suppose to make sense, honestly. And it comes down to GM wanting to do it, so they decided to do it.

[2cnd chance]

You're looking too far past the simple explanation. It's not about the engine's "size", but the engine's performance and ability. The Z/28 was/is a track oriented car. You want/need a high-revving engine for that, hence the LS7. The ZL1 was/is a powerful engine in a Camaro. some say well yeah, but the ZL1 in 1969 was stripped...that's how many were ordered, however they could be ordered with most options and some were (even with the RS hidden-headlight and trim package).

[DRTH VDR]

[QUOTE=Sven59;6669414]I understand that the 427 is not compatible with superchargers,...............................QUOTE]

Really? You're not serious right?

[morgnstern]

Originally Posted by PYROLYSIS

Cause those purists didn't want a ZL1. They wanted a Z/28.

They didn't make enough ZL1's for there to even be purists. Many don't even know they existed. I would love to have a 69 ZL1... They are worth a TON of money!

[lbls1]

It would have been clearer conceptually IMO if Chevy engineered the current zl1 with the 427 engine, and if they developed a de-stroked version of the ls3 to a displacement at or near 302 cubic inches for the z/28. It is my belief that little doubt would be left concerning the concept and purpose of either model if the planning of them were closer to the original cars.

On the other hand, Chevy also had to utilize "economy of scale" in order to produce the models and to make a profit. It is to chevy's advantage to use powertrain components already in production in order to produce newer models, even though the models are conforming to a concept of cars which are no longer in production.

Another thing to consider is the context of the market of high horsepower performance cars of today. The performance cars of today are comparatively more powerful and fuel efficient than the muscle cars of yesteryear. GM and Chevy needed more advanced technology and more efficient manufacturing in order to produce a performance car that could achieve the power levels of modern sports cars, in addition to being more fuel efficient and conforming to current regulation. Thus, utilizing the current lsa and ls7 seemed to have been a logical choice.

The ZL1 and Z/28 are outstanding performance cars, and if their specifications suggest it, they will become the new legends that future car enthusiasts will look up to.

[Rikki Tikki Tavi]

Originally Posted by 2cnd chance

You're looking too far past the simple explanation. It's not about the engine's "size", but the engine's performance and ability. The Z/28 was/is a track oriented car. You want/need a high-revving engine for that, hence the LS7. The ZL1 was/is a powerful engine in a Camaro. some say well yeah, but the ZL1 in 1969 was stripped...that's how many were ordered, however they could be ordered with most options and some were (even with the RS hidden-headlight and trim package).

I think it is about the engine "size" if were talking about "purist". Which is why the price and make-up of this currnet z28 makes no sense. Why market this car as being a pure throwback, then neglect the most important aspect of it which is the engine. The original z28 came with a 5.0. The original ZL 1 had a 427.

Ive always maintained that the z28 should not be a stripped down 427. With todays technology, GM should've been able to produce a better car if they're gonna charge $70 grand.

[Rikki Tikki Tavi]

And the funny thing is Chevy fans fall for this hook-line-and sinker. Watch Ford come out with a mustang more dominant and still have all the creature comforts for the same price. Possibly a Boss 351 hopped up.

[Sven59]

[QUOTE=DRTH VDR;6669682]

Originally Posted by Sven59

I understand that the 427 is not compatible with superchargers,...............................QUOTE]

Really? You're not serious right?

Its a question, somone told me the compression was too high?

[Rikki Tikki Tavi]

[QUOTE=Sven59;6669933]

Originally Posted by DRTH VDR

Its a question, somone told me the compression was too high?

The LS7 should not be used with forced induction. Yes mainly due to high compression. High compression engines are not meant to be used with forced induction.

[BlackinBlack]

[QUOTE=DRTH VDR;6669682]

Originally Posted by Sven59

I understand that the 427 is not compatible with superchargers,...............................QUOTE]

Really? You're not serious right?

Really? You could explain and he is sort of correct. Not so much an issue of compatible as not an ideal platform. See below for reasoning.

Originally Posted by Sven59

I understand that the 427 is not compatible with superchargers, so I think the upgrade of horsepower in the LSA is much more possible than with the 427. Does anybody know the max horsepower people have gotten out of the two engines?

It is not that you cannot supercharge an LS7. The issue is that due to being the same engine package (aka block dimensions) with a bigger displacement (aka the cylinder bores are larger) there is less material in the LS7 block. This makes the motor weaker for boosted applications. Back in the day GM made 400 CID and 350 CID motors. Both were based on the same design. 400s were notorious for having issues with overheating and head gasket problems especially between the two middle cylinders. Most people did not build 400 CID based motors for NO2 and boosted applications due to these compromises. It was not that it could be done (in fact people did do it) but the 350 CID block was a better starting point.

Today the factory LS7 block has similar compromises Vs the factory LS3, LS9 and LSA blocks. LS7 can be supercharged and people do but they tend to hit a lower HP limit or have a lower life expectancy Vs the smaller CID LSx motors.

To sum. LS7 = thinner block which produces more issues when boosted Vs LS3/LS9/LSA blocks which have more material. The LSA and LS9 blocks due to being designed for more power are better than the LS3 block when running higher boosted applications.

If you want to go totally crazy then the aftermarket has blocks that can support an insane amount of boost/HP.

References from wiki:

http://en.wikipedia.org/wiki/GM_LS_engine#7.0_L
"The (LS7) block is changed, with sleeved cylinders and a larger 4.125in (104.775mm) bore and longer 4.00in (101.6mm) stroke than the LS2. The small-block's 4.4 in (110 mm) bore spacing is retained, requiring pressed-in cylinder liners."

http://en.wikipedia.org/wiki/GM_LS_engine#6.2_L
"The Gen IV LS9 is a supercharged 6,162 cc (6.162 L; 376.0 cu in) engine, based on the LS3; the LS7 block was not used due to the higher cylinder pressures created by the supercharger requiring the thicker cylinder walls of the LS3. Cylinder dimensions are now 4.06 in (103 mm) bore and 3.62 in (92 mm) stroke."

"The supercharged 6.2L LSA is similar to the LS9 and debuted in the 2009 CTS-V."

Overall anything is possible depending on the amount of cubic dollars that are applied.

[Mister Will]

[QUOTE=DRTH VDR;6669682]

Originally Posted by Sven59

I understand that the 427 is not compatible with superchargers,...............................QUOTE]

Really? You're not serious right?

It's a common held belief throughout the corvette community. Something about the cylinder heads and block having a problem holding up to the pressures with the superchargers (obviously at the combustion stroke). I've heard from a well know tuner that it was a bad idea, and from a supercharger kit manufacturer that it was okay.

Sure, people put aftermarket S/C kits on them all the time. But I don't think you will see a S/C LS7 block from the factory.

Edit: Looks like I was late to the party.

[2cnd chance]

Originally Posted by Rikki Tikki Tavi

I think it is about the engine "size" if were talking about "purist". Which is why the price and make-up of this currnet z28 makes no sense. Why market this car as being a pure throwback, then neglect the most important aspect of it which is the engine. The original z28 came with a 5.0. The original ZL 1 had a 427.

Ive always maintained that the z28 should not be a stripped down 427. With todays technology, GM should've been able to produce a better car if they're gonna charge $70 grand.

Originally Posted by lbls1

It would have been clearer conceptually IMO if Chevy engineered the current zl1 with the 427 engine, and if they developed a de-stroked version of the ls3 to a displacement at or near 302 cubic inches for the z/28. It is my belief that little doubt would be left concerning the concept and purpose of either model if the planning of them were closer to the original cars.

On the other hand, Chevy also had to utilize "economy of scale" in order to produce the models and to make a profit. It is to chevy's advantage to use powertrain components already in production in order to produce newer models, even though the models are conforming to a concept of cars which are no longer in production.

Another thing to consider is the context of the market of high horsepower performance cars of today. The performance cars of today are comparatively more powerful and fuel efficient than the muscle cars of yesteryear. GM and Chevy needed more advanced technology and more efficient manufacturing in order to produce a performance car that could achieve the power levels of modern sports cars, in addition to being more fuel efficient and conforming to current regulation. Thus, utilizing the current lsa and ls7 seemed to have been a logical choice.

The ZL1 and Z/28 are outstanding performance cars, and if their specifications suggest it, they will become the new legends that future car enthusiasts will look up to.

The engine's size does not make the car "the car" it is or should be. It's the engine's "design". It's what it's intended for. The Z/28 is a track car needing a track designed engine, and on GM's shelf is??? The LS7. In the 1Gen a Camaro Z/28 "had" to be a 5 liter engine, but not now. In the 69' Camaro they put the most powerful engine available into the car and it was a ZL1 which just so happened to be a 427 CI engine. The 427 LS7 is not the most powerful engine at GM today. I guarantee you if in 1969 the most powerful engine was a 502 CI it would have been put in. So for today they put a more powerful engine in the ZL1, however in reality it should probably have been the LS9 in the ZL1.

[morgnstern]

Originally Posted by lbls1

and if they developed a de-stroked version of the ls3 to a displacement at or near 302 cubic inches for the z/28. .

Why this? The 67-69 DZ302 is not a destroked 327 like many people think. It is a 302 block.

I think it would be cool if the ZL1 had a 427 too but I'm not complaining with the LSA. The Z28 should be the high-reving road-racer that it was orginally and the ZL1 the monster at the drag strip. They accomplished that but switched the motors up. If anything, I wish they put the LS9 in the ZL1 and made it 10 less hp to make the vette guys happy.