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TAG UR IT 08-31-2007 03:51 AM

LS3 Specs revealed: GM's 436hp Sick 6.2L LS3
 
This is the info we've all been waiting for....the specs...the #'s...the POTENTIAL. GM High Tech Performance has given all of this to us via the November 2007 issue of GMHTP...page 38. The read alone on this monster engine is great. But, you have to check out the pix as well. And so it is...

SICK six point two

GM's 436-horse LS3

by Tony Whatley

Being a GM enthusiast, there is no doubt that you have been exposed to the buzz going on about the upcoming 2008 updates to the base model Corvette. With the 1997 introduction of the LSX-series engines, GM has continued to raise the bar every few years when it didn't seem possible to do so. The 5.7L LS1 debuted with a rating of 345hp. Then along came the 6.0L LS2 in 2005 to bring the Corvette 400hp under the hood. For 2008, we now have the new 6.2L LS3 engine: SAE rated to 436hp and 428lb-ft of torque! This provides enough motivation for the 2008 Corvette to reach 190-mph top speeds, which makes it the fastest base-model Corvette ever produced.

Short-block

The LS3 is still considered the GM Generation IV architecture small-block, and it shows a nice progression from the LS2, which it replaces. The new engine block is the same as the 6.2L L92 aluminum blocks found in the 2007 Escalade and Denali trucks. It has the typical cast-in iron cylinder sleeves, but the bore diameter has increased from the previous LS2's 4.00 inches up to 4.06 inches, which results in a displacement increase from 6.0L to 6.2L. Some casting and machining updates were made with the LS3/L92 block, resulting in 20% stronger bulkheads inside. It is interesting to note that all of the base model Corvette LSX engines have shared the same crankshaft stroke of 3.62 inches, and this remains with the LS3. By using some simple hot-rodder math, readers have probably figured out that these 4.06-inch cylinder bores can be used to build some relatively inexpensive 414ci stroker engines by just swapping in a 4.00-inch rotating assembly. Looking back in the LSX world a few years ago, it would have required costly resleeving of the 3.90-inch bore LS1 blocks to achieve displacements beyond 382 ci. Needless to say, the GM performance aftermarket loves the parts GM now offers over the counter.

Inside of the block, we find newly designed flat-top pistons with coated side skirts. These hypereutectic cast-aluminum pistons help bring the compression ratio to a pump-gas-friendly 10.7:1. The piston oil control rings have revised tension to handle the higher 6,600 rpm redline. Even the piston profile and pin bore were revised to reduce engine noise and vibration. The pistons use a new pin that is taper-bored to reduce mass. At the big end of the connecting rods, the bolts have been upgraded to 12.9-grade material, similar to what is used in the 505hp LS7.

GM also decided to use a slightly more agressive camshaft in the LS3. The intake lift has increased from 0.521 inch found in the LS2 to 0.551 inch for the LS3. Slightly less overlap was also used for the LS3 cam.

Cylinder Heads

The biggest change between the LS2 and the LS3 is the introduction of rectangle port cylinder heads, which replace the popular "cathedral" port shape of the LSX head family. The LS3 borrows this performace technology from the C5-R and C6.R Corvette racing programs, where similar intake ports were developed and have dominated the race circuits. Rectangle ports first appeared on the 7.0L LS7 found in the 2006 Z06, and have now trickled down to little brother. This is definitely not a hand-me-down to complain about!

The intake port entrance is similar in design compared to the LS7 head, but the location and size of the ports are different enough to require LS3 specific intake maniforlds. The aluminum LS3 cylinder head castings are also shared with the L92 truck engines, mentioned above. Although the castings on the LS3/L92 are the same, the valvetrain is upgraded on the LS3 to handle higher rpm. Lightweight hollow-stem valves are used, along with LS6 valvesprings that can handle the higher intake lift found in the LS3 camshaft. The intake valve diameter has increased from 2.00 inches found in the LS2 to 2.16 inches for the LS3. Exhaust valve diameter has increased to 1.60 inches from 1.55 inches. In order to make room for the rectangle ports and the larger valve sizes, the rocker arms had to be offset 6mm from center on the intake side. The exhaust side rockers remain unchanged from the previous LS2 design. All of these changes result in cylinder heads that flow over 17% more at the same peak flow lift of the previous LS2 casting, and they continue flowing at higher lifts where the LS2 port would stall.

Intake Manifold

One item that isn't shared with the GM truck parts bin is the newly designed LS3 intake manifold. GM uses a lost-core process to manufacture the new composite plastic intake manifold. One unique development is a layer of sound insulation foam, contained inside of an area between the internal air runners and the external top shell. This results in less valvetrain and high-frequency noise transmitted to the passengers. Even the typical Corvette fuel rail beauty covers now have acoustic dampening material added underneath to reduce engine noise. Initial tests show the new SL3 intake design flows much more than the LS2 intake, but also does so with 2% less internal restriction. The fuel rail is identical to the LS2 fuel rail, but now LS7 fuel injectors are used to handle the power increase. The same 90mm diameter, four-bolt mounting-style throttle body is carried over from the LS2.

Summary

The most interesting aspect of these LS3 enhancements isn't how well they perform right off the dealer showroom, it is their potential in the modified engine aftermarket. The flow numbers seen from these LS3/L92 cylinder heads are only scratching the surface of potential when in factory form. The larger bore cylinders only make it easier to build more reliable and inexpensive stroker engines. The newer intake manifold is an impovement over the popular LS6 intake manifold bottleneck. Engine builders are using these heads and blocks to produce beasts making 700hp on engine alone, and that is with very little development or experimental testing. It seems every year LSX world records are set when GM releases new engines, which makes this a truly exciting time to be a part of the GM performance community. The real horsepower wars didn't happen in the 1960's-the are going on today!



and there you have it. Ok...fingers are tired...go buy the mag...

Dark Knight 08-31-2007 08:44 AM

Damn you typed all that?!?!! BIG BIG props to you TAG for doing all that!

about the article....all i can say is HELL YEAH!!!!

LSxcellent 08-31-2007 09:07 AM

Big thanks for typing that in Tag... its no small chore!

~LSx

Rock36 08-31-2007 10:04 AM

+1 on the effort, and that was an awesome artilce.

I need to quit visiting this site...because I just keep dreaming about owning an LS3, and the wait is becoming unbearable :cry: :brokenheart: :cry: :brokenheart:

Mr. Wyndham 08-31-2007 10:28 AM

:clap: TAG, thanks - I haven't read anything like that, yet. :clap:

:eyebulge:

I know it's been said - but this thing is a tamed LS7...with better potential! The article said it, and it's true - this is the time when being a part of the GM performance community really pays off. Who else offers an engine quite like this? Nobody! :laugh: Whoooo! Go GM!!!

dgraves 08-31-2007 10:58 AM

:thanks: Tag.... I think I need a smoke now!!! :thumbup:

TAG UR IT 08-31-2007 11:23 AM

Quote:

Originally Posted by Dragoneye (Post 21708)
:clap: TAG, thanks - I haven't read anything like that, yet. :clap:

:eyebulge:

I know it's been said - but this thing is a tamed LS7...with better potential! The article said it, and it's true - this is the time when being a part of the GM performance community really pays off. Who else offers an engine quite like this? Nobody! :laugh: Whoooo! Go GM!!!

:p No problem typing it...it was my pleasure. I'm actually getting pretty quick on the keyboard. But, this is just one more thing I like to do. I guarantee you other sites have something posted up like a one line snippit of the article. Or, maybe they just quoted certain parts. I could have done that too...but I'd rather give ya'll the entire story.

Dragon said it all when he said it's a tamed LS7...with better potential. That's the best way to wrap up and summarize this article. I mean...436 bone stock hp...all the way up to 700hp w/ somewhat simple swaps...prolly cam, heads... This is truly an amazing engine. Now, if they can only integrate VVT, cylinder deactivation, and all the other gas saving techniques, ....OMG! I mean, a race engine that gets 30mpg's???:eyebulge:

This IS truly an amazing time for the hp wars.:thumbsup:

SSFreak11 08-31-2007 01:04 PM

For a lack of words, I'm going to leave it to the smileys... :bow::burnrubber:

MerF 08-31-2007 02:44 PM

Quote:

Originally Posted by SSFreak11 (Post 21723)
For a lack of words, I'm going to leave it to the smileys... :bow::burnrubber:

Even better, I'm just goona quote you for the same effect...hehe. :thumbup:

Thanks, Tag.

Mr. Wyndham 08-31-2007 03:10 PM

Take that Toyota. hmmf...:laugh: Same mileage as your Camry with 4x the Power!!! :burnrubber:

The_Stache 08-31-2007 04:51 PM

Check it.... Manual transmission in a STOCK 08 vette LS3 gets 389 RWHP.. that estimates actual crank HP at between 430 and 450 HP..

Talk about underrated...

LS3 dyno


Edit - assuming average of 15% hp loss in powertrain (standard) thats 447 HP at the crank..

Edit 2 - also reports of 484 RWHP with headers, intake, cam and NO tune all else stock....

CamaroSpike23 09-02-2007 11:10 PM

http://forums.corvetteforum.com/show....php?t=1749988

Mr. Wyndham 09-02-2007 11:27 PM

Quote:

Originally Posted by diarmadhi (Post 21754)
Check it.... Manual transmission in a STOCK 08 vette LS3 gets 389 RWHP.. that estimates actual crank HP at between 430 and 450 HP..

Talk about underrated...

LS3 dyno

I can't believe that that thing starts right out of the hole with over 200hp...What I drive now doesn't even have a peak of 200!! :eek: And I thought it was zippy [my vehicle]...:drool:

boxmonkeyracing 09-02-2007 11:49 PM

Quote:

Originally Posted by diarmadhi (Post 21754)
Check it.... Manual transmission in a STOCK 08 vette LS3 gets 389 RWHP.. that estimates actual crank HP at between 430 and 450 HP..

Talk about underrated...

LS3 dyno


Edit - assuming average of 15% hp loss in powertrain (standard) thats 447 HP at the crank..

Edit 2 - also reports of 484 RWHP with headers, intake, cam and NO tune all else stock....

that dyno sheet was with one with exhaust. but still. some mad numbers.

CamaroSpike23 09-03-2007 12:02 AM

Quote:

Originally Posted by boxmonkeyracing (Post 21918)
that dyno sheet was with one with exhaust. but still. some mad numbers.


the other dyno sheet shows with LT's all the way (no cats)

bcannan354 09-21-2007 08:51 PM

Damn, that sounds sweet to me:thumbup: :w00t: :thumbup:


Do we think this motor (LS3) will be available the first year of production?
I am sorry if this is a dumb question but I have a hard time following all this info. I would be great if someone could put down all the things we know and then all the thing we speculate. I guess the things we know list would not be that long now would it? Oh well.

JeepinMatt 09-21-2007 09:49 PM

Kudos for typing all that out. I'm getting psyched. But is the LS3 gonna get replaced by something Gen V soon after? Not that it'd matter

CamaroSSR 09-22-2007 11:17 PM

I feel you bcan, I have trouble keeping up with all the info, busy with work 24/7 its hard to keep up. Bravo Bravo Bravo Tag!!! A real camaro Fan!

TAG UR IT 09-22-2007 11:49 PM

Thanks again guys. Any article I find that's got some good info, I'll type up. I'm pretty fast on the keyboard, so it's no problem!

Kahlis 10-25-2007 07:07 AM

So basically this is the LS3 getting dropped in the 'vette. But can we expect the same motor in our Camaro? A 436hp motor with high moddin' potential is exactly what I'm talking about!!!

Mr. Wyndham 10-25-2007 08:45 AM

Quote:

Originally Posted by Kahlis (Post 27904)
So basically this is the LS3 getting dropped in the 'vette. But can we expect the same motor in our Camaro? A 436hp motor with high moddin' potential is exactly what I'm talking about!!!

:iono:
No one knows for sure...but the chance is there. And so is the question that backs it up: What else can be put in?

DGthe3 10-25-2007 09:22 AM

The beauty of the GM small blocks is that if one can fit, they all can fit. They can literally put anything they want in there. But I know that I have read somewhere that the Camaro team "is not worried about the 425 hp 6.1L Hemi". No confirmation on that is available though

Mr. Wyndham 10-25-2007 09:57 AM

Quote:

Originally Posted by DGthe3 (Post 27916)
The beauty of the GM small blocks is that if one can fit, they all can fit. They can literally put anything they want in there. But I know that I have read somewhere that the Camaro team "is not worried about the 425 hp 6.1L Hemi". No confirmation on that is available though

I read that, too!
I also read that they plan (and will be) a class leader in performance.

TAG UR IT 10-25-2007 11:12 AM

Hasn't been confirmed yet....but, oh...it'll find it's way in there! It has to. I would be very suprised if it wasn't dropped in the 5th Gen.

Jeff 10-27-2007 12:14 AM

I honestly think a LS3 just may be dropped in the Camaro, we'll see eh ;p


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