http://forums.corvetteforum.com/show....php?t=1759223

The car is not even broken in yet and is making over 395 HP. I want an LS3.

 

Simply awesome.

 

It's only about 15 horsepower more than the LS2.

The LS2 had a bigger jump (about 50 horses) over the LS1.

Any horsepower gain is nice and always welcome, but 15 extra horsepower when we're already talking about 405 horsepower isn't exactly worth stopping the presses over.

Wake me when we start talking about 50 horsepower gains at the 400 horse level.

 

There have been LS2s dynoing 380-382 in stock form?

 

Holden actually rates their LS2 cars at 412HP

 

So I wonder what the purpose of moving to the LS3 was? I'm sure it wasn't that cheap to make the transition - so all for 15 extra horsepower (real world)?

I've heard that the LS3 makes a better platform for forced induction, which is why it will be the basis for the LS9, rather than the LS7 being used as the basis...

 

No. The LS2 Vettes are rated at 400HP and are closer to 330rwhp auto and 350rwhp manual range as far as I know. The LS3s are dynoing 40rwhp higher and are only rated 30HP higher at the crank (or 36 with the optional exhaust). It is safe to say that the LS3 is significantly more powerful than the LS2.

The LS3 has more displacement and it has better heads than the LS2. The LS3's heads are based on the ones in the LS7. Why it is a better platform for FI than the LS7 is not completely clear to me.

 

I've never heard of an LS2 dynoing much if any better than 360rwhp. ~350 seems more common. A lot of LS2 GTOs were lucky to hit 335, which probably has to do with the crap tune the GTO LS2 got.

 

Cylinder wall thickness. The LS7 is at the limit, from what I understand. The LS3, being of smaller displacement, has thicker cylinder walls due to it having a smaller bore. That's why the supercharged Northstars in the Caddy STS-V and XLR-V are 4.4 liters instead of the naturally-aspirated version's 4.6 liters - they wanted thicker cylinder walls to stand up to the boost.

 

My LS2 GTO put down 355RWHP/350RWTQ with replacement mufflers...I'd say that is a slightly larger jump to 395RWHP

Awesome numbers....this motor is something special.

 

Ah, Guy, these are rear wheel horsepower numbers. The LS2 makes about 400 at the fly wheel. The LS3 is evidently making 370-390-ish at the rear wheels (depending on auto vs. manual).

That not a trivial jump. The difference is 28-36 hp on paper. Perhaps it is a bit more in the real world... Either way, it is more than a 15 hp difference.

 

GM Powertrain

 

That torque curve looks sinister!!!

Btw, LS2 does not have the the LS3's L92 heads (similar to LS7) nor the L76 manifold, which have proven to produce big horsepower gains.

We're not just talking a mere 200cc increase in displacement here by virtue of the bigger bores. The engine is in a different league (potentially) to the LS2.

 

You are right, I forgot that they basically maxed out the bore.

 

Wow! Did everyone catch the fact that this car has 6 (six) miles on it and was dynoed on a 90 degree day? Holy ****!

Is it possible that a broken-in LS3 could dyno the same number at the rear wheels as the LS2's flywheel horsepower?