Gripenfelter

GMHTP says that GM never re-certified the GS's LS3 and that on their dyno it put down 415 rwhp.

Anyone have the complete specs on it? Curious to know why it makes so much more power than the LS3 in the regular Vette.

Looking to build a similar LS3 for my Camaro.

rod442

pretty sure its the same motor. nowhere does the GS package talk about a motor upgrade. Guessing its like almost all ls motors, they are a bit underrated; OR its a "happy" dyno.

Gripenfelter

Well no actually they said the GS motor is different. Not only does it have the dry sump oiling system, it's also handbuilt. I'm guessing there are other changes as well.

rod442

got a link? pretty sure the C6 GS's dont have a handbuilt motor. My dad has one. EDIT, he has a convertible.

OK, only the coupe w a manual have the dry sump - handbuilt motors.

I read about that car now. it may have showed those numbers on the dyno, but at the track it only ran 12.8@112. some of that can be driver; but it sure isn't trapping like a true 400+ rwhp vette.

and FWIW, in the trouble and costs of getting all the parts to make a dry sump GS motor (pan, long nose crank, pump etc); you could build a regular LS3 with a cam that would make more power. maybe even build a stroker 6.2 for the same money.

SSCamaro99_3

As far as I know it is just the dry sump system. They may have a dual mode exhaust as an option.

Edit. Forged crank. May be a little lighter than the cast unit freeing up some power.

Gripenfelter

I'm sure there are more differences. They just don't know what. Latest GMHTP magazine.

415 rwhp is a huge jump from what the normal LS3s put out at 375-385 rwhp. A lighter crank is not going to give you 30 rwhp.

The car ran 12.8 because of poor track conditions. His 60 foot was 2.2 which means if he can get a decent hook it would be a very low 12 or high 11.

SSCamaro99_3

Nothing I have read says there are any cam or head differences. Could be in the tune. I do not know how much the dry sump may clean up on windage losses.

rod442

I agree with the et being poor due to 60', but 112 traps are still crappy for 400+rwhp. UNLESS it was getting lots of wheelspin on the 1-2 shift or even the 2-3. 400+rwhp should = around 120mph traps in a 33-3400# car. period. I'd hope that driver error isn't killing 7+mph.

I still say its not making any more power than the rest of em (ls3's). Happy dyno. After all, they weigh 3375 which is close to what a 4th gen f-body weighs (3450ish). and they run 112mph with 330rwhp. till it performs like a 400rwhp car, it aint making the power.