I just purchased a C6 Z51 (due in August) and would like to increase the HP to approx 450. I'm considering intake and exhaust modifications but wondered if a chip would hurt the longevity of the car. Any thoughts?

 

What you would get is a programmer, and program the chip thats in there now.

 

Ok thanks. As I'm looking through these posts, I don't understand why some of the C6 Dyno's are closer to 350 then 400. Any idea why? IS GM advertising the HP at the crank and NOT RWHP!

 

Correct - GM lists rated HP @ the crank, not RWHP

 

What can I get if I reprogram the chip without hurting the motor?

 

Most if not All car manufacturers advertise HP based on the crank not rear wheels, GM is no exception.

 

That's fair but with the TransAm they advertised RWHP. Oh well, I'm still pleased with the purchase but feel dumb for not knowing the HP stats better.

Rick

 

Changing chips was old tech. The newer engine management computers use NVRAM. You simply write new maps into memory with a laptop and the proper software. That software isn't quite at release status for the LS2 yet (it uses a different computer than last year's LS1), though beta copies are beginning to circulate. The goodness of the tune depends on who is doing the tuning. It is quite possible to really screw things up.

Chevy had to get the 400 hp for this engine from somewhere, and that somewhere is basically where hotrodders have been getting it, by using pieces that give the engine good flow, and by tweaking the computer. So you're not going to get a lot more by following down that road, the factory has already traveled it.

The FAST manifold has shown power gains on racing versions of the LS2, but you really need to have done heads and cam to take advantage of the extra flow capability of that manifold. Changing the airbox and air filter won't do much for you, the stock air cleaner is not the primary flow restriction in this car. In fact, on the dyno, removing the airbox and filter entirely doesn't produce a measurable power gain, showing that the stock pieces are not limiting air flow.

Headers will make a difference. Good long tube headers show clear performance gains on the LS2, but require relocating the cats which violates the Clean Air Act. Catbacks don't make any significant difference. The stock catback flows well. About the only reason to change the exhaust is to make more noise.

If you're looking for at least 50 hp, you need to think about at least changing the cam, or installing a nitrous system.

Now with respect to longevity and driveability, nearly anything you do to produce more power will put more strain on the engine and drivetrain, so longevity and reliability will suffer. If you get somewhat radical with flow improvements, driveability will suffer too. In other words, there is no free lunch.

 

They did? No kidding.

 

If your talking crank power then headers and on back with steeper rockers and tuning will get you there. This would likely be the most cost effective outside of forced induction or nitrous which can be relatively inexpensive but have there own issues.

 

Hmm. My 99 WS6 was advertised as 320 at the crank, and previous year models were 305 at the crank if I remember right. I don't think the manufacturer will do a rating at the rear wheels unless they want to break that number down between a AT and MT separately.

 

nope. one of my older brother's had a TA... and the advertised HP was at the crank..not at the rear wheels.

 

Ok, thanks for all the feedback. As far as the TA, I have one in my garage with the DYNO report in the glovebox. After 148K miles I'm still producing 315 and the rear wheels. I only used free mods no engine work. I did replace the exhaust but other then that, just tuning....no chip.

One of the thngs I was looking for on this site was a list of suggested modifications such as MAF, exhaust, wires, etc. I believe you guys are correct, if GM did a good job, we shouldn't be able to improve the HP very much without mechanical changes such as cams. etc. Thanks again.


Rick

 

This post is so good it should be added to the FAQ. Thank you for taking the time to write this down.

 

Yes .. thank you very much ... you saved me some money .. I will only do the exhaust for the sound effects and leave the rest until the warranty is out ... and I am more solvent hehe

 

Hey, very nice piece. I'm a Ford guy and this is my First Corvette. So what is the primary flow restriction on our car ????

 

Well not quite intentionally...they rated the cars lower than they actually were because they didn't want to offend the Corvette guys ...it just turned out that the cars were typically dynoing at the wheels right around what they were rated at at the crank which was also right about what the C5s were dynoing as well.
Not a coincidence though, they have the same exact engine (other than the 'throttle by wire' and slight air intake/exhaust manifold/exhaust differences) and nearly identical transmissions.



WS6s, Firehawks and SSs were rated higher (ram air hoods/air boxes) than the base Trans Ams, Formulas and Z28s but they all dyno'd roughly the same numbers (manual to manual and auto to auto that is). 320 from '98-'00 and later 325 in '01/'02...the base cars were 305 and later upped to 310 but again these were just ratings for they all dyno'd around 290-315 at the wheels just like C5s.

 

Well not quite intentionally...they rated the cars lower than they actually were because they didn't want to offend the Corvette guys ...it just turned out that the cars were typically dynoing at the wheels right around what they were rated at at the crank which was also right about what the C5s were dynoing as well.
Not a coincidence though, they have the same exact engine (other than the 'throttle by wire' and slight air intake/exhaust manifold/exhaust differences) and nearly identical transmissions.



WS6s, Firehawks and SSs were rated higher (ram air hoods/air boxes) than the base Trans Ams, Formulas and Z28s but they all dyno'd roughly the same numbers (manual to manual and auto to auto that is). 320 from '98-'00 and later 325 in '01/'02...the base cars were 305 and later upped to 310 but again these were just ratings for they all dyno'd around 290-315 at the wheels just like C5s.

 

The stock exhaust manifolds and cats. Next in line would be cam timing and lift. Head porting would follow, then the intake manifold. (The latter two might swap respective positions on the list, it is a close thing between them.)

 

There had better be a difference in hp and tq between measuring at the crank and the rear wheels otherwise the end of the world has happened (ie. we just started violating the known laws of physics)...think 12 - 15% loss thru a manual drivetrain...more with an automatic...