gixxerbill

Some guy at hot rod night was saying 390 but it's really closer to 420 isn't it? Also he said he could get me an additional 50hp with computer tune, headers and cold air for about $2000. Does that sound right or is it inflated. Also will those mods mess with traction control and/or shifting?

Would those mods void 36k or 100k warranty?

Thanks.

SK360

Dynos are tuning tools, they all read differently and can only be compared against themselves.

My car put down 408rwhp/406rwtq on a friends Dynojet.. others see higher numbers and others see lower. I could drive down the street to another one and put down 420 on it.

gixxerbill

well those things aren't very accurate then. . Did the factory release rw numbers or only crank?

robert miller

What the guy is telling you is true here. Ever dyno is diff a little plus car temp & air temp and a few other things have really a lot to do with a # from a dyno.. Robert

SK360

They're accurate against themselves for tuning purposes or swapping parts on the dyno but calibration can vary between them as well as other factors (where the weather sensors are placed for correction factors, what correction factors are used, how the graph is configured etc). And between different dyno manufacturers theres an even bigger variance for example I could very well see the C7 putting down 380-390 on a properly calibrated Mustang Dyno vs 400-420 that seems common on a DynoJet

Factory releases SAE certified crank numbers from an engine dyno.

eboggs_jkvl

GM says NPP adds 5 HP to whatever way the horsepower is measured. 460 vs 465 Crank HP from GM

Elmer

Elite275

And don't forget there will be variances based on whether the vehicle is auto or manual. As mentioned already, the dyno is just a tuning tool but the dyno queens will lead you to believe otherwise.

meyerweb

50 hp with those mods is possible, but sounds a little bit high to me. And note that a tune will give GM a reason to refuse to honor warranty claims on the engine and drivetrain if they choose to.

Ask him if he'll guarantee 50 hp or its free.

rcooper

I don't think that you'll get 50 hp but I am sure that you can kiss your warranty goodbye.
You would be better off with some headers that don't require a tune and some intake work. I have done that on a couple of previously owed Vettes and never had any trouble with the warranty work at the dealers I used. Although those dealerships were very Vette friendly.
Also note that it is 455 and 460 for the hp ratings from the factory.

gixxerbill

I know that but that is at the crank. I wanted to know the the factory put out rwhp. How much hp would a headers and cold air intake get me? Also which headers would you recommend and $$$?

eboggs_jkvl

The thread title asked " What is the rear wheel hp of the c7 with npp exhaust?"

Depending on the weather, the altitude, the system (dynojet vs mustang) being used to measure the HP, the transmission in the car, the answer is 5 HP gain of the NPP over no NPP.

Secondly, any tune you do is going to blow away your warranty on the drive train.

Is the potential of ~50 HP a satisfactory gain to negate your warranty?


Were I blowing off my warranty, I'd put a 200-300 HP gain on the darn car and be done with it.


Elmer

LuckyGuy

American Racing Headers and Halltech cold air intake. Will run you about $2800 plus installation ...but you get what you pay for

Elite275

That was my chosen path!!!

MikeyTX

I posted a thread in the tech section with the before and after hp/torque numbers. Used the same dyno for all the pulls. Used forum vendor 21st Century Muscle Cars. First set of pulls car was none stock. Second set after the aFe cai install. Third set after the ARH mid length header install. No cel with several thousand miles on the car since. And, no tune needed.

CanadianVetster

$2k is a very good price for those mods.
I think 50 rwhp is a generous estimate.

Offer to "pay per HP"

He is suggesting $2k for 50 = $40 per hp
I'd offer $50 per HP and I think you will still come out ahead.

MikeyTX

This is a link to my thread in the tech section. https://www.corvetteforum.com/forums...e-install.html

rcooper

The last one I did was a 2001 C5, added Hooker's and Vorteck intake, gained about 30 hp, also added Billy Boat mufflers. All in I had about $2500 installed. Car went from 28 mpg to 30 mpg, go figure.
Sounded great and went good. Nice combination.

4GS7

Put your car on a dyno. That's the only way to answer your question.

///ADMAN

Vetteman Jack

Hard to give a definitive answer as it seems each car can come up with slightly different numbers on any given day.