Rayboy1

Guy's,
How much horsepower will I really gain by adding long tube headers to my stock 04 Z06?

falcon5619

About 20-25rwhp.

Blue Blood

On the dyno, after a tune I got 33hp at the wheels. From 356 to 389.

Higgs Boson

I got 40 to the wheels from a tuned car to a tuned/long tube.

fej

35rwhp for me in an 01z, which was tuned a little more aggresively from the factory than the 02-04 was which has a bigger cam. I only got about 9 more rwhp from the tune, and Robert @ advanced is the man

Fej

JerryX

Is this with cats or without?

falcon5619

The tune accounts for about 10-15hp by altering the Power Enrichment AFR and timing.

Higgs Boson

not if the car was already tuned before installing the headers, as mine was.

also, mine was with high flow cats.

Millenium Z06

I believe his point is that un-tuned, your car or any car with LT's would have about 10-15less rwhp than a tuned car, which I agree.

I made 382rwhp (stock ranges from 349-360rwhp) with LG Pros and RT cats untuned. I expect about 10-12 more rwhp once I get a tune.

Higgs Boson

I put down 325 stock.

BCBZ06

I'm getting ready to add some LG's myself and find out. The car had several mods when I purchased it last year and I can't wait to see where I am with HP. I'm hoping for just under 400rwhp.

falcon5619

Is you car an 01 Z06? Maybe the elimination of the pup converter enabled you to get a higher than average gains from the headers alone. Also, depending how much you leaned out your AFR and timing could affect the gains a bit. Temperature, humidity, etc. Lots of variables,. Very nice gain though.

Higgs Boson

yes it is an 01 and you are right about your theory on the extra exhaust restriction. factory af ratio was 10.5:1 however, the car was tuned before the headers and retuned after the headers. no gain from the tune.

falcon5619

Yeah, my 02 Z06 was set to 11.5-11.9 AFR (factory) in power enrichment mode, I bumped it to 12.5.