Was wondering if someone could give me an estimate on horsepower gains on my new exhaust I will be putting in. My car is an all stock L69 with the original L69 exhaust. It dynoed at 187 HP and 220 Lb/Ft Torque. Stock specs were 190 HP and 240 Lb/Ft Torque. Dynoed pretty decent for a 22 year old car. My new exhaust consists of the Hooker 2055's and y-pipe, Catco High Flow cat 9118, 3 inch dynomax i-pipes and a 3 inch chambered muffler in stock location. Turndown after the muffler. Just curious how much, if any, horsepower gains I would recieve from my setup. I am going to get the car dynoed after I do it, but I just want to see some figures before hand. Thanks a lot!

My guess 20 to 25 HP.

wow, you dyno-ed very closed to the stock HP #, would that be RWHP though?

I'm excited to hear a real world dyno result of exhaust work. My guess is also ~25HP.

What do you mean by that? Is it not RWHP? It was on a Dynojet if that helps at all.

All dyno's correct the actual measurement to a standardized one using a factor derived from athmospheric pressure, temperature, and humidity. This is in order to be able to compare readings between different places and conditions. A rear wheel dyno such as the DynoJet also often corrects the actual measured rwhp, using a guesstimate of the drivetrain losses, to present an approximation of the crankshaft horsepower. Any correction factors used I expect should be on the dyno slip I hope you received.

I put on 2055's and Y pipe. Left on the stock catback pipeing with an 80 series muffler. I gained 2 mph in the 1/4 mile.

If that is RWHP, that is very impressive for a stock 22 yr old L69

I never thought to ask the guy who was running the dyno to print out my sheet. I know, probably a bad idea, but it was my first time ever dynoing a car and it was at a dyno day type event for a car club im in. Those numbers I gave are what he told me my car was making. So, are they right or will I never know without the actual sheet?

I know he has a file on the dyno's computer with my pulls, so I will see if he can email them to me to post here. Thanks for the help guys!

i put eldelbrock TES headers on my 305 tpi and i noticed a difference but i highly doubt it was 20-25 HP. i would guess more around 12..

That wouldnt be AZFBA would it??

Hes not just doing headers, hes doing an entire header-back.

I say 25 too.

o ok i thought he said just headers. id say 25 is pretty close then. my 305 tpi ran a 15.3 @88 with just a flowmaster catback and stock manifolds and a hypertech chip.

Ehc, hypertech. I would think you could tap high 14's though, no?

He probably would if he took that Hypercrap chip out of there. LOL! (just messin around)

what does ehc mean?

o know though, i have heard people complain about the hypertech chips but i paid like 30 bucks for mine b/c i got it used off this website i think. but people complain b/c it lowers your mpg and doesnt give much performance. i no longer have a computer so it doesnt matter.

btw when i ran that 15.3 i had a cracked distributor and the car had sat for 3 years and i didnt do a tune up on it so it could have probably run a high 14 with little thinks like timing and a tune up.

Yeah I am a member there. Went on the Jerome cruise earlier this year, and will be at the dyno day November 14th to see what shes puttin down now. Whats your name on AZFBA?

"84L69TA"