Flowmasters

[Aurora40]

Originally Posted by Hib Halverson

snip

The Flowmaster catback uses 2.5" pipe and stock is 2.75, however, the decrease in restriction with the Flowmaster cat-back makes using it a net gain.

The Flowmaster resonator, is single in and two out. We modified it to accept a larger inlet.

Right, I mean an unmodified single inlet. I assumed it was bigger than 2.5". Is that the size where the single inlet hits the resonator?

[Hib Halverson]

Darn!
16hp is pretty impressive from just an exhaust.

Were the two pulls made on the same day. If not, is this data SAE-corrected or standard-corrected?

[Aurora40]

Originally Posted by Hib Halverson

Darn!
16hp is pretty impressive from just an exhaust.

I believe that's 26hp.

[blackjack]

i originally installed a borla cat-back system,2 1/2"...then i heard about the restrictions inside the pipes,apparently there to cut down on interior resonnance...so i decided to make my owm,with help from some friends..we installed 2 1/2" pipes from the cats,removed the resonator and put an x pipe in its place,and installed back the borla mufflers...we did not dynoed the car before or after,but the gain in power was really noticeable...the sound is deep and mellow,and i didnt notice any resonnance inside,at any rpm
blackjack
91-1735
4:10 , lucas injectors,fidanza flywheel(noisy)

[Hib Halverson]

Originally Posted by Aurora40

I believe that's 26hp.

My bad on that. Can't add late at night.

I was wondering if those two dyno pulls were done on the same day? If not, can you say if the data is either SAE-corrected or standard-corrected?

[Aurora40]

It's not my dyno run, though the labels for the Y-axis' both say "SAE corrected" on them.

[Hib Halverson]

Originally Posted by Aurora40

It's not my dyno run, though the labels for the Y-axis' both say "SAE corrected" on them.

26 hp at the wheels, SAE-corrected, from a stock engine after just an exhaust change is absolutely incredible.

[Hib Halverson]

jonszr1 is posting to a number of other threads today and I had not read them all when I posted above. In reading a few of them a few minutes ago, as I understand it, the car has headers and not cats. That makes a *huge* difference. Now that I know that, I can see 409 at the wheels.

I'll add that headers and no cats hardly makes the engine "stock"

The AutoMasters Street Skinner in my #140 makes 412 at the wheels from a 475-500hp engine which uses stock manifolds and cats. Where I to switch to headers, with appropriate recal., I'd easily make 425 and 430 at the wheels might be possible.

Also, there's a lot of discussion in recent years of replacing any resonator in the system with an "X-pipe". I've thought about doing that too.

I've thought about revising the article on the CAC about my exhaust system by adding a set of Dawson Racing Headers, cats off a new Z06 and an Z-pipe then going back to WesTech's dyno for more tests.

[jonszr1]

hib ' I didn't mean totally stk . as an old ahra drag racer headers was stk sorry. my car has ported inj housings jeal headers dyno tech hi-flowcats ccomplete flowmasters 21/2 in exhaust. and a custom prom . the best thing is no knock event at 5200. Corey henderson did the porting and the tune as well as installed 410 gears. his ph 210-867-6286. he would have the answers on nthe sae figure. i remember reading your modsto the flow master and really wanted to hit 420 rwhp a personal goal. i really just wanted to share what a fine job that young man did. i have been in hotrodding 35yrs and as we all know it can be hard to find a relly good shop that does what they say and giving a good monitary a plus. I wasn't bragging and sorry if any one felt that way, notmy intention at all. Corey is just getting ready to open up a real business instead of his back yard and thought to share my experience to give the zr1 guys another choice if they so desired. I wanted to pick your brain about that xpipe in a muf to see what your thoughts were. this old guy would like to be a little on the sleeper side .loud is for young folk Imho. if you have suggestion on how to improve my ex tract i would be very thankfull. Maybe i can get corey to post the dyno sheets . alli have is a lapp top. sorry

[Hib Halverson]

Originally Posted by jonszr1

(snip) i have been in hotrodding 35yrs and as we all know it can be hard to find a relly good shop that does what they say and giving a good monitary a plus.

Hard to find a really good shop?

You said a mouthfull there!!!