Tally TransAm

iTrader: (17)

Car is stock shortblock, TC76, stock 317's with patriot duals, ls6 cam, etc etc. Runs like a champ. ZERO complaints

Dynoed in oct when i finished the setup. 9#'s of boost and 17 degrees of timing. roughly 75 degrees ambient. did 542hp/555tlbs.

fast forward to setup today. 11#'s of boost, 15 degrees of timing. and added a muffler to the once open downpipe because i didnt like the sound at idle. not gonna lie, the muffler is substantially larger than i thought and i didnt really like the size but i already bought it so whatever. roughly 105 degrees ambient in the shop. 523hp/550ftlbs.





i figure some of the difference is heat but i figured id be 560-570 with the added boost and minimal drop in timing. could the muffler really be killing that much? its coming off tonight just in case but this is more curiosity talking

transammiller

iTrader: (21)

cutout? bro i have a TC76 front mount TA as well and when the cutout is closed it runs like a stock car. but when i open it, it goes into INSTASPOOL mode! i have a 3" downpipe that goes to a cutout under the passenger seat then into a Hooker Aerochamber catback. i will get track times at 11 psi open and closed. there is a huge difference in power. you drove it open downpipe? your poor ears.

Tally TransAm

iTrader: (17)

**** my ears, theres no way im losing 20+hp for a little but of noise resolution. that ****** is coming off tomorrow

camaroturbo

I just went to the dyno and picked up 100rwhp by taking off my bullit muffler it was night and day open DP for now on

kaotic_ws6

im taking my bullet muffler off in the morning as well, i hope i see a diff

sbcgenII

iTrader: (1)

so you went from 75 degrees to 105 and pulled 2 degrees of timing and installed a muffler and lost 20hp and only 5lbs of tq? And only added 2 psi of boost? I do think its much of a problem for you.

transammiller

iTrader: (21)

i went out today and tried my 2 step with the cutout open and closed. with my 2step set to 3700 rpm and ambient temp around 103 degrees, it built 103 kpa WOT with the cutout closed. with it open it made 126 kpa and got the cops called on me for a noise violation.

Tally TransAm

iTrader: (17)

heres the graph

a/f was right around the 10.9 range across the board. power falls off a little earlier than i would like. think i need to add a little timing up top

venom ws7

iTrader: (13)

Bigger *** muffler , Less timing and very hotter weather sounds about right.

Was the old runs with the same A/F Ratio?

I know your running very safe A/F Ratio for the stock short block but I really think you can get more power with 11.2 - 11.5 A/F Ratio..






Keep us posted.

stevieturbo

So you didnt dyno before and after on the same day, same dyno, same conditions ??

The difference in results dont mean **** then IMO

Tally TransAm

iTrader: (17)

i think that was stated in the first post

stopping a local dyno day to pull my car off the dyno to pull off my exhaust isnt really an option.

stevieturbo

What is the makeup of the silencer ?

Chambered ? straight through ? etc

Photochop

iTrader: (74)

I think its more conditions and just a different day really. That muffler doesnt look too complicated or restrictive. You might try a 3" magnaflow straight thru or a dynomax bullet to keep the sound down some.

kaotic_ws6

i noticed you have your exhaust wrapped... how does that help? is it somethin i should do