laughatrice

iTrader: (12)

I'm running an F1A at about 16psi on a LS1 418. 800rwhp (dynojet, m6, moser 9") roughly nothing exact as I'm still dialing in the boost no track times yet. This is slightly low I would have expected 850 plus with the m6 but it's not done yet. EPP blower cam and patriot heads. Big FMIC inlet temps are reasonable 110-130 WOT no meth.

All tuning has been with the cut out open which is right behind the y-pipe. Here's the rest of the exhaust.

Thunder racing 1 7\8" long tube headers ceramic coated
mufflex 3" y-pipe w/4" collector
magnaflow catback exhaust system
3" QTP electric cut out

So how restrictive is my exhaust it seems it would be causing some problems at these power level. I'm about to swap the tranny and it's a good time to fix the exhaust.

Any ideas?

'Trust'

iTrader: (24)

I went from 773RWHP with true duals to 754RWHP with a Kooks ORY, and a Magnaflow (no cutout). I went to a custom ORY with dual cutouts and with them closed, when the car made 808RWHP open, it made 784RWHP with them closed and the custom ORY (which consists of mandrel 3" to a 3" to 3.5" Flowmaster merge to the Manaflow Catback. With the cutout open, I'd be surprised if you gained more than 15RWHP going to a TD or 2 cutout system.

I know your blower is bigger than mine and your M6 to my A4 isn't the best comparison, but I'm making right above 800RWHP with a dual cutout setup and it is MUCH nicer to drive around on when they are closed. If you do anything, I'd ditch the single cutout and add 2 to the ORY, duals drone and drive me nuts.

cablebandit

iTrader: (37)

im in the same boat and about to see if a cutout right before the over the axle pipe will help. i already have one in my 3.5" intermediate pipe but its only a 3" cutout. my catback is a magnaflow as well. people always comment aboiut how quiet it is with the cutout open so maybe i need more exhaust

Pro Stock John

iTrader: (34)

Dual cutouts for a max effort street car sound good to me. I've had several sets of duals and they've all been pretty loud.

4SFEDZ

iTrader: (6)

i dont think the EXTRA cut out would help any!

laughatrice

iTrader: (12)

I'm not to concerned about sound it's not really a street car any more just putting a built TH400 in it with an insane stall. Although I do like being able to shut it up so I can talk to my passenger.

I just think the y-pipe is restrictive and an xpipe that dumps before the axle would be the way to go.

Thanks for those numbers your car is making almost the same power as mine gives me an idea what different exhaust might do.

'Trust'

iTrader: (24)

If it's not a street car, I would do true duals 3" straight back, personally I'd have no H/X but you could, to either bullets or Magnaflow Race Mufflers (my old setup).

2001WS6Vert

Dual cutouts open netted me 10 rwhp/15rwtq, I have a 4" Mufflex with Spintech muffler

laughatrice

iTrader: (12)

Thanks it sounds like I'm looking at 10 or 15rwhp if I dual it out. I'm going to leave it for now. When I start doing weight reduction I'll probably drop the catback and dump them at the axle.