Vetal

iTrader: (3)

My DP will be coming out of bumper, so only 3ft long... Is 4.5" diameter fine for that power level? I mean, will it allow to squeeze every bit out of TC78?

projectcam

iTrader: (12)

It is more then enough

Grr

iTrader: (2)

that one downpipe would be enough for 2 of those turbos

Vetal

iTrader: (3)

Actually while reading I decided for now to stay with conventional exhaust (all the way to the rear). I plan to expand from 3" to 3.5" right from the turbo, go all the way to the tranny cross-member and then go into existing 3" Flowmaster pipe and muffler. Does it sound like a good plan? I hope that will provide good enough spool on the street and enough power for now to go 11.5s - any faster and we have to get cage here, and I don't want to do this

boosted4life

iTrader: (4)

That is nearly exactly what I have.

Grr

iTrader: (2)

sounds good, but that flowmaster muffler will cost you a considerable amount of power, they are garbage

Sluggish

iTrader: (10)

That tc78 will make enough power to go 9s.

Johnv

I went 3" off the turbo for about 2 1/2 feet then step up to 3 1/2" for the rest of the exhaust, just a single straight through muffler at rear.

Vetal

iTrader: (3)

Heard opinion that stepping up 3->3.5" and then back 3.5->3" is not a good idea, but I can't agree with that considering all the bends that will be there before pipe will reach tranny crossmember...
Grr, that's what I have now, and it will stay for now...

Vetal

iTrader: (3)

Also I really would like to rejoin wastegate pipe into main pipe. Otherwise I won't hear what is going on in the engine when WG will be screaming on boost. But it looks so damn hard to do that... Should I still rejoin it to main exhaust somewhere, or just relax and dump it and not to try to listen to engine?

hellbents10

iTrader: (10)

That will be plenty big. We ran about 12ft of 4" off a tc76 and it was good enough to get a 5850lb truck to trap 127mph with 22" wheels.

Phil99vette

iTrader: (11)

Fireball is making 1600hp with a 4".

Vetal

iTrader: (3)

What about rejoining wastegate flow? Seems like good thing to do, but maybe I'm too obsessed with listening to the engine?

98Z28CobraKiller

iTrader: (17)

I dont understand what you are saying about "listening to the engine". It's not like an open cutout. It's just the cool whooshing sound that turbos make and it's only when you are under boost. Try it open and if you don't like it, tie it in later. The turbo does alot to quiet the exhaust down so a chambered muffler isn't neccesary. I ran mine with just a 2 foot downpipe right off the turbo and it was still quieter than my true dual 3" exhaust with Borla XR1's on my old 408. Now with the 4" magnaflow bullet, it's really quiet unless your on it and I have it exiting before the rear. If you go all the way out the back it would be even quiter.

Vetal

iTrader: (3)

When WG is dumping exhaust gases, it is just loud as hell. It is when you're on boost when harmful events happen and you should be listening for detonation, not just screamer pipe
And flow through WG is not even going through turbo...

Grr

iTrader: (2)

tie it back in, dumped wastegates are one of the worst sounding things in the automotive world. You can tie it in anywhere space permits, but i suggest using a flex joint of some sort.

Shearer

You tie the wastegate back in and you need a bigger exhaust. I have seen 35hp gains be venting the screamer pipe, car was a 2L with a 3" exhaust making near 700hp.

SPRAYED 01

iTrader: (22)

I had mine running back into the exhaust. Then i changed setups and vented it and i love it. Sounds cool.

Vetal

iTrader: (3)

Can you hear engine at all when under boost with screamer pipe?

TURBHOE

iTrader: (4)

i agree with mine open if i get into boost people beside me freak out. i have to roll up the windows if the kids are in the truck and i have to pass someone.