951_RS

Hmm, now I want to know what sort of pressures my exhaust is seeing.

David Floyd

Emissions test port in crossover pipe will work

TRP951

Yep thats a great spot since its already got the bung on it. Ive measured some pretty low back pressure running a #10 hotside with 3" dp and exhaust. Now I will be running a T3 0.82 housing and a slightly enlarged crossover modified to fit the GT turbo

V2Rocket

what would be an ideal number for exhaust pressure? are we hoping for a vacuum?

Rogue_Ant

No vacuum in a turbo car...
An ideal pressure would be less then 1 : <1 (intake vs exhaust).
But that won't happen without a huge turbine side (lots of lag).
Good would be 1 : 1.5
And acceptable is 1 : 2


-Rogue

pjburges

I wouldn't say there is any ideal number. Take the cat off your N/A car and go drive it around dumping at the headers. It will run like hell. Loud, but not good. With turbo cars it's somewhat of a different ballgame. Exhaust backpressure and the manipulation of it effects the torque curve of an N/A car. For a turbo car, its as mentioned above (to the limit of my knowledge).

V2Rocket

i have wondered what the 944 would sound like with a straight pipe all the way to the back of the car. i have heard it open headers, that **** is loud lol

Rogue_Ant

Too loud.

V2Rocket

maybe just a large diameter pipe, no cat, to a turbo muffler then...

V2Rocket

think those are good rule of thumb ratios for a supercharged car? only reason i ask is the lack of a big restrictor in the exhaust flow(turbine)

Rogue_Ant

No, a supercharged car will not have the same amount of backpressure to contend with. In fact, cam/exhaust selection with a supercharger is more similar to an NA car then a Turbo one.
For a mild supercharger application (yours), I suggest running the stock turbo exhaust (without a cat if possible). The stock turbo stuff is 2.5" with a straight through muffler - perfect setup for cheap.


-Rogue

V2Rocket

i wish i could lose the cat (and all the other emissions crap) but cali says every year emissions testing soo...


i will look into the turbo catback though.

CarbonRevo

Spencer- Friend had a catted 951 with no muffler. 112db's...

V2Rocket

OMG lol

Rogue_Ant

And an NA would be even louder... No turbo to help muffle the exhaust.


-Rogue