exhaust on a roots car.

[chunkybs]

motor is 3.8 s/c'ed. i'm used to building turbo motors where you want little to no restriction in the exhaust, mine ran open downpipe most the time. would running the downpipe on the 3.8 benefit PERFORMANCE WISE? i know it'll sound like shit but i'm talking track use. does a supercharger benefit from a open exhaust like a turbo does, or because the 3.8 has the boost before the exhaust does it need the back pressure the exhaust causes?

 

[Sean]

backpressure on a supercharged motor can cuase a myriad of problems. None of which are easily resolved and good flowing exhuast on a SC engine just like a turbo motor is very benficial to performance. Just make sure you have enough fuel to cover the engine.

motor is 3.8 s/c'ed. i'm used to building turbo motors where you want little to no restriction in the exhaust, mine ran open downpipe most the time. would running the downpipe on the 3.8 benefit PERFORMANCE WISE? i know it'll sound like shit but i'm talking track use. does a supercharger benefit from a open exhaust like a turbo does, or because the 3.8 has the boost before the exhaust does it need the back pressure the exhaust causes?

 

[chunkybs]

so would you suggest having the car tunes open DP then having it just run a little rich on the street?

 

[soap]

IMO........with an open down pipe (which I assume is open shortly after the header) you will gain a few hp but you will loose tons of torque.

You can have a good flowing exhaust (no restrictions) that will make great hp, but you do not have to go overboard or you will loose low end torque too.

--Joe

 

[Sean]

Lots of independante testing has been done over the years. Most mildly cammed roots engines actually gain significant Tq by freeing up the exhuast just beyond the collector. I would think a collector exstension 20-24 inchs would be sufficient to keep things happy.

As always YMMV

IMO........with an open down pipe (which I assume is open shortly after the header) you will gain a few hp but you will loose tons of torque.

You can have a good flowing exhaust (no restrictions) that will make great hp, but you do not have to go overboard or you will loose low end torque too.

--Joe

 

[DarkoStoj]

Lots of independante testing has been done over the years. Most mildly cammed roots engines actually gain significant Tq by freeing up the exhuast just beyond the collector. I would think a collector exstension 20-24 inchs would be sufficient to keep things happy.

As always YMMV

i have heard great things about the collector extensions, I plan to run them on my blown camaro once I get my trans I've been waiting on for a year