[randy]

Does it make any difference what size downpipe you have 3" vs a 4" downpipe? Is there any performance difference?
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[Slowpoke]

I also want to know this...

Performance and sound wise...

 

[randy]

Someone out there to help us? As I am planning to make a custom downpipe from the turbo manifold.

 

[Craig King]

i have a 3" dp...... i wasn't aware of 4" dp's....... I'm interested in this now too

 

[Slowpoke]

For the love of God, please somebody answer us!!!

 

[Jade Supra]

I am not aware of a 4" downpipe for the stock turbos, but I know of 3 1/2" ones. The 3 1/2" dp has clearance issues under the car. It hangs pretty low. I can't imagine what a 4" would be hitting. Probably every speed bump in parking lots. Especially if your car is lowered. Hope this helps.

 

[randy]

We want info on performance? Is there a H.P gain from a 3" to a 4" downpipe and also is there a problem with not having enough back pressure ? What happens then? Also im sure we can fabricate additional clamps to keep the downpipe a little higher to gain more clearance. Afterall we are talking of just an inch.
:bthumb:

 

[Lagtime]

A 3" DP will flow all you need for a car still on stock turbos, the 4" pipe would be a waste of time and money.

Also, there is no such thing as too little backpressure on a turbo car.

Just buy one of the 3" mandrel bent DP's and move on.

 

[pwpanas]

A 3" DP will flow all you need for a car still on stock turbos, the 4" pipe would be a waste of time and money.

Also, there is no such thing as too little backpressure on a turbo car.

Just buy one of the 3" mandrel bent DP's and move on.

Fwiw, I agree 100%. Last year at Tx2K1, I put down 685rwhp with a 3" dp.