2.4 inch vs 3 inch exhuast dyno

[civickid81290]

I was trying to find some info online about 2.5 vs 3 inch exhuast for b18c turbo and i couldnt really find any good dyno sheets online, so I though I would put mine up.

Setup:

B18c1 block
B16a head
100 % stock
skunk 2 intake manifold
t3 t4 57 trim @ 11 psi
3 inch downpipe

Before: 2.4 inch exhaust

After: Full 3 inch exhuast

 

[civic92si]

i dono but i think 3inch is better for turbo apps...

 

[xxsenceo89x]

If you wrap the entire exhaust youll notice a difference. Once the exhaust air starts to cool down in the pipe it expands making it harder for the motor to push it out. You want the exhaust to stay hot so everything keeps moving.

 

[Billy.]

i think you mean the air contracts. when things cool they contract into a more dense mass. but yes, the idea is correct, the cooler denser air creates back pressure and turbos don't care for back pressure. but the volumetric flow rate of a 3" pipe is drastically improved over 2.4" given the air is the same temp so yes, upgrading to 3" should improve your power and turbo response

 

[Autoworks]

good work.
Larger exhaust on a turbo car will be beneficial in almost every case.

 

[DarkCreep]

I cant see the dyno sheet for the 2.4" exhaust, and was the car retuned for the 3" or slapped on and dyno'd?

 

[got traction]

I cant see the dyno sheet for the 2.4" exhaust, and was the car retuned for the 3" or slapped on and dyno'd?

there are 2 pulls on the dyno sheet.

 

[DarkCreep]

Darketh Creepeth is a retard.

But I still wanna know if the car was retuned, that be crazy if it wasnt.

 

[Billy.]

5 dyno pulls between base line and final run.. so i'm thinking it was tweaked a little to clean up the map

but yea 40whp increase is a big difference. i know i lost about 25whp when i went from open downpipe to full exhaust on my setup, so i believe 2.4" going to 3" could make those kinds of increases

 

[DarkCreep]

brb getting 5" down pipe.

 

[somejaykid]

brb getting 5" down pipe.

 

[civickid81290]

Yes the car was retuned with the 3 inch before the dyno