I came across this article from turbo magazine.
http://www.turbomagazine.com/t...aust/



This is the gain from switching to a 3" exhaust. Could it be attributed to the fuel management?


let me know what you think

 

Hmmmm.... interesting....

You would think that going from 2.25 to 3 inches would really free up the flow from the turbo...

I'm thinking maybe 2.25 is fine for the less than 200 hp that the car was making. I would think that you would be better off with a 3 inch if you are wanting 200+...

Plus, they only ran the test at 7psi and a FMU... ( I don't know why you would only run 7psi on a fully built motor!)

I bet if they did the test at 14psi the increase would be much much more significant with a 3 inch exhaust...

 

Interesting, i think its a good start.

I would love to see someone test several different increments of piping, specifically 2.5" to 3" to 4".

I'm currently trying to decide whether a 4" DP is going to be more trouble than its worth as compared to a 3".

for other input

 

I expected a bigger gain going from 2.25" to 3" on a turbo car.

Is that an EGT probe on that guys intercooler piping?

 

I would have to agree, if the boost was tunred up and it was creating a lot more flow then I think the power increase would be a lot noticable though the increase they showed was not bad considering the car, motor, and turbo they were using.

 

I'll have my dyno up soon of 60mm to 3" turboback (and a manifold change - drag to IP).

No peak difference, 5-15whp and wtq gain from 4-6500. There were some small differences though...some maintenance items, and my downpipe sitting on one of my charge pipes. Ill go back soon with those fixed and post the graph.