toniotran

I did a search but didn't really find any results concluding positive/negative feedback with running a test pipe that is smaller than the exhaust. To help get a better picture of the situation, I currently have a 63mm berk test pipe and a 70mm invidia exhaust. I was wondering if it will be ok if I go that route, or should I just buy a 70mm test pipe?

iDomN8U

IMHO you're fine and won't see much in the way of hp with a 70mm, you're gradually stepping up the exhaust which is ideal

iDomN8U

If you didn't have a test pipe and want to buy one, and going with a aftermarket header, then I would say get the 70mm

negcamber

Going from smaller diameter to larger diameter is better than the other way around.

toniotran

I was pretty much assuming the same thing. Is this aka as the "bottleneck" effect? Would it effect the performance in any way when going from a smaller diameter test pipe to a larger diameter exhaust? Any thoughts or experiences...

K1LL3R 1NS1D3

you'll be fine going 60mm tp and 70mm exhaust