Hey guys,
well I am just starting to get into the modding process with the z. My first couple mods will be catback and test pipes followed by a spacer and popcharger. My only question is if I should find 2.5'' ID test pipes or 2.25''? Will I see any noticable gain in 2.5? And if so what company manufactures these pipes (preferably resonated). Also I am wanting to go with the borla true dual catback...so what will be a good compliment to that. Thanks,

Adam

 

For an NA car on the dyno, there is very little difference between the 2.5 and 2.25" test pipes.

Since you will be going with a Borla exhaust, which is 2.25" piping, use the 2.25" test pipes to avoid any sudden contractions in the exhaust flow.

Tony

 

Exhaust volume and velocity, and the resulting dyno charts, will be different. Not necessarily better or worse but different.