hello,

my evo 8 is tuned on 3.5inch exhust which was custom made but I really heavy 28kgs

mods are fully built engine, built head with s2 cams, fp red ss on 33 psi of boost making 625whp on mustang dyno with e85... ecu is link g4+

my down pipe is 3 inch mated to a 3.5 inch pipe using a reducer and then to a kakimoto muffler.

question is if i go too a total 3 inch titinum exhust instead of my 3.5inch exhust will that effect my tune/afr or boost?

thanks

 

no one? 😬

 

Oh, absolutely will affect the tune IMO. May not be a huge issue, but for sure the change in pipe diameter will affect engine exhaust flow

Should have a brush up tune to make sure

 

damit i was afraid of that... oh well ill keep saving up for a titinum 3.5 inch exhaust and replace my heavy ss exhaust.

 

Hey, dont make the decision just based on my comment. Let me get my lead guy to comment @Biggiesacks

 

I think it's safe to set your expectation that any significant change to the exhaust will require some kind of work on the tune to maximize the setup.

These things are pretty sensitive to exhaust, AFR and WGDC are usually effected.

 

understood but will it also make a difference if i go different brand of exhust or metrial same size?

 

The geometry of the exhaust comes in to play too.

I don't have experience with this, but I wouldn't be surprised if material properties also factored in. The better the material can absorb and shed heat the better for the turbo.

 

^^^Well said

An experienced tuner probably knows what the percentage difference is allowed w/ intake & exhaust flow that will not negatively affect the tune.

As an example, maybe +/-3% (or some value) maybe allowed w/out drastically affecting AFR's & such?

Anyway, after all these years, I think we know that any change in intake or exhaust affects the tune