Just bought a 4-2-1 jg header for my b16. Here is the question I have. I have a bone stock b16 with intake and I plan on slapping this header on it but the jg header was modified and has a 3 inch outlet after the 2 pipes become one for about 3 feet. Can this damage my motor? Should I have them modify it to a 2.5 outlet? Can I modified the 3 inch outlet after the 3 feet back to a 2.5 outlet so that I don't undo the beautiful weld job they did? Feed back please asap.

 

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just run a 3 inch exhaust?

or sell it and get what you want?

definitely NOT going to damage your engine in ANY way...

 

Anything past the merge is restriction basically.. You'll be fine, you wont have "optimal" low end, but it will make more power.

 

So ur saying that with the bigger outlet ill have more top end hp but less low end? And should I run a 3 inch exhause or smaller?

 

A bone stock b16 will see gains with a 3'' exhaust, how much? That number is uncertain...search alittle bit, if the b16 is going to be stock, i'd go with a 2.5'' exhaust system behind the collector. Your motor isn't creating enough velocity flow to take advantage of a bigger pipe diameter, thats why on the low rpms, the car might not have "that low end".. then again, when has a b16 had low end LOL.

You'll be fine.