Sup all,

In the process of installing my 18g kit onto my b18c1. For the time being, I plan on using the strawlike downpipe( ) that come with the kit along with my current 2 1/4" exhaust piping(funds are low). However, I do plan on getting a 3" downpipe along with a 3" exhaust in the near future. My question is...if I install the 3" exhaust after tuning with the smaller exhuast.....will I have to re-tune my ride?

 

Yes because boost will come in sooner in the RPM band with the 3" downpipe and also will make more power or FREE up more power.


EDIT:Real world #s my car was tuned WITHOUT exhaust on, then later went to a dyno contest the car made 503whp 28psi through a 3" Thermal R&D exhaust, dropped exhaust and later the car made 573whp no exhaust. Also the flex pipe was only a 2.5inch that was dropped off also, so I am sure a 3" flex pipe would've been different. But with and without exhaust and or bigger downpipe is going to be a pretty good difference.

 

so is it best to get the car tuned without exhaust initially?? then u can slap on any exhaust u want and know that the car is running safely?....ofcourse ur performance will suffer by doing this but this would be a tempory thing until I can afford to go back to the dyno...

 

Get yur car tuned when you are running everything you intend to run.

With a free flowing exhaust, you will tend to run leaner somewhere in your band.