topspeed

Would i need to retune my car if i upgrade my exhaust system from stock catback to full straight 2.25 inch without cat? I have a 2.5 inch DP right now into stock cat and piping to a can muffler.

djfob

You might be running leaner but you might be able to get away with it. Hard to tell unless you acquire a wideband. When I upgraded mine I never retuned but it's only because I knew my tune was conservative.

baldur

I had to retune my Suzuki when I replaced the exhaust, it went lean as hell on the mid range.

98ctr

u might want to retune. i went verry lean when I went from 2.5 to 3" exhaust.

you will also boost a bit more since there is no more back pressure. The good thing is that you can just increase the fuel pressure regulator and you should be good. But it has to be done on a dyno or on the street with a wideband o2 sensor hooked up.

izzie

i would recommend getting it retuned as you always want optimum performance don't you - why settle for second best (don't answer that - this forums full of a load of cheap skates )

just be happy its not a two stroke bike with a new exhaust - they have to bed rejetted if you add a k&n or an exhaust ffs

topspeed

what i would like to know is if this piping setup is really that restrictive? How about if i tune with open DP?

Heres the setup
2.5--->Cat--->stock piping---slightly larger piping(2 inch?)---Straight through muffler.
It does't seem that restrictive i really don't want it to lean out either thats why i'm really concerned as i'm getting my car tuned tommorow.

djfob

stock cat and piping is very restrictive

topspeed

so would you recomend tunning open DP and then get my pipes done asap? is open DP loud?

djfob

I could only stand open dp for one day but i'm weak :P........why don't you just wait to get your exhaust done than tune.

topspeed

ohhh nooo if i wait i WILL blow my engine, i can't help boosting on my basemap as is...ohh well ---- it i'll just suck it up and pay for a retune i guess.