exhaust pipping size Options

[maikl]

i have 70' custom exhaust pipping for my beams engine and i've started to wonder if they are too big for my set-up.... ofkorse my car wont stay as it is the aftermarket parts and mods will continues aslong i have my car... do you thing tha an 2,5 inch pipping will better?

[recneps]

the exhaust piping is dependent on a lot of things.

a larger piping size and or more free flowing exhaust will push your peak torque up in RPMs, assuming youve got the cams for it. a smaller and less free flowing exhaust will push your torque band down in the RPMs.

if your peak torque is higher in the RPMs its going to result in more horsepower, this relationship is easy to see with the formula for horsepower.

hp = (peak torque * the rpm you got it at) / 5252

i think 5252 is right.

its up to you if you want nice topend and more horsepower but not so hot bottom end stay 70mm if you want a torque band you can play billards on i would go with something smaller.

so..... the thing now is: will it worth the money and time to change my pippings from 70 to 65? the gain that is.... will it effect the whp of the car? the torque? and if yes in theory how much gain will i get?

you might lose 1-2whp on the dyno by pushing your tq down in the rpm range.

but really that could be dyno error, its not going to be noticible changing 5mm.