Honda Car Forum

Are there any drawbacks to bigger exhaust pipes?

Yes your 3" pipe can stick into my stock. And from what I know the bigger the better.

Yes. It gives it more air flow

yes, but really, you should look into the new 4" exhaust pipes. They are less restricting than the 3 inchers!Backpressure only applies to 2 Stroke engines....Some people get confused.

And now for a serious answer....yes, too large an exhaust pipe can drop your horsepower...it has to do with engine backpressure....

unless u have a turbo or a supercharger you will LOSE HP... You need backpressure for your motor to run right. My opinion would be do other stuff first. Like maybe a Cold Air intake and under drive pulleys and headers.

Even 2.5" would be too big for a stock civic. 2.25" is more the size you need, and would still accomodate furture (bolt-on)upgrades.Contrary to popular belief, you do not want ANY exhaust back pressure. People seem to think that continually increasing the size will continually decrease the back pressure. As you know(or 'should') as cross sectional area increases, the gas velocity will decrease. Having an exhaust that's too big will actually INCREASE back pressure. The gasses will slow down to a point that the piston will have to work harder to push it out of the exhaust. You need just the right velocity for any given application, so obviously if you're flowing more air, you need to increase cross sectional area to keep velocity in the ideal range(vise versa for less flow).2.5" would be more for a highly upgraded(incl. pistons/cams) NA(naturally aspirated) 4 cylinder, up to 2.2 liters. 3" would be for supercharged or turbocharged engines in that same range(up to 2.2l), again depending on how much air you're flowing("boost", for simplicity).In summary, go with 2.25"...

No. Too much air flow will kill your bottom end power (something Hondas already dont have much of). So unless you plan on adding lots of power later that will need the increased air flow dont do it.

ever heard of "too much of a good thing" ... bigger is not always better. i say go with the 2.5' ... 3' is too wide, you need some restriction to get hp.