4inch vs 5inch exhaust

[KTMotoRider1]

Is there a big power difference between a 4 and 5 inch system? it seems to me that there wouldnt be because your bottle necking the exhaust flow through a 4inch downpipe. what are your thoughts???

[smotrs]

As I understand it, no. It's mainly a deeper sounding exhaust then the 4in but the power stays the same.

[SANDSAILOR]

Not sure on power but 5" is louder. and a larger 4" down pipe makes it louder as well.

[dieselbrat]

As far as I know there is no difference, again sounds better then 4". I was told once that u loose a little power with the 5". I don't know if thats true or not.

[D3VST8R96GT]

i have never seen a dyno sheet comparison....i seriously DOUBT you lose any power ...

[08stroker250]

There should be no power loss, and really no power gain. It will move more air post turbo, have a deeper and slightly louder exhaust note, and it will MAYBE lower EGT's at WOT and lower them quicker at idle.

[powerstroker67]

THere is little difference in performance between a 4" and 5" system. As noted in KTM rider's post, the downpipe IS the restriction. The stock downpipe on these trucks is really closer to 3" id, what you are looking at on the outside dia at about 4" is the outer wall of a double wall pipe. While a 5" exhasut will give a slightly deeper sound, the downpipe is where the restriction is.