golf-mk3

i got a full 3'' exhaust with a 2.5'' muffler at the end. im going to be replacing the muffler with a 3'' muffler, mainly because the old muffler looks beat up. will my tune be effected.

sleepencivic

if you run a wideband on the car you can see if your rich or lean after the swap and go from there

Muckman

iTrader: (2)

If you are moving more air then you need more fuel to make more power. Watch your wideband, you will probably be a little leaner now.

SiRCiviC94

Doubt it

FlewByU352

The muffler portion is not a huge restriction given it is a 2.5" N1 vs a 3" N1. There is restriction no doubt, and it will show up on the dyno. But it is not a major problem until you start really pushing the upper 3 digit HP numbers.

sleepencivic

A few years back my APexi muffler had a removable silencer that restriceted the muffler flow to about 2 inch exit from a 3 inch exhaust. When I took it out there was a noticable difference in the AFR's, if you dont have first hand experience keep your 2 cents worth! It will effect the AFR's but not by much!

EsotericImage

iTrader: (8)

well, its at the end of the exhaust, i doubt it will make a difference. If we were talking replacing the whole DP exhaust to 3" then yes.

LS AzZkIkr

I did the same thing and there was a very small change in AFR's. Nothing worth getting a re-tune over.

wantboost

iTrader: (2)

As stated, the muffler represents a very small section of the overall exhaust system. If you were going from say 2" to 3" or something similar then you might want to re-tune but with just replacing the muffler the change in air/fuel ratios is negligible. I am assuming of course that you mean just the muffler and not any other section of the exhaust system.