Thread: 2.5" or 3" exhaust for 300 tdi

which size exhaust would be best for my 300 tdi defender 130 ute im thinking 3"

The stock system is 60mm (2.375") with mandrel bends and a straight through muffler, so they are pretty good stock.

2.5" or even better 2.75" is probably ideal, I made mine out of 3" as at the time 2.75" tube was bloody exxy but it's probably overkill.

Not a huge performance upgrade, it did extend the useful rev range through the gears so obviously dramatically reduced back pressure and dropped EGT's by over 25*C with stock pump settings so gives more scope for tuning. (long 130 system)

Noise and resonance is an issue with the bigger tube, you do need good a good muffler and particularly a resonator.