Exhaust mods for 2.8L MU

Joined: 25 Sep 2007 Location: Cairns

Probably been covered before.....

Got the 2.8L '91 model MU & wanted to know whether to go with a 2.5 or 3" zorst from turbo back. Think the turbo outlet is 2.5". Will be press bent not mandrel... Should I run a muffler???

Would also like to hear any feedback on revs when speedo spools up, fuel economy, power increase, negatives....

IS it worth intercooling also???

Joined: 15 Jun 2005 Location: Ipswich QLD

2.5"

Put on a free flowing muffler it will cut down some of the drone.
Do the exhaust in conjunction with getting the boost aneroid on the fuel pump adjusted to suit.

This will give useful boost from 17-1800 rpm rather than the 2200 rpm you have now, makes for a much nicer drive.

Power increase probably around 10 to 12 kw at the rear wheels.
Fuel economy if driven as normally around town/ trips etc will not be much different from what youre getting now, it will use more off road and more again on sand, but its worth it.

Intercooling can give benefits and the bits are readily available from wreckers for these cars.

Get it dynoed after the exhaust or intercooler, get the exhaust temps and fueling correct and they go fairly well for a little stone axe simple diesel.

Joined: 25 Sep 2007 Location: Cairns

Yeh will be getting the fuel pump adjusted to suit.
What boost are these running stock? 10psi??
With the intercooler are you able to wind up the boost a bit to suit the application. Does it all work the same as a turbo petrol?

This is a daily driver & doesn't get off the black stuff all that often. Will reliability be effected at all?

Joined: 15 Jun 2005 Location: Ipswich QLD

Youll find the boost will rise from whatever you have at the moment to around 11 to 12 psi.

An intercoler will lower boost a smig as it will cool the air, cooler air = denser air at a slightly lower pressure.

Diesels work somewhat differently to petrol as the MORE fuel you put in the richer the mixture MORE heat you get, less fuel ie leaner = less heat.
Simple diesels have a straight through air intake ie fully open all the time and the amount of fuel is varied to change power etc.

When finished with your mods get it dynoed to suit whats been done and keep the exhaust temps lower than 600 deg c post turbo.

No apart from anything going wrong with the things your fitting it wont effect reliability.
It will be a much nice car to drive as it wont die in the arse as it f probably does ATM if your not in the right gear at the right time.

Joined: 25 Sep 2007 Location: Cairns

Thanks a heap Guzzi

May look at doing this with tax back $$$