4JG2 Bighorn Turbo Upgrade?

[Stu-]

Hey guys, I'm new to the forum so bear with me.

We've got a 91 Bighorn Irmsher that we've had for years and years. Bloody reliable and great for towing. About 100,000km ago we front mounted an intercooler and made a cold airbox to scoop from where the old topmount sat. We wound the boost up a bit and its been a great and very reliable improvement.

However we're currently looking at making up a new larger exhaust system from the turbo back and I'm very tempted to upgrade the turbo at the same time. Has anyone done this before on here that could recommend a good upgrade? Doesn't have to fit the stock exhaust manifold as I may make a new one anyway.

Any input would be appreciated.

Thanks
Stu

[Drurban]

Hi Stu,

Welcome to the site it is a great place with alot of advise, I am in the process of doing the exhaust on my truck which is a 1997 Mu 3.1L Turbo Diesel which has the 4JG2 Engine, Iam going from the back of the Turbo 2.5" straight thru with a flange I have cut.

I wont be replacing the Turbo as this is still going good, I would look through the rest of the posts.

But I have read that you can use a Turbo from a Subaru, but I have not investigated this enough to go ahead and say do that.
I would recommend going to this site www.clubisuzu.com they are very helpfull with issues with Isuzu only.

Cheers

Ruben

[gimmemud]

Friend of mine use to have an MU with the 3.1 and a turbo from the 2.8 on on it with the boost and fuel wound up a tad. Went insane. I have heard the 2.8 turbo's are much more reliable?

[Stu-]

Thanks for the reply.

I have heard they are better turbos for reliability but its hard to find turbo maps for them to compare flow. Kinda had in mind a big step up rather than putting something similar on. Got a few leads - just need to compare compressor wheel sizes

[Crash bandicoot]

the 4jb1 with boost and fuel adjustments will keep up with any new common rail diesel(and a few petrol's too). a chap i know used to have a holden/isuzu rodeo, even managed to wire up a vaccum actuator and solenoid to the injector pump to open the blow off valve to dump the excess pressure on gear change. used to leave the 3.1 for dead.

with the turbo working nigh on full time used to sound like a 747 coming down the road with full 3 inch piping and top mounted intercooler from a bighorn.

the beauty of it was the BOV was plumped back to the airbox with a 15 psi spring in it, would go on boost at 1300 rpm and stay there.

awsome truck, only ever had one problem and that was the power steering leaking

[Stu-]

Sounds very cool! I like the idea of the BOV dumping into the airbox. How long did the turbo last like that?

Will be running a 3inch exhaust this time around to free things up a bit.

[Crash bandicoot]

its still goes as hard as it ever did, pulled a safari off sandtoft beach on the weekend with it. lmao.

[pruggerdore]

as said look at subaru turbos, very similar