Mitsu with 3" exhaust?

[Dodge Aries K]

We're putting a "new" engine into the LeBaron convertible I have. 2.5L TI with a mitsubishi turbo. As I want to keep the old engine with the Garrett on it for a future project down the road, the Mitsubishi will stay on there. I have a boost controller gizmo that I will set for 10 PSI. Car won't be intercooled for a while. What am I looking at for trouble here with a 3" exhaust, no muffler, and a high flow catalytic converter? Can the Mitsubishi be drivable this way? Thanks for the insight.

[3Bar_Mopar]

Can the Mitsubishi be drivable this way? Thanks for the insight.

I don't see why not....you may have some spiking issues with that big an exhaust on the mitsu, but nothing you couldn't tweek out with your boost controller.

[Dave]

Let me tell you, you WILL have spike! I had a 2.5" exhaust on my old Spirit and the mitsu couldn't be controlled, I had a HP Performance boost controller, a real nice unit as well.

Good luck though.

[cordes]

I had creep with my old setup on the shadow. non-ICed, 3" catless exh. with a high flow muffler from where the cat was back to the bumper.

It would creep to cutout.

[GLHNSLHT2]

yep, the spike isn't the issue, it's the creep. Creep is when you get to your boost point then as the rpms rise it just keeps going up and up and up. Mitsu's can't flow enough to keep the turbine speeds down. Porting the wastegate might help as it'll let more gases flow past the turbine. But if I were you I'd throw the garrett on as used turbo's don't like to sit. They'll smoke after throwing them on the car. I'd run it just to keep it fresh. Besides, by the time you get to that other project you might be thinking about a T3/T4 or a GT turbo instead.

[The S is Silent]

yep, the spike isn't the issue, it's the creep. Creep is when you get to your boost point then as the rpms rise it just keeps going up and up and up. Mitsu's can't flow enough to keep the turbine speeds down. Porting the wastegate might help as it'll let more gases flow past the turbine. But if I were you I'd throw the garrett on as used turbo's don't like to sit. They'll smoke after throwing them on the car. I'd run it just to keep it fresh. Besides, by the time you get to that other project you might be thinking about a T3/T4 or a GT turbo instead.

+1. I can't agree with this statement more.

[iTurbo]

+1 on the creeping issue with the 2.5L + Mitsu + 3" exhaust.

I had this setup on my old Shadow ES and it wouldn't spike at all, but even with full manifold pressure on the wastegate (no boost controller at all), it would creep to cutout before I was ready to shift while racing. It was REALLY bad on cold nights. Upgraded to a Garrett TurboII turbocharger and all was well again.

[Ondonti]

I would think you could to a little port work and help things out a lot.

[Dave]

I would think you could to a little port work and help things out a lot.

Shoot I'd say if you're going to pull the head you might as well put a Garrett on it. That's what solved my problem. I even tried shimming the WG but it still didnt work.

[Lugert]

I never had any spikes or creeping with my mitsu and 3" exhaust.
I did have a cat and a muffler.

[Ondonti]

Shoot I'd say if you're going to pull the head you might as well put a Garrett on it. That's what solved my problem. I even tried shimming the WG but it still didnt work.
Well thats true. I have a garret here that im not even sure why I own. Needs rebuild and it has a bolt that broke off.

[turbocoupe]

were the waste gate port is you could port it a lil more and it shouldn't be a prob i think someone did that here on this site and it wasn't any problem for them it did the trick.

[Dave]

Mitsus just plain suck. :)

[Lugert]

Mitsus just plain suck. :)
Tell that to Gus, or many other people who have had success with the Mitsu!

[cordes]

Tell that to Gus, or many other people who have had success in spite of the Mitsu!

Fixed it for you. ;)

[turbocoupe]

Hey that's your opinion on mistu suck I think their great for low amount of boost only thing they have a problem is over boosting but then again it fixable.

[Mario]

I believe FWD Performance Did/Does sell a 3" Swingvalve for the Mitsu Turbo.