Porting 2.5 T1 Voyager stock Mitsubishi Turbo

[jefo]

Hey Guys,

Since I have seen no one port the stock mitsubishi turbo for the 2.5 I decided to give it a go. I am pretty much done with the turbine side of things, the compressor side is tomorrow. I am just doing a mild porting. I opened up the waste-gate hole from 0.85" to 1.04" all the way through to try and get rid of my boost creep with the 3" exhaust. It is about as big as I can go with the puck still sealing. I smoothed out the ridge that is right after the turbine along with the exit after the turbine. I ported the 2.5" swingvalve. I ground away a decent amount of the protruding edge at the entrance of the turbo right after the turbo manifold flange (right before the entrance to the waste-gate hole). I removed some material where the swing valve hits on the swingvalve housing and turbine housing so it can open more.

Here are some pics, let me know what you think. It is my first time porting a turbo. Do you guys think a 1.04" hole is big enough to cure creep with an open 3" downpipe?

http://www.pinkbike.com/photo/9021943/
http://www.pinkbike.com/photo/9021945/
http://www.pinkbike.com/photo/9021944/
http://www.pinkbike.com/photo/9021946/
http://www.pinkbike.com/photo/9021947/

[Force Fed Mopar]

Should be, I ported the turbine and wg hole on a Mitsu for my Daytona, put 3" exhaust on it from the turbo back, had no boost creep problems. I didn't do the swingvalve or the compressor on mine, just opened up the turbo inlet and the wg hole. Also this was on a 2.2 T2.

[jefo]

Here are the photos of my ported compressor housing:

http://www.pinkbike.com/photo/9024206/
http://www.pinkbike.com/photo/9024204/

[Vigo]

Wow, i like how that compressor housing is turning out.

This is making me think about trying to use the 15g upgraded mitsu i have on my 2.2 spirit.

Rob, what rpm would you say your powerband ended at with your mitsu 2.2? Like where did you shift?

[GLHNSLHT2]

looking good, I'd go more on the compressor outlet, and I'd smooth and clean all you can get in the turbine inlet. I'd also radius the bottom of the turbine housing from just after the wheel down to where the exhaust bolts on as much as you can to help turn the air down.

[cordes]

looking good, I'd go more on the compressor outlet, and I'd smooth and clean all you can get in the turbine inlet. I'd also radius the bottom of the turbine housing from just after the wheel down to where the exhaust bolts on as much as you can to help turn the air down.

I agree with all of the above. I'll try and see if I have any pics of the porting I've done to a few compressor covers, turbine housings and SVs.

[jefo]

Well I put the turbo back in, and it still creeps. With the open 3" downpipe cutout open it starts creeping at 5k rpm instead of 4k rpm before the porting. It definitely pulls harder though! If I had to do it again I would put a bigger flapper on the wastegate and port the hole out bigger. The porting (other than the wastegate hole) probably added to the creep.

[GLHNSLHT2]

a buddy has a T2 garrett on his 2.5 mini, ported WG hole, released tension on the arm, ATP swingvalve and 3" exhaust with a big magnaflow type muffler. His creeps up to about 13psi now even with the WG flapper flapping in the breeze. Before porting the hole it would creep to cutout by 4500.

[Force Fed Mopar]

Wow, i like how that compressor housing is turning out.

This is making me think about trying to use the 15g upgraded mitsu i have on my 2.2 spirit.

Rob, what rpm would you say your powerband ended at with your mitsu 2.2? Like where did you shift?

I pulled it to 6k. That's where it felt like it was falling off.

[jefo]

I solved my boost creep with the cutout open. On the end of my 3" electric cutout I bolted this:

http://www.pinkbike.com/photo/9037921/

An exhaust Restrictor! This was the largest size hole (1.5" dia) I could have without getting creep. So the exhaust exits through this and the stock catback exhaust.

[Vigo]

So basically, the internal wastegate is beyond its limits. Unfortunately, there is no real way to address the root cause without removing the turbo again. And, if you remove the turbo again, it may just be a good time to put the creep issue to rest forever by upgrading the turbo setup to something with an adequately flowing wastegate.

Although, personally, i am wondering about an even more drastic modification that retains the mitsu and it's turbine housing. My idea is to separate the turbine and wastegate flows entirely with a barrier (such as Pat did on his Aries http://www.turbo-mopar.com/forums/sh...l=1#post825212), and then remove the puck completely, open the hole as much as it will go, and put an external wastegate on the pipe coming off the wastegate hole.

But, it is a crazy amount of effort to retain an undersized turbo for no real good reason. But since you have time and effort invested in your turbo, you may at least like to consider it for 1 to 2 seconds.

[jefo]

Yea my plan as of now is to just keep the exhaust restricted to control creep, but when I get a calibrated computer and an intercooler I will turn the boost up (~16psi) I will take off the restrictor and let it creep all it wants.











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[Force Fed Mopar]

I ran 20 psi on mine.

[jefo]

Was that with a shimmed wastegate or just unplugged hose? And how long did the turbo last?

[ShelGame]

I run 20psi on mine, unported, no creep issues. Of course, 20psi is kind of the limit for a Mitsu. I don't know that it would actually go much higher. And, I have about as open an exhasut as you can get. It's a 2-1/2" DP, about 8" long, followed by a 24" long x 4" dia megaphone that points at the ground just behind the k-frame.

The boost creep you're getting with your exhaust can likely be fixed with a calibration. I had to significantly change the WOT WG duty cycle to get it to work.

[jefo]

I should have mentioned, I am running a Grainger valve for boost control. My exhaust consists of a ported o2 housing as seen above, then a 3" downpipe from the flange to a reducer right before the stock cat and exhaust. I then have an electric 3" cutout. Here is the downpipe: http://www.pinkbike.com/photo/8564818/










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[Force Fed Mopar]

Was that with a shimmed wastegate or just unplugged hose? And how long did the turbo last?

Shimmed heavily I did have the boost control hooked up and working though. I think it was actually set to 18psi, ran 20-22 w/ the can unplugged. It lasted 6-8 months I think.

[turboboostman2]

hey guys new here, but not new to mopars, i have a 1989 spirit t1 with the upgraded fwd performance mitzu (Rebuilt 12G wheel to a larger 15g wheel on the compressor side with a 10 degree clip on the exhaust wheel for better flowFlows approx. 30% more than stock) i have alot of boost creep!!! how far will the boost creep?

[cordes]

hey guys new here, but not new to mopars, i have a 1989 spirit t1 with the upgraded fwd performance mitzu (Rebuilt 12G wheel to a larger 15g wheel on the compressor side with a 10 degree clip on the exhaust wheel for better flowFlows approx. 30% more than stock) i have alot of boost creep!!! how far will the boost creep?

Was the waste gate hole ported at all? It'll creep all the way to cutout on a stock computer in my experience.

[Vigo]

Cordes hit it on the head. If it starts to creep, it will definitely keep going. It is self-reinforcing.. Hopefully you still have the stock 14.7psi cutout to save you from it!