I need help on turbo decision

[RACER-X]

I did a search but couldn't find the answer to satisfy what I really needed answered.

I (out of stupidity and anxiousness) pulled the intake off my GSX a few weeks ago .. custom air intake pipe was to fabbed to close to the tranny and was not letting the tranny engage in 4th and reverse.

I had a hunch it was the intake pipe so I pulled it off and went and did a few pulls to make sure it wasnt my 4th gear syncro. Well I forgot to pull the coupler off the compressor housing and 3-5 miles and 25psi later I came back with not all of my coupler, seem that it was a long drive and my turbo got hungry and badly chewed up 6 fins in the process which brings me to my question.

I'm going to be rebuilding my turbo and since its getting a rebuild and I will be replacing at least the compressor wheel, I was wondering what I could do to make my turbo more efficient in both spool up time and added hp.

To better assist me I'll give a brief run down of my mods and then my what I like to call my "Frankenstein Hybrid turbo"

Built 6bolt, .20 over pistons, full ferrea valvetrain w/duel springs, fp2 cams, 780cc inj, Griffen big core, 3" custom piping, Head and both intake and exh. mainfolds are ported, o2 housing is custom with open dump, custom 3" exhaust (no flex section, or cat), EVC VI, AEM EMS for tuning.

Turbo I can honestly probably say there isn't another one made like it.. previous owner had his own shop and one of his buddys builds and repairs turbos ... this was probably one of there experiments.

Turbo is mitsu center (mitsu bearings) .... he said it started out being a Red, how much truth to that who knows, it has a Greddy metal stamp on the cover but the cast of the compressor has the mitsu emblem next to the .70 A/R.. looks a lot like a 20g compressor cover. The compressor wheel is a GT35R, turbine wheel is a TD06 with the .82 A/R turbine cover.


Right now I'm making 420 AWHP @24psi on 93oct. I'll be looking into replacing my stock ported intake and exhaust manifolds and going with bigger inj. I'm trying to get somewhere in the neighborhood of 550-600whp with better efficiency if I'm able to.

 

[my98gsx]

wow that sucks... good luck with the rebuild. I took my old mitsubishi turbo apart and did some port work myself. If the turbo still has the "step" in the exhaust side, youll want to smooth that out and make it flow beter. This can be done with a dremel and some patience. Make sure you unbolt your hot side, you dont want all those shavings going into your turbo. I also ported out my compressor outlet ( but i dont think that made such a diference. ) Last thing, if you are running an internal wastegate you can port out the wastegate area to cut down on boost creep. This did make a knoticable difference in my 16g. Have fun, and hope you have some time to spend on this project, it takes a while.

 

[JusMX141]

Turbo is mitsu center (mitsu bearings) .... he said it started out being a Red, how much truth to that who knows, it has a Greddy metal stamp on the cover but the cast of the compressor has the mitsu emblem next to the .70 A/R.. looks a lot like a 20g compressor cover. The compressor wheel is a GT35R, turbine wheel is a TD06 with the .82 A/R turbine cover.

Definitely interested in seeing pics of this beast. As it would stand, you have the largest compressor I've ever seen on a Mitsu center housing.....possibly too large for the same thrust system that supports compressors as small as a 14B.

 

[RACER-X]

I have a picture of the compressor side but thats the only angle I have. I took it to post the damage that my coupler did, at the time I couldnt believe that two little pieces of rubber could do that much damage.

I'll post that pic so you can see it.

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It was a tight fit getting in there that closeup pic is all I have at the moment. I'll see if I can get a better pic some time today.

 

[hurricanecris24]

wow that wheel is done

 

[RACER-X]

wow that wheel is done

Yeah, tell me about it, and can you believe there is no in and out shaft play, ZERO none, and just a hair of up and down movement. Good thing the GT35R compressor wheel is only $100



If I need to replace the compressor cover, or go with a different turbine wheel for more power or efficiency I'm willing to do it.

If you know of a better (and I'm sure there out there) or have exp of a 35R combination let me know. I'm sure that there has to be better option in putting together a more efficient and higher hp turbo then what I have put together.

 

[JusMX141]

Doesn't look nearly big enough to be a GT35R wheel....looks more like a 50-trim to me.

I'm curious to see what the inducer/exducer measurements of that wheel would be, as well as what modifications were needed to make it fit the Mitsu turbine shaft (most Garrett compressors modded to fit Mitsu shafts are ground flat-backed, and the shaft bore would obviously need to be bored larger).

 

[RACER-X]

Doesn't look nearly big enough to be a GT35R wheel....looks more like a 50-trim to me.

I'm curious to see what the inducer/exducer measurements of that wheel would be, as well as what modifications were needed to make it fit the Mitsu turbine shaft (most Garrett compressors modded to fit Mitsu shafts are ground flat-backed, and the shaft bore would obviously need to be bored larger).

Well I seriously doubt they went through that much trouble to put a Garrett compressor wheel on.

Like I stated before, I was told by the previous owner that the turbo started out as a Fp Red. ... of course that is indeed not a fp compressor cover, and I was told that a GT35R compressor wheel replaced the Red's existing compressor wheel.


Let me see if I can go snap a few more pics, so that someone like yourself can better help me identify what exactly I'm running on this car.

Without removing vac lines and hose (no time right now) this is as good as the pics are going to get.

Tried to get as much info off the compressor cover.. but its a tight fit. Wont be pulling it off till around the end of the month or so.

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[Cassera]

Well, you cant really have faster spool up time WITH added horsepower.....The only thing I could think of is getting a TwinScroll setup and getting a holset turbo.

Since holset is made for diesel which are slow flowing and cooler gasses they tend to spool quicker while still providing high output.

If you dont want to go holset I would recommend just getting a twinscroll mani.

 

[JusMX141]

Well I seriously doubt they went through that much trouble to put a Garrett compressor wheel on.

What do you think is done for every FP Green, Red, and all of the Frank Level 1-5 20G's that are out there?

Like I stated before, I was told by the previous owner that the turbo started out as a Fp Red. ... of course that is indeed not a fp compressor cover, and I was told that a GT35R compressor wheel replaced the Red's existing compressor wheel.

It obviously began as a Greddy 18G, not a FP Red.

If the wheel is a 50-trim as I guessed, that would mean it could be basically the same turbo as a FP Green....however without removing the cover and measuring the wheel, it's just a guessing game that we may never know the answer to.

I'm just trying to help figure out what you had, that way you know what to upgrade to.

Have you every logged airflow with this turbo on the car? Obviously if you were only making around 48lb/min at 25psi it's not a GT35R compressor.

 

[RACER-X]

What do you think is done for every FP Green, Red, and all of the Frank Level 1-5 20G's that are out there?

It obviously began as a Greddy 18G, not a FP Red.

If the wheel is a 50-trim as I guessed, that would mean it could be basically the same turbo as a FP Green....however without removing the cover and measuring the wheel, it's just a guessing game that we may never know the answer to.

I'm just trying to help figure out what you had, that way you know what to upgrade to.

Have you every logged airflow with this turbo on the car? Obviously if you were only making around 48lb/min at 25psi it's not a GT35R compressor.

I was saying that in the line of thinking that I was lied to and that I seriouly doubt they would have gone through the trouble of taking a 18g and working everything over to out fit a GT35R compressor wheel to it... for that much work it would have been easier to just get a Garrett CHAR. I know it is done just doubt it would be done by the tool that sold me my car.

I know and I'm very appreciative for all the help and info thus far.

Well I run a EMS so if logs air flow... crap just text my buddy and the flash drive he had my logs saved on he no longer has. Well there went the easy way.

 

[brute]

I'm not entirely sure what you're asking. Your compressor is done, and you see the open door to upgrade? You want this upgrade to be in the form of rebuilding the current turbo, right?

I agree that I would like to see inducer/exducer measurements of both wheels on your current turbo. This would help to see what you're upgrading from, and we can start giving some options. I don't know what your housings are, but, again, if we can get some more pictures/measurements it'd be better than guessing. If your housings permit, you may be able to buy a whole CHRA and just swap that in, rather than remounting a compressor wheel.

You are going to take the turbo off to rebuild it, so can't you do it right now so we can get some good pictures?

 

[RACER-X]

I'm not entirely sure what you're asking. Your compressor is done, and you see the open door to upgrade? You want this upgrade to be in the form of rebuilding the current turbo, right?

I agree that I would like to see inducer/exducer measurements of both wheels on your current turbo. This would help to see what you're upgrading from, and we can start giving some options. I don't know what your housings are, but, again, if we can get some more pictures/measurements it'd be better than guessing. If your housings permit, you may be able to buy a whole CHRA and just swap that in, rather than remounting a compressor wheel.

You are going to take the turbo off to rebuild it, so can't you do it right now so we can get some good pictures?

Correct, center section seem fine(spins freely, doesn't make noise when I start the car, and has no shaft play, no smoke, ect), but I'm not sure what the center section is now that I know I've been lied to I really can't take what was said that it is as truth.

I totally agree, however time and money are not permitting me to remove the turbo at this time, I hope to be able to have the turbo off by the end of the month, I have 4 children and a wife in college, so between semester finals, work, over time, and taking care of 4 I only get about 30min to an hr to myself if Im lucky and waiting till 9:30pm to get started may be my only option so it will take me a few days at 30 min at a time. I can say this though I see nothing but vacume till 3,800 rpms and in looking up the number on the compressor cover its a TD06 18g not a TD05, the 2nd set of numbers after the dash ...I wasn't able to find any info on it 49179-58590