🔧 BUILD Upside-down M90 GTP build thread

[Turbocharged400sbc]

It's pretty much plug-in play the GPS ranges the same the wire colors are even the same and if I recall the IAC is also the same electrically, although the pintle diameter might be different it shouldn't affect it since it's still the same number of IAC steps

 

[Rdrnnr]

I'll bet between a welder and all of us we can get it figured out

You got it all tore apart yet? Open test and tune this weekend and cruise night weekend

 

[Mr_Roboto]

The 86-87 throttle would have to be sealed since the MAF is pre-turbo. I have no idea what kind of pains would be in involved in making the IAC and TPS work with a stock 3800 computer though.

IAC and tps just need the right connectors spliced in typically. done it between my tbi, typhoon, lt1 and tpi throttle bodies.

 

[GTPpower]

Any of you gn guys have a stock TB you want to sell? That accufab is a bit steep.

 

[GTPpower]

The other thing I don't like is I'd have to switch to something other than the stock maf.

 

[Rdrnnr]

The other thing I don't like is I'd have to switch to something other than the stock maf.

Am I wrong here or did you dial this thing in from the trans up?

 

[GTPpower]

Am I wrong here or did you dial this thing in from the trans up?

It's a fairly stock maf curve, other than being scaled. I just don't want to have to buy another maf and all the connectors to make it work.

 

[Rdrnnr]

Man I might be wrong and you'd think I'd know with my stock and ls1 sensor sittin 8 inches from each otherbut I'm almost positive that it and the 4.3 and 5.7 vortec mafs are the same connector even. The other two are just a hair underneath the ls1 in what they can read. And once you have stock sensor dialed in it shouldn't take much but a flash or two to match it back in but I'll have to let you know for sure.

Mine shouldn't be scaled now that I'm back on 91 for a short time and I'm gonna start tuning back in today to make some hits tomorrow so if I'm close to maxxin it again before I'm out of fuel pump I'm gonna wire it in and I'll keep ya updated on my thread on how it goes. Be cool to be able to open both our bottleneck throttle bodys a bit by gettin rid of that restriction and shove even more through these things

 

[GTPpower]

The throttle body isn't a restriction though, once it's under pressure.

I wouldn't mind going to a lq4 maf, but it's just another thing I don't need if I can figure out how to fix the stock TB.

 

[Rdrnnr]

Hear that and if you can keep it simple it's that much easier. Mines gonna have to go either way tho

 

[GTPpower]

I might have figured something out here. Not sure if these will work though. They are the orings I use on the hydroboost lines. They are a little small, but I think I can stretch them over the shaft. I just need to make sure they end up in the right spot.

 

[Turbocharged400sbc]

See I knew you could Kluge that thing together

 

[GTPpower]

Well, that doesn't work. It adds too much resistance to the shaft turning and I don't feel comfortable about it possibly hanging open .

 

[Rdrnnr]

That was the kinda stuff I kept runnin into. I did have mine pulled apart but it didn't take me long to say screw it and go get one

 

[v6buicks]

Any of you gn guys have a stock TB you want to sell? That accufab is a bit steep.

The stock GN stuff is small. Only 2.5" IIRC. I won't be selling my Accufab for anywhere near brand new pricing. If you want to borrow it to see if it works, I'll send it. If you want to keep it, it won't cost you a ton. Just PM me.

 

[GTPpower]

The stock GN stuff is small. Only 2.5" IIRC. I won't be selling my Accufab for anywhere near brand new pricing. If you want to borrow it to see if it works, I'll send it. If you want to keep it, it won't cost you a ton. Just PM me.

Which accufab do you have?

 

[v6buicks]

Which accufab do you have?

I'll have to measure when I get home on Monday. It came with the car.

 

[GTPpower]

So looking at GN throttle bodies more, I don't think it will work easily.

I'm wondering if these would work. Are there any dsm guys on here?

Extreme PSI Throttle Body Seal (PAIR) Mitsubishi Eclipse 91-99 DSM 4G63 1G 2G | eBay

Do you have a turbo DSM with a leaky or sticking throttle plate?. Are you hearing a large amount of air rushing through the throttle body when you use our leak tester?. You may have worn-out throttle shaft seals.

www.ebay.com

 

[GTPpower]

So, did some more playing. Found an oring that fits the OD pretty well. Then used on of the hydroboost orings for the inner one, and ditched the stock seal.



I think it's better, but it still leaks. So, back to the drawing board.

 

[GTPpower]

James, do you think something like this might work? I'd have to put two of them together.

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

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[GTPpower]

This one might actually be the perfect fit. #204

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

 

[GTPpower]

Well, I ordered them yesterday, and they showed up already. That was quick.



New is on the right, original on the left. I think it'll work, but we will see.

I put a thin layer of rtv in the cap to hold it in, so letting that dry before I put it all back together.

 

[GTPpower]

So, still leaking, but it's better. I think it's leaking around the outside of the seal retainer. I think the shaft seal is pretty tight. So I am going to put some rtv on the retainer and try that.

 

[Mr_Roboto]

Have you done any power testing yet?

 

[Rdrnnr]

Have you done any power testing yet?

If he hasn't he better bring a pair of streets to throw on it the next time he comes around here ?