🔧 BUILD Upside-down M90 GTP build thread

[GTPpower]

Figured it out today. Started spraying around with starting fluid, and found what I thought was a vacuum leak right by the throttle body. I pulled the tb off to look and reseal it. Here's what I found... this is the thrasher TB spacer with a port for a nitrous nozzle. I forgot to plug the port. Whoops.



At least it was an easy fix. The car runs great now. I changed oil on it, have the coolant system bled. I even drove it around the block. All appears to be well. Harvest is getting close, but if it holds off another week, I may try to get it to the track next week.

 

[GTPpower]

The car sits too low in the front. The axles aren't straight, so I need to raise it up an inch or so.



The collars on the coilovers are siezed up, so I cleaned the threads up and sprayed with penetrating oil and a mixture of acetone/trans fluid. Hopefully I can adjust it tomorrow.

I need to schedule an alignment, plumb the intercooler water lines, and tune it. I'll also have to put an afc on. I bought the afc about 10 years ago. Hopefully it works.

 

[GTPpower]

I was able to raise the front end about an inch. I basically destroyed the coilover collar and sleeve though. Maybe I'll just buy new ones this winter and install them.

But, I put a few miles on it today. It looks like it's running good. Alignment is scheduled for Wednesday.

The blower is annoyingly loud, even at just cruise.

 

[Rent Free]

I love this thread so much and Id love to see this thing in person again someday!

 

[GTPpower]

If I get the body work finished this winter, maybe I'll head up North with it next summer for some better elevation.

 

[m_dogg]

Sounds like a pissed off cat

 

[GTPpower]

It is so damn annoying. Anything above about 2k rpms it whines. If I decide to do much driving with it, I'm going to have to put a filter or something on to quiet it down. I was thinking about doing Rocky mountain race week with it, but I would go crazy from the noise.

It rained here all day, so not much progress. I did get the water lines run.




I also painted the front bumper cover. I just rattlecanned it for the time being to make it look decent from 10'.

 

[v6buicks]

Lol nice. I wouldn't have guessed just by looking at the picture.

 

[GTPpower]

Pulled my slicks out of storage on Monday, and noticed they were in rough shape.




So I ordered a new set from summit about 1 o'clock on Monday and selected free shipping. They just showed up. That's pretty sweet.

 

[10sec]

Put a stock airbox in there when you're just cruising it around, that'll silence the blower easily and you can find those all over the place if you don't already have one.

 

[GTPpower]

I've thought about that. That could be a good option. I'll have to look and see if I have one someplace.

 

[GTPpower]

I changed my alignment appointment to tomorrow because all it's doing is raining today. I'm a bit scared to drive the car in the rain without wipers.

 

[10sec]

I've thought about that. That could be a good option. I'll have to look and see if I have one someplace.

I was replying that I might have one you can get but forgot you live far far away But I'm sure you'll find one if that's the route you want to go. It'd be kinda cool to see your setup pull through a stock airbox with a K&N and see if it loses power and how much.

 

[GTPpower]

Yeah that would be interesting. It would probably be significant. I picked up 8whp on a bone stock gtp doing just that.

 

[Mook]

I was able to raise the front end about an inch. I basically destroyed the coilover collar and sleeve though. Maybe I'll just buy new ones this winter and install them.

But, I put a few miles on it today. It looks like it's running good. Alignment is scheduled for Wednesday.

The blower is annoyingly loud, even at just cruise.

Is that the fuel pump in the background?

 

[GTPpower]

Yes. It is loud as shit. Weldon makes a controller for it so it's not running 100% all the time. I may end up buying that in the future.

I also just added 4 gallons of distilled water in the ice box. I'll probably need a couple more from the looks of it. But holy shit, this pump moves some water.

 

[GTPpower]

Getting it aligned.




For some reason the trans won't shift into 3rd at wot. It's either a tune problem, or something is wrong with the transmission. I think I'm going to race it anyways. It'll at least help me learn a bit more about it.

Got the front end all put together.






That pump flows some water.

 

[GTPpower]

Ready to roll. They cancelled T&T for today due to rain. So we are headed out in the morning. Probably leaving here between 5 and 6 to get there when the gates open.




Did some tuning this morning. I also installed the afc. Still no 3rd gear, so my times are going to suck, but oh well.

It's making decent power on low timing. This is a 2.7 pulley with 5%OD crank. Through stock manifolds, stock downpipe and cat, and stock exhaust minus resonator and u-bend. I wasn't even running the intercooler pump during this. This intercooler is awesome. Intake air temps are reading post blower. Afc is scaled 82%. Yes, that's about 460 crank HP.

 

[GTPpower]

Had a great time at the track. Even without 3rd gear, most of my runs were 12.7-12.8. My 1/8 mile times are about all that matters. Plugging those into a converter shows the car would run low 12's or high 11's with 3rd. I was hoping to be about a second faster than that. Here was my best 1/8 mile run. DA was 3600' on this run.




A few issues I need to work with. 1st off, the car isn't making the power it should be. Looking at my scans today, I either have some belt slip, or a boost leak, or both. I was only making about 9 psi peak with a 2.7 pulley and 5% OD crank pulley.

My other main issue is the brakes suck. I'm thinking that I'm going to ditch this brake booster and go to either the Monte booster or a hydroboost. I'm not able to do a very good burnout because the rear brakes are not holding me in place. So I've got a few things to work through. Overall, I had a great time. It's been a long time since I raced.

My buddy with the turbo gt went 10.8 @ 131. The track told him to get a bar in the car, so he was very happy too.

 

[1quick]

Had a great time at the track. Even without 3rd gear, most of my runs were 12.7-12.8. My 1/8 mile times are about all that matters. Plugging those into a converter shows the car would run low 12's or high 11's with 3rd. I was hoping to be about a second faster than that. Here was my best 1/8 mile run. DA was 3600' on this run.

View attachment 43728


A few issues I need to work with. 1st off, the car isn't making the power it should be. Looking at my scans today, I either have some belt slip, or a boost leak, or both. I was only making about 9 psi peak with a 2.7 pulley and 5% OD crank pulley.

My other main issue is the brakes suck. I'm thinking that I'm going to ditch this brake booster and go to either the Monte booster or a hydroboost. I'm not able to do a very good burnout because the rear brakes are not holding me in place. So I've got a few things to work through. Overall, I had a great time. It's been a long time since I raced.

My buddy with the turbo gt went 10.8 @ 131. The track told him to get a bar in the car, so he was very happy too.

View attachment 43729

Try a vacuum pump if you have a big ass cam for the breaks, 1/8th looks good for low 12’s upper 11’s

 

[GTPpower]

I have decent vacuum. There is just no brake pedal travel. The turbo gt is also running one of these and he has brake problems too.

 

[1quick]

I have decent vacuum. There is just no brake pedal travel. The turbo gt is also running one of these and he has brake problems too.

I had the small booster and it would blow through the brakes, put a cheap vacuum pump on and I could build 10 psi at the line after

 

[GTPpower]

You had the Monte booster, right?

 

[1quick]

You had the Monte booster, right?

I don’t remember it was the smaller one

 

[1quick]

I don’t remember it was the smaller one

It’s been since the 2012 since I’ve had a 3800 I’m trying to remember stuff to help out