🔧 BUILD Upside-down M90 GTP build thread

[GTPpower]

I don't see anything wrong with that. If your car made 450 at the crank, and the trans eats 15%, and the blower takes 60ish, you're right there at about 320.

 

[TurboTPI]

I’ll use my car for example. 3300# race weight with driver, 117 mph trap speed. That’s easy over 400hp. I dynoed 320. There’s no way it’s drivetrain loss. This has bugged me for years

I’ve always thought that there was something going on with these cars. They are way faster than you would think given the whp. Unless they just put the power down super efficiently.

 

[Rent Free]

its the trans. They are basically a 3 speed with overdrive once in OD they fall on their face.

Personally I think the 4Tglass has less drivetrain loss than people think.

 

[Ron Vogel]

I mulled over the thought that it might be the result of the higher TQ to hp ratio, like the old Buick 455

 

[TurboTPI]

I mulled over the thought that it might be the result of the higher TQ to hp ratio, like the old Buick 455

Could definitely be that too. My TPI Firebird has a ridiculous torque curve. It’s way faster than it should be too haha

 

[Rent Free]

I mulled over the thought that it might be the result of the higher TQ to hp ratio, like the old Buick 455

Also why the 4Tglass turns into a grenade pretty easily too.

 

[10sec]

Dyno's should be only taken seriously for the ability to use them for tuning, what really matters is what the car does in the real world.

 

[Ron Vogel]

Dyno's should be only taken seriously for the ability to use them for tuning, what really matters is what the car does in the real world.

View attachment 75125

Exactly, so I’ve come to peace with trap speeds

 

[TurboTPI]

Exactly, so I’ve come to peace with trap speeds

Definitely! Always went by trap speed as well! My Firebird put down like 450whp. But trapped 130mph in the 1/4mile at 3600 lbs.

 

[GTPpower]

Pulled the pan just to check it before I put fluid back in. Good thing I did. Looks like I need a new diff. And my brand new axle lasted about 20 miles.

 

[Turbocharged400sbc]

they tend to grossly overfill em with grease leaving little air for handling expansion/contraction.....that and im gonna guess thats a mushroom crimped band....., they dont clamp as well as the spiral flat band clamps/SS zip ties

the hard plastic boot also doesnt clamp onto the rubber tulip adapter real well in most cases thats why most are round body inner tulips....no need for the adaptor.

 

[GTPpower]

I don't think the clamp was holding it hardly at all. It basically fell off when I looked at it while pulling the axle.

 

[Turbocharged400sbc]

it kinda stretches out though with the 3 lbs of grease feeling like 30lbs at 60mph.....usually only on one side of the boot.....where it cooled down previously.

remove most of it but a mounded tablespoon each tripod bearing, clean and scuff the od of OEM adaptor rubber and ID of the boot and rtv em.

lookup stainless CV boot straps and tool (kinda a winding winch tool)

 

[Rent Free]

god id be pissed about that diff and all the material in the pan.

good luck man!

 

[GTPpower]

I'm just going to send the axle back. It's under warranty for like 2 years.

The diff should at least be an easy fix. I'm just debating if I should use my spare HD diff, or order one from tep.

 

[Turbocharged400sbc]

and itll happen again

 

[GTPpower]

Maybe. I'm convinced this one was defective though.

 

[Turbocharged400sbc]

we're defective

 

[GTPpower]

Is this what you're talking about?

Amazon.com: CV Joint Banding Boot Plier Tool With 10 Pair Clamps : Everything Else

Amazon.com: CV Joint Banding Boot Plier Tool With 10 Pair Clamps : Everything Else

www.amazon.com

The other side is a brand new GM axle too, but no leaks from it.

 

[Turbocharged400sbc]

yup

 

[Turbocharged400sbc]

OEM have solid shrunken SS bands, completly smooth bands, no mushroom clamp section sticking out

 

[GTPpower]

This one has the mushroom/crimp style. I'll have to look at the other side and see what that has. You're probably right....I should just clamp/rtv them and forget about them.

 

[GTPpower]

Hmmmm, different on the driver's side.

 

[GTPpower]

Pulled the diff out. That was a difficult job with everything that's in the way now. But it at least doesn't look like it did much damage. One of the spider gears siezed up. The other is still fine.

 

[Turbocharged400sbc]

do you got a diff squirter brazed onto the governor return tube?