8HP swap?

[Ryan]

I've been overseas for years... I'm out of the car scene... not by choice. My only outlet now is youtube.
Saw a clip about the 8hp. Is this popular in the turbo buick world? Wondering if anyone put an 8hp in a street machine.

 

[WarWagon]

Guruautowerx, Dan Jost, Paul Simmons

 

[Turbo6inKY]

Only a handful. It needs an adapter plate to bolt to our V6, and there aren't a lot of options for a computer to run the gearbox, and what options there are, they're pretty pricey.

And since there aren't a lot of folks doing it, there's very little about how to program the shifts for our engines. It'd be nice if more people would do the conversion and create a market. It's an excellent transmission.

 

[BEATAV8]

Closest thing I've seen is one of those 6 speed TCI 6X 4L80E's in a pro touring GN. Paddle shifters and all that jazz. Seems like it's always shifting gears.

 

[GNVYUS 1]

This topic is also on the Pontiac board.
This guy makes adapter kits for the HP90 etc, maybe he'd tackle this for us.

Pontiac 400 kit for DODGE CHALLENGER / CHARGER / HELLCAT ZF 8HP70 / 8HP90

Full connection kit for Pontiac 400 to DODGE CHALLENGER / CHARGER / HELLCAT ZF 8HP70 / 8HP90.

www.adamat.com.pl

The 8HP90 has a 5.0 first gear, input 700tq and you get 3500tq output vs like 1800 with our 2.74. Better have sticky tires and traction with that thing in there and then we'd all probably need to go to a 3.08 rear gear to calm that down then gain a great 8th gear overdrive rpm at .64.

Just checked out the link War Wagon posted and Guruautowerxs in the united states so probably a better bet.

 

[Turbo6inKY]

This topic is also on the Pontiac board.
This guy makes adapter kits for the HP90 etc, maybe he'd tackle this for us.

Pontiac 400 kit for DODGE CHALLENGER / CHARGER / HELLCAT ZF 8HP70 / 8HP90

Full connection kit for Pontiac 400 to DODGE CHALLENGER / CHARGER / HELLCAT ZF 8HP70 / 8HP90.

www.adamat.com.pl

The 8HP90 has a 5.0 first gear, input 700tq and you get 3500tq output vs like 1800 with our 2.74. Better have sticky tires and traction with that thing in there and then we'd all probably need to go to a 3.08 rear gear to calm that down then gain a great 8th gear overdrive rpm at .64.

Just checked out the link War Wagon posted and Guruautowerxs in the united states so probably a better bet.

Well, that's awesome. The Pontiac 400 shares our bolt pattern, so somebody's made the plate. I think the crank flange is different, so that kit's flywheel won't work, but I'm sure that's a solvable problem.

Now all we need is a solution for the output shaft. It's flanged. Some kind of CV joint needs to go there that has enough plunge to accommodate our solid axle swing.

 

[GNVYUS 1]

After reading more about the Adamat website, they have the gear and skills to do it right so if someone were to work with them on testing and feedback maybe they'll make the flexplate and the rear output shaft solution.

Question in the end is vs the 4L80e, is all this an upgrade or a lot of work to move sideways? Not sure but a modern killer trans in our platform does help our community.

 

[GNVYUS 1]

BTW I notice no one's talking about swapping in the 10L80 or 10L90 trans, real mess GM has with those software and locking up the rear tires on a small % still, like a 5 year engineering fix still going on. One shop fixed it and GM won't accept their help or design.

 

[hemi8]

My question is, will it fit in the tunnel? My TH400 is within a 1/2” of hitting the floor. The 8hp90 is huge. All the parts to do it are available except the trans mount. I contacted Domiworks who make the bell housing adapter and they told me I would use my current flexplate and starter. The year of the trans purchased and what it comes out of is important and best get the converter with the trans. TurboLamik looks like the best controller to me but it is expensive. There is a lot to consider as there are many parts required, ECU/shifter/trans fluid thermostat/ cooler/possible floor pan mods/trans mount fabrication /driveshaft. The trans has to be opened up and the control module reworked/re-soldered which may require sending it out to be done by a professional wiring tech. But the benefits would be great, no more high stall converters, low low rpm at high highway speed, waay better gearing, lockup converter, programmable shift points, multiple shift modes. I think for programming the torque curve needs to be known, not sure on this but if the car has been dyno’ed before that would be easy.

 

[Turbo6inKY]

After reading more about the Adamat website, they have the gear and skills to do it right so if someone were to work with them on testing and feedback maybe they'll make the flexplate and the rear output shaft solution.

Question in the end is vs the 4L80e, is all this an upgrade or a lot of work to move sideways? Not sure but a modern killer trans in our platform does help our community.

An 8HP is an unequivocal upgrade from any four speed transmission.

It's a clutch-to-clutch all planetary design (no drums, no bands). It has eight gears so no matter where you are in terms of speed, if you mash it you're going to get a downshift and acceleration, even at 150+. It's rated for 700nm in the lowest end most common variety, and that's continuous load. It'll probably happily take way more than that for short periods. The TCC clutch is designed to be locked up almost all the time, so once you're moving it's almost as efficient as a manual and you don't get the heat problems from putting a pile of power into an unlocked converter.

First gear is really low, so you'd probably need to pair it with a 3.08 or even a 2.96 rear gear set, otherwise first ends up being useless.

 

[GNVYUS 1]

Thanks I didn't know that, sounds like the Nissan trans for the GTR.

Being able to ditch the drum and bands seems like a plus and being able to lock it up for 0% slippage at the right rpm would be another plus. Now will it fit and be tuneable and not a bank account buster.

Damn 1st gear though is crazy, we all would be in for a 2.04 rear gear to match. LOL

 

[Mr.Spool]

The 8HP90 has a 5.0 first gear, input 700tq and you get 3500tq output vs like 1800 with our 2.74. Better have sticky tires and traction with that thing in there and then we'd all probably need to go to a 3.08 rear gear to calm that down then gain a great 8th gear overdrive rpm at .64.

Ya kinda say right there.
5.0 1st
Now pulling rear gear would really need way below a 3.08
So the rear doesnt help the car at all.
This tranny is not for the buick world
But one can put anything in anything with enough money.

 

[Mr.Spool]

Alot of these 6/8/10 speed transmisions have problems
Nothing is a sure thing.
But who is fixing and servicing the builds.

 

[Mr.Spool]

The TCC clutch is designed to be locked up almost all the time

A tcc clutch is a wear item no matter what its made out of.
We have worn out Kevlar clutches in wot situations on the dragstrip and street on high end converters.
Why many go non lock.

 

[Mr.Spool]

Converters respond to power period.
Our platforms will not go fast or have power on tap with bigger turbos and super tight converters.
These motors cant move the air at very low rpm.

 

[Turbo6inKY]

Alot of these 6/8/10 speed transmisions have problems
Nothing is a sure thing.
But who is fixing and servicing the builds.

That's the thing about the 8HP, it doesn't seem to have problems like the others. And it's still in production, so we're still in the part of the timeline where if you pop one, it's still cheaper to just go get another instead of cracking it open and fixing it. Set the busted one in the corner until the time comes where we start harvesting cores for parts.

 

[Mr.Spool]

That's the thing about the 8HP, it doesn't seem to have problems like the others.

Its always what its behind

 

[Mr.Spool]

And it's still in production, so we're still in the part of the timeline where if you pop one, it's still cheaper to just go get another instead of cracking it open and fixing it.

Thats the nice part of it

 

[hemi8]

https://www.domi-works.com/collections/8hp-adapter-kits/products/gm-bop-to-dodge-8hp-845-850re-70-75-90-95-charger-challenger-scat-pack-hellcat-trackhawk-ram-adapter-kit

This adapter plate and converter adapter plate fits the GN, keep your flex plate and starter.

 

[GNVYUS 1]

Nice, there's a kit.

In case anyone wants to run trans gears and do rpm, mph etc calculations.

Spicer Transmission Ratio RPM Calculator

Use the Spicer Transmission Ratio RPM Calculator to determine your engine’s RPM based on the transmission gear ratio, tire height, MPH, and ring and pinion gear ratio.

spicerparts.com