Build update - 4T80 3800 Turbo (Page 1/8)
LFiero67 JAN 29, 06:31 PM
Car has been parked a few years, since selling the GM Racing input shaft and 1” chain. Was originally parting out the car, and did sell drop spindles, seats and a few other parts.

Recently after seeing Brandon Furches with LS4 King put over 800 whp through a 4T80, I decided to try a one out.

Picked up a 4T80 on EBay for $200 shipped, took it apart, found the clutches still had part numbers on them. Changed some seals, bushings, modified accumulators and separator plate for more positive shifts.

Picked up a set of Pontiac Transport uprights for the rear suspension to accept the larger diameter Cadillac Axles. This change should reduce the instances of this:




Took my spare subframe, control arms and the transport uprights, and used electrolysis to clean them up:





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10.007 @ 135.54MPH. <-- Video
Best 60' 1.42
Best mph 138.82
Billet 6262 Precision turbo, PT1001 intercooler, ST1 cam, 140lb springs, comp pushrods, HV3, stock L32 bottom end and heads.

Old M90 XP Cam time -
11.425 @115.60
1.543 60'

LFiero67 JAN 29, 06:44 PM
Painted everything up:



Transport uprights assembled with new bearings, rotors, calipers. Subframe has new poly control arm bushings, ball joints, inner and outer tie rods.

New front crossmember fabricated and welded in, removing stock crossmember.



Mocked up spare 3800 and the 4T80. Small amount of block ear removed for clearance.
(Not my pic, but same mod)


Lots of measurements and got engine and trans situated in subframe, centered for equal length axles. Built transmission mount brackets using angle iron, plate steel, rectangular tubing, poly bushings and sleeves.

These are before they were cleaned up, and painted.



Added a poly mount to the stock 3800 engine mount:



Cut some mounting tabs and welded everything to the subframe.



This mount setup is much easier to get the engine and trans on and off the subframe. It also should be a bit stiffer than the mounts I was using before.
------------------
10.007 @ 135.54MPH. <-- Video
Best 60' 1.42
Best mph 138.82
Billet 6262 Precision turbo, PT1001 intercooler, ST1 cam, 140lb springs, comp pushrods, HV3, stock L32 bottom end and heads.

Old M90 XP Cam time -
11.425 @115.60
1.543 60'

[This message has been edited by LFiero67 (edited 01-29-2022).]

LFiero67 JAN 29, 06:52 PM
Now that everything is ready as far as subframe and mounts, it was time to drop the old drivetrain out. This is the engine I last installed in 2013, has run 10.00 & 138 mph with the GM Racing equipped 4t65. It is currently bolted to a stock 4t65 that I installed after selling the race trans.

My son has been helping with all of this work, and this was the first time he has been around to drop the engine. He has been excited to help.



Mandatory standing in engine bay pic, first one for the boy.



Next steps are cleaning up the engine bay, getting the good engine bolted up to the 4T80, fit it all in the car. Looking at swapping the stock pcm for TerminatorX Max to make running the 4T80 easier and allow for better fuel tuning and stronger ignition with LS coil near plug.

I will try and update as we progress.

[This message has been edited by LFiero67 (edited 01-31-2022).]

RichLo1 JAN 31, 01:18 PM
Excited to see this progress!

Do you have more info on those transport hubs to accept the caddy axles?
LFiero67 JAN 31, 02:07 PM
Look up 6000 uprights, same setup.


Edit:

Look up 6000 uprights on here, similar changes required to bolt in, but transport uprights also have larger cv shaft splines that match the Cadillac axles.

[This message has been edited by LFiero67 (edited 02-03-2022).]

Dennis LaGrua JAN 31, 03:47 PM
Nice job so far but are your sure that you need a 4T80? That adds weight. Darkhorizon (Scott) on this forum and ran a 9.87 1/4 mile time at 142 mph with the 4T65eHD. From what I have read they can be built to take 900HP.

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

olejoedad JAN 31, 04:43 PM
4T65 series is know to crack the case around the hydraulic pump above 800 ft/lbs.

The -60 series case is actually beefier than the -65 series, and many are using the -60 rather than the -80 for high torque builds.

The -80 is a beast, but it is heavy.
LFiero67 JAN 31, 05:31 PM
Dennis, I am well aware of what a 65 can handle. I had the same parts in mine that Scott has. I sold those parts, they are not available anymore, other than used. As I said, I am trying a low dollar option instead of the $4-5000 4t65 that I used to have.

I ran a 60 before I went to the 65. Couldn’t keep second gear in the 60, but that might have been a wear issue. The chain in the 60 is the “upgrade” for the 65. I destroyed 3 of those 7/8” chains in my 65 with the turbo before getting the GM Racing 1” chain. I also broke a 4340 and 300m input shaft before getting the GM Racing input shaft. The 7/8” chain and aftermarket input shafts are ok for M90 builds, but not with what I am making for power/torque.

I have run a 4 speed manual, a 4t60, a upgraded 4t65, and a GM racing 4t65 in this car over the last 20 years.

The 4t80 is 100lbs heavier, and the suspension upgrades will likely add another 30-50, I am ok with this.

As I stated, people are putting 800 whp through stock 4T80s in FWD applications, I am going to attempt to put 6-700 rwhp through one and see how it goes.

The car is capable of running 1.3x 60’ times, but the stock sized axles were never up to the task. 9 lbs of boost on the launch would give a 1.4x 60’, 10lbs on the launch would shear the axle. The new setup addresses this as well.

There is a chance that none of this will work, but I am going to give it a shot.

------------------
10.007 @ 135.54MPH. <-- Video
Best 60' 1.42
Best mph 138.82
Billet 6262 Precision turbo, PT1001 intercooler, ST1 cam, 140lb springs, comp pushrods, HV3, stock L32 bottom end and heads.

Old M90 XP Cam time -
11.425 @115.60
1.543 60'

[This message has been edited by LFiero67 (edited 01-31-2022).]

Will FEB 01, 09:44 AM

quote
Originally posted by LFiero67:

Look up 6000 uprights, same setup.



Not so much...

At this point the U-Body uprights are probably more common and the '92-'96 minivans have 11" brakes shared with LT1 Camarobirds.

Also, the A-Bodies used 27 spline outer CVs while the U-Bodies had 33 spline outer CVs. The 33 spline U-Body bearings let him drop the Cadillac axles right into place.

[This message has been edited by Will (edited 02-01-2022).]

LFiero67 FEB 01, 02:11 PM
Edit : car uprights were available with 5x115 bolt pattern, but not larger axle splines.

These are 95, so they have the larger brakes, with same calipers as Fbody. Unfortunately they are iron calipers, and 1.25” rotors, so it’s heavy.

Requires the ball joints and outer tie rod ends to match the knuckles, but they bolt onto the Fiero control arm and inner tie rod.

[This message has been edited by LFiero67 (edited 02-03-2022).]