Supercharged 1UZ Bangkok Drag Truck

PARTS FOR SALE: Send an email to [email protected] for availability.


Yep make sure the Allen headed bolts are tight in alloy ring because you cannot get to them to stop them turning..."Oh the joys of playing with these things Lol"...
I find it easier to drop the crank adapter in freezer over night also..
Unless you can get your hands on some liquid nitrogen / C02 etc....
Easier to fit into crank...
Everything is back together now and the "new" motor has started and checked for leaks -- all good. It runs and revs like it is suppose to. Unfortunately, I am off to The States for the next three weeks so will not be able to strip tune it until the new year. Oh well. Happy Holidays everybody.
Drive Ring Complete

Among the many technical decisions I had to make along the road of this %##@% project was how to mate the race 1JZ auto box and torque converter (TC) I already had to the 1UZ engine (using a 1UZ bell housing). Since nothing comes easy when fabricating a unique combination, I discovered that the 1UZ bell was "thicker" than the 1JZ bell, necessitating some kind of spacer between the ring gear (flex plate) and the TC so the torque converter splines would mesh correctly. My initial plan was to put stands between the flex plate and the TC . . . . and then, later, to weld gussets for strength. The more I thought about it, and the more helpful feed-back I got about it, left me uncomfortable with the reliability, at least in the long run, of such an approach. The "right way" to have done it would have been to buy a proper 1UZ race TC and build a 1UZ race auto box. But the next best, and very good way to do it is with a drive ring.
This was the original approach. The parts are labeled.
I later properly welded gussets for "strength" - which could have actually weakened the flex plate.
The proper way: a high quality steel drive ring. The drive ring is the same thickness as the stands in the photo above, but, of course, goes all the way around. There are two ways to bolt in the drive ring: bolt the drive ring to the TC and then bolt this assembly to the flex plate. The other is to put bolts from the flex plate all the way through the drive ring into the TC. I already had bolts the right length, so I used the latter method (even though, as can be seen, the drive ring was machined for either method). The locator knob on the front of the TC still fits into the extended pilot bushing at the rear of the crankshaft -- for support of the trans input shaft as in the standard configuration.

By the way. I pick up the completed race truck tomorrow morning. Next Friday and Saturday I have the drag strip to myself for set-up, test and tune.


Super Moderator
Staff member
Interesting your concern with the welded stands as this was the way Range Rover did their original Torqueflite auto trans.

They used stands welded (and not gusseted) to the flexplate and 25 years later they are still running.

I think your final solution is much more elegent and won't let you down.
Back Home

Thanks, yes, I got the drive ring idea from the Castlemaine web site. I picked up my racer yesterday and trailered it to my drag strip garage. I made one on-and-off blast down the quarter mile at the deserted drag strip to see what the new package felt like. There needs to be some more tuning of the combination, and the PSC (trans controller) needs to be recalibrated to upshift, but it went like stink from 4000 upwards. Next Friday evening I will have a full set-up, test and tune session with all my mechanics and tuner buddies present and see if we can make this little baby light up a number.:D
I finally got around to getting a look at the busted rod. Here are some better photos for the amateur metallurgists to sink their teeth into!
Yep, there's your problem!


New Member
Look at the discolouration of the wrist pin....looks like it's lost oil and suffered major heat issues? Loads up the poor already stressed rod?
My good friend Khun Mac dropped by my race shop today and we had a look at the PCS (transmission controller) and discovered we did not have a signal from the TPS . . . so it is not going to shift until we get that sorted out. However, it was a good chance for him to take a few quick romps to check the AFR. It sounded very healthy, but it is too lean below 4500 rpm. No problem . . . my "tuner," Art, will have at that next week-end. Here is what we did:
I hope you all enjoyed the YouTube clip from last week ( ). All of my 'brain trust' will be at the track this Friday evening for a real test & tune sorting-out-the-combination session.

I have to say, "Oops, I forgot!" about my last posting . . . my friend John, "The High Road Skulker," pointed out that, because of my short header collectors and the location of the O2 probe, I am not getting a good AFR reading below 3000rpm. Installation guides from several AFR/O2 probe manufacturers confirm this. So, I am not really lean at the low RPMs after all . . . . however, a cursory look at the video clip indicates it is a bit rich somewhere in mid range. A proper, data collecting, AFR device will be employed on Friday. Wish me luck.
And the Test & Tuning ENDS! Yep, the new motor is now tuned to perfection: huge horsepower, titanic torque, splendid sound . . . . but too much for the transmission . . . . which promptly broke. Oh well. I now have to think through my options . . . another built A340, a C4, or a Powerglide. I guess I should also pop for that 9" Ford rear-end as well . . that Nissan 1-ton unit is not going to last either . . . and maybe go for the 4-link as well . . . . . Sheesh!


"Supra" Moderator
Staff member
More HP always has a way of finding the weak link in the powertrain.

Another A340 just isn't a good solution for a V8 with lots of torque. You need a TH400 or a Powerglide behind that motor.

A number of guys have converted their high powered Supras to TH400's and it's fairly straightforward. Shouldn't be that difficult to do with a UZ, and IIRC, our member RedSupra did it already for his UZ/Supra project.
Yep, time for a stronger transmission. I made 100+ 1/4 mile runs on that Toyota A342 trans with a best of a 10:53 without failure, and won lots of trophies, so I know they are strong. I am looking at a race C4 trans for the replacement: they can be built strong, are small enough to fit the existing trans tunnel, are easy to adapt to the 1UZ (there is a dedicated bell housing for this combination made in Australia), and three speeds will keep the engine up in the RPM band where the little supercharger makes boost during more of the run. I will also build a bigger/stronger rear end as well . . . . all the parts that my new horsepower and torque would find as the weakest parts . . . . I do not really know my horsepower numbers. If you have followed this thread, my dyno event was a bit of a debacle . . . and those numbers were on a motor that was overloaded and eating itself up. this past week we tuned the lower RPMs by reading the plugs, changed the plugs, and got a major jump, literally, in torque. I will dyno again later. We disregarded the AFR below 3500 (O2 sender too close tothe end of the collector). More later.


Yep we have 4 pinion built C4's in our drag 4.0 Ford 6 cyl turbo cars..
A billet steel 20mm X 30mm girdle plate between alloy pan and housing prevents housing twisting...
600+ rwkw and bags of torque they have held up fine..With 10.5 X 28" slicks..
You'll gain with trans brake & two step also...


A Class $3800 with converter and bellhousing adapter & transbrake 4000 rpm converter..

Tony $5k with a little more adaption, sump girdle and converter 3000 rpm..
What they said they would do is just EXACTLY as they said..

Have thought of a Powerglide with lower 1st gear ??
Only 50KG dry...Summit have good PG's for $2k although it doesn't have adapter and converter ...

The Jap auto as used in newer Nissans etc seem to strengthen up well...
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