Builds 550hp 2JZ 1978 RN28L Build

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

Used to get corner weights for road racers with that tool before corner scales were a thing. At one time could buy the tool from places like Pegasus Racing. Now I can't find them sold anywhere.
Best accuracy happens when the beam is level with the tire ever so slightly off the ground. Can see the various holes that have been drilled in the stand to achieve that.

I have pondered putting one of those valve spring testers that are used in a vise or a press in the stand to make it easier to take a reading. Just don't use it enough to go to the trouble.

A model that I made of it years ago so that someone else could copy it:

i-7gbmzcS.jpg
Your setup actually gives me a lot of ideas. I could take that layout and put the crane scale getting pulled in tension on the right and get a really accurate reading, and then instead of the wheel lifter could make that jog down and just have a little ramp to drive onto it. I've thought about converting the crane scale into a tire scale, but never put much brain power into it but your rig gives me lots of ideas.
 
I finally got some clips of the truck!



As far as overall truck updates, I was very concerned earlier in the week that the engine was having issues. I got lunch in it and the truck kept dying on me, but only when I would stop. It turned out it was the low oil pressure safety kicking in and turning the engine off. My oil pressure at idle was dropping below 15psi which really freaked me out, I was pretty convinced something was fried. Additionally my catch can had a ton of fluid in it, though I hadn't checked it in a few drives.

upload_2025-3-27_20-27-4.png


I had not changed the oil yet, maybe a bad move, so I drained it expecting the worst but it didn't look absolutely terrible? I didn't take a photo, but it was very dark and shimmery but there were no big chunks left on the sides or bottom of the bucket, and cutting the filter open and it looked fine. After talking to my neighbor, and the tuner, and researching, I've kind of concluded I just freaked myself out. First of all, the engine probably has 100 miles on it without changing the oil and this includes the break in oil and s*** still in there (probably should've changed it sooner, oh well). The filter being clean and no big chunks anywhere should mean the engine is fine, and the oil just being dark and shimmery would be expected from initial break in and flushing all the s*** out from machining and assembly.

The catch can being so full is most likely since I have very loose ring gaps (.028-.030) which is intentional if I ever want to up the boost, plus the rings probably aren't seated yet, and every single time I drive it it sees 20psi of boost. And at idle there's no crazy blow by, you open the oil cap and there's nothing choofing out, and the exhaust looks fine. With that said, I do need to be diligent about checking the catch can, this below is one drive after emptying it:

upload_2025-3-27_20-31-47.png


It doesn't smell anything special, your usual catch can brew. So I think that's fine, and comparing it to my buggy which is built very similar and seen a lot of abuse, it fills the catch can pretty fast (much faster than my Tundra for example) and it's likewise a built engine, loose rings, and sees boost and doesn't get a lot of miles.

Going back to the oil pressure, the 2JZ spec for idle oil pressure minimum is 7psi. SEVEN. That seems insane! But multiple people I've read from multiple places say that their idle pressure is 15-20psi, and as long as it's above 7psi don't sweat it. It seems weird to me that it seems to have dropped so much with miles on the engine, but by 2000rpm it's at like 50-60psi and over 100psi at high rpm. The low oil pressure safety was just kicking in when you'd punch the clutch, rpms fall and overshoot so it'd hit like 700-800rpm and then before the ECU brings the rpm back up it sees the pressure is below like 15psi and turns the ignition off. My normal 1000rpm idle the pressure is pretty consistent at 18-20psi which sounds pretty common actually, and the tuner was unphased by it and just said he recommended lowering the oil pressure safety limits at low rpm.

With all of that said, I did change the oil over to the Amsoil 10w-40 that the buggy runs and swapped filters. I'll change this oil in another hundred miles probably and see if there's a trend, but from a raw feeling perspective the engine feels totally fine and happy (knock on wood). Last time when I had the main bearing let go, I could FEEL it, the engine just felt off and felt like there was a drag on it, and I noticed that two blocks from the house after the bearing started to go. This doesn't feel like that, it doesn't feel like anything, it pulls like an absolute freight train, idles great, runs great, no indication anything is wrong. Based on all of that, I think it's fine and just keep monitoring stuff like usual.

I'm also already getting parts from Quick Performance, so far they've done 2nd day air on everything for who knows why, but I'm not complaining! I have everything besides the axle housing. Today the diff and axle shafts came in, and a few days prior the brakes! I'm so excited for this!

upload_2025-3-27_20-39-1.png


upload_2025-3-27_20-39-12.png


upload_2025-3-27_20-39-24.png


upload_2025-3-27_20-39-36.png


And it needs it so bad, I thought I felt some bad axle wrap the other day, but after throwing the GoPro back there, you can see in that video the axle moves so much it's insane. I'm guessing that's what actually broke the pinion more than anything else. She needs links real bad, but with how fast Quick Performance is sending me stuff that might happen sooner than I'm prepared for!

For the moment I've chilled on working on the truck so much. I did tweak the boost control and went back to the setup I had before of just straight duty cycle control of the wastegate with MAP vs RPM and that has stopped it overboosting, but it needs a lot of work still and is pulling too much boost more often than not, but I'd rather ramp up the boost instead of boost protection kicking in which feels like the driveshaft exploded or something and is so abrupt and jarring you think something broke since it instantly turns fuel off. So there's more power to be had with the current tune, but it's happy and I'll slowly up the boost and control logic as time goes on! It is such a fun little truck and makes so many turbo noises, the sounds are so cool and a huge part of the driving experience, it's unlike anything else I've been around with how much personality and emotion the drivetrain has.
 
Another day, another story
:D


Some friends were heading out camping yesterday, and they said their first campsite was only 1.5 hours down the road so I decided I'd take the Hilux and stay with them the first night. The truck has been running great, has the engine protections working, so even if my laptop died so I lost my gauges I was confident the truck would be fine. I threw a sleeping bag, sleeping pad, tent and a couple clothes in the truck. My friends also packed my Coleman mini bike in the bed which happens to be the perfect size to sit on the frame rails sideways, and then a camp chair strapped to the cage and that was the extent of planning I had!

upload_2025-3-29_9-34-14.png


upload_2025-3-29_9-34-30.png


We went over the mountain on the way to Bryce Canyon. Truck's first time climbing the mountains with the new setup, and no issues going up. I was worried about water on the road, but besides a few trickles nothing bad. Just had my headphones in, laptop with the dash up in the footwell, just cruising between a GX and a F250 and some beautiful weather! Sadly though, my wife was correct not an hour earlier saying she didn't trust the truck to not break hahaha

I literally texted her saying the truck is doing fine, don't worry, and then not two minutes later said can you come get me.

upload_2025-3-29_9-37-59.png


upload_2025-3-29_9-38-12.png


upload_2025-3-29_9-38-26.png


The GX passed two cars, and another car was coming the other way so instead of being in the GX's ass since the truck is way faster, I just chilled, let the other car come by and then went to pass. I didn't think I was particularly pushing it hard, but it's so hard to tell, I rarely use more than 50% throttle in the truck because it makes so much boost, so fast, and the torque and push back in the seat is immense without needing more throttle. I think I was in 4th gear, and just letting it rev out, and then higher in the rpm got the (now classic) thump in the rear. For some reason my mind always defaults to the axle falling out? Regardless, hear/feel the thump as I shoot past the second car I'm passing and instantly the truck is going sideways in a clockwise spin. Around 180deg I see smoke everywhere, and the whole time I'm kind of spotting and waiting for the truck to roll. Again, not sure why my mind defaults to that, maybe it's from all the offroading I do and rolling vehicles so I expect anything will roll if it gets sideways. The truck spins past 180, and has now essentially pirouetted around the second car, going from passing on the left, to spinning clockwise and now facing forward again in the right hand lane, and then sliding off the shoulder. Once the truck started sideways I hit the brakes, I figured locking them up (no ABS) wouldn't make any difference since it's already out of control. The first time the rear end let go we still had brakes and control, this time it was instantly sideways almost at the same time I felt something happen in the back.

What I THINK happened, there was so much axle wrap that the U joint got maxed out, and that locked up the rear end. This is why it started spinning right away. The diff still spins, but one of the yoke ears got ripped in half and the driveshaft is buckled/twisted, and the rear tires have flat spots. and the leaf springs are noticeably warped now. The U joint maxed, locked the axle for a second, the engine kept spinning, twisted the driveshaft and broke the yoke.

upload_2025-3-29_9-48-44.png


I'm sure the cars I passed absolutely s*** themselves as a loud little truck passes them and then bursts into smoke and 360 spins in front of them. I was totally fine, the back of the truck was maybe 4ft off the side of the road, so no banging around or anything since it just spun down the road and then settled into some loose dirt. I called the wife, and she grabbed the Tundra and trailer to come get me. In the mean time the front right bead had been popped, so we got that reseated.

upload_2025-3-29_9-48-22.png


We then flat towed the truck to a gas station back where the two highways joined, and waited for the wife to show up.

upload_2025-3-29_9-49-26.png


And needless to say, that ended my camping trip! I thought the truck was going to do great, and I was even trying to be mindful of loading up the rear end since we know it was a weak spot. I figured it might break at some point, I didn't figure it'd be so fast! Especially after all of the tuning and WOT runs lately, I thought it had somewhat proven it would be fine staying at lower power---but as I said, "lower power" can still be a lot!

This morning I unloaded it to see what other carnage there was besides the obvious. Maybe the most sad actually is one of the Coleman's tires got popped.

upload_2025-3-29_9-52-54.png


The Coleman was fine throughout everything, and then FLAT TOWING the truck to the gas station, the front tire shifted and got rubbed through on the back tire of the truck! This was probably the saddest part, some stupid collateral damage that was totally avoidable!

upload_2025-3-29_9-54-0.png


But back to the truck, both cooling lines this time broke.

upload_2025-3-29_9-54-24.png


upload_2025-3-29_9-54-35.png


Of course the exhaust once again got mangled. On the plus side, I will definitely install a muffler to try to quiet it down this time I fix it!

upload_2025-3-29_9-55-19.png


The rear diff still spins fine, but there is a lot more backlash and some radial play now. The yoke has an ear ripped in half, and is actually cracked in half down the center.

upload_2025-3-29_9-56-3.png


The driveshaft that I got a week ago is now dead, albeit not in two pieces! Arguably the little diff hoop helped.

upload_2025-3-29_9-56-48.png


Lots of dirt and mud under the truck, coolant, gear oil from the trans, but at least the axle didn't spit oil everywhere!

upload_2025-3-29_9-57-29.png


Probably need new rear tires already, we'll see how bouncy they are. At least they're cheap!

upload_2025-3-29_9-57-56.png


The current mystery is the front right alignment is WAY off, the tire is shifted backwards an inch or two. I can't find anything so far that's obviously bent or broken. I do have the 3D scan of that corner though, so have been comparing scan to real life measurements. So far the lower ball joint seems to be pushed back 1.5-2.0", and the upper arm seems to be in the same spot. But the lower arm doesn't seem to be bent, the mounting points vs the the ball joint are the same distance. There is some dirt that is shifted in one or two spots, maybe that amount of motion is enough to have moved the LCA backwards that far?

upload_2025-3-29_10-0-31.png


I'll need to investigate more, maybe there's just some bushings or the LCA bolt got bent or something, since the frame seems fine, UCA seems fine, LCA seems fine, but the LCA seems to be angled back quite a bit.

And that essentially wraps up the latest fiasco with the truck! My neighbor said this is twice the truck has tried to kill me, I said first of all the first time you were driving, and second of all both times the truck has stayed straight down the road. It's not like it has tried to veer into a telephone pole or something, so maybe the truck is trying its hardest to contain the fury. All of this was kind of expected, and why I went ahead and bought the 9" axle so all these failures I keep having will stop happening. Axle replaced, go to a linked rear in, she'll be built like a tank to handle the power. I was hopeful it would last a bit longer, but oh well, the truck will go under the knife next to get the front right corner fixed up and then fix everything underneath and cut off all the leaf spring and axle parts in preparation for the 9". And since the radiator is now drained, I will also pull the heater core and replace that since it seems to have a slow leak onto the floor.

upload_2025-3-29_10-6-22.png
 
You are a mad man. And I like it. If you aren't dead, keep building
As much as it may seem, I don't have a death wish or even want to go that fast. I just like to build cool stuff and want it to work, if the rear axle could just work that'd be great and wouldn't look like I have a death wish :grinpimp:
 
Are you determined to go 4 link? No denying that axle control needs to happen in the worst way, but what about using some housing rotators with a set of ladder bars? I'd think those could all be bought off the shelf for reasonable.
 
Are you determined to go 4 link? No denying that axle control needs to happen in the worst way, but what about using some housing rotators with a set of ladder bars? I'd think those could all be bought off the shelf for reasonable.
I'm not married to it, but a counter question would be why NOT to link it?
 
No idea, was just throwing out there as a possible option. Simpler, gains the needed control for a bit less effort & possibly cost (no C/O's needed).

OTOH, this is a toy to play with, so effort level doesn't seem like a concern.

[EDIT] Something like these: Pro Street Sportsman 36" Ladder Bars - https://www.cachassisworks.com/p-305-36-sportsman-pro-street-ladder-bars-adjustable-lower-tube.html I'm going to have to dig a little for the rotators.[/EDIT]
[EDIT again] There we go! C/E3740 -Housing Floaters (Pair) - https://www.chassisengineering.com/product/c-e3740-housing-floaters-pair/ [/EDIT again]
 
Last edited:
No idea, was just throwing out there as a possible option. Simpler, gains the needed control for a bit less effort & possibly cost (no C/O's needed).

OTOH, this is a toy to play with, so effort level doesn't seem like a concern.
I've had a number of friends recommend ladder bars or traction bars, both seem like a janky solution that doesn't gain much unless your goal is to avoid buying shocks or a couple extra joints so I haven't even looked into them to be honest. Granted, I'm not a suspension expert so maybe there's a benefit besides cost/effort to those setups, but otherwise a 3 or 4 link seems superior for handling and adjustment. And laying out and setting up suspension stuff is a lot of fun for me, I think linking it will be a breeze considering how little travel the truck will have and how much room is out back.

Right now I'm leaning towards a parallel 4-link, originally I was going to do a triangulated 4-link since it's simpler, but after some reading there was one good reason to do a setup with a panhard--and that's individual adjustability. With the panhard you can isolate anti squat from roll center adjustment, where as with a triangulated 4-link those are coupled together. If you want to change the roll center with a panhard you just move the panhard up or down, with a triangulated 4-link if you want to do the same without adjusting anti squat you have to move all four links (and vice versa to adjust anti squat, compared to just moving the uppers or lowers on a 3 or 4 link with panhard). I think panhards are ugly and not as visually simple as a triangulated 4 link, but in this case I think it will be the better option. With that said, I don't plan to have a swiss cheese mounting bracket of all the adjustment options since I think that's ugly, I'll probably have like three holes on the upper link chassis mounts, and three holes for the panhard so I can do some adjustment but keep it simple looking and hopefully have the link position correct out of the box.
 
Dig around my link above, they've got kits out the wahzoo for both ladders and 4 links that are drag or "Pro-Street" oriented. I've no doubt that you can build all of those parts, and likely for less overall, but there maybe some tech that can be learned from looking at them and possibly some parts that will be simpler to just buy.

The end goals for a pure drag race suspension set-up are a little different from a "Pro-Street", 4x4, or road racing set-up. They seem to want a high rear roll center, or used to anyway. Been a while since I was immersed in all of that.

Ever played with a Watts Link or a WOB link? Both are designed to get a more linear vertical travel path than a panhard bar can provide. More common to see either in a road race suspension (& the WOB is pretty rare).
 
Dig around my link above, they've got kits out the wahzoo for both ladders and 4 links that are drag or "Pro-Street" oriented. I've no doubt that you can build all of those parts, and likely for less overall, but there maybe some tech that can be learned from looking at them and possibly some parts that will be simpler to just buy.

The end goals for a pure drag race suspension set-up are a little different from a "Pro-Street", 4x4, or road racing set-up. They seem to want a high rear roll center, or used to anyway. Been a while since I was immersed in all of that.

Ever played with a Watts Link or a WOB link? Both are designed to get a more linear vertical travel path than a panhard bar can provide. More common to see either in a road race suspension (& the WOB is pretty rare).
Never heard of a WOB but looks neat. The watts has never turned me on, I think it's cool but seems like a lot of additional parts and complexity for minimal improvement.
 
To me the downside of a Watts is that if you're after a really low (or really high) RC the only option is to lay it flat, and I'm not convinced that it will work as designed like that. Real risk of running out of angularity in the joints.
The WOB has just as many joints and moving parts, but does allow placing the RC lower than a Watts.
Both result in a shallow 'S' shaped travel path, where the panhard is a simple arc. Downside to a very low RC panhard is making the chassis mount strong enough while hanging way down there. Unless you're a Brit and put the frame under the axle......

If I couldn't make a long panhard (to keep the lateral dislocation to a minimum over the expected wheel travel) I'd go with one of these other options.
 
Always good when stuff is falling out before you even pulled the diff!

upload_2025-4-2_8-30-26.png


upload_2025-4-2_8-31-13.png


upload_2025-4-2_8-31-29.png


Quick Performance is wickedly quick! I got another tracking number, and I think it's for the axle housing already! Should be here later this week. With the rear stripped down I'll now scan the back and throw everything into CAD to design the brackets, figure out axle placement, look at suspension geometry, and size what shocks to buy. But first I decided to scan the front right again so I can compare them in CAD and see what's bent since visually everything is fine.

upload_2025-4-2_8-33-18.png


Overlaying the two scans is a pain to actually get very close. This position seems the most correct I've come up with, and roughly matches the ball joint position difference I got with the tape measure.

upload_2025-4-2_8-33-47.png


The gist of it is, I think both upper and lower control arms themselves are bent and that results in the hub being pushed to the rear over an inch. I was hoping to find a set of new arms, but so far haven't found anything. For $150 there's a couple options on ebay of used nasty looking arms.

upload_2025-4-2_8-40-14.png



If I can't find any new replacements, I think I will just cut the front of the control arms, bend them back forward, and then weld the arm back together in the correct position. A bit janky, but we're not looking for perfect handling, and the whole front suspension will get deleted in the future anyway.

Next up will be scanning the rear and hopefully this weekend figure out everything to buy for the new axle!
 
any possibility later model 2wd arms would work?
pretty sure there are am version available too.
 
What are you thinking to eventually replace the front suspension with? I had been thinking to just make some tube arms patterned off the good one until you mentioned that.
 
What are you thinking to eventually replace the front suspension with? I had been thinking to just make some tube arms patterned off the good one until you mentioned that.
Hadn't put a lot of thought into it, but delete the whole subframe, add normal brackets welded to the frame, some type of adjustable arms so I can get easier caster and camber adjustment. I have a Prius steering rack and electric assist already, so install that, move the steering rack to the front, front diff on the back side, then probably some billet aluminum spindles, maybe billet control arms if I'm feeling froggy. Maybe increase the turning radius depending on how drifty I want to be. And convert to (normal) coilovers. Oh and some bigger brakes and vented rotors.
 

Users who are viewing this thread

Back
Top Bottom