550hp 2JZ 1978 Hilux Build

Looks great!

 

So your truck already had an 8" in it? Interesting. Have you looked into an 8.8 from an explorer? Easy way to get disk brakes and 3.5 or 3.7 ish ratio. Alot of guys in my offroad group got a land cruiser 9.5" axle and centered it using the existing 8" axle tubes. That way can use original shafts and brakes and no changes to width or suspension.

 

So they chopped the axle housing tubes off the 8" diff and welded those housings to the 9.5" diff?
What vehicles are they doing that to?

 

The main draw to the 9" is aftermarket support and it being the go to axle for essentially everything. I thought about a narrowed 9.5 but I don't know if you can even get axle ratios high enough, and you're very limited for differential options (and just in general it's not a common diff since only the LC came with it). I have not looked into the 8.8 since the 9" is the good to axle in general, it looks like the 8.8 might be trivially lighter but the 9" has way more aftermarket support and can handle more power, and when you can get a complete 9" for $2k cost isn't a big factor then.

 

I couldn't handle it, Ford 9in ordered!



Quick Performance website is pretty dope, and lots of good reviews on them so I gave them a call and a guy talked me through all the options. He said they're at a 4 week lead time for the housings, so I said fuck it let's do it and get it going!

I think I'm going to pull the 8" diff I just installed, thinking about it I wonder if a bearing is fucked up and that's why it feels so awful. I can pull the ring gear out and see if the pinion and ring gear bearings are all spinning nicely. If they are then I'll put it back in and send it, but I'd hate to put $100 of gear oil in just for a bearing to be messed up and it shits itself instantly. If I can get the 8" to work combining parts from the old diff, great. If not then oh well and I'll start cutting the leaf spring brackets off the frame! At least the final solution is now on order! In a few weeks I'll order link parts and find some coilovers.

 

Nice! You'll have a much harder time breaking that one.
Should be a one and done solution.

Thanks for a great (ongoing) build and write up!

 

Fixed that for you . . .

 

Talked to dude I got the 8" from, he said it used to spin fine so was probably just gritty or had rusty bearings. Ran out to the shop before dinner, pulled it back out and tore it down. Turns out the pinion nut was just so tight it squished the bearings and that's why it was so hard to spin. With the yoke off it turns like a champ! And this was a good move since there's no pinion seal on it, so if I filled the axle it would've just leaked everywhere. If I had swapped the adapter flange that I didn't have time to do yesterday, I probably could've solved all of this since I would've seen there was no seal, and probably would've found out the pinion bearings being overloaded was the issue. Oh well. I'll get a seal, slap it in, throw the adapter flange on it, tighten it on the bench to make sure it can still spin nice, and then slap it back in the truck and we're good to go. I'd call that a successful 15 minutes today!

 

Yep pretty much. 8" axle tubes welded to a 9.5 housing so that the 9.5 is centered and you can use the 8" shafts and brakes and all existing suspension. Popular upgrade for old 4runners and pickups. Lots of guys in our rock crawling group have done it.

 

Dang, links and coils yet too! You don't F around!

 

I learned something new. Thanks.

 

Disc brakes too!

 

That's how I got my Tundra. Little story to explain, if I may.
I was looking to convert to rear discs on my long travel RCSB S/C'd Tacoma. Searched to see if the then current Tundras had them. Searched to see it there were RCSB versions of the then current Tundras. Discovered that there were. Bought one.

 

Got the diff together and back in the truck and she spins real nice now! I did not look at the crush sleeve or if there was a spacer or anything, I swapped the flange on I needed and just tightened the nut until it felt good and then staked it!

The coolant tube had welds cracked, so pulled that and welded those up. It also got beat on real good in a couple spots, they didn't appear to be cracked but I filled in the gouges with weld to be safe.



The exhaust got absolutely destroyed.





Ordered some new 3.5" tubing but it has not shown up yet. I dropped the driveshaft off and got it back yesterday, threw some paint on it and installed it. Filled the truck with coolant, and today went for a test drive and everything seems to be working! Oh wait the radiator fan isn't turning on, the relay isn't getting signal from the ECM.



Turns out that gouge in the frame did some damage even though it looked like it missed the wire bundle. Only the fan signal wire was fully broken, and good thing it was otherwise I would've never looked! Fan and fuel pump signal wires were broken, as well as whatever the bigger brown wire is (I should probably know what that is but I have no memory of it). The fuel sender wire (black) was untouched though!

After fixing those, time to hit the car wash and get all the gear oil off the back of the truck! In the process of washing it though, I found the source of a new rattle!



The driveshaft did a lot more damage than initially thought. The yoke off the pinion somehow slammed all the way forward and dented the bedside and even the body! Dented bedside/body, dented frame, wiring cut, coolant line broken, exhaust crushed and a hole in it, driveshaft broken in half, and lastly the pinion sheared off. A lot of damage! Could be worse, luckily I'm not super concerned about cosmetics, and the rest of the fixes are straight forward. I'm thankful that the radiator somehow lived, and the back glass.

Tomorrow is more tuning, primarily around full throttle. I'm hopeful the diff can handle it if I'm "gentle", but it's also the first time on the big sticky tires. Based on how much damage occurred, I really didn't want to do all of this over again in the event it snaps the pinion again even being gentle now that it can (hopefully) hook up. I was really on the fence about this, but pulled the trigger on the most janky fabrication this truck has ever seen. Introducing the differential driveshaft loop!



I cut some parts on the plasma table, quick wire wheel on some spots, and cranked the MIG and sent it. Then added some absolutely awful gussets. Obviously this is temporary, new axle will not have (need) shit like this. But until that shows up in a month, this abomination will hopefully keep the driveshaft at least vaguely lined up with the diff if the pinion breaks off again. It's not even meant to stop it flailing around, but just to keep spinning in a zone where it won't start flinging all over the place again.

With all of that said though, the truck is back and driving (albeit extremely loud since the exhaust terminates a few inches before the back of the cab, but it's quiet enough I can still go tuning and drive it, and the new exhaust piece shows up tomorrow). I haven't really gotten on it, well let me rephrase, it has seen 18psi but hasn't experienced full throttle yet! Looking at datalogs is wild, on the way home from the car wash it was at 18psi of boost and was below 50% throttle still. I feel like it's revved out and it's not even at 6000rpm yet. The thing pulls so hard and is so quick that you don't even have to get high in the revs or really on the throttle for it to absolutely haul ass. Other fun facts, I'm running 650cc injectors at 43psi and I think have seen 80% duty cycle once. I was worried the injectors would be too small (and I can absolutely crank the pressure with my fuel system) but they are actually right on the money currently and hardly working for the most part. The intake air temps are also surprisingly low, if it really heats up they'll climb 30deg and that's at 18-20psi through a few shifts. I feel like that's perfectly acceptable since the IATs will edge over 100F at full boost, and that's with the derpy intercooler I have which will eventually get swapped out for a much wider custom one.

Tomorrow morning hopefully wraps up the tuning, and then probably get the exhaust fixed after that, and hopefully that (mostly) ends the saga of the powertrain upgrades!

 

That’s how my turbo drives. You don’t need much throttle to get it to 0psi but from there it’s a toe twitch to boost. I was having some fun tonight with the truck and jumped on it from the light and the wife asked how much boost I got in to. Told her 4.1 but wasn’t even half throttle but was winding out to 6000rpm.

I love that turbos are load based and not rpm based. Driving 1650 miles recently from sea level to 8k feet and back, just being able to tip into boost to help pull a hill or pass someone and not have to go full throttle makes life so easy.

 

When are you doing the Dragy runs?
Truck looks proper with those wheels and tires. Excellent work as always!

 

I really want to, but I'm worried a proper 0-60 will break the diff again, so I think I'll wait until the new axle is here. I guess I could do a halfhearted gentle pull to see how she does...

Just got back from more tuning, I think it's spinning a bit in 2nd but otherwise is hooking up really nice. Took it to limiter for the first time and did a bunch of WOT pulls. Truck is running absolutely awesome. Need to fix the exhaust today and then maybe later today can do some more tuning to finish up some throttle tip in hesitation. Maybe I'll get a video later.

 

Saturday morning before more tuning I threw a limit strap under the driveshaft, which you can barely see in the below photo. I had been on the fence about doing it since I think the transmission side will be fine, but the wife really wanted it and it is a good idea. There's not a good place to put it, plus I didn't have any straps that were the right length, so I ended up psuedo-ghettoing it and just welding some studs to the frame and then taking two straps and twisting them (an offroading trick to shorten them) and that got them tight enough to not drag on the ground. I'd like a better setup to keep the shaft from destroying everything, but ultimately this is to prevent it pogo sticking the back of the truck and without adding another crossmember there's not really a sexier way to do this, so I'll keep it as is I think (and probably buy a correct length limit strap).



At 9am we did a bit more tuning, but the truck was so insanely loud with the exhaust dumping under the cab we couldn't do much since dude couldn't even hear me on the phone. Of course, the exhaust tubing showed up a couple hours later so I was able to make the truck not sound so loud (at least in the cab).





I drove around some more playing with the truck, and she is properly nasty! The truck seems to spin a bit in 2nd gear, but it's very controllable with the new tires. Before the truck would kind of torque steer all over the place, and now it shoots really straight when you get on it. Tires made so much difference and made it so much easier to drive which I wasn't expecting. The steering feels the same too, I was worried the increased scrub radius would make it a bitch to turn but didn't seem to really affect it.

The tuning needs a bit more work. At this point I'm thinking I'll wrap up the rest of the tuning myself, I got everything I wanted out of the tuner (mainly a good timing map). The last two things the tune really needs at this stage is there's still some boost control issues. Earlier in the week I had set it up where there was just a fixed boost solenoid duty cycle based on MAP and RPM, and the tuner changed that to a boost target and rpm based table, which seemed to be working fine at WOT but I've had a couple times where in like 4th gear I'll get on it and by 4300rpm the boost cut at 23psi is triggered, so how the turbo is building boost at high load and lower rpm is a lot different than at WOT, so that needs to get sorted. And then there's also a slight hiccup sometimes at low rpm, like leaving from a stop where if the rpm drops below idle for a second it seems to have a half second hiccup until it recovers. Not sure what the deal is there, I'm thinking it might be related to the low timing at idle and the truck using timing to control the idle rpm. Besides that though, the truck runs and drives awesome.

There was a little car meet in town on Saturday so I swung by since the weather was actually nice for once and the wife was doing things. There ended up being another 1978 model there too, though mostly stock!



His was a RN23L, I figured the L stood for long bed but his was a short bed and the same year, so the difference between the RN23L and RN28L is at a minimum the bed length. Not sure how the numbering works, I figured the lower the number the older the truck but maybe the second digit is the overall length or something? It was cool to finally meet the guy and look up close to the sister truck I've seen in town.



On the way home, of course I end up being the only vehicle on the road, I have no working speedometer and a cop is behind me. Who knows how slow I'm going since I have no traffic to base speed off of. Was probably doing 10mph under the speed limit. Dude eventually goes to pull around me, and then instantly jumps back over behind me and lights on. Awesome.



Turns out the right side running light at that instant in time decided the bulb was no more. Dude was following me, decided I was fine, and then the running light blows right as he goes to pull around me and that was too much so he pulls me over. Of course, no bumpers, the "tires stick out too far without mud flaps", and no running light. And I'm sitting there in a mini truck with a rear cage, fuel cell, drag radials, side dump exhaust, with a laptop on in my passenger seat and I'm wearing pajamas hahaha

Dude takes my stuff, comes back and thankfully gives me a warning and not a fix it ticket, and then he leans over and goes "so does it actually have a 2JZ?" I'm like damn straight, want to see it? And end up giving him a full tour of the truck. I think he's the first person to ever read the license plate "2JZ HLX" and actually know what it meant. We talked for a bit and I told him I have all the bumpers and stuff and still getting it dialed in since it has a fresh engine in it. He eventually had to bail since he had a ride along with him hahaha. Overall a nice wholesome moment, went from playing with the truck all day, to going wow the day ends getting a ticket, to ending up with the cop being a car guy and appreciating the truck build and letting me off.


To wrap everything up, I've been wanting to weigh the truck and yesterday got around to it. Threw some chains and my crane scale on the lift and pulled it up.





Because the front is lifting off the frame and not the axle, need to do a bit of statics and the overall weight comes in at 2545 lbs! 1046 lbs over the rear axle, and about 1500 lbs over the front axle.

Trying to find a weight for a stock truck, on a mini truck forum one person says a stock truck is around 2500 lbs, another guy actually coincidentally says the truck weighs 2545 lbs too. I thought it'd weigh quite a bit less to be honest, but at least I can say it weighs the same as a stock truck. And 2500 lbs with 500hp or so is still no slouch!

 

I finally got some clips of the truck!

https://www.youtube.com/watch?v=O2g7jJHW9cc

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.



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 shit 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 shit 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:



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!









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.

 

Awesome!! It makes all sorts of noises!
Dang thing gets right up and scoots along, does not sound bad at al!, and that rear differential looks like it'll handle anything!
HA!!! Very nice lill truck!

 

That third is pretty dang industrial looking.

 

Ya, copious amounts of axle wrap.
I noticed the EGTs just touched 1400F, I recall that being the max that was suggested for the 5VZ-FE in the first gen Tacomas to prevent all the spinning thingies from liquefying and has always had me wondering why we haven't been watching those on our 3URs.

 

Can't believe how well it hooks all things considered! Straight ripper. Rear diff sounds just like my car on decel lol

 

Different piston material?

 

Taking the video gave me the first chance to really look at the EGTs and Lambda, could pull that in the datalog but always forget. I think gas engines can handle quite a bit more EGT temp, I want to say like 1800F is what I've read. 1400 doesn't seem too bad. It seems like EGT is less of a concern than on diesels.

It does hook up pretty well! I still haven't done a proper launch in 1st, I did some halfhearted pulls the other day just to see (a healthy 0-60 of 6.0s lmao) but the rear axle has me so worried I'm waiting to do any proper pulls until the 9" is in. It feels like it'll spin a bit in 2nd, but it's very controlled and just feels like a little slip but the back doesn't try to walk around or anything. Once I start getting comfortable with the new axle I'll get launch control setup and maybe play some games lowering boost in 1st so I don't have to pedal it to hook off the line.

 

Nice! Yea for sure. Smart. That axle wrap definitely helped kill your other pinion lol. Been there, done that in a turbo 4runner lol although the leafs bent a "w" before the diff blew up

Once your new diff is in and 4 link is set up right and she can squat for traction without wrapping, it's gonna be an animal lol

 

Another day, another story

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!





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.







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.



I'm sure the cars I passed absolutely shit 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.



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



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.



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!



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





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!



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.



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



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



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



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?



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.

 

Glad you're ok and no one was hurt! That's a lot of power on a rear wheel drive mini truck. I remember spinning out in my 4-cylinder 1998 2-door Tacoma. It's so easy to do. Awd conversion?

 

Wow, that could have been messy. Glad to hear that you came out of it unscathed.