Build 550hp 2JZ 1978 2WD Hilux

Steve300xcw said:

This was a badass thread until I saw those sideways light switches. Now I'm not so sure

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I didn't build or wire (most) of the shop, so that is valid I'm also too lazy to clean up the cluster **** of switches, and after installing some new lights it's very confusing to new comers when only a portion of the central switches do anything

bad zuki said:

Seeing that bed cut up pains me, but seeing this thread updated is worth it.
Thanks for the crossposts.

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The bed is a bit odd, all of the inside metal seems in good flat shape, but the outside has a lot of bondo on it. Near the stock gas cap location it's probably 1/4" thick of bondo and chunking off in a few spots. I don't understand why the bondo is there since the sheet metal on the inside seems fine. All of the body panels are generally that way, 50ft away it looks fine but up close a bit of ****ery and really makes you debate if it's actually clean enough to justify trying to clean it up or repaint it. Honestly the perfect condition imo, no worry or regret chopping things up and modifying it but just driving by and for pictures it doesn't look like an absolute ****box---and it embraces not painting anything and looking rusty

Ran out of sawzall blades, picked some up, laid some whoop ass on a kid in a Mustang, so let's continue getting this thread up to date so I can post actually recent information

I weighed the truck awhile ago, all in is around 2550 lbs. 1050 lbs of that is on the rear tires.



At this point the parts from QP were coming in, they are very quick about shipping stuff though the housing took a couple weeks. I got a housing with the same WMS of the stock axle so it was a "custom" setup that needed to be built.







This is the fanciest axle, which is a low bar for me, I've ever gotten. Though pretty basic, centered diff, 35 spline since why not, and spooled since I was worried (and QP agreed) that a limited slip would eventually fail. In retrospect not sure if I want to try a limited slip again, it is nice knowing when you put the pedal down it's guaranteed to go where you want and not do anything weird but manual steering makes corners a bit of a bitch. I do have a Prius power steering unit and rack on the shelf that I want to eventually try to swap in but still haven't to this day.

I had some friends come by, and decided to cruise up the hill to Bryce Canyon for a completely impromptu 15 minute planning camping trip with the truck. Threw my **** in the passenger seat, brought the laptop so I had gauges, and off we went!





Unfortunately.....







Do you like my ghetto axle side driveshaft loop? (There's a transmission side loop too don't worry).

I was middle of the pack of three of us, went to pass a car and I intentionally avoided accelerating very fast, but figured I'd just let it wind out to high rpm but keep the power and torque lower down to save the axle, right as I came up alongside this car the rear end let loose, locked up the rear and the truck did a pirouette around the car I was passing, spinning a full 360deg while I was doing probably 60 or 70mph and slid back into the right side lane and then slid off the road. I couldn't really see what was happening since there was tire smoke everywhere as I spun around. Luckily I didn't hit the other car and no one else was around, I'm sure they **** themselves as this little ****box goes flying past and then spins out of control back across the highway.

If you watched the video I posted you saw the insane axle wrap I was getting. I suspect even though I was trying to avoid exactly that, either it made enough torque or maybe I forget and shifted and the whole axle moved, but I think the U joint locked up OR the driveshaft ran into my little hoop I had made. All of this literally a week after fixing the exact same thing happening.

The front right tire got de-beaded when I slid into the dirt, and of course the coolant line got battered again and some other stuff.

Called my wife, she came and picked me up and the boys left me to continue their camping trip.





This driveshaft now sits on the wall as memoribilia





And this was the first signs (although nothing obvious) of a much larger issue up front:





This diff really got the **** beat out of it in it's couple dozen miles of being in my hands



The front right was definitely bent, and I scanned it since I had the scan from when I sized the wheels and tires, and you can obviously see the hub is about 2" off from where it should be, and this was correlated with the driver's side measurements relative to different frame points.




A bit of hopping around in the timeline again. But if making the truck first run was stage 0, and building the engine and turbocharging it was stage 1, this was stage 2 and was suspension time. It took a LOT of measuring and trying to figure out what to do with the front. There was no single piece that could be blamed for the bend. The frame seemed a bit tweaked, the lower arm was tweaked, the upper arm was tweaked, nothing individually a lot but collectively all added together. What I eventually did was cut up the LCA frame bolt that you see in the scan, and convert it into two stubs that bolt to the frame and were on slots so I could individually adjust the front and rear of the LCA to dial in the alignment. The stock arms have zero alignment adjustment in the conventional sense, at best case the frame is literally shimmed to the subframe and that is all the adjustment for caster and camber.



With the tabs I could now adjust caster and camber on the passenger front end. I have a friend who owns an alignment shop in town and we got it on his alignment rack and dialed in the front end so the camber was correct and the wheel base matched the driver's side. The caster was quite a bit off from the drivers side (which is zero in factory form). We thought it might drive funky but it actually drives great now and very straight (spool certainly helping force that a bit). Once I got back to the shop I did some heavy tacks on the tabs to keep them from slipping.

That crossmember behind the oil pan was also starting to crack, so while I was in there I welded in some gussets too. Excuse my terrible looking welds, it was a battle to get clean metal anywhere under there, and I don't claim to be a welder!

The front end as a whole though got some big upgrades. I did some measuring and concluded I could stuff some coilovers where the stock shocks go. Unlike the next generation of truck, the 72-78 trucks had coils around the springs and were not torsion bars. The springs are absolutely huge, like 3.75" diameter as I recall, large enough you could fit an entire 2.0" coilover inside of just where the factory springs went. With some measuring, making some mounts, and a bit of machining of the coil perches I was able to make the truck have a 100% bolt in coilover.













What I ended up doing was machining the spring collar so it both holds the spring AND indexes into the stock coil spring bucket. Then on the lower A arm side just made an adapter. As I recall this is a 5.75" travel shock. The stock bump/droop stops still work, and with these Viking shocks it has full rebound and compression adjustment. I forget what spring rates I got, I think the front is like 550 lbf/in, which my math ended up being pretty spot on and the truck sat with the tires about level with the fender well and had 2-3" of up travel remaining.



I also rebuilt the exhaust AGAIN, and this time added the largest resonator I could find that would reasonably fit to try and quiet the truck down.





Lots of iterations (or should I say fixing) of the exhaust, but I've gotten pretty quick at building them. I do 7.5deg cuts on the band saw in each direction so each piece is 15deg total, then I mock it up by hand, tack weld with the MIG, and repeat that until everything is where I want it, then pull it off and TIG weld it. Usually the fitment is so close I don't even worry about filler at this point and just fusion weld it. And frankly at the beginning I was pretty try hard, at this point on the truck I don't even back purge it and just send it with how fast it goes through iterations.

With the resonator I added another V band right in front of the resonator, so the exhaust splits into the resonator/side dump, a straight section next to the driveshaft, and then the downpipe from the turbo and waste gate. It's pretty easy to install, though the downpipe is an utter bitch to slide between the frame/trans/body. I've debated down grading to a 3.0" exhaust, but the 3.5" is pretty dope.

The front suspension is now back together. This is far away not the final form, the front shocks were absolutely blown before so the coilovers were needed and I was already in there measuring things. Eventually I would like to design my own subframe and front suspension and convert it to AWD or 4WD, so don't think this is the final form (albeit it still is this way currently).

The rear suspension I always planned to swap out when I did the axle, and the axle had now arrived from Quick Performance! And there's lots of pictures in this section so brace yourselves.



I bought some joints from Summit Machine, I have wanted to run these for years and wanted to on my buggy but they're not cheap. Even for the truck I had to justify them some way. If I got weld on joints for one end and adjustable for the others they were about the same price as running adjustable heims everywhere, and I figured I should really only adjust it once so having adjustment on the truck isn't a big upside. I bought their smallest joints, which are huge and look so cool!



I designed a triangulated 4 link for the truck.





It has some minor adjustability. Honestly I hate the look of the swiss cheese brackets people do with all the adjustment holes, so I did two holes for the uppers and two for the lowers so I have four possible ranges of anti squat without the swiss cheese look.



The scans of the axle turned out so good and made it really nice to model the brackets to be self aligning on the axle and perfectly fit without any modifications.



I then cut them out on my plasma table out of 1/8" and started welding!





I really suck at welding small fillets where two plates meet with the MIG, so I like to use the TIG there and then since we are trying to "not be too serious on this project" I MIG welded the brackets to the axle and frame. I used to try and do TIG on everything, which I think helped get better at it, but now as time has gone on I pick my battles with the welders---sometimes TIG works better, sometimes MIG gets the same result in a lot less time.

I started grinding off the leaf spring perches because they sit where the lower link mounts go, then said **** this, cut it out with the plasma and welded a plate in. I hate grinding.



You can see a lot of the offroad influence in the build with the rear end. Doing a triangulated 4 link instead of something else, the huge joints, the bracket setup, like for the lower link brackets I tried to keep them tucked up high. I think I had mentioned it early on, but this was my first 2WD vehicle ever and frankly most car stuff looks some flimsy and pathetic, I wanted this to be overbuilt and tried to do the same methodology as my buggy. I had even debated doing massive shocks in the back and trailing arms for no reason other than to be different----but I didn't want to go too crazy! A classic simple 4 link with coilovers won out.







I decided to scan the completed (or at least the link mounts) axle housing to put it into CAD and figure out link lengths. It's cool to design something on the computer, make it, put it back into the computer and it lines up beautifully with the original computer design! The green is the scanned complete axle. You can see the lowers don't line up perfectly, but I was stoked how close everything was for tape measure aligning.



I got the link lengths for the alignment I wanted and welded them up. As I recall they are SLIGHTLY different, I think the lowers are like 1/2" longer so the links could swap top to bottom in a pinch.







The links turned out so cool! I've envied these joints as long as I've known about them, and made in Utah too! I also thought having a bushing type joint and trying it out for an onroad vehicle all made lots of sense too. Low loads, and I don't want it squeaking, and it will see lots of miles so rebuilding is nice. Things I care less about on the buggy---again justfiying how expensive they are, but they look so cool! These are also 1.5" diameter DOM links, she's built like a brick ****house.



The shock mounts I didn't have a very elegant solution for, so ended up just making some big drop brackets to mount the shocks off the back of the axle. The issue is I want the option to have a floor for the bed, so didn't want to mount the shocks above the plane of the frame, and the fuel cell is right behind the axle (like an inch or two behind the diff bulge) so it really forced my hang where to put the shocks, and ended up just doing these somewhat janky and blocky shock mounts.

The rear got the same, albeit a bit longer (maybe the rear is 5.75" and the front is like 3.0", I forget), shocks that the front has. One of my friends recommended the Viking brand, and they are surprisingly cheap with lots of good reviews. They might not be a Fox or King, but they have tons of adjustment and ride great and are a great price.
















Additionally I cut the stock rubber bump stops down about an inch, this gives me right at 2" or so of up travel. I can't really get any more without modifying the frame, even though I'd like if the rear sat an inch or two lower. But modifying the frame (I guess more than I have?) is a step too far. The truck has around 2" of up travel all the way around with adjustable coilovers all around. Compared to how it was, it rides absolutely amazing. I never thought 2" of up travel could ride so well!



And you know I added some limit straps!



I forget the rear spring rate, it's insanely low, I think the first set of springs was too high and the second set that I now run is like 45 lbf/in. Which sounds overly low from some quick napkin math, but I'm pretty sure that's correct...






And with that, the "stage 2 evolution" was done with the suspension getting lots of rework! The shocks have like 12 or 15 levels of adjustment for both compression and rebound, the front I want to say is around like 8 or 9 on both (and the shock has their softest valving to being with), the rear is at like a 5 on the high end since there's no weight back there. It rides amazing compared to the stock setup, and the tons of adjustment, particularly on the rear, is really nice. At full stiff the shocks are essentially locked. Since the rear spring rate is so low it works out, you load something in the back and crank the shocks to the stiffest level and even though it will be just about on the bump stops it still rides surprisingly well and uses all 1/2" of up travel amazingly well.

I still have not messed with the link setup or screwing with anti squat. It drives great, and I don't know anything about drag racing or launching but it hooks up pretty well and the tire setup is great for it. It can break traction for a moment in 2nd or 3rd getting on it, but it's extremely controlled and doesn't slide around and then hooks back up a moment later. The truck doesn't have any sway bars currently and definitely needs some. I've gotten confidence back for the rear end not exploding, so far the rear suspension and axle has been amazing and I have zero worries about it getting hurt which is what I wanted.

And that will end this round. Still a lot to come, this post has brought us up to June of 2025 in the build. Lots more photos, some videos, things breaking, building better, and some extremely cool (imo) features I eventually add and can't wait to share!

For being a dang cheap truck, you've put a ton of money into it.

Bell housing adapter was kind of surprising how much it was.

Are the rear tires already bald?

Penetrode Offroad said:

For being a dang cheap truck, you've put a ton of money into it.

Bell housing adapter was kind of surprising how much it was.

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Funny how that works isn't it

The adapter was very expensive, I think it's the single most expensive buy on the entire truck. All the money has to be in the flywheel, which is nice but they're probably making a fat profit on it considering what it is. There were cheaper adapters out there, but this was the only one as I recall that didn't requite cutting up/swapping the bell housing and was a straight bolt on setup.

rattle_snake said:

Are the rear tires already bald?

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Just about brand new in the pictures. Full tread depth seems to be a 1/4" or so which I think is wild, but maybe that's standard fair for drag or track tires?

snivilous said:

Funny how that works isn't it

The adapter was very expensive, I think it's the single most expensive buy on the entire truck. All the money has to be in the flywheel, which is nice but they're probably making a fat profit on it considering what it is. There were cheaper adapters out there, but this was the only one as I recall that didn't requite cutting up/swapping the bell housing and was a straight bolt on setup.

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I'm running an Colorado AR5 (also found in Pontiac solstice/skyy/sling shots) behind mine which takes a factory Toyota R154 bellhousing then piecing together mostly off the shelf clutch parts depending on what the goal is (push, pull, multi disc, etc). Supposedly it is good to 500-600 hp.

I paid $200-ish for the trans from a local yard, $250 for a new china bell housing, then however much for a clutch/flywheel (mine came in a package deal with some nice rods/pistons that I ended up selling).

snivilous said:

Just about brand new in the pictures. Full tread depth seems to be a 1/4" or so which I think is wild, but maybe that's standard fair for drag or track tires?

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More tread would add a lot of wieght

Gots_a_sol said:

I'm running an Colorado AR5 (also found in Pontiac solstice/skyy/sling shots) behind mine which takes a factory Toyota R154 bellhousing then piecing together mostly off the shelf clutch parts depending on what the goal is (push, pull, multi disc, etc). Supposedly it is good to 500-600 hp.

I paid $200-ish for the trans from a local yard, $250 for a new china bell housing, then however much for a clutch/flywheel (mine came in a package deal with some nice rods/pistons that I ended up selling).

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This is great stuff.

snivilous said:

Just about brand new in the pictures. Full tread depth seems to be a 1/4" or so which I think is wild, but maybe that's standard fair for drag or track tires?

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I'm assuming the new tire pics are from a year ago based on your text below it. With big hp they won't last long, nor will any tire. I get about 3-4k miles out of drag radials, they work just as well completely bald.

rattle_snake said:

I'm assuming the new tire pics are from a year ago based on your text below it. With big hp they won't last long, nor will any tire. I get about 3-4k miles out of drag radials, they work just as well completely bald.

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That's good to know! I wasn't sure if you got 1/4" of tread and that was the end of the tire, or just don't get caught in the rain when it becomes a pure slick and it was still fine.

Rain and drag radials have totaled many expensive toys.

Although the salvaged drivetrain become available for something else.

Since you are in UT, not really an issue. Don't be stupid when slick.

A torsin diff is pretty common in street cars and should spin both tires pretty much no matter what.

Spool is cool for drag racing or drifting, but sucks for everything else

I run a spool on the street, not really a downside so far for me. It shakes a bit at full lock turn.

This post is actually from today, we'll continue the story connecting the previous post from a year ago, but this was too fun and hilarious not to share now.


It's Friday, weather is cool for probably the last time for months, found a shop down the hill and said let's see how weak the 2JZ is







Did only one pull which told me everything I wanted to know



292whp hahaha

And to reiterate from a long time ago, stock warn out NA the truck made 125whp.

It's not far off from what I was expecting, I was hopeful it would be over 300whp but figured there's no way it's over 350whp. I wanted to confirm that before going to a different turbo, which is probably still many months out. The truck felt about as fast as my Tundra at best (which made 500whp), and it literally weighs half as much, which meant the truck had to be below 400hp. Additionally the truck has 650cc injectors, and they are at 70% duty cycle, where as my Tundra is at 90%+ duty cycle with 725cc injectors plus has two extra cylinders, so the truck just wasn't consuming enough fuel to be making much power.

On the one hand it's pretty pathetic that a 2JZ at 20psi of boost isn't even making 300whp, but on the other hand it means there is tremendous growth potential (should be able to about double the horsepower on the truck safely). The fact it's so fast for making such little power is impressive too, the benefits of weighing 2500 lbs.

The curve is obviously very weird. I started at 2500rpm in 4th and floored it, it hit the full 20psi by 4000rpm, then the waste gate came in trying to control the boost and held it within 3psi for the rest of the pull. Around 4200rpm it started richening out way too much.



Essentially the truck made a good bit of torque, and then when the wastegate came in to stop the boost that then completely killed the torque and it running so rich didn't help things. Even though the truck was still making 17-20psi for the rest of the pull the acceleration dropped considerably and the rpms were slowly climbing so I let out at 5600rpm. This mirrors driving on the street pretty well, it pulls hard and then when the wastegate comes in I short shift at 4500-5000rpm since it just falls on its face.



There was no point doing any more pulls and adjusting things, I'll spend more time dialing in the fueling on the street and didn't want to waste the shops time. Talking to the dyno guys they thought the exhaust on the turbo was choking the truck out, which is what I had been suspecting in the past. I didn't really care what the numbers were, I just wanted to know the starting point so when I change the turbo I have an apples to apples comparison. This exact setup should be making around 500whp or more on pump gas. This confirms how much power is on the table and I'm not insane how "slow" the truck is so I think going to a bigger turbo is all but guaranteed now. I do think there's a few other things I'll need to setup first though, I want to have a boost dial to control how crazy I want the truck to get and then probably should figure out a way to get wheel speed or a gear position indicator to the ECU so I can run boost by gear to prevent it just lighting up the tires in the lower gears.

Ultimately all I really want is to be able to rev the truck to the full 7500rpm and have it pull the whole way, it feels quick now but having to shift so early is annoying for something built to rev so much higher.

Radass Hilux