Builds 94 KZJ78 Prado Build (3 Viewers)

[WTK KZJ78]

Hi All,

Finally decided to make the purchase of a KZJ78. This one is currently making its way over and should hopefully be here in a few weeks. This will be my new daily, and I have a bunch of mods planned for it so thought I'd just start a build thread for anyone that's interested and to seek advice along the way!

 

[WTK KZJ78]

Car arrived yesterday - very please with the overall condition and great to finally see it in the flesh. A few signs showing its age here and there, but overall very happy!

First impressions: very unique car, a little slow haha however not complaining - still a fun car to drive around. The exterior conditon is great for its age, previous owner had given it a repsray in its original colour so paint job is almost brand new. Interior is also looking good considering, the previous owner had the seats reupholstered essentially in the original trim colours so they look and feel new.

I'll need to get the car over the pits soon to get it roadworthy and licensed to drive here. Also booking the car in for a full sevice next week hopefully to set a baseline given I don't know the service history of it, so just playing it safe for peace of mind.

Current mods:

• 2" Dobinsons lift kit
• Custom exhaust (I think 2.5" without measuring it) There seems to a some sort of a high flow cat & a resonator, then a muffler delete
• Pioneer 9" touch screen (wireless Android auto is a life saver )
• Upgraded speakers however unsure of brand - will try to remove the front dash cover to see over the weekend (may upgrade if I don't like them)
• Pioneer underseat sub + remote (currently between middle and third row seats)
• Limo tint - too dark for my liking and is illegal here so it definitely won't pass inspection. Will remove prior to inspection & replace with a 20% tint after
• Rear LED tail light & all clear indicators

I ran out of time today and was losing sunlight quick, so only took a couple of shots...wil try to get more over the weekend:

 

[chap79]

Very nice. Welcome to the addiction!

 

[WTK KZJ78]

Very nice. Welcome to the addiction!

Thanks, definitely feels that way!

 

[WTK KZJ78]

Gave it a wash today - the front grille is painted all black which kinda makes the 2x side indicators look disjointed. I plan to have the upper and lower lip of the grille chrome wrapped to match the indicators so it all ties in, and will also chrome the 'TOYOTA' text at the same time. I tried sourcing a replacement grille which has the chrome/black already but hard to find over here, so thought wrapping will achieve the same result I'm looking for.

Also noticed a bit of rubbing in the middile of the bonnet with the body. The middle of the bonnet sits lower by approx 5mm which I think is causing the rub. Will get it looked at by a panel beater this week to hopefully straightened it back. Will post update photos when completed...

 

[kgrove]

Gave it a wash today - the front grille is painted all black which kinda makes the 2x side indicators look disjointed. I plan to have the upper and lower lip of the grille chrome wrapped to match the indicators so it all ties in, and will also chrome the 'TOYOTA' text at the same time. I tried sourcing a replacement grille which has the chrome/black already but hard to find over here, so thought wrapping will achieve the same result I'm looking for.

If you like the look of the current grill, you could also paint the chrome trim around the corner lights. I've seen that done a number of times. You could go an extra step and also paint the side mirror either body color or the same black as what was used on the grill. That would be a fairly consistent look and not particularly time consuming or costly.

 

[WTK KZJ78]

If you like the look of the current grill, you could also paint the chrome trim around the corner lights. I've seen that done a number of times. You could go an extra step and also paint the side mirror either body color or the same black as what was used on the grill. That would be a fairly consistent look and not particularly time consuming or costly.

Yep nothing wrong with the black grille, but I do prefer the chrome trim - I think it adds to the somewhat classic look I'm going for!

PS I see you used to have a couple of these dark green ones (both now sold?)...didn't think I was into the colour at first but it's definitely growing on me now that I've seen it IRL...

 

[kgrove]

Yep nothing wrong with the black grille, but I do prefer the chrome trim - I think it adds to the somewhat classic look I'm going for!

PS I see you used to have a couple of these dark green ones (both now sold?)...didn't think I was into the colour at first but it's definitely growing on me now that I've seen it IRL...

I had 2 different 2-tone green KZJ78 over the last few years. The first I sold a couple years ago and then sold the other very recently. I had that same paint scheme on an HDJ81 as well, and yes, I like the color combination other than two-tone adds complexity if you need to paint a body panel. My daily driver is a black KZJ78. I’ll likely sell it in a few months when I’m done playing with it, though I think I’ve been saying that now for at least 2 years.

 

[WTK KZJ78]

I had 2 different 2-tone green KZJ78 over the last few years. The first I sold a couple years ago and then sold the other very recently. I had that same paint scheme on an HDJ81 as well, and yes, I like the color combination other than two-tone adds complexity if you need to paint a body panel. My daily driver is a black KZJ78. I’ll likely sell it in a few months when I’m done playing with it, though I think I’ve been saying that now for at least 2 years.

Did any of your power antenna work? Mine doesn't and I don't know where to start. How does it activate? Starting the car, or radio?

I also have an aftermarket unit (Pioneer ZF9350BT) and not sure whether that had anything to do with it. I didn't install the unit so I don't know whether it was working before either.

 

[Bad Mojo]

Did any of your power antenna work? Mine doesn't and I don't know where to start. How does it activate? Starting the car, or radio?

I also have an aftermarket unit (Pioneer ZF9350BT) and not sure whether that had anything to do with it. I didn't install the unit so I don't know whether it was working before either.

I know that question was more pointed to @kgrove, but here is a data point for you. Ours deploys when the radio is turned on either by turning the radio on or if the radio was left on when the truck was turned off. It retracts when the radio is turned off or when the truck is turned off. It does have an aftermarket head unit from Japan in it currently.

 

[kgrove]

I've had 4 Prado over the years... two for sure did NOT have functioning power antennas - one had the premium sound option (amp in left rear quarter panel, antenna on left side of car, 14-pin stereo connector), and one with the standard sound system (typical Toyota stereo harness). The other two Prados (Pradi?) I don't recall whether the antenna worked or not. On the two that know the antenna did not work, I never retraced my steps on the install (performed by me) or investigated why the power antenna did not work. On the one I just sold, I just ran out of time and never got to it. On my current daily driver, it's because the antenna had been somewhat badly bent in the past and I figured it wouldn't automatically deploy anyway even if the circuitry was good. I'd like to say I'll eventually get around to looking at it, but it probably will never rise high enough on my to do list to get done.

I do remember a couple of the LCs I've had where I did solve the power antenna issues, but I can't recall if it was a Prado, HDJ81, or one of the 100 series I've owned. I seem to recall in one case I determined there was a difference in wiring harness adapters between Metra and Scoshce where they weren't pinned fully the same with respect to power antennas, plus some head units have a dedicated antenna circuit and some do not. I'm blowing cobwebs off the memory so I could be wrong and don't remember the full detail, but it seems like I figured out that I had to wire the power antenna to the head unit power circuit - the downside being that the antenna was always deployed if the head unit was on versus a more elegant solution where the antenna only deployed when the head unit was switched to radio (e.g., the antenna would stay retracted when streaming bluetooth audio etc). I also recall there was one, I think it was on my 100 series, where I could not keep the antenna from showing a little too much excitement at all times... if the head unit was on, the antenna would extend about 2 inches, and then would fully extend when the head unit switched to radio. The only way to fully retract the antenna was to fully power off the head unit, otherwise the car had 2" showing. I think this must have been one of my 100 series where I used a head unit that had a dedicated power antenna circuit (not all do).

I hope this helps... not an answer but maybe gives some ideas where to search.

 

[WTK KZJ78]

Thanks for the info - sounds like the antenna might be in the too hard basket for now haha. I have the car booked in for a service this week so will pick the mechanic's brain

Update: had the bonnet sag fixed and the grille chrome wrapped last week. No more rubbing as it now sits flush. I think the grille now ties in well with the indicators.

Forgot to take a photo of the complete grille so I just extracted frames from a reel I made :

Link to reel:

 

[WTK KZJ78]

Window tint removed - getting it ready for pit inspection (and service) tomorrow.

Also on the list are new wheels & tires, or just replacing to better AT tires. I know there's wheel/tires threads around, but is there a significant power/mileage loss going up in size? Currently 31x10.5xR15 on the car, not sure if this is a stock size? There are also 50mm spacers behind the wheels which brings the wheel about flush with the fenders (spacer needs to go before the inspection, then put back in after). Considering going up to 32's as I imagine 33's will chew up power and fuel consumption a fair bit on these engines.

 

[chap79]

31x10.50r15 was an available stock tire size on the KZJ78, stock wheels on yours should be 15x7 with a -20 offset.

I’m still running 31x10.50 on stock wheels on mine even with a 2” lift, no wheel spacers. Gives it a nice retro vibe. I have no doubt that the 1kz-te with 4.30 gearing will roll 32s, or even 33s. Mountain passes would just be slower than normal.

 

[WTK KZJ78]

31x10.50r15 was an available stock tire size on the KZJ78, stock wheels on yours should be 15x7 with a -20 offset.

I’m still running 31x10.50 on stock wheels on mine even with a 2” lift, no wheel spacers. Gives it a nice retro vibe. I have no doubt that the 1kz-te with 4.30 gearing will roll 32s, or even 33s. Mountain passes would just be slower than normal.

I found this on the driver side chassis, so I'm thinking the original size is 265/70/15 (or 30s) based on the Jap sticker. The english one doesn't seem OEM. A quick search online don't seem to have much tyre options for 32's that will suit the 15x7inch wheel.

Do you think it is necessary to change the gear ratio for 32s? This process is completely new to me so keen to learn. I do have plans to install a FMIC and upping boost/unichip if that makes any difference.

Also reading forums there's mentions of EGR deletes and upgrading to a 10-blade radiator fan. Are these significantly beneficial? Any drawbacks from doing so? If anyone here has performed these changes I'm interested to hear feedback, pros & cons

 

[chap79]

I’ve removed the EGR off mine and am also running the 10 blade fan. I still have the stock exhaust and no intercooler. I have not played with the factory boost.

I decided to remove the EGR (but kept the butterfly in the venturi) when I rebuilt the head. The upper intake was filthy. The sensor ports for the turbo were almost completely closed. I’ve added a pyrometer/boost/temp gauge since the rebuild. Boost maxes out at 12 psi and normal flat driving shows my coolant temp around 176F/80C.

I’ve driven my truck (5sp m/t) cross country a few times on 31s and here is my thoughts. On flat land the truck is very happy at 110-120kmh. Moderate hills can be run between 90-110kmh. Steep hills and long mountain passes will have me down to 75-90kmh to keep the EGTs down. Replacing my exhaust in on my to do list.

I think the truck would drive just fine on 32s in its stock setup. And if you’re not at high altitude of regularly driving over mountain passes 33s could be run without a regear of the diffs and/or transfer case.

 

[kgrove]

I’ve removed the EGR off mine and am also running the 10 blade fan. I still have the stock exhaust and no intercooler. I have not played with the factory boost.

I decided to remove the EGR (but kept the butterfly in the venturi) when I rebuilt the head. The upper intake was filthy. The sensor ports for the turbo were almost completely closed. I’ve added a pyrometer/boost/temp gauge since the rebuild. Boost maxes out at 12 psi and normal flat driving shows my coolant temp around 176F/80C.

I’ve driven my truck (5sp m/t) cross country a few times on 31s and here is my thoughts. On flat land the truck is very happy at 110-120kmh. Moderate hills can be run between 90-110kmh. Steep hills and long mountain passes will have me down to 75-90kmh to keep the EGTs down. Replacing my exhaust in on my to do list.

I think the truck would drive just fine on 32s in its stock setup. And if you’re not at high altitude of regularly driving over mountain passes 33s could be run without a regear of the diffs and/or transfer case.

This is nearly the same exact situation and results as I've found on mine. I deleted my EGR system and used the exhaust manifold blanking plate to insert an EGT probe and also have a 10 blade fan installed. Where mine differs is I'm running 33x12.5x15 tires. My boost gauge says mine peaks at around 14psi, but my sensor is located on the crossover pipe and I suspect it would read a bit lower if I had located the sensor on the intake manifold after the air has passed the throttle body (there has to be at least some minor pressure drop across the throttle plate).

I comfortably cruise on highways at just under 110kph on the speedo, so roughly 75mph actual with the larger tires. Any faster and the car feels more unstable than I like to drive. A better alignment and castor correction might help that. At 110kph and in "normal" atmospheric conditions (i.e., level ground, 60-80F ambient temperatures, low altitude, etc) my EGTs are probably around 900F, but they are more like 975F when I switch to "hot and high" conditions - 6-7,000 ft elevation and 90F ambient air. On steep hills and under normal atmospherics, I really have to push the car hard to get the EGT up to 1200F, but if I do the same at high altitude and warm days, I could blow past 1200F on a hill somewhat easily if I weren't paying attention. At elevation and in the summer, I'd guess I have to keep my speed down to maybe 50-60 kph on steep highway hills to keep my EGT in the 1100F area, maybe an occasional and accidental spike to 1150F. There are always a few big trucks I can tailgate at that speed or slower to keep me company.

So 31s vs 33s for performance reasons... ultimately this boils down to how hard you think you'd be pushing your car and what tools you have to make sure you don't accidentally push it too far and melt your engine. If you knew you were going to be running at high altitude warm days with the car weighted down, my experience says you should only go with 33s if you can monitor your EGT. I wish I knew wether 31s alone would reduce the problem and make it safe to operate without an EGT gauge (I also wish I knew how much the EGR delete was making my EGTs in hot and high conditions worse... if I had installed the probe in the exhaust manifold with the EGR system in place, I could have just blocked the vacuum tube on the EGR valve to see how EGTs changed). If you're driving near sea level, cool conditions, and never really loading the car up that heavily, you could get away with 33s without an EGT gauge and probably be safe.

 

[WTK KZJ78]

Thanks for the info, great insight.

I’ve removed the EGR off mine and am also running the 10 blade fan. I still have the stock exhaust and no intercooler. I have not played with the factory boost.

I decided to remove the EGR (but kept the butterfly in the venturi) when I rebuilt the head. The upper intake was filthy. The sensor ports for the turbo were almost completely closed

@chap79 your current setup is identical to mine (2" & 31s and I assume everything else stock). what EGTs do you see? Would be interesting to see how the 31s EGT compare to @kgrove's 33s, assuming also stock everything else. And how did you approach your EGR delete? Just blanking plates or is there more to it?

This is nearly the same exact situation and results as I've found on mine. I deleted my EGR system and used the exhaust manifold blanking plate to insert an EGT probe and also have a 10 blade fan installed. Where mine differs is I'm running 33x12.5x15 tires.

@kgrove I doubt I will run past 32s, currently on 31s. 33s seems a little too large for my liking on this car. How did you also delete your EGR? I see online there's kits with blanking plates & gaskets. Do i need any other hosing etc? I also intend to install a EGT gauge so will need the plate with a threaded hole.


Re the 10-blade swap, do I need to also change the viscous coupling? I found both of these kits in Aus (blade with coupling $325 vs blade only $53).
In either case are these blades just a direct swap without any other parts? Any noticeable difference? Louder fan noise, cooler engine temps, etc.

Blade with viscous coupling:

Upgraded Viscous Hub and 10 Blade Radiator Fan suitable for Toyota Hilux 1KZ TE KZN165 KZN130 KZJ90 KZJ120 - HD Automotive

The Toyota Hilux Upgraded Viscous Hub and 10 Blade Radiator Fan is a perfect upgrade for those who fighting poor cooling on their 1KZ engine.

hdautomotive.com.au

Blade only:

Online Auto Parts | Car & 4X4 Parts - Right Fit, Right Price

Fast 24hr dispatch* and quality 4x4 and car parts from local Australian warehouses. Top brands and OEM replacements with match-fit guarantee.

www.onlineautoparts.com.au

 

[kgrove]

@chap79 your current setup is identical to mine (2" & 31s and I assume everything else stock). what EGTs do you see? Would be interesting to see how the 31s EGT compare to @kgrove's 33s, assuming also stock everything else. And how did you approach your EGR delete? Just blanking plates or is there more to it?

@kgrove I doubt I will run past 32s, currently on 31s. 33s seems a little too large for my liking on this car. How did you also delete your EGR? I see online there's kits with blanking plates & gaskets. Do i need any other hosing etc? I also intend to install a EGT gauge so will need the plate with a threaded hole.

While collecting EGT data points is helpful, I'd caution against reading too much into any one single set of EGT measurements. There are a lot of other variables between the two cars that could impact EGT - clogged injectors, worn piston rings, sludge in the intake manifold, etc.

I used an EGR kit for my delete - removed the pipe and valve system, rerouted the vacuum tubes on the throttle body VSV, and blanked off the two manifold openings where the EGR pipe had attached. The blank on the exhaust side had NPT threads for an EGT probe. The extra coolant hose running behind the engine for a rear heater makes getting the EGT probe into the EGR blank a bit of a pain (would be easier on a Prado lacking the rear heater option). Getting the EGR pipe off the studs was a royal pain in the a$$. I ended up having to saw my EGR pipe in half so I could remove the exhaust and intake fittings separately as I could not create enough space to remove the pipe off the studs on both sides at the same time.

That said... I'd have two cautions regarding how I did it:
1) Knowing what I know now, I'm questioning whether I should have deleted my EGR in the first place. I read reasonable sounding info supporting both sides, but the more scientifically supported arguments suggest the EGR system reduces EGT rather than increase it. It sounds counterintuitive that mixing hot exhaust into the intake air could reduce EGT, but the rationale is that the spent exhaust is inert and reduces the combustion potential in the cylinder, and therefore the explosion isn't as powerful and EGT is reduced. Since the advent of EGR systems was to reduce NOX by reducing combustion temperatures, it makes sense that disabling the EGR system may increase your EGT. The flip side argument is that if the explosion is cooler and less intense, you'll have to throttle up more to compensate for reduced performance, so your EGT might end up in the same spot either way, especially in real world situations where you're trying to climb a hill at a given speed. Both arguments have a logic, so the only way I could become convinced of which works would be to install an EGT probe on the exhaust manifold and test EGTs under the same condition, once with the EGR fully functioning and once after blocking the VSV that opens the EGR butterfly to effectively disable the EGR system. Without that test, I lean toward a functioning EGR system as being better to keep EGT down as it seems more supported to me, but I'm not going to die trying to capture that hill.

2) If you did want to delete your EGR system, I would lean towards leaving the EGR pipe in place and instead disable the vacuum tube that opens the EGR valve on the intake. I think this would effectively accomplish the same thing in stopping hot air from entering the intake system, but this method is WAY easier to accomplish and can be easily reversed if you change your mind (or the authorities change it for you).

Or if you decide to keep your EGR system functioning, install a catch can so that hopefully your intake manifold stays cleaner.

For my 10 blade - I just replaced the fan as my viscous coupling seemed fine. I do suspect my 10 blade may have hurt my fuel economy a touch. I can't prove that... just a suspicion.

Here is the Prado I sold a couple weeks ago (not the one I'm driving today with the EGT gauge). I included it because it's the same paint scheme, similar lift, same OEM wheels. The wheels don't have spacers like yours, but the 12.5s without spacers probably extend outboard to about the same place as 10.5 with spacers. Looks are entirely subjective so it doesn't matter which I like, but this should give you a pretty accurate idea what yours would look like with 33x10.5 plus spacers.

 

[WTK KZJ78]

Ah I will explore the tube route. I rather not permanently cut into anything if I don't have to. I'll still need to have hole for the EGT probe somewhere though...

Here is the Prado I sold a couple weeks ago (not the one I'm driving today with the EGT gauge). I included it because it's the same paint scheme, similar lift, same OEM wheels. The wheels don't have spacers like yours, but the 12.5s without spacers probably extend outboard to about the same place as 10.5 with spacers. Looks are entirely subjective so it doesn't matter which I like, but this should give you a pretty accurate idea what yours would look like with 33x10.5 plus spacers.

That looks very tidy The 33s definitely fills up the well nicely. My only concern is the performance (or lack of) going up to 33s, and given the stock is wheel is only 15x7, many tyre options for 32s or 33s do not recommend fitting below 8 or 8.5. I take it you have no issues fitting on OEM? What about when airing down?