Hey guys,
Few days ago, I installed the intercooler on my 1KZ-T 4Runner.

For the those of you who haven't followed, here is a link to the previous thread - 1KZ-T TD 4Runner soon to be TDI

I managed to gather all the parts for the intercooler install from a rig a friend and I bought last winter. It was a 2000 Hilux Surf TDI that had the 1KZ-TE. There are three versions of the KZ engine. 1KZ-T with mechanical pump, 1KZ-TE(electronically controlled), and 1KZ-TE TDI, which is intercooled and also electronically controlled.

I have a former UN Runner with the 1KZ-T engine. These were produced only for the UN, under that name and LHD (i think). Otherwise it's known as Hilux SW4 for SA, and the more sophisticated Hilux Surf for the RHD markets.

The 1KZ-T has a turbo and lots of empty space around it.It has an air filter that you pretty much never change and it can tell if you try to feed it water instead of diesel by the water sensor in the fuel filter. That's just about it.

There are no complex sensors of any kind, except the turbo sensor that should signal if the turbo pressure goes too high. The engine's throttle body stays open all the way when driving and is used solely for shutting the engine off, so I got rid of it, to make room for the new adapter that I built. It's just a piece of pipe and a metal plate, that I had to resurface, because it warped during welding.

The head cover is also different when the engine has an intercooler. The positive crank ventilation gases, or blow-by, is separated from the oil in the hump on the head cover. Since the intercooler stays at an angle when installed in the Hilux Surf, the PCV hump is at the rear of the cover. Because of this hump, the cover needs more space at the back. I had to reorganize the HVAC water hoses and re-tighten the main glow plugs' wire at a different angle, to make room for the oil separator, PCV hose, and mounting brackets.

The original PCV vent hose is made up of a pipe and two shorter hoses, unlike mine where it is just a longer piece of hose that connects from the turbo to the cover. I couldn't source the pipe from anywhere, so I just used my original hose and a very short copper pipe to connect the top 90 degree elbow hose that connects to the pcv hump. It turned out fine. Sorry no pic...

When trying to install the intercooler, I had a little trouble with the accelerator and cruise control links (link to a mod of installing a cruise control unit in the ECUless 1KZ-T engine - Cruise Control swap from 4runner to Hilux Surf). The brackets holding them in place, had to be removed, and I just let them hang under the intercooler. So far I haven't noticed any interference. There is enough space for them under it without damaging the fins.

The main problem I encountered during the install, was the pipe between the turbo and intercooler, was rubbing on the air filter box's intake resonator. I removed the original bolts that hold the box, and padded the two mounts closer to the engine, to raise it up enough on that side, so it doesn't rub anymore.

The hose elbow is at 30 degrees and seems as it's under strain from the pictures, but it isn't. I will carry a spare hose, in case it ruptures tho, as this engine without the turbo help, is like a dead man.

One thing to do later is to install a piece of window screen on top of the intercooler, to guard it against bugs, seeds, rocks and anything small enough to fit thru the scoop. Some intercooler fins are already partially damaged from big bugs and grass seeds, so not sure why Toyota does not ship them with a screen from the factory.

Overall the install was a success without any irreversible modifications.
One thing I noticed and read on another forum, is when you shut the car off, it jitters and shakes, when the engine comes to a halt. I realized it's because of the missing throttle body. Apparently it helps by making the shut off calmer. I kinda like it tho!

I do expect a little bit of fuel economy...hopefully.

I may add some gauges in the future for exhaust gas temp monitoring, but it's not necessary, as this engine does come stock with an intercooler and I don't expect it to cause damage in any way. There is a sensor for the air temp in the back of the cooler, and there is the half inch pipe where the turbo sensor attaches, which can be used for attaching turbo gauge and what not...

I drove it on the high here in Sofia, and I noticed that it starts to accelerate much faster at speeds above 20MPH. But no difference during acceleration from a stop. In the future, I will post if I notice any fuel economy, but that would be after the 10th full gas tank.

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Do you have the 'Sport' hood with the hoodscoop? Presumably with the back end cut out so it actually flows some air. Otherwise, I don't think the intercooler will actually cool it down much, past a little bit of initial heatsoak.

How much boost does it run?

Front mounted intercoolers usually do a much better job of... 'intercooling'.

Couple things:

- Screens are not included because they do decrease efficiency of the intercooler. The extra drag hinders airflow across the intercooler. But yes, so do bent fins...
- The 1st point is especially an issue if you don't seal the intercooler to the hood scoop using rubber bellows, foam, etc.
- The throttle body is there for shutdown - and not just for normal shutdown. It is a safety feature in case you get runaway (bad turbo feeding engine oil into the intake, leaking piston rings, etc.). Unlikely, but something to think about.
- You can get 30* silicone hoses from various places, like Intercooler Pipe Fabrication

A front mount would be better, but would require some cutting, etc. This is a 'nice' OEM looking solution that hopefully will increase performance.

-Charlie

Yes, I also bought the hood from the donor truck. It doesn't have the back end cut though. I recently saw a video of that same dilemma. Andrew St Pierre from Australia was asking the same thing. Here is a link to the video - YouTube

As for boost, I have to measure it! I don't know yet! It will tell me how my turbo is doing at 250K km (160K) not taking into account that the speedo may have been rolled quite a bit back!

Hey Charlie, thanks for the advice
You are right about the screen. But when I bought the intercooler, it was full of bugs and grass seeds that did quite a bit of damage to the radiator fins, and had to clean it, which involved breaking of some of them in order to clear the way for the air. I must find a compromise. Will see...

The intercooler itself is sealed. The seal is attached below the hood scoop. I know that the US Runners have the scoop plugged without the intake guide, and no air flow goes thru, but the Japanese versions for the diesels, have the opening clear and sealed.

I cropped the pic to see the intercooler better, but here is the whole pic with the intake guide. Part number is 7610935010.
And one more pic thru the scoop...

I did know that the throttle body is for safety also, but I wouldn't drive a bad engine, if oil spray gets past the pistons to be used as fuel anyway! I figured if it tries to run away, I'd stop it with the transmission and clutch... but helpful to know.

Ive attached some more pics of the throttle body for others to see. It is one of the two or three models used in this engine. This one is the simplest, it has no sensor, and only one butterfly valve. You can see the vacuum actuator used in shutting air to the engine.

I will try to find a guage and measure the boost one of those days...

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The runaway condition to me has more potential coming from a blown turbo seal.

I thought about mentioning the job of the throttle plate but didn’t because my 5.9L Cummins doesn’t have one. If I encounter a runaway condition I’m to direct CO2 into the turbo inlet to shut it down. (Like I have a 20lbs CO2 bottle behind my seat just incase.....).


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Good to hear. Lots of people in both the WRX and Celica Alltrac world (both use top mount intercoolers) remove the air guides when doing intercooler upgrades... which totally negates the intercooler upgrade!

With the guide in place, you will definitely be getting better performance while the truck is moving. Now just add a couple PSI of boost and you'll be off to the races, or maybe just keeping up with traffic.

-Charlie

haha i also have a CO2 bottle in the back!

That's should be my next experiment...before I blow up the engine! There was a hose on the turbo that I can attach a valve, so the waste gate opens a bit later than the factory setting. I'll look it up

I think that guy is missing the fact that the base of the windshield (where the scoop inlet would be if turned around) is a high-pressure area. This is why the HVAC system has its inlet there - it creates a nice positive flow through the vehicle at speed even without the fan turned on.

And you wouldn't really want engine by air existing through the intercooler - although that would be better than no airflow. But the cooling efficiency is highly related to the temp of cooling air moving through it.

At least on a diesel engine, the intake air temp doesn't have the same potentially destructive effects it does on a gas car (detonation - ping ping boom). A diesel engine detonates by design. Hah. It just helps performance some to cool the air - since you get a bit more air mass in the cylinder, then you can burn a little more diesel with it and make a little more power.

I think Andrew got the answer he was looking from another mate in AU. That guy gave the same example with the HVAC, that you mentioned.

Anyways, one of those days, I will try to add a couple of PSI to the turbo, as Charlie mentioned, and see how it handles.

I'll keep you posted