2JZ Overheating Problem

[Christian]

Hi All,

I've updated my MK3 track Supra with a 2JZ-GTE engine.
It runs perfectly but just after about 2-3 laps the problem start!
The engine overheats and I need to stop the session.

The overheating doesn't happen if I drive it on the motorway.

I also bought a MKiV supra and exactly the same problem occurs.:: angry ::

Does anyone has a real solution for the overheating problem

Many thanks for your help.

 

[Blackmk3]

So two to three laps in the engines really starting to pump out some heat. what fan system are you running? how old is the radiator? is it blocked? what condition is the antifreeze/boil in? has the water pump been changed? checked the thermostat?

Could be so many factors. But my guess when conversions happen people don't usually put enough into the cooling systems, removing factory viscus fans and replacing them with Chinese electric fans.

We will need more info mate

 

[Christian]

Hi, I used different radiators initially I bought a new big ALU Koyorad and later I changed if for one from a BMW M5 (V10 engine) also new.
I also used different types of coolant/antifreeze; Toyota Red Coolant, Evans Power sports.
I tried it with a new thermostat and also have tried if removing it makes a difference as I'm only using it on the track.
The water pump was changed with assembly of the engine to get it to fit in the MK3 as it's a lot easier when the engine is out.
I'm using two high performance Spall fans.
The engine build up/conversion was done quite thorough as I wanted to put the BHP later on up towards 600BHP but at the moment it doesn't cope with the fairly standard setup

But I've exactly the same on my MKiv Supra that uses the original radiator and viscus fan.

Many thanks for your help

 

[f00g00]

An oil/water cooled turbo setup would contribute to an overheat condition on a track. Oil cooled only would put less stress on the coolant. Also thermal wrapping the exhaust manifold and downpipe would help underhood temps and also running the engine undercover if your running with it off.

 

[Blackmk3]

How are the fans mounted on the radiator?

does your mk4 have a new radiator aswell? otherwise that could be a age issue likely a blocked radiator.

2jzs don't overheat when taken to the track, so there's something causing it on both your vehicles

 

[Christian]

I tried the fans with a shroud and also directly mounted on the radiator as well, but no difference.
I pressure tested the MK4 radiator as well and the flow seems to be OK.
Also no specific hot points when I measured the temperature.
I've seen some issues on internet with overheating 2JZs only no one posted a solution for it.

 

[shipkiller]

Oil coolers could help reduce the overall temp.
I believe the electric fans are to blame.

 

[Christian]

I already upgraded the standard oil cooler to a much larger one.
The two fans together have more capacity then the original viscus fan.
And I do get the same problem on the MK4 with viscus fan.

 

[Blackmk3]

The way they flow test and claim how many CFM a electric fan can move is free air with no restriction. As soon as you mount it onto a radiator with a big restriction in front of it the CFM output falls dramatically.

Pretty much all 6 cylinder turbo cars ive seen at the track with some electric fans cable tied to the radiator overheat at the track, and this in in NZ were 26C is a hot day in summer

What ambient temperatures are you racing in?

 

[HENRY SIEMON]

Time to cut the head.

 

[Radial]

This is the most common problem to any drifter.
Going sideways reduces engine bay airflow dramatically.

The solutions are usually:
- Install the biggest radiator you can fit. I use a huge 62" wide flex-a-lite universal radiator on mine with a 3500cfm+ electric fan from a OEM powerful Mercedes C-class. (Requires 34Amps of current and special relay :naughty
- Build a large "air duct" in front of the bumber (with simple plastic or aluminum) to guide ALL accessible air in to the radiator opening.
- Install vents in your hood, allowing air to escape more easily.... ideally tilt the radiator, look at the Subaru world rally car IC and Radiator setup, and you get the idea. Heat rises, so a sealed hood will start to trap heat as airflow is reduced. Any motorsport vehicle has asome sort of vent in the hood. http://dbtuned.com/pics/Media%20Storm/WRX%20Rally%20Engine.bmp
- Invest in at least 1x 20+row oil cooler, and NEVER even think that the stock oil/water cooler is stupid. It's an extremly efficient unit for its size, keep it and just add an extra oil/air cooler.

And a popular solution is now to move the radiator to the back of the car. Keeping the IC in front. Forcing lots of air through well thought air scoops into the trunk + large cap fans blowing the hot air straight backwards or underneath the car. Obviously only for Motorsport vehicles, and was very common in the group B rally cars. Nice inspiration there.


So there you have it, a lots to think about.

ANY jz driven "properly" on the track overheats, i've seen it multiple times. These get hot...