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Hi, I have taken my 89 supra out to the track a few times now and I can only do about 3 or 4 full tilt laps until it starts to get really hot and overheat. I've put a new radiator, electric fans, and a shroud, but that hasn't seemed to help. Anyone got any ideas what the problem may be?
 

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blown head gasket (off the top of my head, its a supra )

are you running the belt driven fan at all or exclusively electric. if electric only, what brand

what were the conditions at the track---temperature


you are either running out of cooling capacity OR have a bhg that is pushing coolant out with super heated combustion gasses

a leak down test ---filling a cyl at tdc with compressed air and measuring/seeing where its leaking -- will help diagnose

so will looking the spark plugs. if one or two cylinders are super clean and the rest are normal...coolant is steaming the plugs from the bad gasket

whats the history of the motor, is this a turbo ??
 

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It's 2 electric fans from eBay that came with the radiator. The track is in Arizona, but it's like 70 during the day right now.
 

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blown head gasket (off the top of my head, its a supra )

are you running the belt driven fan at all or exclusively electric. if electric only, what brand

what were the conditions at the track---temperature


you are either running out of cooling capacity OR have a bhg that is pushing coolant out with super heated combustion gasses

a leak down test ---filling a cyl at tdc with compressed air and measuring/seeing where its leaking -- will help diagnose

so will looking the spark plugs. if one or two cylinders are super clean and the rest are normal...coolant is steaming the plugs from the bad gasket

whats the history of the motor, is this a turbo ??
What does it take to blow a head gasket anyways?
 

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It's 2 electric fans from eBay that came with the radiator. The track is in Arizona, but it's like 70 during the day right now.
There's your problem. Put your stock clutch fan back on with a good fan shroud and I'd bet your overheating issues go away. A good E Fan setup is going to cost more than your entire radiator/fan combo likely did.

What does it take to blow a head gasket anyways?
Improper head stud/bolt torque, warped head, too much boost, detonation. etc.
 

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There's your problem. Put your stock clutch fan back on with a good fan shroud and I'd bet your overheating issues go away. A good E Fan setup is going to cost more than your entire radiator/fan combo likely did.



Improper head stud/bolt torque, warped head, too much boost, detonation. etc.

It's a non-turbo with 220k miles in it and we have never taken it apart or anything. I'll see what my dad thinks about putting the stock fan back on, thanks.
 

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What does it take to blow a head gasket anyways?
Getting them hot.....

Never been apart ?
That means if it hasn't compromised the head gasket, it's on it's way to.
eBay fans & radiators are for shit.
Twin low buck electrics don't put out anywhere near what the belt driven fans do.
A $450 Derale almost does.
And for extreme duty cooling you will need about a 2" to 3" thick radiator.
But before you spend any money, take that damn head off, install a metal head gasket, and torque to 75ft/lbs.
One of the reasons the 7M has a bad rep, is because they were improperly torqued at the factory, and all the service manuals have the wrong torque spec. in them.

Consider yourself very lucking it hasn't started blowing coolant out the tail pipe yet.
 

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man if im pushing 15psi through a felpro + arp stud setup there is no reason a non turbo 7m has to go metal head gasket

with 220 k miles this "drift" car prob will die with the rod knock. let that oil level get a little low, hit a long corner with decent g force and the oil system will starve, loose pressure and take out a bearing in half a second at the 5-6 k rpm im sure your running at to have any sort of power in a 3700lb mk3.

or get it crazy hot and get that oil whipped up and thin enough to cavitate the pump (same effect ). im sure the oil pickup screen is nice and clean ;)

playing with fire OP -- good luck (its fun while it lasts....)
 

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It is 100% the ebay radiator and fans. As said before, OEM clutch fan is the best cooling option available. I would bet an OEM style radiator is better then the ebay radiator, but I would suggest a Koyo over everything (Mishimoto is garbage too).
 

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I run electric fans on my setup, but that's only because I have a PWR rad with a 1jz in a Mk3. Mechanical fan won't fit...

...but that doesn't stop me. A quality electric fan will do fine if it's your only option. Note I said QUALITY and ONLY option there. I run a fan setup from a Ford Contour SVT with a custom trimmed shroud and some nice custom ducting.

That said, drifting a 220k mile Mk3, that's both rad and ballsy haha. Have fun while it lasts. Switch back to the clutch fan for and see if that helps, it doesn't take that long... :)
 

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That said, drifting a 220k mile Mk3,
A 220k mile NA MK3 none the less.

I've been running E fans on an old school CSF radiator for going on 5 years now, most of that at 580whp with a little bit at 630whp. It's certainly do-able but your whole cooling system needs to be in good shape and your ducting/engine undercover needs to be intact to make it fully effective.
 

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Unlimited Time Attack A70
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DUCTING, DUCTING, DUCTING!

Air is very lazy, any crack or crevice it can slip by it absolutely will. It will always take the path of least resistance, and passing through a core is not naturally one of them, it must be guided and forces. Air is the working aspect of the radiator, without air it will not do its job. You wouldn't run your car with 30% of your fuel leaking out of your fuel rail, so why only use a fraction of the air entering the nose. Sliding a car sideways drastically reduces the air volume and pressure entering the nose of the car. Proper sealed ducting from the point of entry to the core, fan shroud should be completely sealed up against the radiator on the opposing side. If at all possible, proper evacuation and egress of the hot air should also be a high priority to keep the air pressure and temp down behind the rad.

On top of that a quality core that is dual or triple pass will greatly aid in maximum efficiency of the system with a quality fan set to match.


As many have told you, with your current car in its current condition, you're playing with fire. That motor is not designed by any means to see high g forces, high revs and WOT in the conditions it currently is or even when it was brand new! Just because its a "supra" doesn't make it a bullet proof machine. It will need alot of aspects touched in order to be a competent car that isn't on the verge of destroying itself.
 

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Nick touched on a point that I'd like to elaborate on, and that is 7m oil control. A stock 7m doesn't have the best oil control, and prolonged high rpm use can cause some issues. Old habit of mine was to run an extra half quart or so, as cheap insurance if any oil got stuck in the head a bit longer than ideal...

Wanna see what happens to 7m's when they're held at high rpm for a while? Well, here's what set up my rather spectacularly uneventful journey into rod knock land:


My first proper burnout video. Man that was a long time (and a lot of gray hair) ago haha. Anyway, result of this burnout (I still have that bag of rubber bits, by the way) was two completely spun rod bearings, as well as a fairly destroyed crank. Shame too, I loved how that car sounded...

I'd still advocate proper ducting before all else, but you could always try removing the hood to alleviate under hood pressures and hopefully temperatures. That, and you might get a bit more warning when the engine has finally had enough.
 
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