So as not to hijack JP ECU post

Don,

You mentioned that Adrian was not suprised to hear about your Silverstone incident
Can you elaborate on this a little further?
Did Adrian have an explanation for the overheat?
And why is the swirlpot system essential?

If the cooling system is airating (sp?) what is causing it?
Localised hotspots?
Water pump cavitation?
A N Other reason?

So many questions! LOL

Steve, unfortunately just as I was getting to the heart of the matter with Adrian he was called away to do his next run up the strip I asked him why the system was pressurising but I don't think he knows the answer to that question. The swirl pot/expansion tank solution was much in evidence on all the big power Skylines at the Pod yesterday so I took lots of pics.

Interestingly, there was some coolant loss from Tony C's expansion tank on his ST205. I mentioned this to him and he reckoned he had simply overfilled it slightly......hmmm.

My own theory is that the coolant pump needs to be re-specced for track work. Just running Evans coolant with a swirl pot and expansion tank doesnt seem to be the total answer. If you look at the WRC cars they have had to run different impellers so that the rate at which the coolant is moved through the engine is optimised. Certainly both Ford Focus and Pug 306 have had to run this solution. Probably an external electric pump is the answer. I think a lot of the GT cars and sports prototypes run this. Ideally we need someone on the inside of Prodrive or Riccardo to answer these sort of questions conclusively.

Adrian said the biggest problem is finding space in the ST205 to run a tall tank like he has on the Corolla. That's why Tony has a 'flat' tank where the ABS control lives on our cars.

_________________
Don
GT4DC Chairman
1994 Toyota Celica GT-Four ST205WRC JDM 269bhp @ 0.9bar
1994 Toyota Celica GT-Four Special GT 590bhp @ 1.8bar
1989 Van Diemen RF88/89 Formula Ford 1600
2008 Nissan Patrol GU 3.0L ZD30DDTi 154bhp

Don - did you say that there could be a problem running a Koyo radiator on track with a stock coolant system, (apart from the rad obviously)?

_________________
Kris
95 ST205 - slept for 10 years, now waking up...
Avensis
http://www.gtfours.co.uk
_______________________________________
Turbocharging - the replacement for displacement

No, its just that Adrian said fitting a Koyo would make no difference on track. I think thats a rather extreme judgement. From my experience it is not the total solution on track but it does help. Adrian said he wouldn't go near a track unless he had a swirl pot/expansion tank fitted and I'm inclined to agree at 300+bhp

At the Pod it was interesting to see how few cars ran with this setup. However, all the 'pro' teams seemed to have them.

_________________
Don
GT4DC Chairman
1994 Toyota Celica GT-Four ST205WRC JDM 269bhp @ 0.9bar
1994 Toyota Celica GT-Four Special GT 590bhp @ 1.8bar
1989 Van Diemen RF88/89 Formula Ford 1600
2008 Nissan Patrol GU 3.0L ZD30DDTi 154bhp

Don - mind you I wouldn't have thought that a trip up the track for 10 - 14s would give the cooling system as thorough work out at as 20 aggressive laps of Silverstone?

_________________
Kris
95 ST205 - slept for 10 years, now waking up...
Avensis
http://www.gtfours.co.uk
_______________________________________
Turbocharging - the replacement for displacement

Exactly my point.....maybe Skyline pilots are more inclined to be DRIVERS

I had my leg pulled by Adrian and others about the DC and he asked if he would qualify as a DRIVER ... lol

I said he'd probably just about scrape into the DC if he saw his way to do a few trackdays rather than all this straight line stuff I've convinced Tim, he's on old Formula Ford and circuit driver anyway. Fensport are saying they will be doing more trackdays in 2006. I look forward to it.

_________________
Don
GT4DC Chairman
1994 Toyota Celica GT-Four ST205WRC JDM 269bhp @ 0.9bar
1994 Toyota Celica GT-Four Special GT 590bhp @ 1.8bar
1989 Van Diemen RF88/89 Formula Ford 1600
2008 Nissan Patrol GU 3.0L ZD30DDTi 154bhp

I disagree re the koyo not being the answer though
I am certain that for "normally" modded car (I would classify stormy as normally modded still) it will probably be sufficient.

From your logs it clearly looks as though the stock system is swamped. This, I believe, would be entirely expected. Mr T would have designed the car with (say) 20% more cooling capacity than required. In your particular case you've increased power and hence heat generation by roughly 30% (allowing for "only" running 1.2 bar nominal day to day)
Water temps are climbing slowly but inexorably to crisis point. I still believe that reaching crisis temperature is the failure mode of your system. Pressures exceed 1.5 bar, the rad cap vents allowing an immediate rise in water temps, further boiling, more pressure etc. etc. Also coupled with the inevitable fall in coolant levels meaning reduced cooling capacity and hence even more problems

This scenario is entirely consistant with the slow rise then the rapid loss of thermal control and is also completely in line with what you see when a car overheats in a "normal" on road situation

However, I am in complete and utter agreement on the external pump/swirl pot system in highly modified engines

As far as I'm concerned you need absolute control over cooling. You also, IMHO need to be able to circulate and cool the water with the ignition off to prevent the 150 deg spikes on switchoff. This can only be achieved with external coolant pumping

You never told me that bit though you git LOL

Also,
We have verified that coolant does indeed return from the expansion bottle to the rad. Lord only knows how but we witnessed it happening at Silverstone

I also have another theory that I think I've posted elsewhere

Even with the KOYO fitted Don was still blowing fluid out of the expansion although at no time did it become an uncontrolled blasting out type affair. It was just a little weepy looking sort of thing

I **think** I have the answer to this. As the water heats and expands normally some must be forced out of the system. However, with the KOYO fitted you have also increased overall coolant capacity by quite a lot (mine took an additional 2.5L over stock)
My belief is that this is causing more overflow - since more water expands there must be more overflow - and might well be exceeding the design capacity of the standard tank leading to some controlled overflow from the tank
Thoughts anyone?

A bit of further sleuth work reveals that the 185 wrc also has a swirl pot type system

Images from K & L

You can see that the top hose has been re-routed over the intake. This creates a natural high spot where air will collect



There is a line linking this to the top of the rad so that air will also bleed from the rad

You can then see here that this line goes into an expansion. You can also just about make out the pipe off the bottom of the expansion tank back into the cooling system


Interestingly the c/cooler looks to have some sort of weird system too

IIRC this system is running at 2.5bar !!!

_________________
Don
GT4DC Chairman
1994 Toyota Celica GT-Four ST205WRC JDM 269bhp @ 0.9bar
1994 Toyota Celica GT-Four Special GT 590bhp @ 1.8bar
1989 Van Diemen RF88/89 Formula Ford 1600
2008 Nissan Patrol GU 3.0L ZD30DDTi 154bhp