924Board.org

[Dutch924-racer]

I am rebuilding my engine and doubt if I should modify the cooling system

Some people modify the rear flange on the head and the coolant pipe to this.
Will the water not flow to fast, so the engine hasn't got time to give it warmth of ?

I saw Mittelmotor used all standard parst on there GTS replica with over 300bhp. Even the original radiator.

Hope to hear some experience of you guys, with or without modified coolant system
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937 trackday car
Series 2 engine
951S turbo and intercooler
Fast road camshaft
Forge recirculation valve + boost controller

[ideola]

[Carrera RSR]

This year I re plumbed in the heater matrix. Only coolant mod is larger full alloy 951 rad and 951 header. About 10 litres of deionised water and water wetter fills the system. No anti freeze until Fall. All temps in check.
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1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252

[GeorgeV]

I agree with Dan. But you should get a new (at least stock) radiator as an old one will not flow as well as a new one, and a new thermostat. I run 14psi and have a 951 rad and a 944 coolant reservoir like Carrera. My temps are ok except on super hot days, which is most of summer here.
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1981 932 with mods:
http://www.924board.org/viewtopic.php?t=37921

[Carrera RSR]

[morghen]

And if you live in Germany or you drive in Germany, it might make sense to do the mod as you know there is no speed limit in many areas so prolonged on boost sessions can be happening
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Supercharger and EFI kits
https://www.the924.com

[Fasteddie313]

I am running my heater core and its valve bypassed, and a FMIC in front of my old OEM rad. If I put the heater back in service I will hose it in parallel with the bypass with a T and a Y.. I did have problems with air pockets in the head and the bypass solved this.

I do believe that my thermostat is weak as it runs quite cool via temp gauge, anytime the car is going at a decent pace, on boost hard or not, it runs just below/around the 1/4 mark.
Idling around and putting across the yard sometimes it will get close to the 1/2 mark and the rad fans do there job even on the hottest days, I can feel a LOT of air sucking through my IC when the fans are on.

Mind you all my car ever does is go out, warm up, do a bunch of WOT runs up a big hill, top of 3rd mid of 4th, then a mile cool down cruise back to the house for more tweaking. I'm not sure what you consider "prolonged boost runs" but my hill is about a mile long and I can pull 4th WOT 4 times to 5.5k ish up it due to braking for turns in the middle that slow me down to about 3.2k in 4th at the limit of cornering speed 4 times. If it leaves the yard it's for WOT runs period, I have no experience with it in traffic or slow driving. I have done hard pulls up to 13ish psi and have had no increase in temp readings because of it. My engine seems very happy despite having bounced off the rev limiter WOT at 13psi (oops) with no ill effects, need stickier tires..

One of these days I'm going to replace my water pump, bottom rad hose, and thermostat. I have a new thermostat but I've been waiting for a water pump just as preventative maintenance so I can do it all at once..

Next for my engine is going to be a wideband, IAT sensor/gauge, and make my WUR adjustable, around 110 psi system pressure (maybe more with dual fuel pumps in series until my injectors pop off on there own or something else limiting) and go from there.. I am going to crank the boost up and run to redline until I can't push the CIS any further to stay rich with high system and tuning the WUR, my IATs get too high by running out of turbo (a shop told me my S1 turbo will go 300hp, I don't care if its efficient as long as my IATs stay down), or I start to hear detonation/scary noises or encounter any other problems.. If it blows before one of those limiting conditions are met there must be something else wrong.. But I am quite satisfied with my engine for now as is so I may concentrate my attention on other aspects of the car for a while first..

If I happen to come across a better rad and/or thinner cooling fans that will fit in my car I will grab it up and install it just because but it's not something I think I need and don't think I will need before I run out of fuel with CIS but who knows how much fuel that sucker will put out tweaked to the max. Some say 250hp but I find no reference to what it is capable of at 110 psi system and tuning on boost control pressure via an adjustable WUR until it can't maintain good AFRs anymore.. Maybe I should actually measure how much fuel my injectors will flow with the metering plate maxed out in a certain amount of time @ 110 psi system and find out..
I am running 7 bar system and just over 4 bar (like 4.05) warm control right now and it seems to love it by butt dyno, if anything it should have me richer than OEM and it screams at 13psi boost with no scary noises and a nice cold intake tract, even the intake manifold is kissable directly after hard pulls, my GF is warmer.. Starts, idles, cruises and all that beautifully too, only tuned via dwell @ idle 40-45 duty cycle and butt dyno.
Crap I'm getting OT..
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80 Turbo - Slightly Modified

[WEASEL149]

I would only modify it in proportion to any power upgrades.

Flow is a factor but temperature gradient and system pressure affect heat transfer more.

Just don't do what I'm doing
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1979 UK 932

[gerben1986]

[fiat22turbo]