Jfrahm

Definitely check/change the "thermostat inner seal" I believe it's part 92810616300. These are nearly always overlooked and often so encrusted in buildup that it looks like part of the casting. If it's not functioning, some water will bypass the radiator as I understand it. It seals the secondary disc valve then the thermo is open (hot)
http://en.wikipedia.org/wiki/Wax_the...thermostat.jpg

-Joel.

FredR

Do not run the 75/25 mix without the Redline water wetter or an appropriate anti corrosion chemical package of some suitable kind. Good coolants can be diluted 66/33 without additional chemicals [as I know] but if you do change them out every two years.

I understand the 928 Motorsports radiator has cooling coils in both end tanks. You can probably forget the check on the leaves/crap on the front side of the radiator as it is relatively new.

Rgds

Fred

Carl Fausett

Like FredR's suggestions a lot. They mirror my own.

Keep in mind the 928 barely cools well enough in equatorial/hot climates even without a supercharger. In stock trim, look at the threads about overheating, fans running at stop lights, and radiators exchanges in the hopes of driving the temp down and you know its edgy already.

Fred's right - you must use every tool available to you.

• The right mix of antifreeze - as much water as possible
• water wetter
• clean, unplugged radiators
• shrouds on all sides of the radiator in place
• good fans
• fans wired to turn on earlier or just run them all the time

It has little to do with the supercharger other than more HP means more fuel means more heat. That exacerbates a problem the 928 already has in hot climates.

BUT: it can be handled and solved. Many of us have done it. And SC cars in other climates that are cooler have no issues at all.

Carl Fausett

I do agree with moving the SC heat exchanger away from the front of the radiator in this case also. Cant hurt, will likely help.

Carl Fausett

Electronic fan controllers.

These work very well and they help. Then you can get a jump on the heat rise by turning the fans on sooner. Cheaper than a failed (and overly-complicated)
Porsche 928 fan controller unit.

I sell them cheap, but they are available everywhere:

http://www.928motorsports.com/parts/...ler_switch.php

Carl Fausett

Actually, Fred, we make 'em to spec. No integral coolers, one cooler or the other, or both. Just what you want.

Here: http://www.928motorsports.com/parts/alumradiator.php

FredR

Carl,

The one I saw over here had coolers on both sides if my memory serves me correctly. Assumed you probably did a std spec- clearly not the case. It looked a pretty nice piece of kit.

As a matter of interest what thread size do the cooler connections come with? Presumably it will be something like M18 x 1.5. I am hoping to do some plumbing modifications on mine shortly.

Rgds

Fred

Hilton

After using an IR thermometer to confirm its actually running hot, this would be my first thing to check, along with the thermostat itself (they're in the same place).

Often overlooked by inexperienced workshops or owners.

The coolant bridge is relatively easy to remove - on a stock S4 it can be done without removing the intake manifold - although I'm not sure whether your supercharger setup may interfere with that.

juju

Thanks Carl, I will take a look behind the driver's side (RHD) wheel well tomorrow. Forgive my ignorance, but how do I go about disconnecting the SC heat exchanger? Are the hoses full of water? I'd like to have a go at this job myself but some advice would be appreciated!

j.kenzie@sbcglobal.net

I think the hoses are full of windshield washer fluid, and are fed from that reservoir. I would just clamp the hoses and cut them. Then you need to figure your new locations for the cooler and route your hoses to it. Find some fittings and new hose to connect to where you cut. Extend your wiring to the new location and you should be done.
Good luck,
Dave

ptuomov

My views:
- It helps to make sure that the engine is in otherwise good condition before starting to debug the cooling system.
- The additional heat exchangers should be moved to fenders and away from the front of the radiator. There's plenty of room in the fenders.
- You want to plumb the end tank oil cooler in series with an external oil cooler.
- Belly pans need to be on for the engine compartment to cool properly. Makes a big difference.
- Thermostats need to be working.
- It often helps to clean the radiator.
- Anything that one can do to seal the duct from bumper cover opening to the radiator such that all the air has to flow thru the radiator will help.
- It helps to know the actual temperatures of oil and coolant when diagnosing cooling issues.

Alan

I think the biggest impact of most superchargers is the simple physical one - by limiting the area available in the middle of the back of the radiator it may restrict airflow somewhat - but mainly it limits you from installing dual puller fans with good flow through shrouding - the most effective fan configuration.

Alan

j.kenzie@sbcglobal.net

I think Alan has it absolutely correct (as usual). The design problem is to provide cooling without the large shrouded puller fan/s.
Dave

SeanR

Yep, I've been running the VCB unit which retains the factory fans, I've never had any heating issues and it does get kinda hot here in Texas.

j.kenzie@sbcglobal.net

It can be done, with some effort, if you're running with a man-sized supercharger.