Anybody got any experience with changing the radiator cap to increase coolant pressure? Seen several caps out there that bump the pressure from .9 to 1.3 psi. Just wondering if anyone's done it to the -8 yet. Thanks.

 

I've never heard of replacing the cap to up the coolant pressure, it incorporates within it's housing a PRV which allows, at too high a pressure, the system to vent. I assume this is all within the specs of the engine and should'nt be mucked about with. Saying that I am not an authority on the 8 and someone else may know a bit more about it........Hope you are enjoying Iraq ? I was at SHIABA Airfield last year...awful place....hope I've been a little bit of help

 

If anything, replacing the cap should only increase the maximum pressure possible in the system. Increasing the operating pressure would probably require some sort of change to the pump (assuming the system isn't regularly venting out of the stock cap, which it probably shouldn't be).

Also, increasing the pressure will increase the boiling point of the coolant, but unless your engine is trying to run water temps above the BP of the stock setup, that won't buy you any extra cooling from the system. About the only "gain" would seem to be that the engine would overheat a little later (and at a higher temp) than a stock setup, but whatever benefit that buys you would be balanced by the possibility of an overheat doing more damage to the system than normal.

The money for that cap might be better spent on some sort of "water wetter" product (I'm still trying to evaluate how the stuff is doing in my 8....)

 

Thanks for the replies...it'd been so long since I posted this thread I almost forgot about it...Twiggy, I wouldn't exactly say I'm enjoying Iraq...this is my third trip in the last year or so, and every time it seems to be worse...but, oh well...at least the money's good :D

 

BTW, cap pressure is in bar or kg/cm2, not psi. A .9 cap would be about 13-14 psi, for example.

Anyhow, a higher pressure cap will raise the system pressure and raise the boiling point of the system. It does work, but from what I've understood the '8 has a pretty darn good cooling system. Might be of use if you do a lot of track time, but otherwise you might not be getting the engine hot enough for it to be worthwhile. But, it's a cheap, easy mod if nothing else .

Dale