radiator cap psi
Turbo Mini Forums

Im thinking about upgrading my radiator cap, to go with a new rad, two core type.

there are other makes of cap that i have seen with different range of pressure. what would you reconmend for a 1275 metro turbo, new hi flow water pump running with intercooler boost 7.5-15? not sure what antifreeze.

thanks for any help
After doing some reading would it be beneficial if i was to use an cap at 16psi like http://cgi.ebay.co.uk/ws/eBayISAPI.dll?Vie...e=STRK:MEWAX:IT

std metty one is 15psi,

use a 22 psi stant one like in that link.

just make sure your hose clips are done up tight..........

I have been considering moving the thermostat from the top hose to the bottom hose. This would tend to pressurise the rad with the restriction on the rad outlet. What I dont know is by how much it would pressurise the rad, and which rad cap to fit. I had looked at the standard fitment and its mostly 15 PSI, so im now thinking of fitting a higher rated one like you have Joe

Yes, but the water pump creates 'head' and if, like I suggested, I place the thermostat (restrictor) in the bottom hose, the rad sees the head that the water pump produces. Where as with the thermostat in the top hose, the rad is only ever exposed to the static pressure in the system unless there is an overheat.

snigger, you said "head"

isnt there a much deliberated argument about thermostat positioning and themal shock on K series lumps?

Also Paul you want to beware of using too much antifreeze, allegedly it decreases the heat transfer rate.

"head" like beer, good idea. If i fit a thermostat in the fan switch boss, can i do away with the thermostat in the head? thanks

yeah joe, not sure what im useing yet, theres that wetter stuff as well....

Edited by wintersurferuk on 28th Feb, 2010.

Edited by Sprocket on 28th Feb, 2010.

delta temp eh flash bugger lol

From what i remember about what i read, it was somthing along the lines of the stat opening and dumping cold water into the engine, so your idea should counter that effect.

i'll have to dig it out at some point.

Delta T, delta P, Approach, Pinch, are all terminoligy I use at work for talking about such things as heat exchangers and for all intent in purpose, an engine, as far as the cooling system is concerned, is a heat exchanger .

What you also have to considr is that with the bypass, the temperature at the water pump is an average of the bypass temp and bottom of the rad temp. So I don't really know how it will respond overll temperature wise.

It will certainly make it easier to plumb in.

Watch this space

lol

Indeed certainly woth trying :)

heres the thingy i was thinking of...

http://www.mgfmavhh.ukf.net/

are we OT enough yet? lol

I cannot be arsed reading that right now, but all I will say is that onece the engine is up to temp, the stat is never closed, and they are not slow to respond either. As long as there is a bypass around the rad. Some work in a full flow scenario, while others work in a restrictive, mixing scenario.

With full flow bypass I recon you wont get the heater to work if you have one, there just wont be enough delta pressure () to push the hot coolant through the heater matrix and back to the bottom hose.