Coolant pressure?

[David P]

I have a new ASI aluminium radiator, Demisterman heater matrix and mostly new silicone hoses and clips.

 

Presently the rad cap is an ASI 1.1 bar and I plan to upgrade this before fitting the supercharger.

 

Stant Racing radiator caps are available to fit the smaller Japanese neck rads in 1.3 bar or 1.5bar.

 

Will these components be 'happy' running @ 1.5bar?

[Chris Wilson]

Should be fine but why increase coolant pressure, are you planning on running the engine hotter than normal or something? If not there's little point in a higher pressure cap. They just allow higher water temps without boiling.

[bobapple]

Are the TRD thermostats worth a look into or only really necessary if doing track or hard abuse.

[David P]

Jagman has posted that the supercharger will create a lot more heat, so trying to stay ahead of the game.

 

Already have the TRD (Toyota summer stat) fitted.

[Chris Wilson]

Using a cooler thermostat or a higher pressure rad cap does nothing to improve the heat rejection capacity of the cooling system, it will only allow a higher coolant temp before boil over occurs. I think you will find the stock rad and viscous fan arrangement has a lot of extra capacity, especially if you have the thick core rad type. It is engineered to cope with extreme climates, so over here it won't be working very near its limit at all. You don't want high coolant temps if looking for maximum power. I run my RB26DETT engine fairly cool, with a slightly adjusted `stat.

Edited May 30, 2011 by Chris Wilson (see edit history)

[David P]

Thanks for the input.

 

The full current spec of the cooling system is;

 

ASI 50mm core rad, 1.1bar cap, Meziere electric water pump, TRD stat, thermostatically controlled twin electric fans, Demisterman matrix and water-wetter.

 

I am not planning to run the coolant at a higher temp, just don't want it boiling up if it gets temporarilly toastie.

[Chris Wilson]

You should have the left the stock pump and fan on it then You have added a lot of unknowns there, only time will tell I make it about a 130 C boiling point with a 1.5 bar cap, that should be plenty !!!

[David P]

You should have the left the stock pump and fan on it then You have added a lot of unknowns there, only time will tell I make it about a 130 C boiling point with a 1.5 bar cap, that should be plenty !!!

 

The OE water pump, pulley and fan would be rotating backwards with this design.

 

Looks to be a suck it and see.

 

Edited May 30, 2011 by David P (see edit history)

[Chris Wilson]

That long top belt run may well need an idler pulley just depressing the back of the belt, or any RPM snatches MAY have it developing excitements and jumping off. I had to do this on the PAS belt on my RB26DETT when I put a triple plate clutch in it, the shock loadings were enough to put a harmonic in the belt and it either turned inside out or came off, which was never nice.

[David P]

I have considered that belt whip could be an issue, if so, thinking of making an idler mounted from the centre of OE idler arm.

There are many unknowns that soon won't be.

Thanks for the input.