SR20DET cooling questions

[Thewelder]

I am new to the SR and had a guy mention cooling problems at higher rpm. That is where my autocross car lives. Then add on that I can’t fit a full size radiator in my lotus seven and it likes to get hot quickly. It usually boils over after 6 autocross runs. I don’t think it will be a problem on the street because I won’t be driving it that hard. But if anyone has any recommendations for getting it to run cooler let’s hear it. Stock SR with a knock off civic aluminum radiator.

[Thewelder]

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[clotuning]

An oil cooler will definitely help drop Temps.

Also switching over to a name brand radiator will help. I had a cx racing radiator on my civic with a h22a motor and it was overheating from just drag racing. Switched over to koyo and problem was gone.

[Thewelder]

Thanks. Ever heard of an oversized water pump pulley to slow it down some.

[ericb382]

Originally Posted by clotuning

An oil cooler will definitely help drop Temps.

Also switching over to a name brand radiator will help. I had a cx racing radiator on my civic with a h22a motor and it was overheating from just drag racing. Switched over to koyo and problem was gone.

That’s probably the easiest route. What do you have for ducting. Looks like the rad is at a very flat angle. A lot of air will want to go around instead of through it if you don’t have it ducted to force the air through. Or you could do a rear mount rad.

[Thewelder]

During this winters work I will block off the nose and intercooler to force the air through them. That may be all I need. When I autocross it it lives above 5000rpm and our runs are around a minute long. It gets very little time to rest. Maybe five minutes between runs.

[Def]

Your radiator is likely most of the problem. The really cheap ones have poor fin brazing, poor fin density, and poor fin turbulator design (or usually no turbulators at all).

For autox usage, you should vent the engine bay as much as you can with AGGRESSIVE vents and gurney flaps on the leading edge of all exit areas to get as much extraction as possible at lower speeds. Seal up your heat exchanger to the nose inlet as much as possible, and in the case of a Locost, you might want to open up the minimum nose cone/scuttle area so that it isn't "necked down" there.

An under drive water pump pulley is likely a good idea for a tiny power bump and reducing some very high RPM cavitation, but it won't fix your problem IMO, which is primarily the cheap radiator.

I'd also recommend adding a surge/expansion tank. Don't rely on the top of the radiator header as the expansion tank like stock - it doesn't work well for most setups.

[RalliartRsX]

Cheap radiator (ditch it), ducting and v mount setup.

V mounts can work but ducting is paramount.

[Thewelder]

It is v mounted. I did that and all the piping myself. I will look for a better radiator in that size and duct it like I had already planned. Space is a problem but it is cooling better than when I got it. When I got it, it had a melted throttle cable from the under hood temps.

[Def]

Go with a double pass radiator as well, which will use the small core size better.