I need some help from the group before we go too much further right now.

When I bought my car, it had a V8 conversion in it. The radiator hose was only 1" throughout the car. Temps ran just fine.

I'm converting it to a Subie EJ20, and I went with the same size hose throughout the car. I'm using a dual-pass all aluminum radiator and silicone hose. Its fittings are 1.5" on the radiator and the engine, which isn't a problem, as we can adapt it to 1". But before the work is done, Scott sent me an email asking if I'm SURE that 1" is OK.

I was thinking that the V8 as a much bigger displacement engine, and the radiator wasn't as nice. So with a smaller engine and better radiator, that 1" would be fine. Someone at some point told me that 1" would be fine...but I just want to be sure.

Can I get some second/third/fourth opinions?


Thanks guys.

Doug, I'm running 3/4 & 7/8 w/o any cooling problems. I will be changing over to 1.25 as a precaution to prevent excessive pressure at high RPM. I made this up in my own mind with nothing to substantiate it other than the 3.0 needing a head gasket replaced. If I were running an on demand electric pump I wouldn't even consider going to the 1.25". Glad your getting this completed. The Trifecta (You,me and Chris) will soon be complete.

Trifecta? More like "Holy Trinity"!!

3/4 seems way too small, but if you think I'll be fine with 1".

Any other opinions?

1" will be fine. I'm running the gates green stripe that is 1 1/14" & I have never had a heat issue not matter how hot a weather. A NA suby motor just doesn't take much to cool. I think you will still move plenty of water with 1". So I wouldn't worry to much about changing it.

Yeah you should be fine with 1" Doug. Renegade Hybrids sells 1" hot and 1.25" cold with their radiator kits designed for V8s, some with serious HP.

I switched over to 1.25 and mine runs VERY cool. I'm planning to downsize the radiator to a square 19x19 and lay it flat up front so I can reclaim some trunk space it's running so cool. Can't wait to hear that thing run!

I'm running 1 1/4" gates with a 2.5L n\a Subie. My car runs 180 degrees no matter what the outside temp is.

Thanks for the help guys. Just wanting to make sure we're doing the right thing.

By doing a Subaru conversion

Absolutely

Are you guys running the radiator hose on the bottom of the car or through the interior tunnel on your conversions?

I did 1 " steel lines under the car,..but they duct up nice and tight.

Either way works.

I'm going under the car with gates green stripe. It seems to work fine in that location and keeps it simple and easy. I'm not going really low with the car.
Just one of many ways to make it work.