Both are good .. I am running the Koyo but have heard many good things about the Mishimoto - isn't supposed to look as good, as mentioned by Voodoo_S2K, but in terms of cooling from what I have heard it is supposed to work just as well.

 

Shop around and get a good deal on a koyo. Not saying it will mess up but you will be kicking yourself later for not spending that extra $100. I hate being the test mule

 

[QUOTE=NFRAP1,Sep 28 2008, 08:40 PM] I have the mishimoto.

 

Thanks for the info Chris! My mishimoto cap has been leaking since day one. I just ordered a J's cap, in the larger size.
I know it's gotta just be the cap, because I had a pressure test done and it held great with NO leaks anywhere.

 

Do you know if i need to get the same mugen cap as i would for the koyo? I know you need to get the different one for the koyo.

 

How can you tell that your cap is leaking? Do a pressure test?

I haven't lost any noticeable amounts of coolant, its dropped from the top of the line in the overflow to the bottom of the max line (1-2mm). My problem is that I still smell coolant sometimes after driving for a while.

Do you think its the Rad cap?

If I order the J's racing cap, do I just ask for the larger cap?

 

Yes, I did a pressure test and everything was perfect. Looking at it, I thought it might of been leaking around the neck (welds don't look so good). But, the pressure test was good so I'm assuming it's just the cap. I ordered the larger size J's cap, so I'll let you know once I get it.

 

Koyo fits a CTSC + Ultimate Racing intercooler just fine.

I only upgraded because my old one cracked.

 

I know generally speaking that if something ain't broke, then don't fix it.

But if one lives in a hot environment, (SW US) would this mod be worth the money or will stock do just fine? I've heard that the stock cooling system is sub-par but I haven't seen any data to back claims that either radiator will reduce temps significantly. I was hoping someone who has a koyo or mishimoto radiator can better explain the benefits over stock.

Is the bang worth the buck? Can anyone give me some insight?

 

You heard wrong. The stock cooling system works great. I've done track days in 105+ degree heat and not a worry in the world.

If you are N/A, not anything to be gained over OEM, except bling . No need to replace unless your OEM is broken.