rotoboy661

hey guys just wanted to ask anyone using a koyo radiator if they are experiencing any sort of overheating???

according to gotham racing
" Because of the thickness of this radiator, we've run into fitment problems and cooling problems in RX7's utilizing a front mounted intercooler"

is this statement valid???

the reason i ask is that i have apexi fmic and want to upgrade my wimpy stock radiator for a koyo in the process of install

any help would be great

Scrapiron7

Never had a problem. I never see more than 99C running it hard with a Koyo and Greddy FMIC. More than likely the people who have had problems had other issues as well.

rotoboy661

thanx man i was getting worried there for a min

mike

FormerPorscheGuy

fitment problems, possibly
coolant problems, unlikely

SleepR1

Absolutely no overheating problems on the street. Summer days with A/C full blast in stop-n-go traffic, I see 90 to 94 C (194 to 203 F) Open track the water temps will climb to as high as 120 C (248 F) if pushing hard with 12 psi boost for up 25 minute-sessions. These readings are form my Power FC Commander keypad. Of course my stock dummy temp gauge doesn't register any changes, until about 120 C, and then it just bumps a little above halfway between "H" and "C" LOL. I have a GReddy 2-row FMIC, and Zavier didn't have any problems installing mine with the Koyo radiator core.

zmarko

What turbo(s) are you running? Stock twins? Or single? Nice setup BTW. What I'm aiming for.

SleepR1

Thanks. I have '99 J-spec Type RS twin sequential turbos.

https://www.rx7club.com/showthread.p...hreadid=287944

Good luck with the project!

rotoboy661

thanx guys keep'em comin'

Shinobi-X

Once the car is moving, I don't have any real problems either. Keeping the radiator ducted or some other method for air flow to the radiator has kept me fine. I've also done the fan mod, so it also assist if I need it.

jdhuegel1

No problems here..

Actually my car runs TOO damn cool. There's a thread in here somewhere, but it's technical, so it get's bumped by BOV and Bodykit threads.. LOL

cavellm

Isn't 90 to 94 fairly high for street driving?

And I thought 120c was pretty much to the point of overheating.

I've got a stock mount ic, and don't think I've ever seen water temps reach above 90 as long as I have my undertray on. This is in 90-100 degree Dallas weather.

SleepR1

No, you're just used to the overly cautious people the post on this board.

Quote:

And I thought 120c was pretty much to the point of overheating.

No. See above. Not saying running the motor at 120 C for extended periods is a good thing. Open track driving at sustained 12 psi boost levels is much different from putzing around on the street at 94 C.

Quote:

I've got a stock mount ic, and don't think I've ever seen water temps reach above 90 as long as I have my undertray on. This is in 90-100 degree Dallas weather.

Good for you. You've traded peace-of-mind for warmer AITs, and lower rwhp.

sst760

no problem what so ever, if the car is over heating with koyo that mean it's something else.

austinsFD

with my koyo i have NEVER had water temps over 95c besides heat soak

BigIslandSevens

iTrader: (4)

FWIW: My customer has the KOYO and the Greddy 2 row FMIC. He had temps of 240-250 on the streets just cruising.

I then built a duct for it and run the a/c switch in the #1 position to get the fans on High speed( no a/c anymore) This brought the temps down to 180 cruising and 190-195 when under hard boost.

HOWEVER: His engine recently blew the Coolant seals while cruising down the road at 45 MPH , 58k and change milage ( I was in the car so that is true) Were the two related? Was he haveing cooling issues prior to the install of these parts? IDK, Do to the fact that I installed the water temp gauge at the same time. This was all done rite after he bought the car. It had recently had a new radiator( stock) put in, so i have my theory on a previous overheat session.

I have 2 engines on order from Ray. When we eventually get them I will let you know what the temps are on the NEW engine, With and Without The ducting and fans on. For info purposes.

But you may already have the stuff installed by the time I get my engines!

rotoboy661

ok guy new update

did the fan mod and made sure i have fresh new coolant mixed 50/50 water

now i dont see temps over 94

and freeway driving is at 83-87 pretty cool now!!!

thanx guys for ur informative inputs

mike

SleepR1

Living in CA, you can run a higher water content, more like 75% water 25% antifreeze.

1QWIK7

iTrader: (33)

man

reading this thread and like 10 other, theres like a 50/50 chance of having overheating problems with an aftermarket rad and a fmic

i guess i'll keep the stocker for now, hasnt been a problem yet, summertime will be the test..

ooEfiniRx7oo

I have koyo and I was driving for about 1hr or so on free way and local and when i drove into the parking lot, the temp raised up dramatically.

My motor has Shot Oring...it smokes for about 3min in the morning before i drive. And I have to add water every day or so.

is that the reason why my motor was about to over heat?

DCrosby

Huh !??? Unless you know something I don't...

Anifreeze, doesn't just raise the Freezing point, not an issue in Ca. unless you travel to the mountains... but also raises the Boiling point... which is a big issue... so no, I run 50/50 + water wetter...

BigIslandSevens

iTrader: (4)

SleepR1 is correct. The water is the main heat reduction unit playing a role in the cooling system. That said, there needs to be at least 20% coolant in the mix IMO. I run a 75-25 mix( and 1 bottle water wetter) as well and have no problems. The temp varies a huge 2 degrees between summer and winter so no biggy there.

The statement that the coolant raises the boiling point is true , but that however does not help disapate the heat.( Just allows more to build up before it boils) The water is the main ingrediant.

That is one of the reason's "most" race teams run all water or water wetter type fluid for coolant. ( the other is so when the rad. gets a hole in it the track doesn't turn into a ice rink with all that Antifreeze on the ground.)

G's 3rd Gen

iTrader: (11)

It used to run about the same as the stocker until I opened the air flow around it. Got rid of the a/c system, got a smaller front mount and put a 99 front nose on. She's unbelieveable now!

SleepR1

I run 75% water, 25% antifreeze (extended life), and 1 bottle of Redline Water Wetter, and live in Indy. No problems.

SleepR1

Yup, that'd be the case, my boy...

AntiVenom7

is everyone having this problem using the stock front end? also is it just the KOYO or would you have the possibility of the same issues with a FLuidyne or other aftermarket radiator? Last but not least, is everyone who is having the problem using the GReddy or are other FMICs having the same problem?