Radiator Question?

[g3driver]

I currently have the oem 20 year old radiator. Dont have any overheating issues but I figure the radiator is 20 years old and why wait till it fails so I want to change it out. Couple of questions.
1. Koyo or Mishimoto?
2. Do I need a dual fan set up, or use OEM fan and shroud? I have a ducted hood and dont really drive the car all that often on the street.

As a side note I was looking at dali's pictures of his 2 fan and shroud setup and it looks constrictive, at track speeds the fans are not on and you are using ram air correct?

Thanks guys!

 

[integrals]

I am using a Koyo and did the same thing... switched it out before it failed. A track failure of this component could result in severe engine damage.

I am not sure if the Mishimoto is an "N" pass radiator or not, so went with what i've used on EVERY build regardless of marquee.

I used the OEM shroud and fans.

I have never seen the gauge move, not even in the middle of summer here in AZ.

AEM has recorded a few hits of 220.

10% antifreeze and water wetter... the rest is distilled water.

At speed, the fan is RARELY on. Occasionally on kart tracks it may switch on after a series of slow speed turns...

You have seen FIRST HAND how hard my car is pushed

Hit me up if you have more questions!

-Ravi

 

[bngl3rt]

I am currently debating the same... definitely getting a Koyo rad, wondering whether I should stick with OEM fan or get the Mishimoto dual fan system.

 

[A.S. Motorsport]

Koyo is one of the best ether that or a OEM those are made by SAK.

 

[pingu81]

Go with the Koyo boss. Re-use the OEM shroud and fan.

 

[9doors]

At speed, the fan is RARELY on. Occasionally on kart tracks it may switch on after a series of slow speed turns...

Ravi, I think I disagree here. To my knowledge, as soon as the coolant temp hits ~178 the thermostat will cause the fan to switch on until it drops below that, at which time the fan will turn off.

 

[integrals]

Ravi, I think I disagree here. To my knowledge, as soon as the coolant temp hits ~178 the thermostat will cause the fan to switch on until it drops below that, at which time the fan will turn off.

The OEM Low / High setup is 183 for lowspeed, 194 for highspeed. (Section 23 of FSM). The fan will remain on until it drops below the lower threshold. Having a dual stage setup like this is awesome when you have a large system... It maintains a much more consistent temperature throughout the system!

My statement simply points out that the OEM system is quite efficient as my car usually sits around 180-190 and the highspeed is rarely on. When I come to lowspeed turns, occasionally the car will exceed my trigger of 194 and kicks on the highspeed. Especially Firebird West where there is alot of lowspeed extended turns! Only in the super hot summers does my car exceed the 200 degree mark and trigger the high speed while out on track!

But even so, I still recommend an aftermarket radiator! The OEM Plastic caps WILL fail eventually!

My TT RX7 FD had a dual stage fan as well, after careful research, I ended up eliminating the first stage when I added ducting to the system. Simply because the first stage was causing a air buffetting effect that basically caused the highspeed to kick on alot while at high speeds. When I V-Mounted the system, and ducted it properly and removed the stage 1, the car maintained a lower overall temperature by increasing the airflow by removing the air restricting stage 1. It wasn't optimal for street driving as the removal of the stage 1 fan caused the temperature at low speed to vary greatly.

My point here is the first stage is great for low speed temperature control but usually results in lower cooling efficiency under trackday / enduro type conditions. I may disable the low speed next event and datalog and see if the RX7 experience will carry over.

My NSX will get mounted at an angle eventually once the ABS is gone and I have a hood that will allow this to be efficient! Probably will be eliminating stage one again!

 

[9doors]

Ahhh. Didn't know the low/high speed difference. I forgot, we switched mine to high-speed only...so I only know about on and off. LOL.

 

[RYU]

In the NSX the oem oil cooler is cooled by coolant. I've noticed that a good rad makes a difference here though I wasn't sure if the standard Alum replacement (Koyo, Mishimoto) were as good as the PWR units. I also know that Alum is not the most efficient at cooling. Copper has approx TWICE the cooling coefficient of Alum so I decided to have a Copper unit custom made. I have the two row unit in my car (superior cooling over stock but heavier than stock) in my CTSC NSX. They also kindly supplied me with a single row which is designed to be lighter yet still better than stock cooling capacity.

Unfortunately I haven't seen any real intense track days yet but hoping to post data logs once I get more testing done.

I have the single row sitting in my garage. If someone local would like to test it out and promise to provide some data logs I'll hand over the rad to them

Here's some info I posted on the rad before. The quality is impeccable and the tube/fin technology used here is far superior to the alum units currently out for the NSX.
http://www.nsxprime.com/forum/showt...HP-Turbo-NSX?p=1463678&viewfull=1#post1463678

 

[9doors]

Regan, good stuff. I have heard some positive things about copper, so it'll be interesting to hear your report. I'm selling my Koyo next week at a good price to bngl3rt (lucky him) and going with the dual pass from Shad. I'll be very happy to share experiences with that. I'll also have the dual Mishimoto fans for sale (I haven't put them in the marketplace yet) since I can't use them with Shad's radiator due to fitment issues.

 

[g3driver]

If the deal falls thru on the koyo let me know! I'm in the market

 

[9doors]

You bet. In the highly unlikely event Ben doesn't close the deal, it's all yours brother. I'll PM you in either case next week when Ben is supposed to pick it up.

 

[integrals]

Love that Koyo. Have burned my hand on it many a time hahaha

 

[cptnsx]

the Mishimoto dual fans are terrible, if you get the dual shroud replace them with Spa fans. With my heat exchanger blocking air flow I would get 210-215 here in Vegas. I went with the Koyo and that dropped it 200-205. I then put the dual Spa fans in and I see 190-195. This is all during 100-110 degree heat blasting away on my SOS supercharger with multiple 60-120 runs.

 

[g3driver]

Koyo on order. Thanx for the great info guys

 

[bngl3rt]

My Koyo is here! Thanks 9d.

Now I just need a crack-proof non-eyesore aftermarket coolant expansion tank and I am good for the next 100k miles... anyone got a favorite? SoS doesn't seem to sell any.

 

[9doors]

I was never able to find a crackproof aftermarket tank. Too many reports of weld failures for my taste. I just use OEM ones and use the JDM cover to protect it from the sun.

 

[9doors]

And speaking of radiators, here's my freshly plumbed DA dual-pass...

 

[Ponyboy]

I was never able to find a crackproof aftermarket tank. Too many reports of weld failures for my taste. I just use OEM ones and use the JDM cover to protect it from the sun.

As a counterpoint, reports of cracks (and actual cracks in my OE) caused me to look for the SOS version. I haven't had an issue yet but if I do, I'll just remove and reweld.

For the OP, I use the Ron Davis Aluminum w/ shroud and dual fans. Haven't had an overheating problem ever since. The highest water temp I've seen is 207. Oklahoma isn't as warm as AZ but it we have our share of heat and humidity. That said, use of either the Koyo or alternative, will definitely give you greater cooling capacity. I applaud you taking preventative maintenance - the alternative is a lot of heartbreak.

 

[g3driver]

And speaking of radiators, here's my freshly plumbed DA dual-pass...View attachment 96049

What kind of radiator hoses are those? Custom job? I wonder if I should have that done since I will have the radiator out. Any info would be great.

 

[9doors]

The black came from Shad, the red came from Mark: http://www.daliracing.com/v666-5/catalog/index_browse_part.cfm?focus=1284

 

[peiserg]

as an alternative guys I am VERY VERY satisfied with my SOS custom radiator... dual pass aluminum... and less money than the DA IIRC. They also did a custom twin fan shroud for me. allowed me to run a full 20min session whereas prior to this i was having to dial it waaaay back after about 5-8 hard laps. I don' know the specifics... call SOS with questions..

 

[dlynes]

koyo

looking to replace my oem rad.

is the koyo a direct replacement?

where do you recommend buying one and how much are they usually?

I see SOS sells it for $425, seen other places selling it for $356

thanks,

 

[g3driver]

Went with the koyo and it is a drop in replacement. Using Oem fan with a ducted hood. Works great.

 

[dlynes]

radiator leak

would you recommend repairing or replacing this?