Yeah the MSRP is a bit steep but it seems like its worth it...

Found it here for cheap: http://www.hopupracing.com/hksfanco.html

 

Johnny I just talked to Brad and he has been on your issue all morning. He is currently pulling ALL of the pipe fittings in QC to verify them with a thread pitch indicator to see what may have happened. He said Reggie should be getting a hold of you to let you know what is going on.

 

Adam@Z1 Performance/Auto said Koyo makes most everyone's aftermarket radiators, they just rebrand them.

 

BTW, I had sent an email to F-A-L about some products. Never got one email from them.

 

It's going to be virtually impossible to get an accurate comparison between the different brands of radiators. There are too many variables at play...wish there was some other way to compare which one is "best".

 

True but the Koyo is it looks great , adds more capacity than Stillen, and best of all it costs much less.

Note for those doing APS TT install, you still need to shave the fans even with the thinner Stillen, I've seen one install with Stillen and two (soon to be three) with Koyo.

 

Choosing the optimum radiator is similar to choosing the optimal intercooler. Thicker or larger is not necessarily better, since airflow can be restricted by a thicker radiator.

The Koyo is a bargain..not dissing it at all. Just wish there was a way to objectively compare the different options out there. I do like the look of the Koyo...makes the stock radiator look crude and ancient, in comparison.

 

I think what is better depends on the type of driving use intended. A high HP streeter and drag carcan benefit more from the added coolant capacity , since bursts are few and relatively far between, the extra fluid acts as a heat "mass" and thus damps those large extrmes in load. A road course car sees more airflow in general than a streeter which has to stop and go. So for the track the ability to rapidly dissipate the heat energy at a lighter weight makes more sense. I speculate that a Stillen design may be better at relentless high speed track use, were the Koyo better at power streeting and drags. But of course this is pure conjecture and I'm not at liberty to test the theory.

 

FYI for all you G owners. Stillen is coming out with a G radiator in about 30 days. I bought the 350z koyo and was going to have my shop custom fit, but I am going to sell it and just get the Stillen that made for the G.

 

Brucekgt- if you don't mind me asking, where did you get the longer silicon hoses amd what size did you get?

 

someone correct me if I'm wrong, but I thought the point of getting a better radiator was not to actually lower your coolant temps, but to make sure they never go higher than the optimum 200-210 degree operating temp? I didn't think it would magically lower the coolant temp.

I could see it taking longer to get up to that optimum temp though. I thought you did not want extremely cold fluid cooling the engine cause it could cause damage to the engine.

I have the nismo thermostat which allows coolant into the engine sooner than normal, but after it reaches normal operating temperature it doesn't really matter what thermostat you have, it's going to be wide open. I'm not sure having the nismo thermostat is really of any benefit, but I dunno I just bought it anyway. I guess my thinking was that if the koyo radiator hold that much more fluid and the engine is running that much hotter, then when the normal thermostat lets the coolant into the engine it's more of a shock. The nismo thermostat lets the coolant in earlier and allows the engine to warm up the coolant earlier so it isn't as much of a shock.

I live in AZ and it gets freakin HOT during the summer. The Koyo holds about twice as much coolant and is bigger in almost every direction (more surface area for air to flow on it)

I have total confidence even on the hottest track day it'll do it's job at making sure the coolant doesn't get out of control with heat.

I do plan on getting a vented hood to let the hot air out though. The APS kit has its intakes in the bumper area so I don't even need to worry about rain water getting into the engine and on the air filter

 

For a NA application that is basically true.
However with a high boost FI appication it is the basic intend to lower the average coolant temp and constrain the thermal peaks in order to permit additional boost witout adding a much higher risk of detonation. It lets you tune closer to the edge basically. The optimum with FI is less than 200.

 

ok, so is the conclusion about the Koyo is that it does not do this?

 

the radiator is not going to affect what temps you see...the thermostat will.

If you guys are worried about water temps rising in traffic, as posted, a good set of fans will work wonders...one push, one pull and you should be good to go

A 15 degree swing in water temp is nothing...and if its not even hitting the 215 range, its more than fine

 

For my >500rwhp, hot in Cali , APS TT setup , I have added the low temp thermostat, Koyo, ducted oil cooler , ducted power steeriny and the KJR pulley to "not underdrive the water pump. So I "think" the Koyo will do the job fro street or track. I am tryin gto find a wa yto lower the fan turn on threshold down to match the Nismo thermostat. With all this I expect the temperature guage to never top 190F and change. So yes it and other things should effectively "lower" the worst case operating temperature below 200F. I will also be adding WI eventually after LB break in for safety margin on 91 pump gas.

 

G3po,

was it difficult to make the koyo fit on the G?

 

Ccartwright-
They sourced the silicone hose locally and only charged me $12.00. I haven't seen it to know how long it is. You could have jason@torquefreaks.com send you one.

After talking with Rob Fuller at Z-Car garage and receiving several PMs I had them trim the fan blades to clear the intercooler pipe. They also said the Koyo install was a breeze (I guess I'd warned them it could be a p.i.t.a.) All is well except for all the oil smoke coming out my exhaust.......

 

Mine isn't installed yet , but I have inspected the same setup in another G.
The top mounts just need to be moved. Any good radiator shop can do it.
With an APS kit the fans need to be shaved a littl to clear the FMIC ductwork.

 

Yes the thermostat does most of the work; however, the added capacity damps the temperature swings, I prefer to lower the set point on the OEM fans rather than add yet another fan. Still figureing out the easiest way to do that.

 

^^^A radiator most certainly will effect the temps you see under hot operating conditions^^^

The thermostat stays closed until 175 or 185 F, and then opens. Once the car is above that temp, then the themostat has no control over temps. The fans will kick in, and attempt to drop the temp back down, but under repeated dyno runs, or continuous boost operations, the the themostat is always open, and the fan is always running. When we dyno, coolants temps are always above 200 degrees...and as high as 226degrees. These high temps contribute to detonation, and high under hood temps as well. With a more efficient radiator, these temps will hopefully drop back down to 200 degrees or so...but again..the themostat is still open.