Koyo Radiator vs Oil Cooler
 

How much is one better over the other? I appreciate that an oil cooler would (probably) be better at keeping the oil cool but would an after market radiator be better at keeping the engine and oil cool? I ask because it is my opinion that an aftermarket radiator is more elegant. That is, there are no additional hoses/pipes in the engine bay but I suspect that an oil cooler would be more beneficial.

Sorry, I'm not directly answering your question.
But if you were to install a vented hood, airflow through the radiator and around the (oil-filled) motor block should also be improved:
http://body-kitz.com/contents/en-us/...by_Seibon.html

(Some cars also had vented hoods in stock configuration:
http://www.classicscars.com/rally/205t16new/car1.jpg )

Thanks rx3 for your reply. I have considered this but I would have to get the original hood modified as a carbon fibre hood is not street legal here.

Oil temps on this car rise really quickly (above 100 degrees easy) even on street spirited driving while coolant seems to hold a constant 92 degrees Celsius (obtained from data on this forum). Personally I'd address the oil cooling first because oil contacts all critical engine components directly and can transfer heat from them much more efficiently. Also since this car takes 0W20 which isn't exactly thick, it would be good insurance to keep the oil from thinning too much from heat.

With an oil cooler, you will need more oil for oil changes and when it does get changed, the oil in the cooler and lines don't actually drain. just something to consider.

With that being said, the radiator probably isn't the bottleneck of the cars cooling abilities

I switched to 0W-40 (Motul 300V) for this reason.

A lot of people overlook a GOOD oil at helping keep oil temps in check and stable.

These cars get really hot, really fast. Add in forced induction and even more so. Sometimes I feel like I am dealing with a rotary.

I doubt this engine will EVER be as temperamental as a rotary.

what would you consider to be a good oil? any recommendations?

I was almost 100% set on going with an oil cooler first, but if a bigger radiator like the Koyo can give similar results like an oil cooler I rather go that route. Can anyone else give an explanation between the two?

For the price of a good oil cooler (Perrin) vs radiator (Koyo), it's about half the price for the radiator.

I went with a radiator first. My thinking is if the coolant cools faster, and more, it'll help cool the engine better, in turn helping keep the oil a little cooler. I have no empirical data to back this up, just my opinion. Also, I have a vented CF hood to help the hot air escape better.

I've ordered the Perrin oil cooler. From what I have read water temperatures don't get nearly as bad as oil temps. Ah well, everything's a compromise except for those things that aren't.

What I don't understand is why the oil cooler kits cost 2x as much as a big ass aluminum radiator from Koyo...

Not convincing anyone, but I'll be going w oil cooler first over aftermarket radiator... but that's just me.

Oil Cooler first for me. Same logic as many above.

You can buy generic oil coolers on jegs alot cheaper

Like everyone else, how hot our cars run does bother me a lot, but I'm going to hold off a bit more to see what comes down the pipe. I've got a lot of hope on that one (can't remember who's making/testing it) that uses similar set up as the OEM oil cooler for the other Subaru models (Outback was it?). Should be much cheaper and less complex than the other kits I've seen since the kit/parts are available as we speak. Of course, if you're a serious track star then one of the ones on the mkt now might be a better bet, but I'm not in that category and just want something that will keep the temps down at a reasonable level.

Sorry, I can't provide more info, but I'm in between meetings right now and my brain is fried. :bonk:

If you guys need data I have it. I installed the Koyo first on a stock car to monitor. What the radiator did was allow coolant temps to recover more quickly in open air. It does not heat soak as fast. However once you are in low speed idle situation or in dirty air temps wil rise similar to stock but recover much faster.

Radiator fan will cycle on at 212F. Stock rad the recovery time was twice as long as the Koyo before temps would drop. And stock you could see temps cycling between 212F and 220F in idle and autox However in clean air it was rare to see temps much above 210F.

The Koyo did not help oil temps in any measurable way. As soon as oil temps started to climb they would not recover. After the mocal/perrin oil temps rarely climb above 205F in any street driving and that is supercharged. Before the cooler after about 3 high RPM runs oil would spike to 230F immediately.

So I would recommend the oil cooler first. Its more effective.

btw all the data is backed up from logs no BS.

Oil cooler will help the most because u are adding a bigger volume then stock. Also the oil cooler will keep the temps down.

I have the koyorad on the car I bought an oil cooler first but I'm waiting on all the parts to install it. I was wondering your opinion on getting a cheaper cooler and the mocal sandwich plate. It is pretty simple technology as far as the cooler goes so I couldn't justify spending over about $200 for the whole oil cooler setup. I got the same sandwich plate everyone else is using just a cheap 13 row cooler. Am I missing any huge advancement in the actual cooler in the last few years?

I would stick with a setrab or mocal cooler personally, which you can get for around $130 for a small unit only because it becomes a critical piece.
You can also make sure you one that you can mount easily.

Just remember though doing stainless lines and good fittings is expensive. Thats about $250 right there.

I guess I'll ask: what it the optimum oil temp in everyones opinion?

I think perrin mentioned they saw a performance loss at 230F. But too cool is just as bad as too hot. So where so we draw the line?

Thanks!

I'm going to use all stainless AN fittings and high temp and pressure stainless braided teflon lines. I'm a hydraulics mechanic for air craft so I can get the lines and fittings for next to nothing with our discount. I believe the one I have is a setrab it's still in the box. Thanks for the input I just didn't know if there was something new that made them cool better. I was seeing it that you are paying for better welds nicer fittings and less possibilities of corrosion not really any better cooling.

You can buy the parts individually and put it together yourself for less. I am happy to pay for the convenience of getting a quality kit. Also remember that Perrin is a business not a charity. No business = no Perrin

My 2 cents.

Really if you do not know how to properly build the lines to last I agree you should just buy a complete kit. But you can get the lines and fittings around $80 cheaper if you know how to install them. It only takes me a few minutes to put fittings on a hose but I do it all the time at work because making one is cheaper and faster than ordering a pre built one.

Sent from my Q10

I talked to a few more people involved in spec teams. 215-235 seems to be the magic number for track. If you are running 0w20 obviously lower is better. if you start seeing higher temps switch oil weight.

For daily driving 185 to 215F is optimal. After testing this is totally reasonable if you have a cooler behind the bumper. For the Perrin kit in front and center you will see the oil temp stuck around 165-175F until you go WOT to 6000RPM a few times. From there it will go right to about 185F.

If you idle, no clean air it will climb on its own. The settling point should be coolant and oil temps almost identical for daily driving. 190 to 195F.

Winter will be a different story...

I bought the Perrin kit and if I did it again I probably would still do it just for the ease of mounting. The good thing is I can always re locate the cooler and build new lines if I choose. But you have to deal with making a solid mounting solution.

So just depends. The aeroquip hoses Perrin uses are good for track and street but if it was a track only car I would switch to stainless right away. Which is more for secuirty and abrasion resistance.

If you guys call parker hydraulics and tell them what your looking for they normally have really good prices on lines and fittings and they sell some really good quality stuff.

Sent from my Q10

A) thermostatically controlled kits;
B) piece of cardboard over the cooler for warmup or operation.

Can they put together stainless lines too if you pick the barbs and length?

If you want the tfe lines (better than tube in some ways) they should be pretty simple to put together it's $7 a foot for 5,000 psi 400 degree heat rated hose. If you have some decent grip strenght a vise and some wrenches you can put these together. You have to call to make sure they will assemble for you if not you can do it in about 10 min. It's a handy skill to have for this and brake lines, clutch lines, and even fuel lines. The price of what perrin has in lines and fittings cost me well under $100.

Edit: not bashing perrin at all they have a great product I just have some years in aircraft hydraulics that has shown me were to get the best deals.
Sent from my Q10

[ame="http://m.youtube.com/watch?v=3tjRsbSDA48"]Phenix AN Hose End instalation on Teflon Hose made easy - YouTube[/ame]

Here is a video of how it's done pretty simple stuff. I don't use a screw driver to flare I use a brass pick less chance of damaging the hose. Also rubber hoses have an expiration date these do not. These also handle heat and pressure better. Granted this is a tiny hose be ready to but some muscle on that wrench when you get up to a -8 or -10 line.

Sent from my Q10

I'm intrigued by this discussion... being a total noob, I didn't know these components were available for way cheaper than the kit price. would be nice if someone could put together a DIY, with mounting options on our car.

for example, found one for 350z's here:
http://my350z.com/forum/engine-drive...n-a-na-hr.html

Once I get all the parts in I can do one. I am moving across the country in 2 weeks so no promise it's going to get done before I finish the move.

Sent from my Q10

that would be sweet, looking forward to it! hope the move goes smoothly, had to do that as well not too long ago.

Radiator Parts:
-Aluminum core
-2 Aluminum end-tanks

Oil Cooler parts:
-Adapter spacer
-Thermostat
-Lines and fittings (SS or clamp on rubber)
-Aluminum core
-2 Aluminum end tanks
-Mounting solution (ie not built into the car like the radiator)

That's basically why. The actual cooler isn't that expensive, the thermostat and other bits bring up the cost quite a bit. :thumbup:

Thermostat in the engine will just close quicker. Big radiators are great when you need to kill larger amounts of heat, too big and the engine doesn't heat up as well, we've had to remove mechanical fans on race cars back in the day because water temps would go from warm, to too cold, back to warm, back to too cold, etc from excessive cooling while the system was closed, etc.

In the end though, a larger capacity radiator won't have nearly the effect on oil temps as an oil cooler.

I prefer 250 or less, I see 235 on the track with a 19 row mocal cooler in Florida....

I know this wasn't the point of your statement, but just to add some more..

Thinner oils run cooler, which reduce the need for a cooler slightly. However, the flip side is that they have less oil pressure which is even worse hot. So you will likely find (once you start measuring pressure) that 0w20 results in low oil pressure on the track (IMO anyways, less than the 10psi per 1,000rpm and it DROPS from 7,000 up...) so switching to 0w30/5w30 etc bumps up pressure as desired, at an increase of oil temps (slight but being at 300 stock...) which can suggest a cooler, which then drops pressures a few PSI.

Fun stuff right. :)

Oh and for winter, just block off (or remove) the cooler.

The thermo units are partial bypass generally (and that includes the mocal one people use here), so oil still flows through the cooler, just not full flow. You knew that already, clarifying for others.