High oil temp

**g3driver** · 04-23-2012, 21:50

Hey guys,

I was a buttonwillow this weekend and had a great time but noticed I had some very high oil temps. I need some help.
Air temp was about 100f
Water temp 190-210 - perfect
Oil around lap 4 265f. (hot lap) The sensor is in the oil pan
I am using mobile one 10-30 synthetic

So the question is how high can the oil temp go before there is damange? Mobile one says 400.
Thought maybe about running an oil cooler or maybe mobile one racing 5-15?
Suggestions?

**illwillem** · 04-24-2012, 08:40

I noticed the same thing last summer. I decided not to test my luck and got the SOS oil cooler and increased capacity with the 3qt accusump, The external fan kicks over at 175*. Both have lowered my oil temps by quite a but, ive not been out there on the hot days yet but its good piece of mind.

**RYU** · 04-24-2012, 08:51

Oil cooling is a common problem with NSX on the track unfortunately. Do you guys have some actual figures to share? I think anything under 230*F is ok. Also, from experience, at around 90*F ambient, if you stay off the last 1000 rpm the oil cools down significantly. It's living in the last 1000 that kills the stock oil cooling system (yes there is one lol).

If my snap ring issue didn't grenade my trans I would have completed a side mount oil cooler system Kuni and I were going to test this season. My design incorporates a built-in thermostat for year round driving. It's on hold for a few more weeks but will be done by Laguna Seca I hope.

Ryneen's side vent/scoop mount was my inspiration. So was this...but this guy isn't getting his done fast enough for resale and he thinks no thermo is required which I disagree with. I also don't like how you can't put the oem fender liner back in place with this design. Sweet ass placement though!

**g3driver** · 04-24-2012, 09:46

Originally Posted by illwillem

I noticed the same thing last summer. I decided not to test my luck and got the SOS oil cooler and increased capacity with the 3qt accusump, The external fan kicks over at 175*. Both have lowered my oil temps by quite a but, ive not been out there on the hot days yet but its good piece of mind.

Does anyone know at what temp oil starts to break down? I know in aircraft engines they use mineral oil and the redline is 270

**Hrant** · 05-20-2012, 13:22

Originally Posted by g3driver

Does anyone know at what temp oil starts to break down? I know in aircraft engines they use mineral oil and the redline is 270

I assume you are referring to viscosity and flashpoint. For Castrol GTX 10W/30 flashpoint is >360F with viscosity@210F in the range of 59-65; for Motul 8100 5W/40 it is >390F with viscosity range of 65-76.

Interestingly, over the years i have found that the issue has not been the flashpoint but the viscosity for tracked cars. With 10W/30 prior to a CTSC I was just at the low end of the range with about 3000 miles. With CTSC and Motul, I am again in the low end of the range of the SUS viscosity@210F.

At the track last Friday with ambient temp in mid 80s and moderately pushing the car, my water temp was 190F and oil no higher than 230F. First time I have seen those low numbers! I do have an oil cooler like the one in the picture below as well as a dual Spal encased fans with ducted hood. The oil cooler at best makes about 10F difference. I believe the dual fans are the most efficient in cooling - and this with an 13 year old OEM radiator!

But as RYU noted, the last 1000 RPM are the culprit on high ambient temp days.

**pgilliam1** · 05-20-2012, 14:28

If you're running headers, and who isn't, I foung wrapping the front set, that goes by the oil pan, with a good fiber heat wrap has lowered the dash guage temp by 1 full notch. I don't know what that equates to in degrees, but it is a measurable amount.

**9doors** · 05-21-2012, 22:42

Originally Posted by RYU

If my snap ring issue didn't grenade my trans I would have completed a side mount oil cooler system Kuni and I were going to test this season. My design incorporates a built-in thermostat for year round driving.

Damn! Had I known you were designing/building this I wouldn't have purchased the SOS cooler...

**g3driver** · 05-22-2012, 08:17

Originally Posted by pgilliam1

If you're running headers, and who isn't, I foung wrapping the front set, that goes by the oil pan, with a good fiber heat wrap has lowered the dash guage temp by 1 full notch. I don't know what that equates to in degrees, but it is a measurable amount.

I am running headers. I will try that. Can you recommend a good heat wrap?

**RYU** · 05-22-2012, 08:45

Originally Posted by 9doors

Damn! Had I known you were designing/building this I wouldn't have purchased the SOS cooler...

If Hrant is right then it'll likely only be good for a 10F cooling benefit anyway. I've upgraded to a high capacity high efficiency radiator (though a little bit heavier) and if his dual spa fans work that good theoritically a better than stock rad with fans should work better? This proves what we've also known all along.. a Oil to Water cooler works best, which is what the stock NSX uses.

I'm still planning to build it. Just not so sure on the effectiveness of Oil to Air coolers in general - you need a lot of fin surface area to cool the same amount of oil and the SOS or any side mount unit doesn't seem to big enough.

We'll see...

I'll be incorporating something like this and with full AN -8 or -10 fittings.
http://www.amazon.com/Earls-41310ERL...sim_sbs_auto_3

**BATMANs** · 05-22-2012, 09:20

Group 5 synthetic oil are suppose to be the only oils that is designed to lubricate turbine engines since under heat it doesn't have an affinity for itself and will spread over the heated surface evenly.

**Hrant** · 05-22-2012, 09:44

Originally Posted by RYU

I'll be incorporating something like this and with full AN -8 or -10 fittings.
http://www.amazon.com/Earls-41310ERL...sim_sbs_auto_3

I think the 13 row is the maximum that you can fit in there.

**RYU** · 05-22-2012, 09:59

Originally Posted by Hrant

I think the 13 row is the maximum that you can fit in there.

Yes, not very big at all. I believe you can fit a 16 row if you don't care about using the fender liner which is what the guy above did.

**Honcho** · 05-22-2012, 13:20

It seems like the best way to cool your oil then is to improve the OEM water cooling system. I wonder how hard it would be to fab up a shroud for the OEM rad with two of these?

**Hrant** · 05-22-2012, 14:32

I bought this from an NSXCA/NSXPrime member and it fit perfectly. He had fabricated the shroud.

I believe DaliRacing carries one too but for dual Mishimoto.

**RYU** · 05-22-2012, 15:12

I like this solution a lot. Of course, we're all stuck in the nsxprime bubble so i'm sure no one has tried these

This is for a sportbike but the concept is the same. It'd be nice to find one with larger capacity.
http://www.aaperf.com/oil-cooler.html

**9doors** · 05-22-2012, 16:14

I know Coz has a Laminova and is very happy with it.

**g3driver** · 05-22-2012, 17:10

I figured with a ducted hood and sealed undertray and a custom radiator shroud, thats probbaly as good as it will get for OEM radiator efficency.

**stuntman** · 05-27-2012, 08:37

You lose viscosity as the temperature goes up. You could combat this with a a 5W40 or 5W50 weight oil as well as an aftermarket oil cooler.

For an NA NSX on track, I wouldn't worry too much below 260*F and would probably start considering cooling the car down around 280*F. Yes Mobil the oil wont break down until well beyond the point where the loss of viscosity will cause your motor problems.

Get an oil cooler.