Oil Temps On The Track

[HKS26T]

Might be like a Noobie question - and im not sure whether i have posted in the right section.

But i am getting different responses from different people. What would be considered safe temps -

when will i be pushing the limits of the motor?

Cheers

Steve

[Strik3r]

Might be like a Noobie question - and im not sure whether i have posted in the right section.

But i am getting different responses from different people. What would be considered safe temps -

when will i be pushing the limits of the motor?

Cheers

Steve

bit more info is needed.. rebuilt motor ? oil cooler ? what oil ? whats the tune like AFR wise and what do your water temps do ?

In the end it comes down to film strength. If the oil can maintain a good film strength at 110 or 115 and your not overheating the motor (as oil temps to tend to have an effect on water/engine temps), then keep racing. I tend to get to 105 pretty quickly, then it creeps towards 110 but doesnt seem to go much past that. If i saw 115 on the oil, i'd probably pull it in and let it cool to be on the safe side. I know guys who have hit 125-130 and considered that to be 'ok'.

[Snowman]

Yeah 130 is generally considered the danger/stop point for oil temps.

[HKS26T]

bit more info is needed.. rebuilt motor ? oil cooler ? what oil ? whats the tune like AFR wise and what do your water temps do ?

In the end it comes down to film strength. If the oil can maintain a good film strength at 110 or 115 and your not overheating the motor (as oil temps to tend to have an effect on water/engine temps), then keep racing. I tend to get to 105 pretty quickly, then it creeps towards 110 but doesnt seem to go much past that. If i saw 115 on the oil, i'd probably pull it in and let it cool to be on the safe side. I know guys who have hit 125-130 and considered that to be 'ok'.

Motor is built with pistons and rods, Oil cooler present, Running Royal Purple not sure which one (but was a special order and about $180 and runs at lower temps? is there any truth to this?)

AFR are at 11:1 throughout the whole rev range.

I have notice that it gets to 110 pretty easy, but once you are on your hot laps, it gets to about 120. Water temp at this moment is at 105 degrees as well.

I have been told if it was to get above 115 to ease up on it - i dont see how this is possible - temps stay at 120 when i did 3-4 continuous laps - would this be dangerous? i have noticed the quicker you go the hotter the temps? i had no problems when i was about 5 seconds off the pace

Are there any ways of keeping the temps down? i have removed the left blinker light to get direct air flow onto the cooler - would there be any benefits in removing the thermostat that controls the oil cooler?

Would the heat from the brakes affect the oil temp if there is no inner mud guards?

i believe the production cars can run all day in the mid 130's when they are racing?

Cheers

Steve

[HKS26T]

Sorry these readings are off Defi sensors and gauages BF series

[Strik3r]

Ok so sounds like your running the Royal Purple RP41 (their racing oil) which is same as what I use. Thats good as it maintains high film strength as the viscosity of the oil drops when it heats up.

Removing the thermostat on the oil cooler isn't going to help as by the time your oil is at operating tempreature it is wide open (as long as it is working correctly - can always test this).

105 on the water is definitely on the warm side, and that might be where your problem is originating (if your water is getting hot it will cause the oil to heat up). Are you still using the stock radiator and clutch fan? I dont think I've seen my water temp go much past 90 degrees even on the hot track days, and it normally hovers around the 85 mark. If your still using the stock cooler, perhaps its time for a nice chunky alloy cooler. I'd retain the clutch fan and shroud though, particularly if the car is used on the street as well as the track.

[BezerkR32]

x2, i max oil temp at 120, but water temp at 90.

Ok so sounds like your running the Royal Purple RP41 (their racing oil) which is same as what I use. Thats good as it maintains high film strength as the viscosity of the oil drops when it heats up.

Removing the thermostat on the oil cooler isn't going to help as by the time your oil is at operating tempreature it is wide open (as long as it is working correctly - can always test this).

105 on the water is definitely on the warm side, and that might be where your problem is originating (if your water is getting hot it will cause the oil to heat up). Are you still using the stock radiator and clutch fan? I dont think I've seen my water temp go much past 90 degrees even on the hot track days, and it normally hovers around the 85 mark. If your still using the stock cooler, perhaps its time for a nice chunky alloy cooler. I'd retain the clutch fan and shroud though, particularly if the car is used on the street as well as the track.

[MrStabby]

My best guess is that HTHS is the oil property you should be interested in (its measured at 150 deg C IIRC), and the max temp you can safely run an oil at is at least partly related to that and therefore not the same for all oils. HERE'S some figures i've pulled off the Internet - so usual caveat about accuracy. PM me if you look up the Royal Purple spec and i'll add it.

Some time back Porsche issued a tech bulletin that recommended using oils with HTHS above 3.8 (or was it 4.0?) in their engines.

[HKS26T]

My best guess is that HTHS is the oil property you should be interested in (its measured at 150 deg C IIRC), and the max temp you can safely run an oil at is at least partly related to that and therefore not the same for all oils. HERE'S some figures i've pulled off the Internet - so usual caveat about accuracy. PM me if you look up the Royal Purple spec and i'll add it.

Some time back Porsche issued a tech bulletin that recommended using oils with HTHS above 3.8 (or was it 4.0?) in their engines.

Im not too sure about what you have just said but i think it has something to do with the operating temps of diifferent oils?

Any way, striker ! i think you have hit the nail on the head!

i put in a greddy alumin radiator in which i believe could be the problem - i have put david craig thermo fans on it x 2 but in my personal opinion - i dont think is doing much because it has no shroud (it is running opposite fan direction). Should i run the standard fan and shroud as well?

Cheers

Steve

[MrStabby]

To summarise/translate: better oils handle hotter temperatures better. If you paid $180 for an oil change it should be top stuff.

At speed the fans/shrouding does nothing because you've got plenty of air being pushed through the radiator. You'd only look at them if you were getting hot at low speed (ie in traffic). Check if the radiator is blocked and if the thermostat is opening all the way. You could also try Redline water wetter if you aren't using it already, it can be worth 10 degrees or so.

[Strik3r]

The only thing i'll add to that is that at high speeds, poor thermo setups can actually impede air flow, therefore causing overheating issues around a circuit. The shroud is only important if your going to be in traffic often, but if you can go back to the stock clutch operated fan, you may find that your thermo's are actually causing the problem. If i read what you wrote correctly, your thermos are blowing back towards the front of the car through the radiator ?? If so, then thats probably your issue. Fine for when you are stuck in traffic, but when you are actually moving they are actually stopping the air from rushing through your radiator. If you can turn your thermo's off when your racing, as long as they are able to free spin, that might be enough to fix your problems. Else just get a 2nd hand stock fan and put that back on.

I went form regular coolant to water watter and didn't notice any significant changes in water temp.. but then I never had any problems to begin with and just went with water wetter as a precaution.

[Beer Baron]

My best guess is that HTHS is the oil property you should be interested in (its measured at 150 deg C IIRC), and the max temp you can safely run an oil at is at least partly related to that and therefore not the same for all oils. HERE'S some figures i've pulled off the Internet - so usual caveat about accuracy. PM me if you look up the Royal Purple spec and i'll add it.

Some time back Porsche issued a tech bulletin that recommended using oils with HTHS above 3.8 (or was it 4.0?) in their engines.

great little table. yeah I won't go less than 4.0 in a car that is street/track. I use chrono 300v in my street/track cars as it's still viscous enough at lower temps to give good lubrication but does not get too thin at high temp and has a good film strength and anti-shear. for a full on track car I'd probably go to the 300v comp as low temp viscosity is not such a concern and it has better film strength and a more suitable high temp viscosity.

and the other advice was sound too. water wetter can help with a few degrees of temp. not a bad idea for some extra insurance.

[HKS26T]

The only thing i'll add to that is that at high speeds, poor thermo setups can actually impede air flow, therefore causing overheating issues around a circuit. The shroud is only important if your going to be in traffic often, but if you can go back to the stock clutch operated fan, you may find that your thermo's are actually causing the problem. If i read what you wrote correctly, your thermos are blowing back towards the front of the car through the radiator ?? If so, then thats probably your issue. Fine for when you are stuck in traffic, but when you are actually moving they are actually stopping the air from rushing through your radiator. If you can turn your thermo's off when your racing, as long as they are able to free spin, that might be enough to fix your problems. Else just get a 2nd hand stock fan and put that back on.

I went form regular coolant to water watter and didn't notice any significant changes in water temp.. but then I never had any problems to begin with and just went with water wetter as a precaution.

I have the thermo fans in the engine bay because i could not mount them b/w the fmic and the radiator. Naturally the air flow will be against the norm when driving - so i reversed the direction so it travels with.

I am also running water wetter. Its begining to worry me now how do you check whether a radiator is blocked? of ineffecient? it was a second hand unit.

I might go back to the standard setup and check what is happening.

Would it be bad to operate at 105/120 degrees? when will i start to cook the motor?

[Beer Baron]

yep, my advice would be definitely go back to the standard rad for a meet. I've seen a lot of problems solved this way and unless you have done major stuff to fit the new rad it's usually an easy thing to change (20min tops).

what type of radiator is it. i have seen lots of guys come undone with the current flavour of the month cheap, thick, chinese made alloy radiators. they usually do a much worse job than a standard rad and standard fan and shroud set-up.

radiator upgrade is one of the last things you need and usually only on very serious track cars. the reason people get problems in general with water temp is because they fit a big, thick, cheap intercooler and it blocks all the good air to the radiator. a good, but not too thick intercooler (like ARC etc) coupled with the standard radiator and a nicely mounted oil cooler is usually enough for most moderately powered track cars. only once you get up over about 500hp do you generally need to get more serious than that.

[BezerkR32]

you are the guru baron, advice is always clear to understand and most importantly correct. you should have your own talk back column lol. your knowledge is very much needed in the forced induction section where everyone thinks they are an expert lol.

yep, my advice would be definitely go back to the standard rad for a meet. I've seen a lot of problems solved this way and unless you have done major stuff to fit the new rad it's usually an easy thing to change (20min tops).

what type of radiator is it. i have seen lots of guys come undone with the current flavour of the month cheap, thick, chinese made alloy radiators. they usually do a much worse job than a standard rad and standard fan and shroud set-up.

radiator upgrade is one of the last things you need and usually only on very serious track cars. the reason people get problems in general with water temp is because they fit a big, thick, cheap intercooler and it blocks all the good air to the radiator. a good, but not too thick intercooler (like ARC etc) coupled with the standard radiator and a nicely mounted oil cooler is usually enough for most moderately powered track cars. only once you get up over about 500hp do you generally need to get more serious than that.

[HKS26T]

yep, my advice would be definitely go back to the standard rad for a meet. I've seen a lot of problems solved this way and unless you have done major stuff to fit the new rad it's usually an easy thing to change (20min tops).

what type of radiator is it. i have seen lots of guys come undone with the current flavour of the month cheap, thick, chinese made alloy radiators. they usually do a much worse job than a standard rad and standard fan and shroud set-up.

radiator upgrade is one of the last things you need and usually only on very serious track cars. the reason people get problems in general with water temp is because they fit a big, thick, cheap intercooler and it blocks all the good air to the radiator. a good, but not too thick intercooler (like ARC etc) coupled with the standard radiator and a nicely mounted oil cooler is usually enough for most moderately powered track cars. only once you get up over about 500hp do you generally need to get more serious than that.

I will definately go standard at the next meet on oz day. For some reason im thinking the david craig fans are not complementing the setup.

Car makes 600hp

Radiator is a Greddy unit

FMIC is a Greddy unit

Oil Cooler is HKS

a suggestion of ducting to guide air through the raiditor will be experimented after we rule out that the h2o over heating isnt from the aftermarket radiator

will keep everybody informed and thanks for the input

[Beer Baron]

ok, well 600hp is getting pretty serious and as we all know power generates heat so it's understandable that you need some decent cooling.

is it a GTR? Greddy intercoolers are pretty decent with air flowing through the core to the radiator. do you still have the A/C core between the intercooler and radiator? if so it's probably time to remove that one. the only time I've seen people have trouble with air flow through good coolers like greddy ones are when they are too thick (using a drag cooler on a track car) for the application. how thick is the core? you don't need a super thick intercooler on a circuit car as they get lots of clean air through them as long as the bumper is fairly decent. for 32 GTRs you can get an insert which bridges the side gaps between the bumper opening and the intercooler effectively sealing the cooler to the bumper and thus forcing the air through the cooler core, it's a good idea. so is ducting air from the intercooler to the radiator. air will always take the path of least resistance so without sides forcing the air through the cores most of the air just hits it then flows around the gaps on the sides with not much actually making it all the way through and on to the next core.

the greddy radiators are not bad, but I would still do the test with the factory radiator and if possible the factory clutch fan and shroud. it is not too hard to change and doesn't cost you anything to try (providing you still have the old bits of course!).

with the oil cooler where is it mounted? actually just reading up above you said you removed left indicator to get more airflow to it. so I guess it's mounted on the side? some ducting around it will really help too, and you need to have an exit path for the air so that once it's through the core it can escape so some kind of vent into the wheel well is generally the way to go (either hole saw some vent holes in the plastic guard liner or cut out a big hole and install a louvred vent).

always try the cheap fixes first like the ducting etc and see how you go. the other problem we have with radiators and intercoolers etc is a lack of exit path for their air flow too. if you have big power and are generating a lot of heat it may be time to look at a bonnet that has an extraction vent to allow air to flow through the cores and then up and out through the bonnet.

[Beer Baron]

you are the guru baron, advice is always clear to understand and most importantly correct. you should have your own talk back column lol. your knowledge is very much needed in the forced induction section where everyone thinks they are an expert lol.

lol, don't make me blush!

there are lots of guys as smart or smarter than me on this forum. I am just a frustrated mechanic whose spent far too many years toying with peoples race cars. having lived and breathed working on and driving race cars for the last 15 years I would hope I'd learnt something!!!

we are lucky that there are lots of very capable, logical guys on here (like your good self!) who are willing to share their knowledge, ideas, and experience with everyone.

[JAGR33]

Interesting topic and many good responses in fixing the problem.

Another factor which may cause the problem is mounting the oil cooler in front of the radiator.

Would be beneficial in mounting it to the passenger side front intake in bumper bar (driver side has blow off valves and not much room).

I have a Trust 76mm thick intercooler, HKS type S oil cooler located behind passenger front indicator, and a Trust alloy radiator. The car still runs A/C so nothing has been removed in front of radiator. Car makes around 550hp, has no weight stripped out of it (ie. full weight) and have not seen temps past 90 degrees.

Now that is going flat out for 4 flying laps (maybe only 3 at Phillip Island).

My tyres go off by then and engine temps are at around 90 and oil at around 120.

Just my 2c...

Oh, and Baron IS THE KING!!!!

[DRIFTER]

i've got head bleeds, breather tank and modified pump. my water and oil temps don't go past 90/100. if the other things don't work you might want to try some of these.