need help with high oil temps on e46 track car

[70chevelless]

Okay, so I finally got my car up to VIR this past weekend after completing my build for GTS3 and was able to give it a good shakedown. The car performed great all weekend and was an absolute blast to drive. The only problem though is that now I'm having some overheating problems that I think are due to the front aero package I have on the car. Water temps are not a problem (never got over 176 all weekend), but my oil temps would jump up to 275 at times if I was really pushing it. I'm running the BW aluminum radiator and oil cooler, along with the lower thermostat and oil diverter valve. When I had the car up to VIR in Oct., my oil temps were never a problem (had no front aero on the car), but this time was a whole different story. The front aero parts I'm running are the APR CF splitter and BW CF dive planes, and I'm thinking that b/c the splitter goes so far back under the engine it is cutting off any air flow to the oil cooler from underneath the car. So, has anyone else out there run into oil temp issues after installing a splitter and what did you do to fix it? I'm kinda worried about this b/c we haven't even gotten into June yet, so I want to come up with a solution before I get to the track again and end up hurting the motor.

[PerkM3]

Okay, so I finally got my car up to VIR this past weekend after completing my build for GTS3 and was able to give it a good shakedown. The car performed great all weekend and was an absolute blast to drive. The only problem though is that now I'm having some overheating problems that I think are due to the front aero package I have on the car. Water temps are not a problem (never got over 176 all weekend), but my oil temps would jump up to 275 at times if I was really pushing it. I'm running the BW aluminum radiator and oil cooler, along with the lower thermostat and oil diverter valve. When I had the car up to VIR in Oct., my oil temps were never a problem (had no front aero on the car), but this time was a whole different story. The front aero parts I'm running are the APR CF splitter and BW CF dive planes, and I'm thinking that b/c the splitter goes so far back under the engine it is cutting off any air flow to the oil cooler from underneath the car. So, has anyone else out there run into oil temp issues after installing a splitter and what did you do to fix it? I'm kinda worried about this b/c we haven't even gotten into June yet, so I want to come up with a solution before I get to the track again and end up hurting the motor.

I'm interested in what people say, I have a very similar setup. I don't see how a splitter is any different from the oem undertray though, they both cover the exact same area.

[jekaio]

OP could you cut a hole in the bottom of the splitter and run some kind of ducting from the top fo the oil cooler to the back side of the hole, and make a channel for the air to flow out of?

[70chevelless]

OP could you cut a hole in the bottom of the splitter and run some kind of ducting from the top fo the oil cooler to the back side of the hole, and make a channel for the air to flow out of?

I was thinking about that but wasn't sure if it would decrease the effectiveness or rigidity of the splitter

[will v]

I was thinking about that but wasn't sure if it would decrease the effectiveness or rigidity of the splitter

Have you talked to the guys at bimmerworld? I'm sure they have a solution or at least know what would cause what you are seeing.

[70chevelless]

Have you talked to the guys at bimmerworld? I'm sure they have a solution or at least know what would cause what you are seeing.

yeah, I was planning on doing that this week sometime but figured I'd see if anyone else on here had dealt with the same issue first. In fact, the guys that helped me finish the car (Bimmer Performance Center in Raleigh)were talking about calling them this week when I was discussing the issue with them at the track on saturday. Unfortunately, they had to come up there a few times throughout the weekend to try and help figure out the problems that Callahan was having with his e36.

[magnetic1]

How are you measuring the oil temp? The stock sender is notoriously inaccurate.

[70chevelless]

on the AiM pista dash, which is getting it from the DME (I think?) It's kinda weird b/c yesterday during my runs the only times it would hit 275-280 would be at the top of the uphill esses. By the time I would hit oak tree it would be down to 260, and at the end of the back straight it would be around 245-250. It did that lap after lap for 30 minutes straight, where the alarm would only go off after getting to the top of the esses. I also have a set of stack gauges in the car that has the oil temp, which is being measured at the top of the oil filter cap. That consistently reads about 30-35 degrees lower though than what the AiM says, so I figured that the stack gauge wasn't getting an accurate reading from the top of the cap?

[bawareca]

Do you have a proper ducting to the oil cooler and radiator?If they just "sit" in the air stream they wont be very efficient.With a "cooling unit" on my turbo car-intercooler,water cooler and oil cooler stacked together(and air gaps sealed) and ducted properly i dont see more than 200F oil temp.

[magnetic1]

on the AiM pista dash, which is getting it from the DME (I think?) It's kinda weird b/c yesterday during my runs the only times it would hit 275-280 would be at the top of the uphill esses. By the time I would hit oak tree it would be down to 260, and at the end of the back straight it would be around 245-250. It did that lap after lap for 30 minutes straight, where the alarm would only go off after getting to the top of the esses. I also have a set of stack gauges in the car that has the oil temp, which is being measured at the top of the oil filter cap. That consistently reads about 30-35 degrees lower though than what the AiM says, so I figured that the stack gauge wasn't getting an accurate reading from the top of the cap?

Ive got another sender at the oil housing. It can read over 50 degrees lower than the stock gauge. Ive stopped relying on the stock gauge since it measures temperature via oil level and can be inaccurate with all the oil moving around.

[70chevelless]

Ive got another sender at the oil housing. It can read over 50 degrees lower than the stock gauge. Ive stopped relying on the stock gauge since it measures temperature via oil level and can be inaccurate with all the oil moving around.

so you have another sender on the filter housing? Where do you have it mounted? With mine being on the top of the housing I was just figuring that not enough oil was getting to it to get an accurate reading since there was such a discrepancy between the two readings.

[magnetic1]

so you have another sender on the filter housing? Where do you have it mounted? With mine being on the top of the housing I was just figuring that not enough oil was getting to it to get an accurate reading since there was such a discrepancy between the two readings.

There is a port w/ a plug in it. I found the temps there to be much more stable and doesnt fluctuate all over the place. Ive been going by that temperature for many races now.

Also of note, I had the BW oil cooler before the aero/splitter and it was reading the same temps. So it isnt the aero/splitter. Josh Smith did some testing too and found the stock gauge to b off by a wide margin with large fluctuations

[JamesM3M5]

Oil temp on the S54 is taken from the pan, where you'll see those high temps. Measuring after the cooler ensures you have the oil at a proper operating temp - 210-220F. That's where the S50Euro measured oil temp.

Also, as others have mentioned, proper ducting to and from the oil cooler is paramount. Without any ducting the air just spills around the cooler. Any gaps over 1/8" allow too much air to spill out, too.

[J Smith]

X2...spend some time looking at your ducting. Make sure air cannot escape around the cooler and that it must flow through it. I have a combination of factory plastic pieces and some I fabricated. All air coming through the center cutout on my bumper has no other place to go but through the cooler.

Also, X2 with what Wonger said....the factory oil temp gauge is not an accurate number to go by. I have a SPA sender in the oil distribution block and the measured temps there much lower than the factory gauge.

[70chevelless]

okay, so I have no duct work from the cutout in the bumper going back to the radiator and oil cooler. Are you guys (Josh and Eric) running duct work from the grill area in the bumper to just the oil cooler, or to both the oil cooler and radiator? I ended up pulling the factory plastic piece off the front of the car (behind the bumper support bar) this past weekend that I believe was used to direct air to the stock radiator and oil cooler, but since the BW pieces are larger the bottom of that plastic piece was sitting right in the middle of the BW oil cooler and I thought that it might be disrupting air flow to the oil cooler. Was I wrong in that assumption? Would my best bet be to just fab up a piece to direct all the air from the bumper grill to the oil cooler? Thanks for the help and suggestions

[jonmacs22]

X2...spend some time looking at your ducting. Make sure air cannot escape around the cooler and that it must flow through it. I have a combination of factory plastic pieces and some I fabricated. All air coming through the center cutout on my bumper has no other place to go but through the cooler.

Also, X2 with what Wonger said....the factory oil temp gauge is not an accurate number to go by. I have a SPA sender in the oil distribution block and the measured temps there much lower than the factory gauge.

Hey Josh, nice new wheels.........

[magnetic1]

Im using the stock ducting piece. It's pretty large and goes up to the kidney grills but the bottom part I think properly directs air to the oil cooler...

[70chevelless]

Im using the stock ducting piece. It's pretty large and goes up to the kidney grills but the bottom part I think properly directs air to the oil cooler...

well, I pulled that piece out over this past weekend b/c the bottom part was sitting right in the middle of the oil cooler and I felt like it was doing more harm than good.

[magnetic1]

well, I pulled that piece out over this past weekend b/c the bottom part was sitting right in the middle of the oil cooler and I felt like it was doing more harm than good.

I think mine doesnt caus I am running a stock radiator. Can you cut/alter the stock piece to work? Or just seal up the area around using some other method.

[bawareca]

Oil temp on the S54 is taken from the pan, where you'll see those high temps. Measuring after the cooler ensures you have the oil at a proper operating temp - 210-220F. That's where the S50Euro measured oil temp.

Also, as others have mentioned, proper ducting to and from the oil cooler is paramount. Without any ducting the air just spills around the cooler. Any gaps over 1/8" allow too much air to spill out, too.

Even the most efficient oil cooler wont make more than 10F difference before/after the cooler,so this maybe a very small part of the problem.
Proper custom ducting may need a relatively small front openning,leading to a decreased drag,as a side benefit.

[70chevelless]

I think mine doesnt caus I am running a stock radiator. Can you cut/alter the stock piece to work? Or just seal up the area around using some other method.

yeah......I threw that piece out while at the track, lol. With BW radiator the cooler sits lower than it would with a stock radiator, so I felt like that plastic piece was just splitting the air that could be going to the oil cooler. Since I'm running an electric fan on the radiator should I just try to fab something up to direct all the air coming through the bumper opening to the oil cooler?

[magnetic1]

yeah......I threw that piece out while at the track, lol. With BW radiator the cooler sits lower than it would with a stock radiator, so I felt like that plastic piece was just splitting the air that could be going to the oil cooler. Since I'm running an electric fan on the radiator should I just try to fab something up to direct all the air coming through the bumper opening to the oil cooler?

You should direct air from all openings to their respective cooling parts of the car (radiator / oil cooler). And hook up your stack sender to the AIM.

[70chevelless]

Thanks for the help guys!

[70chevelless]

so here's what I came up with to help direct more air to the oil cooler:



Once I have the track bumper with all the aero parts on the car the bottom will be completely sealed up since the oil cooler sits flush up against the splitter. This way all the air coming through the bumper opening will be forced to go through the oil cooler. What do you guys think?

[RangerGress]

Nice fab effort and you'll certainly get a lot more air flow. The problem tho is that oil doesn't give up it's heat as easily as water. You can compensate for that more easily with a larger oil cooler than you can with increased air flow.

Note also that 1) A terrific way to reduce oil temps is to reduce engine temps. That is to say optimize the coolant system and oil temps will go down. 2) Lots of air flow on the oil pan also has a significant cooling affect. I don't run an oil cooler any more in my SpecE30. After an awful lot of experimentation I figured out that a big radiator and lots of air flow on the oil pan did 20deg better than the OEM oil cooler (ducted and shrouded) and 5deg better than a big aftermarket oil cooler.