Fighting Track Temps

[amg6975]

Problem: As I and the car get faster and faster I'm having more and more issues with temperatures at the track. Particularly, oil. As my car is a 1 series with the M3 drivetrain swapped in, I have packaging issues that most of you guys don't.

Goal: Go out and hammer laps for a whole tank of gas and not worry about oil temps.

Solution: Who knows.

I'm keeping this log here as opposed to the 1 series forum because other than the body panels, it's an M3 and I think I'll get more useful participation here.

What have I already done? When I swapped the car I could not get the M3 oil cooler to fit like it will in a 1M bumper (my car is still narrow body E82.) So I fabricated a bracket that bolts to the radiator supports, that hangs a generic CSF 8066 oil cooler I did some ducting in front of and behind the cooler so most of the air going in the lower grill goes through the cooler, and vents down under the radiator, very similar to how the M3 works.

*insert pics of oil cooler set up*

I have a CSF [basically a stock] DCT cooler and DO88 radiator. Larger Al DCT pan, overfilled by 1L. No AC so no condenser.

All that works ok, for a couple laps and then the oil temperature starts to get a bit uncomfortable.

Exibit A: Even when doing pedestrian pace laps in perfect weather, when the opportunity to chase a NASCAR truck with an ARCA driver behind the wheel comes along, the car gets pissed.

(yes, he botched T7 and I got past him)

If it's not super hot the DCT and water stay at pretty reasonable temps. 240s for DCT and 220-221 for the water but as you can see, oil can approach 280 if I let it.

This year I pulled the oil thermostat and installed a bypass, which seems to work a bit better, and certainly helps cool it down a lot faster on a cool down lap, and to my surprise actually drops the temp a few degrees while WOT on the straights. It seems to climb very quickly when on the brakes though, I'm not sure how or why.

The plan I have right now is to install a water to oil heat exchanger between the output of the radiator and the water pump, and then plumb that in series with the oil to air cooler. My theory is this will help keep temps down, and also help warmup since the oil thermostat is gone.

I printed off a mock-up of a Canton unit I'm going to try to fit, so we'll see how that goes.

I'm also planning on installing an aux water cooler from a 1M (or N54/55 PPK2 kit) in the driver's side air duct and running the water from the heatercore/DCT loop through it before returning to the car to help alleviate the extra heat in the water from the oil. Let's see how that goes, parts are all ordered, I'll just need to get it plumbed in.

Couple very initial questions I have for the brain trust:

1. Where is the oil temperature sensor in the flow path? Is it sump temp attached to the dipstick or somewhere in the flow to/from the cooler? - Nevermind, it's in the level sensor.
2. Thoughts on the water-oil exchange being pre or post air-oil?
3. Which port on the OFH is the out, and which is in the in?
4. Why the hell does the oil temp rapidly increase under braking and drop during acceleration?
5. What else am I missing?

[roastbeef]

i'd love to have mezzo technologies make a micro tube radiator for our cars... since they are much more efficient, i'd like to integrate the oil cooler into the lower 1/4th of the main radiator and get rid of the detached cooler setup. this would simplify packaging and ducting, and probably help out the guys with closed bottom splitters. they are pretty expensive, and i'm not sure what the ballpark range on cost is.

that being said, how is the packaging and ducting with your custom fab job? i think DRLane (if i'm recalling correctly) made a scoop that was forward of his oil cooler to prevent air from flowing around it.

edit- yep, it was doc.
https://www.m3post.com/forums/showthread.php?t=1912278

[DRLane]

Originally Posted by roastbeef

i'd love to have mezzo technologies make a micro tube radiator for our cars... since they are much more efficient, i'd like to integrate the oil cooler into the lower 1/4th of the main radiator and get rid of the detached cooler setup. this would simplify packaging and ducting, and probably help out the guys with closed bottom splitters. they are pretty expensive, and i'm not sure what the ballpark range on cost is.

that being said, how is the packaging and ducting with your custom fab job? i think DRLane (if i'm recalling correctly) made a scoop that was forward of his oil cooler to prevent air from flowing around it.

edit- yep, it was doc.
https://www.m3post.com/forums/showthread.php?t=1912278

I did and that worked well! Sealed up nicely although ideally I’d have used a replica piece on the backside as well.

Happy to share the send cut file if anyone wants to order it. Then had it made in carbon. Ultimately gave it away as I’m attempting a rear mount.

[omgzirra_exe]

Originally Posted by DRLane

I did and that worked well! Sealed up nicely although ideally I’d have used a replica piece on the backside as well.

Happy to share the send cut file if anyone wants to order it. Then had it made in carbon. Ultimately gave it away as I’m attempting a rear mount.

you're so nice man

[bigjae1976]

I'd make sure the ducting is sealed up around the radiator and oil cooler.

Do you have hood vents with gurney flaps? That should help lower the air pressure in the engine bay and will allow more flow through the radiator.

[tdott]

Down here in FL, it's pretty hard to keep a DCT car cool at a fast pace.

Setup:
Do88 DCT, Do88 Oil, Do88 Rad + Water wetter. Oil Diverter Valve. 200tw tires.
Slon Pan + 1L Banjo overfill.
Lightweight battery, Recaro Sportster Seats, but otherwise full weight, full interior.
Metal undertray with oil cooler duct in place.

I only started logging since Sept 2024 and I have only done time trial type of events since then where I would only do short sessions, usually not longer than 10-12mins. Normally that's just an out lap, 2 hot laps, maybe 3 if I really needed, then cool down.

Peak oil temp logged so far is 277F in 95F heat.
Coolant temps got up in the 230s.
DCT 240F

I know if I keep going Oil Temps will cross 280s but I just haven't since AiM logging. Previously before logging, I know i got closer to 300F on the oil gauge and I've hit the yellow coolant temp warning, and dct warning before when I used to do longer sessions.
All data from stock can-bus data/sensors.

[spammysammich]

What are track regulations on things like water spray on intercoolers etc? Has anybody tried this on the DCT cooler?

[omgzirra_exe]

Originally Posted by spammysammich

What are track regulations on things like water spray on intercoolers etc? Has anybody tried this on the DCT cooler?

Basically, you’d build an Interchiller system that uses the A/C to rapidly cool components. It’s usually used to chill intercoolers and intakes, but you could repurpose it to cool the DCT cooler.

I've thought about it, but i'm not $2,500 dollars thinking about it. lmao.

[amg6975]

Originally Posted by bigjae1976

I'd make sure the ducting is sealed up around the radiator and oil cooler.

Do you have hood vents with gurney flaps? That should help lower the air pressure in the engine bay and will allow more flow through the radiator.

It's pretty well sealed up, I used expanding foam weather stripping to get a good seal around the rad and oil cooler.

No hood vents, that seems unlikely to help oil temps but it's on my list paired with a carbon hood. I think especially after adding the aux water radiator water temps won't be a concern, unless the oil heats the water up way more than I'm expecting. Lowering water temps will certainly help everything once the water-oil exchanger is in but I want to try to change as few things as possible between tests.

Parts are still incoming (from Germany) so I haven't started the tear-down yet to get good pictures of what I have and what I'm thinking.

Biggest question right now is which port is in and which is out on the OFH. I'm thinking I'm going to go from there to the water/oil, then to the air/oil. That way the water/oil exchanger will have the best heat transfer, and the oil will hopefully return to the engine slightly cooler than the water because of the air.

[spammysammich]

Originally Posted by omgzirra_exe

Basically, you’d build an Interchiller system that uses the A/C to rapidly cool components. It’s usually used to chill intercoolers and intakes, but you could repurpose it to cool the DCT cooler.

I've thought about it, but i'm not $2,500 dollars thinking about it. lmao.

I’m thinking even more basic and doing what we used to do on old STIs, using a water spray kit to mist the intercooler. JDM cars and the group N cars came stock with a button you could press to activate the spray. I remember some people would set up an automatic spray based on IAT but then you had to be super careful about always having water in the tank.

[omgzirra_exe]

Originally Posted by spammysammich

I’m thinking even more basic and doing what we used to do on old STIs, using a water spray kit to mist the intercooler. JDM cars and the group N cars came stock with a button you could press to activate the spray. I remember some people would set up an automatic spray based on IAT but then you had to be super careful about always having water in the tank.

I know what you meant, had it on the evo and sti, pretty effective but meh. Interchillers are better haha.

[bigjae1976]

Originally Posted by amg6975

It's pretty well sealed up, I used expanding foam weather stripping to get a good seal around the rad and oil cooler.

No hood vents, that seems unlikely to help oil temps but it's on my list paired with a carbon hood. I think especially after adding the aux water radiator water temps won't be a concern, unless the oil heats the water up way more than I'm expecting. Lowering water temps will certainly help everything once the water-oil exchanger is in but I want to try to change as few things as possible between tests.

I'm assuming you have the OE e9X oil cooler? On an E9X, the oil cooler is vented out of the underbody panel. In that case, venting the hood likely won't have much effect on oil cooling.

If your oil cooler is just venting into the engine bay then venting the hood will make a difference.

[DRLane]

Originally Posted by amg6975

It's pretty well sealed up, I used expanding foam weather stripping to get a good seal around the rad and oil cooler.

No hood vents, that seems unlikely to help oil temps but it's on my list paired with a carbon hood. I think especially after adding the aux water radiator water temps won't be a concern, unless the oil heats the water up way more than I'm expecting. Lowering water temps will certainly help everything once the water-oil exchanger is in but I want to try to change as few things as possible between tests.

Parts are still incoming (from Germany) so I haven't started the tear-down yet to get good pictures of what I have and what I'm thinking.

Biggest question right now is which port is in and which is out on the OFH. I'm thinking I'm going to go from there to the water/oil, then to the air/oil. That way the water/oil exchanger will have the best heat transfer, and the oil will hopefully return to the engine slightly cooler than the water because of the air.

Confirming my understanding of your proposal -

Oil comes out of OFH => water oil heat exhanger => air oil cooler => engine?

[Ximian]

A vented hood helped me with lower oil temperatures but what made it work even better is removing the lower part of the stock air box. I have the aFe carbon-ish intake and it's rigid and light enough to just stay in place without the lower support. I can go a whole session without getting above the 3rd mark for the oil temperature while on slicks. Caveat is that I'm short shifting by a bit instead of going all the way to the red line. However, even when short shifting, I used to get pretty far above the 3rd mark for the oil temp.

https://afepower.com/afe-power-54-31...-intake-system

[Redd]

Originally Posted by Ximian

A vented hood helped me with lower oil temperatures but what made it work even better is removing the lower part of the stock air box. I have the aFe carbon-ish intake and it's rigid and light enough to just stay in place without the lower support. I can go a whole session without getting above the 3rd mark for the oil temperature while on slicks. Caveat is that I'm short shifting by a bit instead of going all the way to the red line. However, even when short shifting, I used to get pretty far above the 3rd mark for the oil temp.

https://afepower.com/afe-power-54-31...-intake-system

This is interesting. Any pics of your setup pls? How are you sealing off the filter from engine bay heat?

[Ximian]

Originally Posted by Redd

This is interesting. Any pics of your setup pls? How are you sealing off the filter from engine bay heat?

It's not sealed off at all which is a minor issue. My concern is the filter getting wet which may damage the filter media.

There is enough venting for good air flow that I'm not worried about it being a hot-air intake. I would like to find something that that can cover the top of the filter and maybe even connect it to the duct from the lower part of the bumper (pictured).

[Redd]

Thanks for that. Any analysis why removing the lower air box would significantly reduce oil temps? Maybe it's allowing high pressure airflow from the front bumper inlet to evacuate faster thru the bonnet vent, thereby sucking hot air out of the engine bay?

[Ximian]

Originally Posted by Redd

Thanks for that. Any analysis why removing the lower air box would significantly reduce oil temps? Maybe it's allowing high pressure airflow from the front bumper inlet to evacuate faster thru the bonnet vent, thereby sucking hot air out of the engine bay?

Pretty much my thoughts. The air box limits the airflow on the driver's side of the engine bay and almost acts as a heatsink as well.

I got the idea from the E46 M3 CSL style intakes where they have half an engine bay between the duct in the bumper and the intake - https://ind-distribution.com/product...-carbon-airbox

[tdott]

Originally Posted by Ximian

A vented hood helped me with lower oil temperatures but what made it work even better is removing the lower part of the stock air box. I have the aFe carbon-ish intake and it's rigid and light enough to just stay in place without the lower support. I can go a whole session without getting above the 3rd mark for the oil temperature while on slicks. Caveat is that I'm short shifting by a bit instead of going all the way to the red line. However, even when short shifting, I used to get pretty far above the 3rd mark for the oil temp.

DCT or manual?

[Ximian]

Originally Posted by tdott

DCT or manual?

DCT

[bigjae1976]

Originally Posted by Redd

Thanks for that. Any analysis why removing the lower air box would significantly reduce oil temps? Maybe it's allowing high pressure airflow from the front bumper inlet to evacuate faster thru the bonnet vent, thereby sucking hot air out of the engine bay?

The air entering the lower bumper inlets would typically be lower pressure. I think the OE hood vents allow for some venting from the airbox to allow for more flow through the airbox. If you remove the bottom half of the airbox, it would theoretically increase the air pressure under the hood which would result in increased drag and lift over the front wheels.

You could use these probes

https://www.amazon.com/dp/B0CSJC4M4K...sin_title&th=1

Just need some cheap tubing connected to a manometer. Then mount one probe in the engine bay and one near the air filter. Take a differential pressure to know with and without the airbox. Then you'll know. You can see the manometer in my video.

And that's about the extent of my knowledge at this point.

[amg6975]

Update on my project. I got the unobtanium 1M parts to add the aux radiator but it's a bit more complicated than I originally thought. The rad interferes with the bottom of the OEM airbox, and the angle of the outlets is not ideal to fit any plumbing in. Both could be solved with some time and trimming but the tubing diameter is a lot smaller than the current return path of the water, and I don't really want to find out what happens if we choke that flow.

I also tried to figure out how to get a water to oil exchanger in the main return path of the rad and it would be a real pain. I may still go down this path by fabing a bracket to put the exchanger where the AC compressor used to be, but this isn't a mid season project. Right now I think I'm going to get a Setrab/Mosselman oil cooler for the left side duct and call it good until I can spend the winter tinkering.