E46 M3 C&R Oil Cooler

[sdwz_m3]

To update and close this thread, I've reached out to BW with my results. In regards to cooling, the data C&R collected between their graphed coolers were bench lab tests (not hooked up to an engine), and specifically measured heat dissipation with flow. To increase the flow, BW recommended their oil diverter valve in order to maximize the effectiveness of the oil cooler. BW believes that I wasn't pushing the cooling system hard enough both in oil temp & oil flow rate to actually see a noticeable difference between these coolers. 240F is relatively low, and their concerns begin when oil temp reaches 290F.

In regards to the weight, they admitted a probable mistake of comparing the C&R to the OEM cooler, while they should have compared it to a competitor. They mentioned they'd update the listing, but I haven't seen the change at the time of writing this post.

In summary, running the stock oil cooler will be sufficient for most individuals (even if it appears to be gunked up). If needing a replacement, I'd recommend finding another OEM cooler in decent shape in lieu of upgrading; although I can say that the C&R cooler is made well, and should last for a long time.

[bigjae46]

You might also consider doing a horizontal oil cooler in front of the radiator that ducts downward under the car at speed and upward from convection at a stop, like all of the new M cars. This would help cooling but hurt downforce and might be a quicker/easier solution than ducting upward. The non-m radiator does seem like a much better option than the M radiator with the added bonus of running a proper OEM ducted electric fan shroud from the 330i.

I’d certainly be interested in duplicating this on my car as well - but I have to use the non-m undertray unfortunately because I use the ZHP front bumper.

Stacking the coolers reduces the overall drag by reducing the surface area. Separating the coolers will increase overall drag. When stacked, you maximize the use of the cooling air by placing the hotter radiator on the backside. This also helps warm up the oil faster at start up. For me, this could fix three issues - lack of cooling, a long time to warm up, and adds front downforce while reducing overall drag.

Of course, venting the radiator out of the hood can screw up the airflow up and over the car.

[Altaran]

You might also consider doing a horizontal oil cooler in front of the radiator that ducts downward under the car at speed and upward from convection at a stop, like all of the new M cars. This would help cooling but hurt downforce and might be a quicker/easier solution than ducting upward. The non-m radiator does seem like a much better option than the M radiator with the added bonus of running a proper OEM ducted electric fan shroud from the 330i.

I'd certainly be interested in duplicating this on my car as well - but I have to use the non-m undertray unfortunately because I use the ZHP front bumper.

Before this I would convert to a water intercooler and an oil cooler delete. The water cooling circuit has the extra capacity. The you can lower the radiator and have a lower center of gravity. Probably no weight savings as the extra intercooler is not weight free.

For now I run a DO88 oil cooler and I have little negative effects, only that its slightly heavier than stock due to the extra capacity. Together with the oil thermostat delete temps are well within acceptable range.

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[Bry5on]

I think that is going to be in line with the results you should expect - not so much a drop in peak numbers but a quicker drop when cooling down.

Your biggest limitation is the airflow on the backside of the oil cooler. The beat up OE oil cooler probably generated a decent low pressure region behind the cooler because it was clogged. The C&R is probably creating a higher pressure zone behind the cooler since it is not full of stuff with bent fins. My theory is the airflow on the backside must be controlled and vented to a low pressure region - probably under the car would be the closest source of low pressure air flow.

I've been studying this so I am making an informed decision as I look to lower peak oil temps. I'm leaning towards installing a non-M radiator with a large oil cooler on the backside of the radiator then duct it through the hood. How the ducting is designed is important in achieving a sufficient low pressure region behind the coolers. A stacked setup will typically yield more efficient use of cooling air and the ducting should improve the pressure differential to increase airflow and cooling. It seems that bigger or more radiators will not necessarily result in lower peak temps or will be inefficient from a cooling vs drag ratio.

I haven't tested any of this so I'm only youtube trained thus far. So take it for what it’s worth. But I wouldn't be concerned with the data you collected. 240's is still really good...and some heat in the oil isn't a bad thing. I really don't get concerned until I see 275 and higher.

You might also consider doing a horizontal oil cooler in front of the radiator that ducts downward under the car at speed and upward from convection at a stop, like all of the new M cars. This would help cooling but hurt downforce and might be a quicker/easier solution than ducting upward. The non-m radiator does seem like a much better option than the M radiator with the added bonus of running a proper OEM ducted electric fan shroud from the 330i.

I’d certainly be interested in duplicating this on my car as well - but I have to use the non-m undertray unfortunately because I use the ZHP front bumper.

[CrisSilberGrau]

Agreed. I'd like to figure out a way to vent the air behind the cooler, and not have to add the weight of an aluminum skid plate.

This data is without a splitter; I've heard that the addition of aero can have differing temps from that of a stock-bodied car. I also wanted to collect the data to help others make an informed decision, as there isn't a whole lot of info on this specific cooler.

Then create similar ducting to the pow3r motorsport skid plate byjust cutting up the oem plastic body panel, I see no downside to this. Perhaps this will give way to some fabrication DIY. I like the pow3r motorsport option because it's literally on the floor, weight +\- 10lbs or near as makes no difference and the ability to go full race splitter down the line. The smooth front flat bottom can also give way to some aero DIY on the suspension arms in the wheel well (dreaming now but still).

It's wild just how good he OEM stuff is when considered as a complete working package. I dont think I've seen this on many other car makes and models....

[0-60motorsports]

I just switched back to the OE Oil cooler as I think the BW oil cooler was causing heat soak in traffic and causing for me to run much higher oil temps. Once i would move of course the temps would drop but then that IS the point of a racing oil cooler, it cools while you are moving.

Someone needs to make a better "street" version as in not too big and thick so as to prevent heat soak in traffic.

Before you all even think it or don't think it Bahrain has constant 120-125f days and high humidity and when stuck in traffic the actual ambient temps can be much higher than 125f (due to cars around you and small country running ACs all day. If you havent been to Bahrain/UAE/Saudi/Qatar in summer.....Well the you will never know LOL

[sdwz_m3]

Agreed. I'd like to figure out a way to vent the air behind the cooler, and not have to add the weight of an aluminum skid plate.

This data is without a splitter; I've heard that the addition of aero can have differing temps from that of a stock-bodied car. I also wanted to collect the data to help others make an informed decision, as there isn't a whole lot of info on this specific cooler.

[bigjae46]

I've collected data from the weekend, and have tried to compare it to the best of my abilities to my past data. I will be going out again next month and should have some more comparison data. In the meantime, refer to the attached chart for what my car read (again, this is from OEM sensors, through CAN bus).

I did not see a large reduction in cooling temps. What I did see, and what isn't shown, is the drop in temperature on the cool down lap. From finishing my last hot lap, and coming back into the paddock, oil temps dropped to ~220.

I will reach out to BW to try to understand how they collected their info, and why my results weren't as positive as I'd hoped for.

I think that is going to be in line with the results you should expect - not so much a drop in peak numbers but a quicker drop when cooling down.

Your biggest limitation is the airflow on the backside of the oil cooler. The beat up OE oil cooler probably generated a decent low pressure region behind the cooler because it was clogged. The C&R is probably creating a higher pressure zone behind the cooler since it is not full of stuff with bent fins. My theory is the airflow on the backside must be controlled and vented to a low pressure region - probably under the car would be the closest source of low pressure air flow.

I've been studying this so I am making an informed decision as I look to lower peak oil temps. I'm leaning towards installing a non-M radiator with a large oil cooler on the backside of the radiator then duct it through the hood. How the ducting is designed is important in achieving a sufficient low pressure region behind the coolers. A stacked setup will typically yield more efficient use of cooling air and the ducting should improve the pressure differential to increase airflow and cooling. It seems that bigger or more radiators will not necessarily result in lower peak temps or will be inefficient from a cooling vs drag ratio.

I haven't tested any of this so I'm only youtube trained thus far. So take it for what its worth. But I wouldn't be concerned with the data you collected. 240's is still really good...and some heat in the oil isn't a bad thing. I really don't get concerned until I see 275 and higher.

[sdwz_m3]

I've collected data from the weekend, and have tried to compare it to the best of my abilities to my past data.  I will be going out again next month and should have some more comparison data. In the meantime, refer to the attached chart for what my car read (again, this is from OEM sensors, through CAN bus).

I did not see a large reduction in cooling temps. What I did see, and what isn't shown, is the drop in temperature on the cool down lap. From finishing my last hot lap, and coming back into the paddock, oil temps dropped to ~220.

I will reach out to BW to try to understand how they collected their info, and why my results weren't as positive as I'd hoped for.

[Feffman]

My $0.02 spewing. 😎 I went with a Fluidyne stacked plate oil cooler as stacked plated are more efficient at cooling if a little heavier than a tube & fin design. It fits nicely into the original location, but required (with all the racing mods) a simple fabricated bracket for each side. As for C&R, I run their radiator. This has been a very effective combination of cooling.

Feff

[sdwz_m3]

I would definitely give this feedback to BW and that's an ECS-esque pack job IMO.

I'm primarily interested in the actual cooling ability--if it's better than stock, with an essentially stock fitment as you've mentioned, I'm in. The weight savings claim, while problematic in that it doesn't appear to be accurate, isn't such a big deal for me.

On a side note, I asked my dealer about the stock cooler availability and they told me that the new part number is 17-21-8-854-480, on order from the supplier but no ETA.

Shoot, I wish I would've known that last week haha. I thought they were discontinuing all manufacturing. If anyone wants to ship me a new oem cooler when released, I'll be happy to continue my testing

I'd imagine a new cooler from BMW will be at a close price point of the C&R.

[PSUEng]

C&R oil cooler installed. Here's my initial review, I didn't get out for a test drive yet. Photos to come in my next post. I'll start with the good:

It's almost an exact match of the oem oil cooler. It's an 1/8” taller, which makes for a snug fit in the oem shroud. It bolts up to the oem lines without an issue. I also received this within a week of ordering, so supply doesn't seem like an issue.

The bad:
Obviously the price isn't the lowest as compared to other aftermarket coolers. However, seeing that other aftermarket coolers are larger, and require other means of mounting or ducting, it doesn't seem like a terrible option, as the OEM cooler is now discontinued and scarce to find brand new.

I was a bit disappointed in the packaging of the cooler. I was expecting it to be in its own small box, secured with styrofoam at both ends (like CSF). However, it was packed in a large box, in a bunch of paper, with a sheet of cardboard protecting the fins. I inspected the cooler and found no issues, but I expected more from what seemingly is a “higher end” product.

Weight: Bimmerworld claims that this cooler weighs half as much as the OEM cooler “allows this stock-sized and stock-mounted cooler to outperform its OE counterpart by almost 30% while only weighing 2.6 lbs, or a little less than half!” This was a reason why I was so intrigued. After weighing both, the C&R came in at 2 lbs 7 oz, while my gunked up OEM cooler (that was 90% drained) came in at 2 lbs 11.5 oz.

To be honest, I wasn't expecting a 4 oz delta. Will be testing at Buttonwillow this weekend.

I would definitely give this feedback to BW and that's an ECS-esque pack job IMO.

I'm primarily interested in the actual cooling ability--if it's better than stock, with an essentially stock fitment as you've mentioned, I'm in. The weight savings claim, while problematic in that it doesn't appear to be accurate, isn't such a big deal for me.

On a side note, I asked my dealer about the stock cooler availability and they told me that the new part number is 17-21-8-854-480, on order from the supplier but no ETA.

[CrisSilberGrau]

sdwz_m3 I was referring to BigRussia 's post on the CSF vs OEM and noting he'd lose the 8lbs or so if he's interested in the switch to BW. Aware that we're looking at BW/CR weight claims. This would be a second product that has inaccurate weight claims (recaro podium).

For your specific needs, I can only suggest changing oil and having adequate ducting for the oil pass through air like this:

https://europowermotorsports.com/products/e46-m3-undertray-skid-pan

[sdwz_m3]

Been following this thread and waiting for your results my main intrigue for this oil cooler was the claimed weight savings but man that is disappointing its only .25lbs lighter than the oem. Thats a far cry from BW’s claim of nearly half the weight! Sounded too good to be true but with the ‘premium’ price i was hoping it’d be a decent weight saving delta.
Here’s hoping the cooling performance is a significant improvement over the stock cooler at least! I have no doubt youll see some improvement regardless just going from an old gunked up cooler to a fresh new one with clean fins regardless if its an upgrade.

I currently run the CSF oil cooler and its actually totally adequate cooling wise for track duty. My oil temps never reached 250F ever even in the hot summer months (water temps have always been my cars issue which switching from the CSF radiator my car came with to a new oem BMW one helped with). But my issue with the CSF oil cooler is that it was an extra 8lbs added to the nose of my already front heavy car, so yeah disappointing to see the C&R one isnt really lighter than the oem for the price its at and what bimmerworld claims, i always held BW in high regard and didnt think they'd do bs marketing like that.

I am considering reaching out to BW and sharing my findings in hopes for them to get the ad updated. I’m only running a CSF rad because the plastic connections in the stock rad broke.

While on this topic, below are my cooling modifications to pair with my pending data:


CSF Rad/spal fan

AC deleted

Clutch/aux fan deleted

Oem air duct installed

Trackspec hood vents

LM 10W-60

[sdwz_m3]

I hear you, but you're 8lbs heavier with CSF and you're upset cause you'll lose 8.25lbs if you switch to BW? Something doesn't add up.

Also other option is d088 oil cooler, which I think will be my next purchase since oem new is NLA.

I dont know how much lighter you can make an oil cooler with increased capacity and lighter weight without using some crazy materials or not making it street friendly.

It should also be noted that if oil temps are truly a main concern, then you also have to address the pass through air that just gets trapped in the front plastic cover. A solution to that would be the pow3r motorsport alu undercover with a cutout for the hot pass through air.

This post is a comparison of OEM to C&R/BW, and not BW to CSF. One of the reasons CSF is so much heavier is due to the additional oil capacity that it can hold. The disappointing factor here, was that the BW cooler was NOT half the weight of the OE cooler, as they claimed on the ad. The BW cooler does not have an increased oil capacity, and oil temps are not a concern, as noted in my original post.