Deleting Oil Cooler


#61

regarding the fact that BMW put oil coolers on our cars so they must be neccesary…my Mercedes 250C euro has an oil cooler…probably been disconected for 20 years. BMW put coolers on the early e12 chassis 635’s but not on the later cars, backwards of the e30…why??

Al


#62

The first time i hit a deer in an e30 about 9 years ago I ended up plowing up sod in the ditch using the oil cooler at 70mph. Although being severly bent, twisted and pushed into the frame it did not leak. The only failure point are the flexible lines just because rubber doesn’t age very well. Unless you also take your se30 to the demo derby I don’t see how you can consider it a failure point. As for the “racing” oil coolers the only thing high performance about them is the price.


#63

turbo329is wrote:

Re. failure points. Oil tstat can fail to open until 210 degrees like Levie’s or fail to open all together.

Re. vulnerability. In front of the subframe is asking for trouble no matter how many deer miss it.

Re. performance.

  1. Air flow. The OEM oil cooler’s air flow is lousy because the subframe is right behind it.

  2. Oil pressure loss due to plumbing. It’s lines are a fair amount longer then they need to be, and not nearly as big as -10 so it’s lines create more oil pressure drop then an aftermarket oil cooler with -10 lines.

  3. Oil pressure loss due to design. The OEM oil cooler is long and skinny. That means fewer small pipes in the heat exchanger going a long ways. Aftermarker oil coolers are more rectangular. That means more pipes in the oil cooler going a shorter distance. Therefore a quality aftermarket oil cooler is likely to have less flow restriction.

I’m not sure how much we really need an oil cooler. But if I was going to do one, I’d do a real oil cooler and not the crappy OEM one.


#64

Ranger wrote:

[quote]
2) Oil pressure loss due to plumbing. It’s lines are a fair amount longer then they need to be, and not nearly as big as -10 so it’s lines create more oil pressure drop thenso it’s feed reduces OP more then a bigger aftermarket oil cooler with -10 lines.[/quote]

Yes, but my lines go to 11.


#65

On my turbo car they are -10 and it has been moved up above the bumper.


#66

Gress, since you love to test, would you please just run the test on this theory and see what the oil pressure drop is through the stock cooler, compared to the temperature change. That would be interesting to see.

-Scott


#67

BigKeyserSoze wrote:

[quote]Gress, since you love to test, would you please just run the test on this theory and see what the oil pressure drop is through the stock cooler, compared to the temperature change. That would be interesting to see.

-Scott[/quote]

I have good data on oil cooling variations, but not on pressure. Pressure is hard to do because it’s dependent on oil temp and type. “How you are measuring” oil temp plays a big role in the results. So a person has to remain consistant in how they are measuring oil temp in order to have comparable info. And all I’ve done consistantly is kill motors.

But the bottom line is that I’m going to try. I’ve got my dash all pulled apart redoing my gauges. Once I get that done I’m going to get serious about logging data with Oil T, Coolant T, OP and maybe A/F getting recorded. That will make it a helova lot easier to gather good data.

I spent 2hrs tonight trying to get my f*****g A/F sensor & gauge working. Fail.


#68

Re. my discussion of how much cooling you get out of an oil cooler. I’ve had some years to think about those experiments and I think a clarification is necessary. When I put a temp sensor before and after the big oil cooler I did get up to 14deg of delta between the two sensors, but it would not be accurate to say “that’s 14deg of cooling”.

Here’s what I think was happening. Our engine is not designed to dump heat into the oil. The water jacket surrounds the cylinders and combustion chambers, there is no oil-jacket sort of thing. Also, oil isn’t as good of a heat xfer medium as water is. This sums up to oil being slow to warm up, slow to cool down, and not moving a helova lot of heat in the process.

So imagine a scenario where the oil is flowing into the oil cooler at 220deg and flowing out at 206deg…a 14deg delta is reached and the engine seems to have a steady state oil temp of 220deg. Lets say the oil cooler is dumping 100btu/min. I pulled that number out of my butt, I have no idea what it really is.

Then remove the oil cooler. Now the oil temp starts to get really hot because that 100btu/min of heat loss is what was keeping the oil temp at 220deg. As a result the oil temp goes higher and higher, ultimately reaching 250deg.

So on the one hand it’s accurate to say that my big oil cooler was worth 14deg of cooling, but on the other hand in the absence of the oil cooler the oil can get pretty darn hot if there isn’t some means to cool it.

My later experiments looked at how much cooling I could get if I had air blasting on the oil pan. I found that if I had no oil cooler and my skidplate blocked air flow from the oil pan that my oil would hit 250deg during a hot session. So altho the big oil cooler did create only a 14deg temp delta across it, the oil cooler was also responsible for a drop in steady state oil temp of ~45deg.


#69

Is it legal to remove the oil cooler? I don’t see it mentioned on the first or last page of this thread, but I admit I didn’t read the ones inbetween…

I did look at the rules though, and don’t see any provision to remove it. The only line I see is here:

9.3.1.6.6. Oil coolers may be added or replaced, an d their location within the bodywork is unrestricted so long as they are not mounted within the driver/passenger compartment.


#70

Just replace it with an invisible oil cooler.


#71

[quote=“JustinHoMi” post=75987]Is it legal to remove the oil cooler? I don’t see it mentioned on the first or last page of this thread, but I admit I didn’t read the ones inbetween…

I did look at the rules though, and don’t see any provision to remove it. The only line I see is here:

9.3.1.6.6. Oil coolers may be added or replaced, an d their location within the bodywork is unrestricted so long as they are not mounted within the driver/passenger compartment. [/quote]
The oil cooler might have been standard on all US bound 325is’s, but it was optional on some or all model years of 325i.