2020 BMW M2 Comp | Motul Xcess Gen 2 5-40 | 4150 Miles

MSH

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2020 BMW M2 Comp
Car is tuned. Mild M4GTS+ level of tune bumps power from roughly 410whp/410wtq stock to 485whp/465wtq
2nd car used 75%-80% of time for aggressive canyon runs and spirited drives here in Colorado.
Very little daily driving.
I'm wondering if the tune and my use case with a lot of hard charging driving is contributing to the higher fuel dilution?
Also, car doesn't get driven much over Winter months if that matters. Last oil change was May of last year.
From mid November last yr until sample was pulled 10 days ago only put on ~700 miles.
Previous Blackstone reports never showed any fuel dilution issues but I know the sentiment here is that Blackstone testing in that area is crappy.
Screenshot 2025-03-12 at 5.38.48 PM.webp
 
A tune can definitely cause fuel dilution. The OEM tune could be doing split injection to get all the fuel to atomize and who knows if the tune is doing that. But overall I don't see much to complain about with the UOA. Fuel dilution is a little high but not outrageous. Wear is in check and the oil condition is still usable while the viscosity has dropped a little bit but is probably typical.
 
If it went from 13.5 to 12.1, is 3.9% FD even realistic... ?
Street driving should not cause major fuel dilution with dual injection, not with a good tune IMO.

Did you start it up without driving during winter?
 
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If it went from 13.5 to 12.1, is 3.9% FD even realistic... ?
Street driving should not cause major fuel dilution with dual injection, not with a good tune IMO.

Did you start it up without driving during winter?

I just drive it very little in the winter. There were of course times I started it up to pull of of the garage and pull into driveway to do something in the garage and then pull back in after
On the day I did do the oil change we did have very nice weather so I took it out on a pretty aggressive backroads drive and then straight into the garage for the oil change. Not sure if the heavy throttle driving right before the oil change would have made a difference here.
Yes they are street miles but again the low miles I put on annually are fairly aggressive in nature.

Keep testing if you can. :)
Looks like Al might be taking a hit but more results will tell the tale.

My aluminum readings always seem to be higher than universal averages on all my fun cars I think because the mileage is predominately long aggressive canyon drives. The last 2 UOA from Blackstone on this car were at 12ppm when Blackstone indicated universal average is 7 ppm.
Most of the miles on this car is pretty much like any of these videos on my YT channel-->
https://www.youtube.com/@pushdaenvelope
 
Sure...more boost to push fuel-laden blowby into the crank case.

Thanks. I think I'm just use to the Blackstone reports which never have called this out as an issue on my last two UOAs since I have had this car and my prior Golf R which was running much higher than stock boost with a hybrid turbo tuned on E85 (~520whp). The Golf R would beat down the oil viscosity on that car on 3k-4k changes Same use case as this M2 running Motul Sport oils almost exclusively. I suspect that there was higher fuel dilution on that car as well contributing to the viscosity loss.
It will be interesting to see Blackstone's report (when it comes back in a month ha!) as I sent them a sample as well to compare against this Oil Analyzers report. I suspect if I was using Oil Analyzers all along for this M2 and the Golf R I would have seen more elevated levels based on their more accurate testing.
 
It is tune. If you did spirited driving before, you did your due diligence to send a good sample.
I am actually surprised by KV100 and such fuel dilution. That tune definitely requires XW40 oil.
 
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Thanks. I think I'm just use to the Blackstone reports which never have called this out as an issue on my last two UOAs since I have had this car and my prior Golf R which was running much higher than stock boost with a hybrid turbo tuned on E85 (~520whp). The Golf R would beat down the oil viscosity on that car on 3k-4k changes Same use case as this M2 running Motul Sport oils almost exclusively. I suspect that there was higher fuel dilution on that car as well contributing to the viscosity loss.
It will be interesting to see Blackstone's report (when it comes back in a month ha!) as I sent them a sample as well to compare against this Oil Analyzers report. I suspect if I was using Oil Analyzers all along for this M2 and the Golf R I would have seen more elevated levels based on their more accurate testing.
Yeah b/c BS was just estimating it from the flash point, you likely had much more fuel before but just didn't see it.
 
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2020 BMW M2 Comp
Car is tuned. Mild M4GTS+ level of tune bumps power from roughly 410whp/410wtq stock to 485whp/465wtq
2nd car used 75%-80% of time for aggressive canyon runs and spirited drives here in Colorado.
Very little daily driving.
I'm wondering if the tune and my use case with a lot of hard charging driving is contributing to the higher fuel dilution?
Also, car doesn't get driven much over Winter months if that matters. Last oil change was May of last year.
From mid November last yr until sample was pulled 10 days ago only put on ~700 miles.
Previous Blackstone reports never showed any fuel dilution issues but I know the sentiment here is that Blackstone testing in that area is crappy.
View attachment 267789

More fuel means more opportunity for fuel dilution especially when the engine is running rich to reduce combustion temps. Does the M4 GTS run the same ring pack as your M2?
 
More fuel means more opportunity for fuel dilution especially when the engine is running rich to reduce combustion temps. Does the M4 GTS run the same ring pack as your M2?
Yes doesnt matter all F8x platforms (M2 Comp, M3, M4's) all had the exact same S55 engine/internals. Only difference was how BMW tuned each one. The M2 Comps were neutered from the factory at the time since they didn't want the M2C to have higher HP vs the M3's and M4's. The M4 GTS (followed by the M3 CS and M2 CS) had the highest HP from the factory of all the F8x but they also run water injection for better cooling since it's use case is really track intended focus
 
Yes doesnt matter all F8x platforms (M2 Comp, M3, M4's) all had the exact same S55 engine/internals. Only difference was how BMW tuned each one. The M2 Comps were neutered from the factory at the time since they didn't want the M2C to have higher HP vs the M3's and M4's. The M4 GTS (followed by the M3 CS and M2 CS) had the highest HP from the factory of all the F8x but they also run water injection for better cooling since it's use case is really track intended focus
Oh that M4 GTS. I was thinking G8x.

I suppose you could have a bad injector leaking fuel. Have you looked at other S55 M2 UOAs?
 
Oh that M4 GTS. I was thinking G8x.

I suppose you could have a bad injector leaking fuel. Have you looked at other S55 M2 UOAs?

yes there is no M4 GTS on the G series.
G series has the S58 engine
Other than the base M4 and Comp you can get a M4 CS or M4 CSL on the G82.

Factory Hp Figures for F8x M2-M4s
*same S55 engine for each...just a difference in factory tunes for each of these models*
F82 M4 GTS = 493hp
F80 M3 CS = 453hp
F80 M3 Comp & F82 M4 Comp = 444hp
F87 M2 CS = 444hp
F87 M2 Comp = 405hp

I will keep track of things on future UOAs. I'll take OAs advice and maybe change oil early @ ~3k and retest.
I did some more digging with talking to my tuner and others (+ comments above) and the consensus seems to be its just that my car is tuned and my use case is contributing to the higher readings.
The technical folks I spoke with that know this platform well told me if there were any major fueling issues I would be throwing a ton of codes.
With that said I may still hook up my Bimmerlink app and do some live fuel trim logs
 
Try a good fuel injector cleaner like Redline SI-1.

Otherwise keep hammering!
Thanks. I have used the SI-1 on previous cars but not on my m2c. I'll give it a shot.
I see you have a M2C as well and judging by past posts you are on PPE 5w40? Your tune is more aggressive than mine and seeing you are on flex fuel I assume you are running E85 regularly, which of course really beats down oil. My previous Golf R was a hybrid turbo E85 tuned and even at 3K OCIs it beat down the viscosity of Motul Sport 5-40 and the 5-50 I sometimes ran as well.
I noticed on one of your posts that your aluminum has been around 12ppm on your last few UOAs and you were thinking of trying Redline? So far my aluminum #'s (12-13 ppm) are similar to yours with a 4k mile average OCI. Is that whats in your M2 now? Curious to see what your UOA comes back looking on it if so.
 
More fuel means more opportunity for fuel dilution especially when the engine is running rich to reduce combustion temps. Does the M4 GTS run the same ring pack as your M2?
These engines run pretty lean. Low 13s, high 12s AFR at WOT.

Thanks. I have used the SI-1 on previous cars but not on my m2c. I'll give it a shot.
I see you have a M2C as well and judging by past posts you are on PPE 5w40? Your tune is more aggressive than mine and seeing you are on flex fuel I assume you are running E85 regularly, which of course really beats down oil. My previous Golf R was a hybrid turbo E85 tuned and even at 3K OCIs it beat down the viscosity of Motul Sport 5-40 and the 5-50 I sometimes ran as well.
I noticed on one of your posts that your aluminum has been around 12ppm on your last few UOAs and you were thinking of trying Redline? So far my aluminum #'s (12-13 ppm) are similar to yours with a 4k mile average OCI. Is that whats in your M2 now? Curious to see what your UOA comes back looking on it if so.
In the winter so far I've been running mostly Shell 93 but put E85 in the last couple tanks.
I have yet to put the Redline oil in and since I got the 5w40 I'm waiting for temps to get above 50f.
I'll be sure to post the UOA and I'll get one from OAI so that the fuel numbers are comparable.
Probably in August sometime.

M2CPPE2.webp
 
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Adding in the Blackstone report that was run on the same sample as the Oil Analyzers report in my original post.
Surprisingly, Blackstone had a 1 week turn on this report. My last few have almost taken a month.
I wonder if they have made some changes to get reports turned quicker or I just was lucky this goaround?

Anyway, this is the first time they have called out fuel dilution on any of my UOAs thus far on my M2, so at least there is a mention of it.
Also, Blackstone's Viscosity # (100°C) is a fair amount lower vs OA's #.
Moving forward I will shift to using Oil Analyzers as it's much cheaper and turnaround on reports (other than this Blackstone report) is much quicker


Screenshot 2025-03-18 at 6.23.34 PM.webp
 
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