I have dark black soot (rich fuel mixture) in my tail pipe on a new 2012 Mini. After reading through the threads, this appears to be rather common, but not something I'm used to. Does Mini set the fuel mixture rich on a new Mini during a break-in period?

All my other cars have always been tuned to coco brown. Should I have my new Mini re-tuned to fix this rich fuel issue?

After about 2,000 miles I'm only averaging 27.5mpg. That's not even close to the 32mpg average I expected. Because of the black soot in the tail pipe I'm guessing it is set rich for a reason.

A bigger concern for me is the rich fuel exhaust affect on the catalytic converter!

What are your thoughts?

 

Give it a little. If you are still seeing low numbers at say 10k get it looked at. The other problem might be from staying in the gas a lot.

 

The sooting is normal...

 

I have the same thing happening on my 2011 MCS. I didn't notice it so much during break-in with the stock exhaust tips, but once I swapped my exhaust for the Magnaflow + larger tips it became very noticeable, especially on the right tip.

 

My mileage is increasing as I get miles on my car. Car was doing about 25/26 when new and now avg about 27/28 in the city. Also be mindful of normal things to get good mpg.

I track my mileage on fuelly.com

 

I think the sooting occurs mainly at startup and while the engine is warming, due to the ECS enriching the mixture. In the olden days, you'd pull out the choke **** for the same effect. Once the engine's warm, the mix is leaned out.

Spridget

 

If it's not an S you should be getting WAY better mileage than that. I get 31 around town in my JCW. The black soot is normal though, just keep it clean.

 

I have the soot. I thought it was normal for all cars but more noticeable on MINI because of the chromed finish on the inside edge of the exhaust tip?

Note that the owners manual suggests to not do extended warmup at idle.

'10 Clubman Pg 39 (PDF version)
"Do not let the engine warm up with the vehicle at a standstill. Move off immediately at a moderate engine speed."

For Mileage:
Do you run your car in defrost mode allot? Defrost will run the AC compressor depending on the outside temp.

Tires up to proper pressure?

 

I get the soot also on my 07 MCS. Mileage around town is about 30 mpg and on the interstate if I stay below 70 mph I get about 34-36.
Mine has 63,000 and cat converter is still ok so apparently the soot/? rickness doesn't impact it.

 

I'm avg. about 33.4 overall. My tailpipe gets sooty, but I wash it often so it doesnt embed/stain the tip. I also have an MCa. Most of my driving is rural/suburban though.

 

Are you guys calculating your mileage by hand, or using the ecu that tells you? Either way, you guys must not drive as spiritedly as I do. I avg about 26.5 mixed highway/city, if i'm really conscious about mileage i'll see 28-29. But 32-36? Sheesh, i can only dream about those numbers. But then again, I bought the car for the fun of driving, not to save gas monies.

 

My mileage is usually around 27-28, but that is nearly 100% suburban streets, no freeway. My record is 38 on a road trip, 100% freeway through Ohio with low speed limits .

 

That's driving conservatively without A/C. If I'm driving spirited, no.
Also, it's quite flat here were I live and not a whole lot of stop and go traffic. All that makes a big difference.
Don't know if the NM CAI makes any diff., some seems to think so but I'm not sold.
I've calculated both ways.

 

I calculate by hand (road trip app on iPhone) OBC on car tells me over-all 35.6mpg.

 

If its winter in your area, your fuel economy will significantly drop. I took a 1,200 mile trip during summer and again two weeks ago. Summer fuel economy was average 44 mpg. Two weeks ago, because the temperature dropped by about 50 degrees compared to summer, my fuel economy was averaging 31.2 mpg for the same exact trip and driving habits. Is it winter by you?

 

Thank you for all the responses. This sure is a great community.

Quote:

Originally Posted by Porthos

Give it a little. If you are still seeing low numbers at say 10k get it looked at. The other problem might be from staying in the gas a lot.

I have given the Sport Mode a good workout in my new car testing, but not the last few tanks and they came in the same. At 10K I sure hope the MPG is better...

Quote:

Originally Posted by drewstermalloy

If it's not an S you should be getting WAY better mileage than that. I get 31 around town in my JCW. The black soot is normal though, just keep it clean.

Not an S, just-a MCa. 31-32 average would make me happy.

Quote:

Originally Posted by djdraddy

The sooting is normal...

I always hate it when the dealer/manufacturer says something is normal when you know it isn’t suppose to be that way on a properly tuned engine. The last dealer that told me the loud tapping at start-up until the engine warmed up was “normal” ended up putting 3 engines in that car at their expense. It turned out to be improperly design oil flow to the piston pins. Far from normal as they originally claimed and they ended up redesigning that motor (but they didn't do a complete recell on them , just dealt with the issue on a one-on-one casis...)

Not saying that is the case here, as it does seem everyone has the same dark black tailpipe on their stock builds. Might be the computer tuning though.

Quote:

Originally Posted by klricks

I have the soot. I thought it was normal for all cars but more noticeable on MINI because of the chromed finish on the inside edge of the exhaust tip?

Coco brown soot gives me the warm fuzzes , but dark black has always meant rich fuel mixture in my book.

I start and drive all my modern cars, just drive them easy until they are thoroughly warmed up. No defrost needed much here in SoCal. It’s been in the 60’s and 70’s since I took delivery. Tires are new Conti Extreme Contact DWS set by the installers. I’ll go check them to make sure they are up to snuff.

Quote:

Originally Posted by drsimmons

I get the soot also on my 07 MCS. Mileage around town is about 30 mpg and on the interstate if I stay below 70 mph I get about 34-36.

That is what I expected to get, about 30city/34hwy and about 32avg. That's not too much to ask for with the stated MPG ratings. Hope it gets better.

Great to hear you have the soot AND the cat converter hasn’t had issues in 63K.

Quote:

Originally Posted by amancuso

I'm avg. about 33.4 overall. My tailpipe gets sooty, but I wash it often so it doesnt embed/stain the tip. I also have an MCa. Most of my driving is rural/suburban though.

I’m getting encouraged that it will improve!

Quote:

Originally Posted by SooperCuperErik

Are you guys calculating your mileage by hand, or using the ecu that tells you? Either way, you guys must not drive as spiritedly as I do. I avg about 26.5 mixed highway/city, if i'm really conscious about mileage i'll see 28-29. But 32-36? Sheesh, i can only dream about those numbers. But then again, I bought the car for the fun of driving, not to save gas monies.

I calculated mine by hand; full tank to full tank. The best I’ve gotten is 29.256mpg (mostly on cruise set to 65mph), compared to 27.279mpg (mostly on cruise set to 70mph). That’s odd because my average is 27.463mpg since new. I’m wondering if/when the cruise down shifts on a slight FWY grade to 5th it really sucks up the fuel(?). probably best to just slow down a bit on any grades for better MPG…

Quote:

Originally Posted by christomapher

If its winter in your area, your fuel economy will significantly drop. I took a 1,200 mile trip during summer and again two weeks ago. Summer fuel economy was average 44 mpg. Two weeks ago, because the temperature dropped by about 50 degrees compared to summer, my fuel economy was averaging 31.2 mpg for the same exact trip and driving habits. Is it winter by you?

Never Winter in SoCal! Looks like a few folks here are getting 31-32mpg average, so I’m hopeful. 44mpg? Wow! I caught a 44” Trout the other day, but it was so big it broke the line so I don't have a picture!!!

 

This is the first 6 tanks in my JCW. I don't think I drive conservatively. At least I think that is what all the yelling the passengers are doing is for.

 

happened to me so i turned off my sport mode and started getting 32-34 mpg

 

MPG can be effect by the type of gas sold in your area. Each State has its own rules for what additives go in it. Here in Colorado the amount of oxygenation additives (ethanol) goes up in the winter to cut down on air pollution this cutting your MPG by 10% plus. Just saying many local factors can affect your MPG.

 

I average about 28mpg. The wife drives it to work on the highway and LOVES to DRIVE it.I get it on the weekends and am usually in sport mode.I think if we both backed off a little the number would go up.I also get the black soot.I just wipe with a damp rag every couple of days....not giving up my fun for a little soot.

 

Thanks again for all the replies. It looks like the soot thing is no big deal if it doesn't shortten the catalytic converters life. Surprised that the S's seem to be getting just as good of mileage as the just-a's (even the JCW's). I'm going to chaulk my current mileage up to too much Sport Mode and a heavy foot. Will continue to monitor my mileage until I'm satisfied with what Black Ice is getting, then I can go anti-**** and stop logging all the details... ;-)

 

Decided I couldn't take the ugly black soot issue any more. The stock Justa single exhaust doesn't look too bad when it is clean, but most of the time it looks like the second photo with black soot dipping out like a flooded two-stroke!



Last week I picked up a 3" ID - 3.5" OD dual wall SS exhaust tip that was made to be welded to 2.5" SS exhaust pipe. I'd been looking for a 3" ID - 4" OD to help fill the arch cutout, but settled for what I found for a cool twenty-spot.



I was going to mount it the way it is designed to be installed by cutting off the tapper and cutting back the outer dual layer so I had room for set screws, but after looking at it's shape I kind of liked the tappered look inside the larger outer circle. Plus I'm guessing the soot won't venture over the rounded up edge as easily, so it will stay clean better too; all the while giving the exhaust on my Justa a unique one of a kind larger custom look.

First I painted the stock tip and the inside of the new tip black with VHT Flame Proof exhaust paint.



Then I mounted it backwards with three set screws underneith through both layers of the new tip and just the outer layer of the stock tip. This is the final result.



I like the new unique look. Hope it stays cleaner than the OEM soot drooller. I know it will be easier to clean because I only have to wipe the outside off now.

$20 dorky exhaust tip!

 

The soot on my '12 S is worse in sport mode, must be those dribbles of gas exploding in the exhaust :-).
Soot doesn't bother me as much as stock brake pad dust. Even though the car downshifts itself, which means I don't brake nearly as much as in other cars, one day of driving 12 miles at 25 mph gets the rims dirty.

 

Same on my 13 CMS. I've noticed the engine runs cooler in sport mode (90C vs 105C) so it must be a richer fuel mixture adding the soot.

 

On a non-S, I'd be inclined to think it's creating more soot built up than I personally would expect. If that were on a turbocharged S, I'd say it's normal. But honestly, there are plenty of cars out there that black up the tailpipe more than others. The engine design, emissions design, exhaust design and cat/muffler designs all factor into how much of that carbon residue get's through. It doesn't look alarming to me honestly.

And I gotta put my own 2 cents in, that tip mounted on there backwards looks horrid.