Speed3 Running rich?

Hey guys, first post here!

I got a Gen 2 about 2 months ago and have been getting acquainted with it throughout the time. Car has 117k miles currently.

I noticed my exhaust tips were regularly coated black, and a few weeks ago week I noticed that when on higher revs, I get some smoke out the back. I saw it when I was in the car, so I couldn’t see that well but it wasn’t too much, after a few seconds it dissipates but there’s definitely black smoke coming out. I also get a nice lil’ backfire every now and then, which I can’t say I hate! I’ve gotten the smoke when revving in neutral as well as in gear.

My mileage is noticeably better with 91 octane rather than 93 for some reason. I typically “Lose” about 80 miles from the cars computer estimated range when on 93, and on 91 it’s closer to 45. On a full tank of 93, I think I get around 210 miles, which is REALLY low, right? Should be closer to 300?

I don’t really beat on it too much, and even when I do drive “spiritedly” I’m not really doing anything aside from just revving it out, going around maybe 100 mph for a bit, then calming down and going back to around 75. Never for more than a few minutes, honestly. Also never autocrossed it yet as I still need to replace the serpentine belt tensioner and rear control arms.

I also noticed that if I do a pull shifting close to redline I can smell what I THINK is oil almost right away, but it doesn’t happen when shifting around 4-5k. Again, nothing that makes me think the car is broken, but just keeping my eye out. It’s my first turbo car so I’m a little paranoid about anything unexpected.

My car has a cork sport exhaust and a HKS BOV, for reference. Otherwise, should be all stock.

Is there anything I can check to have a better understanding of my car? Spark plugs should be good although I wanna swap ‘em out anyway. Any filters I should clean to check if it might be that?

 

Black smoke is normal on stock tune it runs rich at wot.

I can't imagine why your mileage would vary with the octane change though the mileage is really that bad city vs highway so make sure you are comparing similar trips.

The oil smell could be the transmission not venting pressure correctly though gear oil smells different than engine oil.

Make sure that the bov is set to full recirc.

Check your spark plug gap and if replacing use stock heat range

 

OP are you keeping tabs on your oil consumption?

If I were you I would be checking weekly at that milage at least until you get a feel for how much oil your motor uses. When mine was on its way out I didn't realize how much oil it was using and ran low a couple times.

 

I would argue that you can tell if a factory car is turboed by whether or not the exhaust tips are soot soaked.

 

I appreciate the feedback, guys! My exhaust tips are DEFINITELY soot soaked, so much so that sometimes I wipe a little off with my foot just to remind myself they aren't matte black lol

I'll make sure to check the BOV and set it to recirc if it isn't. I typically drive very similar trips, a good mix of highway and city driving since I barely ever go into manhattan and mostly go to Long Island when on longer drives.

My oil consumption is pretty minimal, I'd say. I changed the oil on it over a month ago and the dipstick still reads full. Pretty black though, actually made me consider getting another oil change sooner rather than later although I hear black oil is also typical for turbo cars quickly.

Also, I wonder if it still has the stock tune on it or not, although I don't have the accessport so that means I probably can't have any other tune aside from base map on it, I figure. I thought about that the first time I heard the engine go up to the rev limiter and being surprised at how quick it bounces back compared to other engines. I take it that's normal, then? Clearly I know nothing about the car but I do appreciate all the advice

I can't much tell the difference between the different oil smells, I'll keep my nose out for if it happens again. Seems like everything is running as it should though! What spark plugs do you guys recommend I get?

 

Here you go

https://mazdaspeeds.org/index.php?threads/spark-plug-data-base.1436/

 

I did smell yesterday some kind of oil, although incredibly brief and subtle, and it was when I shifted a few times in a short amount of time. I think it was a couple downshifts followed by a few upshifts, then downshift again, etc...

It's probably the trans oil, then? Should I look into renewing it, or doing any other kind of preventative maintenance?