I have a new 2009 rx8. i am getting heavy black carbon buildup on the end of my exhaust tailpipes. is this common for this car? should i change the type of gas i am using. Also, i often make a 450 mile roundtrip drive for work all highway at 75 mph. the engine was down 2 quarts of oil from that trip and a few extra days. i knew the car is known for its oil thirst, but how often are you other owners adding oil on new engines and with what octane gas? thanks for all posters. i've read here that many owners are using regular gas rather than high octane and not getting any adverse engine or performance problems. comments welcome.

 

Yes, it is common for most as the '8 typically runs rich. A better tune somewhat alleviates but even then you'll get some.

You'll burn oil dependent on your driving style and duration of course, but you shouldn't be down anywhere near 2 qts after only 450 miles!!! The 2009 and on have a third oil injector and slightly higher metering, but you may have to have the dealer verify the proper Oil Metering System setting code in your ECU.

Most run 93 octane to assure best performance, but 91 is fine. Some run 87 fine but at the expense of some lost performance and potential ping.

 

My '09 uses a quart every 1500 to 2000 miles driving about 2/3 city and 1/3 highway. What kind of MPG are you getting?

 

as the car is so new i need to give it another 500 or so miles to get a baseline. i will also take the info from these replies to the dealer or my on shop to check the settings. what kind of oil should i use? other posts have said 5/30W others have said 5/20. for winter i'm thinking of the 30.

thanks to all of you regular posters. great info here by real drivers.

 

i run 5w30 year round.

 

Oil choice is a major food fight on this forum. You'll find as many different opinions about oil as there are members. Do a lot of searching and reading on the huge threads. You'll see soon enough which members simply yell, and which have experience to support their opinions. Bottom line: with few exceptions, it's mostly conjecture. Read............and decide. There are lots of good choices.

 

As do I (5w-30 Castrol GTX year 'round, but there are alot of other good oils).

 

I don't doubt you have carboned tailpipes if you're burning a quart of oil every 250 miles! It's not the gas. But all tailpipes get some carbon.

I do remember the first 500 miles I did have fairly heavy oil consumption, so you've got the right idea to wait till after break-in to get a baseline as long as it's running ok.

Mazda's guidlines for the S1 were 1 quart or less per 600 miles. I typically get around 1000-1200 miles per quart in town, 2500-3000 strictly highway. It varies with driving style and conditions. Not sure what an "average" 2009 model's consumption is; maybe a little higher?

Typical break-in suggestion: give it some varied runs if possible, not just long steady cruising at one rpm.

Octane shouldn't affect oil consumption afaik. I typically run 87 octane. I found a damaged spark plug around 12,000 miles and for a short time went to higher octane, fearing detonation. But I eventually returned to regular and haven't had any problems since. We are close to sea level here.

 

Alot of performance cars these days run rich as a precaution. You should see the tailpipes of STi and 335i. Their pipes are black!

 

my car had castrol gtx for its first 35k miles. the first 20k miles were 5w-20 though. since then its had mobil 1.

 

There a stickie on oil and if you do a search, you'll come up with lots of threads.

Use at least 5W-30. I use 10W-40.

 

My 2009 has about 2200 miles, and I've probably used about 3/4 of a quart of oil, aside from one change at about 1500. I also have the black carbon-filled exhaust. Maybe someday I'll get a tune for a little leaner running, but not yet.

 

+1 on 5w-30 GTX and I use only 93 octane Amoco Ultimate gas with Lucas UCL in every tank. I have averaged 20 mpg since new (on both engines ) and now have around 88,500 miles.

2 quarts in 450 miles is 2 many IMO, but it's better than too little I guess.

Black tailpipe tips are pretty much a part of life.

 

I am using about a Quart of engine Oil every 3000 Miles, 2 Quarts from what you describe is too much.

Please make sure you are checking the Oil Level correctly, on a flat carport surface, and on 5 minutes when you switch OFF your HOT engine.

DO NOT fill up to the F mark if you are checking on a Stone COLD engine..
If you want to check on a COLD engine that has sat overnight, the correct FULL mark then is about a quarter of an inch or 5 mm below the F mark on the dip stick.

Do not over fill to F when cold....as you are putting in too much oil...if filled on a Cold Engine to the F mark on the dip stick it is about 400 mils or about 14 ounces too much.

AND NO... the 09's~ is actually meant to use LESS oil than the Series I...not more..much depends on driving style as mentioned.

 

Ash:

I have inadvertently done this a couple of times with no apparent negative results. What are the implications of overfill in this manner.

 

+1 on that...

 

^ +2 Greg

I go through about 1 qt. every 3k between oil changes
Carbon build up is normal and more evident on the 8 then other cars. all cars burn oil no matter if its a Rotary or a piston engine. Oil injection on rotaries is the cause for higher consumption.

Get yourself some good polish (mothers) to take care of the tarnish

 

Too much oil...??mmm

Well in a Banger you can get the crank whipping up the oil too much turning it into cream, can cause higher than normal Oil Pressure (have heard of oil hydraulic lock), filling up crank case vent valves or breathers, in some cases (depending on engine design- mainly old carby engines) you can get push-back of oil through to intake...resulting in high oil burn and smoke, fouled spark plugs, can put a strain on rear main engine and timing cover oil seals, causing oil leaks.

In rotaries, while not certain, I think you run the risk of increase of oil pressure as basically the oil pump are the same or similar to bangers, damage to timing cover and rear eccentric shaft oil seals, and possibly oil lock, a possibility of vacuum lines filling up with oil instead of air vacuum, but I am talking extremes in overfilling.

I have heard of banger engines where oil has been filled right up to the oil filler cap, so rockers/lifters are drowning full of oil, blowout of rocker/tappet/lifter gasket.

So IMO, you could have a combination of some of the above, I don't think the engine damage can be a severe as a banger with too much engine oil.

If this happens it is best to get under car and drain some out until level is where it should be.

 

Too much oil in the rotary is not as bad a situation as piston, which Ash8 well describes as "frothing", but you'll likely ingest more then you want into the intake ('04/'05) or service port ('06 and beyond).

 

Thanks for the input on the overfill stuff. I'm very familiar with issues in piston engines but did not know what was up with the rotaries.

I had a leaky float valve once on a 2-stroke racer. It leaked pre-mix into the crankcase. I kicked it over and blew the case seal off the end of the crankshaft, adding about 10 ounces of pre-mix to the primary and gearbox. Nice.

But from what I can gather, a slight overfill in our cars is unlikely to cause major issues.

 

I agree guys...I think you are OK with a small overfill, but I would not like to see it massively FULL..

I think it is a bad habit to get into by 'overfilling' or thinking that by adding a lot more oil than necessary will save you from checking and topping off...Which is Normal for any Rotary Engine or their Owner..

 

Point taken.............

It's just a matter of learning the quirks of the car. I'm a 2 stroke guy and LIKE my car to burn oil. Castrol A747 mmmmmmm.............

 

carbon is sick, yo



I run 1 qt over for heavy autox use in my '05 and my intake area is as clean as when it left the factory

I also run high octane, including the aforementioned 220 rwhp run

sigh ....

.

 

A good safeguard in a '04/'05 is an oil catch can. Cheap & easy mod. See the DIY.