Carbon Buildup on tailpipe
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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.
#2
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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.
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.
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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.
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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.
thanks to all of you regular posters. great info here by real drivers.
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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.
thanks to all of you regular posters. great info here by real drivers.
#8
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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.
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.
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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.
#13
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.
#14
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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.
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.
Last edited by ASH8; 12-07-2009 at 09:23 PM.
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I have inadvertently done this a couple of times with no apparent negative results. What are the implications of overfill in this manner.
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^ +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
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
#18
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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.
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.
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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 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.
#21
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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..
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..
#22
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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..
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..
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.............
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