Top Tier Fuels and Tailpipe deposits

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Hi

Has anyone noticed any difference between top tier fuel brands regarding tailpipe deposits in day to day driving.

For example BP Ultimate v Shell VPower v Catltex etc. are there any which are darker or more prevalent.

I guess I am after which one leaves the least amount soot left behind.

I understand engine running rich, tune of the engine etc are all inputs I am rather when used in the same vehicle and same conditions of use.

Or am I misconceiving something here.
 
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I agree with Chris that there will be little-to-no difference. On top of that, deposits at your tailpipe won't really "clean themselves up". If one fuel leaves deposits, it'll be near impossible to tell if another fuel is any better or worse.
 
Your cars computer has to make adjustments for different fuel quality's. Unless you have fouled plug or it's sucking oil into the combustion chamber from somewhere, you should have clean looking dry deposit.,,
 
Originally Posted By: BigCahuna
Your cars computer has to make adjustments for different fuel quality's. Unless you have fouled plug or it's sucking oil into the combustion chamber from somewhere, you should have clean looking dry deposit.,,
The ECU can only adjust for AFR per feedback on the primary O2. Nothing in the quality of fuel would affect that.
 
Can the different fuel additives and the higher dosage for cleaning purposes contribute differing levels of tail pipe soot.

I read that fuel aromatic content can increase engine deposits and increase tailpipe deposits.
 
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Gas is different in different countries. Even different parts of the country. Also different ways to calculate octane and lets not forget ethanol in some.
 
Does not engine management go open loop with low vacuum/ high intake pressure?

or is everything wideband o2 sense? How do you diagnose a wideband response issue?

May car has low gas mileage and high tailpipe carbon deposit ( ink black).
 
Most cars go open loop with drastic throttle position changes. But if you keep the throttle closed the ECU should set the FIs at idle flow and a very lean mix when moving, my WBO2 will show maximum lean readings (gauge limitation) of 20:1 when coasting above 1200 rpms. The only real way to test AFR is with a WBO2 gauge.
 
Have noticed that when we run E85 and I wash the vehicle and clean up the tailpipes on our Acadia, the black soot doesn't appear as much as when we run BP 93 or Exxon 93.
 
Back in the day Sunoco used to sell 86 octane (the USA method (R+M)/2) and I owned a Firebird Formula with a LS1 in it. I wasn't paying attention when I filled up and accidentally put 86 octane in the car....in the summer. It had very low torque and would smoke at low to mid revs, but I think that was the ECU detecting that I did something stupid and pouring fuel in to save the engine. It had some sooty tailpipe deposits that washed off eventually. I was glad to get rid of that fuel.

Until recently, this was the only time I had fuel make a difference on tailpipe deposits. It had nothing to do with the detergents, etc. but was the wrong octane for the car.

My Impala has the DI 2.5 and the tailpipe is a mess regardless of what fuel I use. If I monkey stomp the loud pedal to pass someone, it lets out a visible puff of black smoke for an instant as the engine is getting up to speed. I think on a DI engine, you are going to have tailpipe deposits no matter what and picking the wheat from the chaff in a "sooty no matter what" environment is going to be tricky. It also seems from my experience that driving conditions have much more to do with exhaust deposits than other factors.

Not sure what your application is, but I'd not spend any time worrying about this. A good "Italian tuneup" merging onto a high speed road will blow any garbage out of your exhaust better than fuel system detergents.
 
Of the vehicles in my sig' only the Hyundai leaves soot on the pipes (also the only GDi). I wash the vehicles bi-weekly and haven't really noticed a difference in soot concentration between Shell, Costco or Marathon.
 
Tailpipe soot was one of the anecdotal "data", that people would rave about FP60 on, IIRC.

I think you'd get a better treatment by adding FP+ or RLI Bio-Plus at their low dose rates, and then choosing the cheaper of top tier gas in your area (if there is a price difference). The cost between gas stations can be $1-5 per tank, where the above fuel additives add only $.30-.80 / tank (RLI is less than half the cost of FP, it looks like).

It all depends on how you much you want to pay for convenience. Closer gas station? Using a fuel add every tank? Some people would rather pay more and save the time. Others like to tinker and compare additives (butt dyno posts!)
 
I've been an avid user of LCD products (FP60 & FP Plus) for a decade and a half or so at this point, switching off with SI-1 over the years and RLI Bio Plus more recently, and I've always had soot on the tailpipe of my cars. I have to believe that it's more a factor of driving habits than fuel quality, additives, or even the vehicle. In that time I've had (in order):

94 Saturn SL1
03 Toyota Matrix (1zz-fe)
01 VW Golf TDI
08 VW Rabbit
06 VW GTI
13 Ford Fiesta
13 MINI Cooper S Clubman
13 VW Golf R (APR Stage III)
08 MINI Cooper S

I am very thorough about auto detailing, tailpipes included, so they've all been stripped down to bare metal during their time with me. Every one of them has ended up with a nice healthy coating of soot. My current one (last on the list there) was cleaned up and polished ~2.5k miles ago and has a nice patina all over the outsides and light coat of soot inside. The Golf R got a new exhaust in November, and by December had a pretty heavy coating of black soot. That one belched a bit of soot on the pavement every time I started it too, so some are more aggressive about it than others :p

--Matt
 
Originally Posted By: blupupher
People look at their tailpipes?

I can't recall the last time I looked at one to "check for deposits".


Lifetime experience looking up your tailpipe. Recommended.
 
Hey I polish my exhaust muffler and tip. Looking can at least give you idea of whats leaving your exhaust emission wise. Get it warm and drive it. Received a car after my grandma passed and OE mufflers were SHOT from rust and carbon. Called Edelbrock and installed SDT mufflers,gained power and cheaper than replacement. I would use good quality fuel if and when possible.
 
I'm sure Sunoco has plenty of cleaners in it but just not the number needed to be TT. All gas has the epa minimum.
 
Originally Posted By: Marco620
Hey I polish my exhaust muffler and tip. Looking can at least give you idea of whats leaving your exhaust emission wise. ...


If you have a polished or chrome tip, then I can understand you would see it if you cleaned it, but my truck has a plain exhaust tip and my wifes is too low and under the car to really see it (plus I rarely wash it, make the kids do it).

Truth is, if it does not set a CEL, I pass emissions inspection and it is running well, then I really don't care what is leaving.
 
Originally Posted By: MichiganMadMan
Back in the day Sunoco used to sell 86 octane (the USA method (R+M)/2) and I owned a Firebird Formula with a LS1 in it. I wasn't paying attention when I filled up and accidentally put 86 octane in the car....in the summer. It had very low torque and would smoke at low to mid revs, but I think that was the ECU detecting that I did something stupid and pouring fuel in to save the engine. It had some sooty tailpipe deposits that washed off eventually. I was glad to get rid of that fuel.

Until recently, this was the only time I had fuel make a difference on tailpipe deposits. It had nothing to do with the detergents, etc. but was the wrong octane for the car.

My Impala has the DI 2.5 and the tailpipe is a mess regardless of what fuel I use. If I monkey stomp the loud pedal to pass someone, it lets out a visible puff of black smoke for an instant as the engine is getting up to speed. I think on a DI engine, you are going to have tailpipe deposits no matter what and picking the wheat from the chaff in a "sooty no matter what" environment is going to be tricky. It also seems from my experience that driving conditions have much more to do with exhaust deposits than other factors.

Not sure what your application is, but I'd not spend any time worrying about this. A good "Italian tuneup" merging onto a high speed road will blow any garbage out of your exhaust better than fuel system detergents.


I have the same experience in my Kia Optima 2.0L Turbo. I have a CP-E catback (polished dual tips) and they soot up very quickly. This apparently is mainly due to the GDI of the engine. Nothing to worry about but does present yet another thing to clean carefully on wash day. FYI: I do the "Italian tuneup" on a regular basis and after a few times, you won't get the "black cloud" effect when you stomp the "go" pedal. It's already blown out at that point.
 
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