I've often heard the the "decarbonization" procedure consists of taking your car out on an unused stretch of road and running WOT for about 20 or 30 minutes. At least that's how it supposedly used to be done.

 

Thanks, I'll use Chevron from now on. Also, I'll run some Techron through. what do they do in a de-carbonization procedure?

 

Last time I did that was in a rebuilt '67 Dodge Charger. Didn't think it worked with newer engines

 

That may have been how de-carbonization was done in the distant past; currently, there is too much liability exposure (such as being cited for reckless driving for WOT runs) to use the WOT approach.

The way I have seen the de-carbonization procedure performed is that the fuel line to the fuel injection system is disconnected and a de-carbonization machine is hooked up (you need to replace the fuel pump pressure to the fuel injection system). (They also pull the fuse to the fuel pump to avoid fuel being pumped by the fuel pump.) The de-carbonization machine is loaded with about a gallon of de-carbonization mix (probably Chevron Premium with the container of Techron to make an even more potent cleaner than the fuel tank + container of Techron that I mentioned earlier). The de-carbonization machine is turned on to create the fuel pump pressure and then the car is started and allowed to idle until the gallon of de-carbonization mix has been consumed. The de-carbonization machine is disconnected and the fuel line from the fuel pump is re-connected to the fuel injection system. The car is then re-started and taken for a test drive to confirm that everything is working.

 

Thanks , I think I'll try the Techron and Chevron. Seems easier. Frank

 

If you can solve the sluggishness with the container of Techron and a tank of Chevron, you will also save on the cost of the de-carbonization procedure.

 

I use the highest octane available in the summertime, around here it's Sunoco 93 or 94. In the winter I use the mid grade usually 89 because the air is cold enough to support the lower octane.

As far as de-carbonization, go to your local GM dealer and get a can of Top Engine Cleaner.

 

Good advice to avoid pinging; but high octane doesn't necessarily mean high detergent levels. If the distributors on the Top Tier list sell 93 or 94 octane premium, then you have both bases (high detergent level + pinging resistance) covered. Incidentally, Sunoco is not listed in the Top Tier Retailers (www.toptiergas.com/retailers.html).

Top Enigne Cleaner is similar to Chevron's Techron detergent additive. It is not a replacement for an engine de-carbonization procedure if the deposit build-up is extensive.

 

I'm not too worried about the Top Tier Retailers. All the gas nowadays is crap anyway. It all comes off the same boat.

If you're talking about Chevron's Techron that you pour in the gas tank, it's good stuff, but not a top engine cleaner like the one GM sells. GM's Top Engine Cleaner is for removing carbon from tops of pistons, combustion chambers, and valves. It goes IN the engine, usually through the throttle body. Let it sit overnight, start the car in the morning and it's gonna smoke out the tailpipe like freight train until the solution burns up taking a considerable amount of carbon with it. Good idea to change the oil after this treatment.

 

In my neck of the woods, the gas is supplied by pipeline from whatever refiner has dumped reformulated unleaded into the pipeline system. When the gas is packaged at the distribution point, the detergent package and octane boosters that distinguishes it as Chevron Supreme is put in immediately before the gas goes to the service station (by tanker truck). I don't think I would agree with the statement that all gas is crap; since BMW has signed onto the Top Tier concept, there is some credibility of the Top Tier concept with BMW.

Interesting appraoch to using the GM Top Engine Cleaner. My recollection was that the container says to put the contents in the gas tank so that it can be run through the entire fuel injection system. The approach that you are advocating sounds more like a variation on the de-carbonization process; just without using the de-carbonization equipment and letting the cleaner solution sit overnight, with the added consequence of needing to do an oil (and presumably filter) change afterward.

 

There is also a Top Engine Cleaner from GM that is used in a machine to accomplish the same task. It is much more concentrated and is fed to the engine from the fuel rail.
The only chemical GM has to put in the gas tank is their Fuel System Treatment. It is formulated to remove carbon from wherever there might be build up, intake ports, valves, combustion chambers, etc.

 

I just purchased a used convertible MC with 4300 miles on it in CA and then drove it home to Texas. On the way back I filled up with cheap gas. I failed to see the writing on the gas cap that says to use 91 octane. I got 25.4mpg. Some of this may be fuel related or the average 87mph. For kicks I moved to the 93 octane to see if there was a difference and I got a litttle over 28mpg. Again it might be the gas or the average 78mph (it was dark) but it was actually a little cheaper to run the with the better gas. When in doubt, here is a quick way to tell. Take the MPG you're getting now and devide it by the cost you paid per gallon of gas. Multiply that number by what you would have paid for the other gas (this means you have to make a mental note or write it down somewhere). That will give you a MPG (break even) that you should expect with the other gas. Buy the other gas and see what happens

 

This has been a most helpful thread - I'm stick'n with the premium as I hope to keep my mini for many years of trouble free motoring.

 

Not to belabor an earlier post, but, be sure to use gas that has a high octane rating (91 or higher) plus high detergent content.

 

FrankG,

If you use Techron, it is best to use a bottle a couple of tanks before an oil/filter service. Some of the Techron remains a liquid as it passes through the engine, even the combustion chambers, and gets into the oil along with whatever junk the Techron loosens.

Sincerely,

RockC.

 

This discussion crops up in various car forums every so often.

Using a grade of gasoline below premium in an engine designed for premium is false economy. A few gallons, even a tank, once in a (great) while, maybe if 90/91 octane is not available is probably not a problem.

The enhanced thermal efficiency derived from high compression ratios represents an effective means of improving fuel enconomy.

By running a lower octane gasoline the engine controller (ECU) will retard ignition to avoid engine damaging detonation.

Because detonation is so harmful, just about anything one can do to avoid it is better than having the engine experience it.

However, retarding ignition is at best a crude "solution" for it increases exhaust gas temperatures (because with delayed ignition timing the air/fuel mixture starts burning later in the compression/power stroke and burns longer during the power stroke).

Heat is the enemy of an engine and this extra heat will take its toll, over time. If you don't intend on keeping the car very long maybe it is not a concern for you. I would as a used car buyer shun a car that was designed to burn premium but the owner instead fed it regular.

By retarding the ignition, less energy from the lower octane gasoline is converted into mechanical energy and you will find that the savings at the pump is countered by a decrease in fuel mileage.

If you want to save money on gasoline, keep tire inflation pressures correct, remove any unnecessary junk (weight) from the car, and watch your driving. Chances are you'll see an increase in fuel mileage that will more than pay you back for what you'd "save" buying 87 octane vs. 90/91 octane for your MINI.

A recent issue of a UK car mag has a very good article on comparing gasolines of various octane ratings and how a car/engine performs on a dyno and on the track. Even at WOT the proper octane of gas delivers more HP, more torque. And at WOT, the engine controller goes open loop (emissions are not a concern) so it can deliver a sufficiently rich mixture of air/fuel to control detonation without having to retard the ignition.

Under part throttle conditions -- most engines spend their lives at 30% throttle or less -- where the ECU can't go open loop (because emissions would suffer and the engine would fail emissions testing) running the proper grade of gasoline will result in even better performance.

Remember too, that here in the USA we are saddled with a premium gasoline that is a few octane points below what UK and European car owners can buy, so even running 90/91 octane (the best most of us can find/buy) finds our engines already having to deal with less than ideal octane gasoline.

Dropping down to 87 octane seems to be a case of penny wise, dollar foolish.

Sincerely,

RockC.

 

Yes, I did. Almost "ruined" my engine also. Once I was able to cycle all the regular fuel out, I switched entirely to a higher octane fuel. You might think that it will become expensive, but the engine performs smoother and better with a higher octane fuel and your gas mileage will improve. Also consider you driving style. My husband likes to downshift instead of break and max out the tach before gearing up. I don't like that. I feel it puts unecessary wear and tear on the machine and burns up fuel. Don't get me wrong, I do not drive like I have Miss Daisy in the back seat, but I don't drive like I'm at the race track either...and when you get on the open highway, the car just hums. Flora Blue

 

Hey Guys,

This seems to be the place for fuel questions. I posted in some other spot on mods for the Mini, but not responce as of yet. my question is on E-85 which is 85% ethenol. It is like 30 cents cheaper than reg. (87) but the octane is supposed to be 110. The 100 octane is $4.00 per gal. here in Las Vegas, so even though that is only like $6.00 per tank, compared to 91, but that does break the budget for gas for me, (not the bank, the budget)

 

I have an '05 MCS and I too experienced sputtering at start up, which began this past summer and then got worse. The first time I called about it, the dealer thought oil might be leaking into the cylinders at night. I reported that the engine did not blow smoke at start-up when sputtering. So, we took a wait and see.

This month when I called about the problem, the dealer said bring the car in and they would update the software of the car to the latest version. That did the trick. No sputtering since. This may also help other year models, I'm not sure. A call to your dealer's service department will tell you.

 

Hi Partsman: I've used Redline (www.redlineoil.com) for the past twenty years in my diesels and in my petol vehicles. This stuff really works. All of my cars have run in excess of 180K miles with no major internal problems and the '91 300SE benz that I have now (TiNY is off for the winter) just cracked 177K and it runs like a swiss watch. I use a half bottle of Redline S1 once a month
.

 

I coughed and somehow sent a message. Anyways, The redline S! is like a 2x formulation of S2 whcih BMW sells in their dealerships. Look at the Redline website and they've got some really good info.
I really believe that Redline has helped my vehicles and gas milage over the years and at my 11k mile (2nd change) dealer service I'm gojng to ask them to use Redline instead of Castrol. I don't know if they will but if they want to get me back as a customer for a 2nd mini they had better.

 

Putting E85 fuel in your MINI would be a very, very bad idea.

E85 fuel is intended only for use with designated Flexible Fuel Vehicles (FFVs) that can run on either standard petroleum fuel or E85. Neither BMW nor MINI makes an FFV model - they're limited to a handful of vehicles from various American and Japanese makers, and tend to be models that are used as "fleet" vehicles: big sedans, SUVs, light trucks, etc.

Running ethanol fuel in your MINI would be like effectively poisoning it. The systems in FFVs are specifically designed to adjust themselves to high-ethanol fuel mixtures, but your MINI is not. It won't be able to digest the E85.

So overlook the high-octane numbers and back away from the pump. If you really want a super-high-octane experience, just buy a pour-in octane additive and use the proper fuel recommended by the manufacturer.

 

What? Do you plan on buying the oil and taking it to the dealership?

 

With the cost of gas as high as it is (and from what it sounds like, it's going to get higher soon), how does everyone here handle paying for premium? Does anyone who recently bought a MINI notice a big difference in their gas spending now as opposed to when you had something that ran on regular? How big is the MINI's gas tank, by the way?

Or does anyone really care about how much they spend in gas, just as long as you're havin' fun motoring??

 

I invest in the oil companies ....So, I call it even and keep putting in the premium