Was out at the drag strip the other night. Sunoco sells racing fuel to anyone who wants to fill-up. I was expecting something like 94 and 98 octane. They had three grades, 102, 110, and 114.

What happens to a MC with that kind of fuel or is it a complete waste of money?

I burned regular unleaded in my 2006 MC for about 6 months, only a slight decrease in performance and no decrease in fuel economy. Switched back to premuim this summer as the air conditioning really does require the premium if you plan on using on-ramps to the expressway.

 

With the high compression ratio of the MC, 114 is really extreme. In reality, with a Cooper, you don't stand to gain anything by racing with race fuel. Stick with the 93. Coopers to include the S, were tuned for 93 octane.

 

you waste money and begin to carbon coat your engine innards

I have no idea how much control the ECU has in regulating AFRs but regardless of what gas you put in the ECU is going to try to make the car run safely and within the map parameters. when it jumps out it will compromise the performance to keep the engine safe.

Now let me ask you a question. You know what Octane is a measure of right?

if you think its power or higher energy for more HP guess again.

 

The 110 and 114 are most likely leaded gas anyway which you don't want. I have a Petro Express down the street which has 100 unleaded that I visit to fill up my track fuel containers. I've run 100 octane in my R56 Cooper on the dyno with a modified cylinder head and tune with no increase in HP so with a stock NA motor IMO your wasting money you could be spending on another tank.

 

Is that RON or MON? I ran SuperPlus in Germany which is a 98 RON but there was never a need to go higher.

Here is a good read...

http://en.wikipedia.org/wiki/Octane_rating

 

I would stay away....I bet it is leaded. Since your car is not tuned to use the higher octane....it would be a waste of$$.
Also the lead can cause numerous issues....some with the Catalytic converter, some with the O2 sensors, some with spark-plug fowling, etc. In general, the removal of lead from fuel has been a boon for automobile reliability (for cars designed to use unleaded fuels).
Add to that that un-approved "racing" fuels may damage or destroy your fuel system......even if it does not, anybody who has run Av-gas (leaded, 100 octane, AKA 100LL (100 Lots-a-Lead) (OK...LL stands for low lead, but 100LL has more lead than ANY car gas ever got, but significantly less than Aviation 130 octane, now a rare fuel used in just air-racing due to cost) on a track car know since it has different burning characteristics, the motor must be set-up to run it to make the best power. Fuels power (BTU) content varies...motor fuel sold at gas stations are a known commodity, with limited amounts of certain chemicals limited to 10% ethanol. Racing fuel has none of these limits, and could be 100% Methanol or Ethanol.

 

it is illegal to sell any gas with lead in the US because it will foul emission equipment. thus this fuel will not have lead in it if its sold at a commercial station

 

Not exactly....you can buy CAM 2 racing fuel (or is it CAM4?), leaded fuel (basically 100LL) at my local Hafners gas station....they have like 15 pumps total...ONE for racing fuel.
It is Illegal to burn in it on a car driven on public roads.....Hense the sign on the pump..."OFF ROAD USE ONLY".

 

yes it is marked as race fuel and clearly marked off road use and is intended for cars with no emission equipment. things like race cars. lead will kill catalytic converters. That is why unleaded gas appeared in the early 1970s

 

I wonder if the lead thing ruining your car might be a bit overstated......I accidentally put 1/2 tank of 110 leaded race fuel in my car, it didn't run a bit better or make more HP, although the exhaust smelled great! Once I got away from the track I filled up with unleaded premium again, didn't see any negative results with my cat or anything else. I don't recommend a steady diet of it, but mixed in with some unleaded on a one time deal doesn't seem to have hurt anything. It also didn't help the power any, fwiw......but boy it smelled terrific!

 

sure one tank of 87 is not going to ruin your car either. The OP I believe was not asking if occasional use was OK they were assuming that the bigger the number the better the gas and prolonged use of a Pb containing fuel will damage emission stuff as well as carbon coat the cylinders, valves et. al.

 

LOL, no it wasn't! It was banned because of lead emissions. High levels of lead used to be found in people due to the burning of leaded fuel so the EPA took actions to remove it. This required the auto industry to design cars that didn't require the lead in fuels and at the same time they needed to raise the octane of the non-leaded fuel. Cats were designed to help even further with reducing emissions but this was NOT the primary reason for banning leaded fuel.

Bottom line is that there is nothing to be gained from running that expensive fuel. You need to run the fuel that the car was designed to use for the best results.

 

really can you name a car that used regular gas that also had a CAT as OEM equipment? Clearly Pb has an environmental impact but IIRC the transition to mandating CATs on cars was coordinated with lead-free gas to avoid damage to the new equipment as much as it was for lowering the negative impact of combusted fuel on the air/water.

 

The huge move to remove lead from fuel started around 73 and the first cat was in 75.... You do the math.

Better yet, here is an EPA article that says what I just said!

http://www.epa.gov/history/topics/lead/02.htm

It had nothing to do with new equipment. The new equipment was an invention that was designed to further help with the cause of reducing emissions, not the reason for the removal of lead. Even better the article states that they have been trying to reduce the lead since it was put in back in the 1920's.

I remember watching the news and hearing them talk about the amount of lead found in people and why it was important to remove it from the fuel. All new cars being produced had a cat and would use unleaded fuel with leaded fuel only being used for older vehicles.

 

Well I did not know that I recalled that both occurred at the same time. Given the family 1974 scamp was a regular fuel car and had no cat I guess I assumed that the transition was simultaneous. I really cannot recall anyone driving a car that was unleaded fuel only that did not also have a CAT but the article implies that the fuel came first.

I did find this interesting article on the politics of it
http://www.thedailygreen.com/living-...llution-461219
thanks for added information to sure up my memory

 

You actually got me thinking back even further (god I feel old now). If you remember, there was also lead in paint and it was removed around the same time.

I actually think that cats were a collision with lead that was the final straw. I remember people hating to have a cat on their car stating that it hurt performance. However, they were a good idea to get rid of the excessive emissions and when lead fuel killed them, it was like the preverbal straw and fired up the need to get it out sooner. It probably would have taken longer if that invention had not come along.

I actually think that this was one of the EPAs greatest victories. I am not a huge greenie, but I remember many cities covered in brown smog and can only imagine how much worse it would be now had we not removed it.

 

I agree EPA did good there. I was surprised on how old the technology for the CAT is and how long the auto industry avoided them.

I lived in Houston for a spell and I can tell you that even with most cars having CATs the smog is awful. I would imagine that big cities such as LA NY and Houston would be unlivable.

 

I think we have successfully hijacked this thread!

 

I love the smell of thread drift in the evening :D

 

Back to the OP.........

Higher octane gas will allow the engine to perform at max longer when lower octane gas would cause it to knock, thus reducing the power.

Under ideal conditions the engine would perform the same regardless if it has reg, premium, or race gas in it. But once the engine encounters knocking it will pull timing and this will decrease HP. Higher octane gas will help by changing the conditions where knocking may occur.

 

yes because the higher then number the greater the resistance to detonation. Conditions that promote knock are higher compression of the air fuel mix and FI. the fact that the S is an OEM FI set up and they have tuned for premium fuel there are no conditions that are good that I can think of where 91-93 would actually knock. If you are buffing up so much so that it would I doubt the car would be very reliable more then a 1/4 mile at a time.

 

LOL Thread Jack!

Most 98, 100, 102, is usually unleaded and is not bad for MC but definatly a waste of money woithout any significant gains. Not sure of 110 and 114?/

 

Dunno about the R53, but the R56 will advance timing for 98 Oct max.
They sell unleaded 110 on the Dragon, but 110 and up is much more common as a leaded variety. Any time I see a race gas pump I take a photo or two.

If its unleaded, you can mix it to achieve 98 (or whatever the max is for R53) and beyond that its a waste.

 

One thing to add...octane is reported using 2 differant systems in the world....Europe, and most of the rest of the world uses a system where premium is 98, and the US is 94, but the tested octane level is the same....it is the testing procedure and the reporting spec that is differant. Not having seen a r56 manual, I cannot tell if they are refering to the euro octane spec or not.

Edit : Europe/most of the world uses RON, the US/north America uses R+M/2. The same fuel when tested results in about a 4 point differance, but more under some conditions...the R+M/2 was desgined to be a more relilable way to judge octane levels, both under rich and lean conditions than the RON method.

 

Huh.......?

There are many different causes of knock. Heat being the most common. And a higher octane CAN and WILL reduce the amount of knock and therefore maintain power.