Mercedes 450SL Fuel Question

[LeonardDraper]

I have a 450SL V8. It runs terrible on ethanol gas. Can I run a mixture of 100 octane lead fuel with the other gas?

[Gilly]

I didn't think they made leaded gas any longer? If it has a catalytic converter the lead will ruin it, in case you are in some 5th world country where they still have leaded gas.

[thayer]

Airports have 100 low lead. They will sell it to you very much like a gas station. Drive your sl out onto the taxiway and to The pump. Helps to have a relationship with the FBO. (Fixed base operator).

Mixing non-ethanol regular with 100LL makes my motorcycle very happy.

What year is the 450?

[Gilly]

Yeah I used to work at an FBO at MSN in the 80s. People also bought Jet A from us for salamander heaters. No cars on the ramp, they had to stay on "their" side of the fence, we could only sell to the public in cans. Even good airport customers. Once in awhile we would allow a limo or bus on the ramp, they could only follow us around, couldn't just let them drive off by themselves.
Still shouldn't run any leaded gas with a cat, it will plug it up.

[Skippy]

Originally Posted by LeonardDraper

I have a 450SL V8. It runs terrible on ethanol gas. Can I run a mixture of 100 octane lead fuel with the other gas?

Octane rating shouldn't be a problem. Pure ethanol is 108 octane and whatever fuel you buy is blended to the advertised octane rating, or a little higher. What might be giving you problems is that ethanol blends have less chemical energy than normal gasoline. This means that if your fuel mixture is on with normal gas, you will be lean with oxygenated fuels, unless your fuel injection system has the means to notice the difference and compensate. Newer systems running in closed loop with the aid of an oxygen sensor adjust fuel mixture on the fly and can adjust for ethanol or non-ethanol fuels. The system on your 450 will likely need to be re-tuned in order to run right consistently on E10.

[dlssmith]

I find with the older vehicles, it's just better to avoid ethanol altogether. When I run non-ethanol consistently in the 103 engine, she's a lot happier. Sure it's more expensive, but ethanol isn't worth the bother.

I ran an experiment when I got my flex fuel 2012 Ford running 4 tanks of e85 in a row. Per mile cost was higher than with 89 octane non ethanol even with the subsidized cost of e85 at $3.15 per gallon compared to $3.75 for regular. Flex fuel system adjusts well enough for the difference in fuels, but the e85 would have to be about $2.50 per gallon to make it worth while.

[Skippy]

Non-ethanol is nice if you can get it. None of the gas stations around me sell it anymore. It's all E10 unless you want to get 100LL from the airport or race gas from NAPA.

[pmckechnie]

Go to HTTP:pure-gas.org (no WWW). select your state and you will get a list of stations with ethanol-free gas. No prices are given, but phone numbers are given.

Paul

[thayer]

Originally Posted by dlssmith

I find with the older vehicles, it's just better to avoid ethanol altogether. When I run non-ethanol consistently in the 103 engine, she's a lot happier. Sure it's more expensive, but ethanol isn't worth the bother.

I ran an experiment when I got my flex fuel 2012 Ford running 4 tanks of e85 in a row. Per mile cost was higher than with 89 octane non ethanol even with the subsidized cost of e85 at $3.15 per gallon compared to $3.75 for regular. Flex fuel system adjusts well enough for the difference in fuels, but the e85 would have to be about $2.50 per gallon to make it worth while.

E85 is not available around here, all just e10 and RUG (regular unleaded gas). The spread between those two should be closer, or at least I hope. I Can run RUG, my concern is that I've been running e10 regular in my m104 for so long, it won't compensate for the small increase in energy per gallon, and the money would be waisted.