2008 Mercedes-Benz C300 Sport: Flex fuel capable
Who says GM is the only one promoting E85? Our new Mercedes-Benz C300 long termer asks for either premium unleaded or E85 ethanol. It even has a yellow fuel filler cap like our old Tahoe.
This struck me as odd given that I haven’t heard a word about the C300’s flex fuel capability despite sitting through numerous press briefings on the latest C-Class...
It’s an interesting alternative given Mercedes' requirement for premium gasoline.
Then again, with the nearest ethanol station over hundred miles away, our C300’s ability to burn it won’t matter much. A closer station is expected to open up soon. Until then, we’ll be paying for the top shelf stuff to keep our new Benz running clean.
Ed Hellwig, Senior Editor, Inside Line
- Permalink | Comments (16)
- Posted by: Ed Hellwig December 6, 2007, 3:51 PM
- Categories: 2008 Mercedes-Benz C300 Sport
I've never seen the cold tire pressure information on the gas cap door before, although I'm not sure I like it. I don't know about most people, but I always fill my tires at home, when they're cold. Since I don't live next to a gas station, this would just make me pop the filler door every time I'd want to check the tire pressure. JMHO.
The E85 option is interesting though, and I'd be curious to see how it performs in a more performance oriented engine versus the Tahoe's V8.
I'd be surprised if there was any performance difference, just poorer mpgs. Why did MB do it? They get a CAFE mpg bump for all flex fuel vehicles.
I'm surprised a car that requires premium can even run E85.
I think that's pretty cool that the inflation pressures are listed on the fuel door. It's a good reminder to check your tires every time you fill up!
Actually estreka E85 has higher octane than premium. E85 ranges from about 100-105 octane but it really doesn't matter because it's all well above the 91-93 offered by premium. E85s high octane is why some cars can be tuned to run on it and get a large performance boost. The Koenigsegg and that concept from Lotus are two examples.
I think that if flex-fuel engines were flexible to control ignition and valve timing to take advantage of that extra octane you wouldn't see as much of a fuel economy hit running E85. I guess you would really need variable compression ratio to truly use E85 to its full potential though.
It would be interesting to see the MPG/$ ratio of the Benz with e85 vs. premium gas. As everyone knows, the cheaper price of e85 usually does not offset the lower mpg, depending on your local e85 price. But that is based on regular gas. Versus premium gas, it might just be worth it, resulting in lower operating costs.
Just a thought.
GM's "flex fuel" ad campaign has been effective to the point that most people don't realize there are a lot of other E85-capable vehicles out there, and have been for years. (The Ford Taurus and Ranger, and Dodge Caravan come to mind, back before GM made their own...) Goes to show you the difference between successful and unsuccessful (or nonexistent) marketing.
Yep, I agree with texases, the very likely reason is so that they Mercedes get a boost towards their CAFE numbers and avoid (or pay lower fines) for not meeting fuel economy standards.
From http://www.consumerreports.org/cro/cars/new-cars/ethanol-10-06/the-problem-with-ffvs/1006_ethanol_ov3.htm (you'll need a subscription to see this):
"In determining the credit, the government assumes that an FFV will run on E85 half the time and on gasoline the other half. For CAFE purposes, the E85 half is calculated as using only the 15 percent that is gasoline. So the government rates FFVs at about 1 2/3 times the fuel economy that they actually get on gasoline, even though the vast majority may never be run on E85 at all. A two-wheel-drive version of our 2007 Tahoe, for example, would normally be rated for CAFE purposes at 21 mpg. But because it’s built to run on E85, it’s rated at 35 mpg instead."
In CR's testing, the above mentioned Tahoe got 14 mpg overall on gasoline and 10 mpg overall on E85.
And yes, E85 has a higher octane rating than premium gasoline.
Never mind that the government's assumption of 50% E85 usage is patently absurd. . . it still plays Corn Belt politics very well.
The only way to get a big performance gain from E85 is to really increase the compression ratio, but then you could only use E85.
Yeah, texases, and you could only drive it in Iowa and Illinois.
While premium and E85 can take a great deal of pressure before they combust (octane), premium has a great deal more energy than the mediocre E85. Because of that, you need more E85 per combustion cycle, hence the poor mileage.
If you used only E85, the mileage could be regained with an extra-high compression ratio. Flex fuel vehicles just aren't the way to go. Running E85 on an engine designed to run on normal gasoline doesn't do it justice at all.
theres an e 85 station off of san vicente next to cheescake factory - its called conserv and etahnol is under 3 bux a gallon.
I have a 6MT and I can't use E85. I guess they fiure the mileage with a manual transmission is good enough. It is very good.
I run E85 in my 1990 volvo 740. I get 21 with e85 and 24 with gas, so i think im saving about 5 cents a mile with e85.