sloanben

Premium gas costs so much more than regular. Has anyone here switched to regular? Any noticiable decrease in power? If so, was it worth the savings?

RRxGrasshopper

Your car will run like POO POO, Dont put regular gas in your car, I dont think it will damage the engine, but MB recommends premium and thats all I put in from now on. Tried to save a little money but the performance just wasnt there and the car ran like crap. Garbage in Garbage out.

Quicktwinturbo

u gotta pay to play bratha~~

FrankW

CA gas already suck. you're risking your car if you want to run on lower grade gas. they don't burn off efficiently as it is.

deltadude388

Ok, this doesn't make sense. You are trying to save money, at most 200-300bucks no matter how you slice and dice it, that's the approx savings a year by going from premium to regular. No disrespect but if you have a problem spending the xtra 20bucks a mth on gas you need to re-evaluate yr choice of rides.

MercedesFTW

Yeah...do the math, you aren't saving much at ALL.

They recently said, for the E320 CDI, or is it blutec now? you need to drive the car for 5 years, to see the money savings over the 350. The E320 costs a little over $1000 more than the 350.

Sell your car to someone who deserves it and go by a hybrid.

kjb55

Not in a million years. Premium and preferably BP, Mobil or Shell.

DarkXerox

I just did the math, but yeah there is a $1k MSRP hike.

Say you drive 15k miles a year, your fuel costs would be as follows:

The E320CDI (MSRP $52,325) (per mbusa) gets 26mpg EPA estimate. That would be about ~577gal/year to go 15k miles. 577* $3.15 (price of diesel near my house) = $1,818

E350 (MSRP $51,325) gets an EPA estimate (per mbusa) of 19mpg. That would be ~770gal/year at ~$3.75 for premium (price here again)= $2,960.

So if you drive a lot, it would break even in a year. If you drive a little, you'll break even in 2.

But to reiterate what people said: you should not have a C32 if you care about fuel economy.

FrankW

sad part is Diesel is more expensive than Premium gas. The saving for driving the diesel compare to the gasline isn't all that great like you said. The only thing that will save you anything is a full-on EV.

Fifth Ring

You have to consider resale value. I am willing to bet that a 4 year old CDI is going to sell for $1,000 more than a 4 year old 350. Ignoring time-value of money, it's like a free ride.

I'm looking at the GL diesel. Putting aside fuel efficiency, it's a high-torque engine that matches the big SUV mission. Get me off the line quick, and then be as efficient as possible.

PS: Regarding using regular gas in a C32 -- why not give up one Starbuck's Coffee visit each week? Better for you and the car.

FrankW

I don't think diesel power will get you off the line quick mainly because most diesel revs slow even tho they produce a lot of torque. to a comparable gasoline engine the one using gas will still be quicker with less torque. Top Gear did that 550i vs 550d test a while back.

Fifth Ring

Torque is torque. It doesn't matter what the revs are, particularly since MB has gone with 7 speed transmissions. Only a test drive will tell. It's hard to find published data, but it looks like the GL450 goes 0-100 Km/Hr in about 7-7.5 seconds while the GL320cdi does it in about 9.5. I would love to see 0-30 numbers since that accounts for 95% of the average soccer mom's driving.

No doubt the GL450 is a screamer as huge SUVs go, and it makes the diesel look that much worse by comparison. If I compare the GL320 to a Land Rover LR3, the diesel performance deficit just about disappears; and amazingly, the GL320 may be cheaper!

jacek9478

Absolutely NO!!!!
I didn't do that to my car but my Wify ( drives 02 Mitsu Montero - also recomends high octane fuel ) did fill up w/ regular (full tank ). 2 minutes after she started engine dashboard lighted up like Christmas tree. ECU went freeking crazy. I ended up dumping all gas out (talking about saving money ) and refueling twice b4 I went to dealer to get the rest fixed. I was lucky that car was on recall list for fuel pump and thats what got blamed for CEL.

Trekman

to solve your problem with the gas. sell the C32 and buy a honda civic or a toyota corola. you will get better gas milage and you can put arco gas 87

flush

speaking of Arco gas, I've seen so many decent cars (M5s, 6) getting filled up at my nearby Arco (closest gas station to where I live, never used it, I drive all the way to a Shell or Chevron) .... I wince each time.

sloanben

Thanks for all the opinions. Only one person who answered has tried it and I guess there was a noticeable drop in power. I'm surprised anyone expects damage to the car. It would surprise me if the ECU was that unsophisticated.

Has anyone else run for long on regular?

ScottW911

I don't use Arco but would not wince at anyone with a nice car doing so. Arco is owned by BP now. Even before that, Arco has been ahead of the curve on refining innovations and additives. Here is So. Cal., Shell and Chevron were playing catch-up to Arco through most of the 80's and 90's. Arco is usually cheaper because they got rid of their finance arm back in the early 80's. One of my business school professors was a consultant to Arco then. He recommended the cancellation of all Arco credit cards and lowering prices to increase their market share. It seems to have been a modest success.

Slater126

Don't do this. You won't save much money and the car will not run right (and may actually use more of the cheaper fuel). I understand your pain over high fuel costs, believe me, but this isn't the way to go about it. Our C32, sadly, has been demoted to second string on our car roster due to high gas prices. I can only manage 16 MPG in our mix of driving, which is pretty bad if you think about it -- large SUV territory really. Our Acura RSX Type-S gets 26 MPG average in the same conditions. So since my wife has a much shorter commute than I do, I took the Acura, and we saved about $70/month doing that. And it keeps the mileage on the C32 down too.

newton22

Running regular fuel on a car designed for premium may cause the motor to ping later on.

For this reason, Mercedes' ECUs automatically retard the ignition timing to accompany the lower grade fuel. Retarding ignition timing can significantly reduce maximum output power as well as decrease fuel economy.

Even with the smart ECU, you are risking motor ping. And pinging DOES damage the engine.

Your call. I'd strongly recommend staying with premium.

ScottW911

Captain Obvious says, "MB says not to do it. I am going with what they say." I do carry some octane boost in my trunk for the times I might not be able to acquire Premium.

The ECU can compensate for some lower octane, but here in California, the risk is just too great. Why risk thousands to save pennies?

Fifth Ring

ECU will retard ignition as much as possible to prevent detonation; but even that has its limits. If you happen to pick up a bad load of 87 octane, you might be at 84 octane and that may be beyond the ECU's ability to adjust. At least if you start at 91 (or 93) octane, you have some room for error.

SolidGranite

I can't believe this thread exists.

Bottom line, you could cost yourself way more money due to engine damage than the savings received on cheaper fuel. Mercedes will be able to tell if less than premium was used on the car and they will not honor warranty work.

sdsilverm3

Why did you buy yourself a car that requires PREMIUM gas?

power-fade

ditto

Harry Madan

+1
it only costs $4-7 more per tank, with premium fuel, really not that big of a difference. and it is clearly stated before u buy ur car that ur car will require Premium if u thought that was going to be a problem that u really need to be looking into getting a different car.
In Canada we can get 94 that is even more $$ then 91 octane but if u do the math it the most u dont pay anything more then $10 per tank.

if u put in 87 gas ur engine will starts knocking in time and u'll get predestination then u'll will be paying a $$$$$ cost to get the car fixed.