Mercedes-Benz Forum banner

1 - 20 of 41 Posts

·
Registered
E420
Joined
·
111 Posts
Discussion Starter #1
We all love and enjoy our Benzes. It’s agile and smooth with all the power on tap but I think it’s time for us to share some tips on how to enjoy our Benzes while on the other hand save some gas.
Lately I really avoid having a jack rabbit start and on the freeway always maintaining 2500rpm and hoping to get some significant mileage increase.

So should these step help??:
• Lower fuel octane rating one step from 91 to 89
• Change to more efficient air filter
• Slightly inflate tire air pressure above recommended number

Have a good Benz day….
 

·
Premium Member
2001 E320 - Brilliant Silver/Ash: 107,000+
Joined
·
17,193 Posts
I have always used at least 30psi in this car, sometimes 31 or 32 and I think that will help. I have seen some people write that they like using the K&N air filters, but I know nothing about them. I would not use less than 91 octane, even if you drive moderately.
 

·
Registered
1997 E320, 1997 S320
Joined
·
2,946 Posts
i agree with musikmann, i wouldn;t put anything less than 91 octane. i actually have compared 91, 92, 93, 95 octane from different quality brand gas stations, and i get a better gas mileage with 92 octane from bp. i would never put 89 in my tank, because it has 10%ethanol, i actually would feel safer putting 87 instead. also i keep my tire pressure close to the minimum (27psi front, 29psi back) because at lower pressure it drives smoother.
but whatever gets done, i don't think it will improve considerably the gas mileage.
 

·
Premium Member
2001 E320 - Brilliant Silver/Ash: 107,000+
Joined
·
17,193 Posts
Tirona, you are lucky to be able to buy so many 91+ octanes where you are. As far as I know, all of the name brand stations here only offer 87, 89, 93. I have seen 92 at a small chain called Go-Mart but I do not know where that gas comes from. I actually got a bad tank of it for another car and I have been afraid to use it since. There is a BP close by and I will check what octane their high test is today. For what this is worth, I refuse to use any gasoline with ethanol either.
 

·
Registered
SLK320, MKV Jetta TDI, Mini Cooper S, Lincoln Mark LT
Joined
·
1,712 Posts
Frankbenz said:
hoping to get some significant mileage increase.

So should these step help??:
• Lower fuel octane rating one step from 91 to 89
• Change to more efficient air filter
• Slightly inflate tire air pressure above recommended number

Have a good Benz day….
Why would one think that lower octane gas would help with fuel economy? All that would do is give you less power because the ECU will adjust the timing to keep it from knocking.

As far as the 3 different Octane ratings at the gas pump, there are only 2 tanks under ground at most stations. The station gets 87 and 91. To get the mid-grade 89, the pump cycles back and forth to give a 50/50 mixture between 87 and 91.

Make sure that you air filters are cleaned or replaced every 10K miles. The filters can be taken out and blown off with an air compressor but it is just as easy to replace them.

Keep the air pressure in the tires at the factory spec posted on the car. It will help save gas and tire wear. Under inflating may give you a softer ride but will waist more gas.
 

·
Registered
1997 E320, 1997 S320
Joined
·
2,946 Posts
musikmann, in my town shell is the only one that has 93 octane, bp has 92, and the other stations like connoco/phillips etc. usually have 91. only one gas station carries 95 (forgot the name), but i got lower gas mileage with the 95 octane (???). a while ago, my girlfriend at the time had my car and she put 87 instead of premium, and i did get a considerable lower gas mileage, but i don't think 87 can do any major damage, but i don't like the 89, which is 10%ethanol (or at least in my town 89 has 10%ethanol)
 

·
Registered
E420
Joined
·
111 Posts
Discussion Starter #8
I don'y even know that there are 93 and 95 out there, I always go to the nearest gas station and what they have is only 87, 89 or 91.
So far I got 3 tanks of 89 and don't feel the difference except a few cents less per gallon. How could ethanol harm your engine or performance?
 

·
Registered
E420
Joined
·
111 Posts
Discussion Starter #9
Musikmann, I read in this forum that K&N could harm your MAF due to the oil it uses. and because MBz's MAF are so sensitive, I dare not to try. On the other hand I used it on my Toyota which uses MAP instead of MAF and I could feel the difference, engine will rev easier, slight gas mileage improvement and better pick up
 

·
Premium Member
2001 E320 - Brilliant Silver/Ash: 107,000+
Joined
·
17,193 Posts
Ethanol

Frankbenz said:
How could ethanol harm your engine or performance?
I don't know that it does, it is just my personal preference to use a purely petroleum fuel. I think this subject has been discussed ad nauseum on these various sub-forums. Sooner or later, we might not have a choice.
 

·
Premium Member
2001 E320 - Brilliant Silver/Ash: 107,000+
Joined
·
17,193 Posts
K&n

Frankbenz said:
Musikmann, I read in this forum that K&N could harm your MAF due to the oil it uses. and because MBz's MAF are so sensitive, I dare not to try. On the other hand I used it on my Toyota which uses MAP instead of MAF and I could feel the difference, engine will rev easier, slight gas mileage improvement and better pick up
I agree with you, and I have not seen a strong enough argument to use them in my MB either. However, I also have a Toyota, so I might look into K&N for that car.
 

·
Registered
SLK320, MKV Jetta TDI, Mini Cooper S, Lincoln Mark LT
Joined
·
1,712 Posts

·
Registered
1997 E320, 1997 S320
Joined
·
2,946 Posts
first of all you will get worse gas mileage with a ethanol blended gasoline, because of their energy content difference. ethanol is a solvent that can dissolve rubber or plastic, also ethanol blended gasoline absorbs water a lot more faster andits life is a lot shorter than regular gasoline. one mechanic once told me that most of the fuel pumps he had changed on different brand cars, their owners were using the ethanol blended gasoline.
 

·
Premium Member
2001 E320 - Brilliant Silver/Ash: 107,000+
Joined
·
17,193 Posts
Good point Tirona, apparently the BTU content is lower for ethanol than it is for pure gasoline. I think it's primary purpose is to "stretch" the higher-priced gasoline out by that 10%. I also feel that it is not good for our gaskets and seals but be prepared for an argument if certain people see us saying that! ;)

I suspect that the greater affinity of water for ethanol is the reason that mechanic noticed ethanol fuel pump problems. Most of them are in the fuel tanks these days, so more water is all around them, plus going through them. As far as I know, water is an enemy of a fuel pump.
 

·
Registered
96 and 08 911 turbos
Joined
·
2,988 Posts
E-Klasse said:
Why would one think that lower octane gas would help with fuel economy? All that would do is give you less power because the ECU will adjust the timing to keep it from knocking.
.
Actually it would. Most cars that are only supposed to use 93 are not tuned at max spark advance for such octane. That results in unburnt fuel, and wasted energy.

The lower octane fuel burns faster, and as such, at the same timing level (which should be possible with 89, perhaps not with 87), more fuel will be burned, giving slightly lower fuel consumption.
 

·
Registered
1996 210.020
Joined
·
3,972 Posts
OliverK said:
Actually it would. Most cars that are only supposed to use 93 are not tuned at max spark advance for such octane. That results in unburnt fuel, and wasted energy.

The lower octane fuel burns faster, and as such, at the same timing level (which should be possible with 89, perhaps not with 87), more fuel will be burned, giving slightly lower fuel consumption.
Octane is not a rating of the speed of combustion. The idea that low-octane fuel burns faster is a myth.

Octane is a rating of resistance to combustion ignition, and nothing else.
 

·
Registered
E320/E250 Bluetec Ford F350 6.7l
Joined
·
36,348 Posts
In old days, when cars didn't have knock sensor, I had to put 78 octane gasoline into Fiat rated for 96 octane.
It surprised me at next fill up, that the gas mileage increased, but after analyzing that come clear. I am the rare driver, that is actually listening to the engine. When I heard knocking, I back off my foot from gas pedal. The result was lower consumption.
 

·
Registered
1999 E320, 1975 450SEL, 1979 280SE
Joined
·
373 Posts
gas mileage, octane

Hi all,
New owner here. I recently purchased a 1999 E320. I live in PA, but had to drive to Florida to trade a car in and pick up the Benz. The E320 is a one owner, older couple, no smokers or kids, 61k mile car. I used mid grade all the way back from Florida. None of the pumps that I filled from listed ethenol in the fuel. The power from the 89 octane was fantastic and I averaged well over 30mpg, with A/C going and driving well over 70 mph whenever I could. I am very pleased with the car, the power, and the economy. Here on the east coast, all we seem to be able to get is 87, 89, or 93 octane fuel. I feel that I will continue to use the 89 octane fuel as I seem to be having good results. I did have the left rear window regulator go on me right after I picked up the car. Yes, it sounded just like breaking glass! But, thanks to this forum, I know how to replace it. I hope to participate in this group for a long time. I also have three 116 chassis cars; a 1975 450SEL, a 1975 280S, and a 1979 280SE.
Best regards, Peter
 
1 - 20 of 41 Posts
Top