2.47 in 300SE - Page 11 - PeachParts Mercedes-Benz Forum

Brian Carlton · #**151** 05-17-2013, 10:40 AM

Quote:

Originally Posted by pawoSD

On long trips in my 420 I usually see about 22-23 hwy on cruise at 75mph....and 20-21 with A/C on.

The EPA rating for the 420 is 17 on the highway...........and that's nothing above 62 mph.

I'll let the forum make the obvious conclusion regarding your results.

pawoSD · #**152** 05-17-2013, 01:10 PM

Quote:

Originally Posted by Brian Carlton

The EPA rating for the 420 is 17 on the highway...........and that's nothing above 62 mph.

I'll let the forum make the obvious conclusion regarding your results.

I guess the EPA is wrong then.

Last summer we drove from here in GR, MI to Toronto, ON did a bunch of driving around in the city there, and drove all the way back, on approx 43 gallons of premium fuel. In the US I was doing about 74mph, in canada about 60-65mph, so about half/half.

MPG results were about 20.93 for the trip overall. I never see less than 15 city, and usually about 21 highway. My dad has a 420 also, and usually sees 16 city/24hwy. He has an open flow exhaust however.

My wife's 300E M103 would get 18 city 23 highway, and that is a lighter vehicle than a Long wheelbase W126 by far.

I bet with a megasquirt conversion on a M103 you could see mid to upper 20's freeway, but not with the antique CIS injection....it wastes a ton of fuel.

compu_85 · #**153** 05-17-2013, 03:54 PM

I know VW guys who convert from CIS or the batch fired electronic system they went to in 1988 (Digifant) see a nice bump in economy. I recall reading one guy who went from Digifant to MegaSquirt went from 28 mpg on the highway to 36

-J

pawoSD · #**154** 05-17-2013, 05:10 PM

Yep, the M103, M116 and M117 are all great motors hindered by an outdated fuel injection system. Seems to have the worst effect on the M103...It was much more of a pain to keep that motor running correctly than the M116's we now have in our fleet.

Brian Carlton · #**155** 05-18-2013, 10:17 AM

Quote:

Originally Posted by pawoSD

My dad has a 420 also, and usually sees 16 city/24hwy.

Does you Dad know the fellows on the BMW forum? They all get 29 mpg on the highway with their E38's and they swear that your vehicle is not in proper tune when you get 22.

This is a 4400 lb. sedan with giant 16 tires and a 4.4L V8.

neanderthal · #**156** 05-19-2013, 03:46 AM

Quote:

Originally Posted by Brian Carlton

The EPA rating for the 420 is 17 on the highway...........and that's nothing above 62 mph.

I'll let the forum make the obvious conclusion regarding your results.

95 E320 Sedan
EPA 18 city. 20 combined. 24 highway.

Currently averaging 23.48 combined.

And that's with having lost most of my fuel economy data when my phone crashed and I had to do a hard reset. (I use an app on the phone.) Prior to the crash it was in the low 25.XX mpgs.

EPA estimates are only accurate if you drive exactly like they do. Hypermile, add more freeway driving, use some common bloody sense, and it's easy to beat the EPA estimate. I do consistently.

Your results may vary.

Edit. Testing the link after I posted, I used the "personalise" link and adjusted the slider to reflect my typical milage (~20k a year) and road type (90% freeway) and it came out to 23mpg.

oldsinner111 · #**157** 05-19-2013, 06:33 AM

If anything for my car,I'd rather have a faster rear end.You can't drive over 85 legal here.I'd rather cruise at 75.But get there faster

Brian Carlton · #**158** 05-19-2013, 08:34 AM

Quote:

Originally Posted by neanderthal

95 E320 Sedan
EPA 18 city. 20 combined. 24 highway.

Currently averaging 23.48 combined.

And that's with having lost most of my fuel economy data when my phone crashed and I had to do a hard reset. (I use an app on the phone.) Prior to the crash it was in the low 25.XX mpgs.

EPA estimates are only accurate if you drive exactly like they do. Hypermile, add more freeway driving, use some common bloody sense, and it's easy to beat the EPA estimate. I do consistently.

Your results may vary.

Of course you can beat the EPA results. I do it all the time with the SD.

However, what you cannot do is to drive the vehicle at 70-75 mph and beat the highway fuel rating by 30%. That is simply impossible.

When you refer to "drive exactly like they do", do you understand what they do and the tests that they perform?

pawoSD · #**159** 05-19-2013, 09:47 PM

Quote:

Originally Posted by Brian Carlton

Does you Dad know the fellows on the BMW forum? They all get 29 mpg on the highway with their E38's and they swear that your vehicle is not in proper tune when you get 22.

This is a 4400 lb. sedan with giant 16 tires and a 4.4L V8.

Well I know I certainly don't get 17mpg on the highway, if that was the case then on my trip to Canada I would have needed to fuel 3x for the distance I covered. I fueled twice, and arrived home with 3/4 tank. So 21ish mpg it is.

Full flow exhaust helps the mpg, he saw almost a 2mpg gain on the highway, city was negligable....usually sees about 16.

The 500 and 560 drink fuel, but the 380/420 strike a balance with much more torque (247ft/lb available lower vs. 192) and less straining than the M103, leading to equal if not better MPGs especially on the highway. Driving around the city in my 420 I can stay between 1000 and 1800rpm all day long and have decent acceleration. The M103 is gutless below 2500.

neanderthal · #**160** 05-19-2013, 11:33 PM

Quote:

Originally Posted by Brian Carlton

Of course you can beat the EPA results. I do it all the time with the SD.

However, what you cannot do is to drive the vehicle at 70-75 mph and beat the highway fuel rating by 30%. That is simply impossible.

When you refer to "drive exactly like they do", do you understand what they do and the tests that they perform?

Yes I do. And it's nothing like the driving that I do. Or most people (i reckon) in fact.

Brian Carlton · #**161** 05-19-2013, 11:39 PM

Quote:

Originally Posted by neanderthal

Yes I do. And it's nothing like the driving that I do. Or most people (i reckon) in fact.

Apparently, you don't.

The highway fuel economy test is relatively benign and stays below 60 mph throughout the test.

Most people (I reckon) drive faster than the EPA highway test and suffer reduced mileage because of it.

Brian Carlton · #**162** 05-19-2013, 11:42 PM

My first fuel results are in:

476 miles on 21.75 gallons.

21.9 mpg for the first tank. 20/80 city/highway.

I was hoping for better.............

Brian Carlton · #**163** 05-19-2013, 11:43 PM

Quote:

Originally Posted by pawoSD

I fueled twice, and arrived home with 3/4 tank. So 21ish mpg it is.

Excellent. Nothing like good data to support your claims.

Brian Carlton · #**164** 05-19-2013, 11:48 PM

Quote:

Originally Posted by pawoSD

Driving around the city in my 420 I can stay between 1000 and 1800rpm all day long and have decent acceleration. The M103 is gutless below 2500.

The M103 in the SE is perfectly fine between 1800 and 2500. It accelerates more than decently and is considerably faster than the SD in this range.

It's not going to perform a 0-60 in 6 seconds, but that's hardly necessary.

The only "gutless" situation is a second gear start with the 2.47. Everything else is excellent. The new setup is shorter than stock in gears 1-3. I realize you don't understand that.

pawoSD · #**165** 05-20-2013, 08:54 AM

A higher stall torque converter would likely be ideal for this setup, I have one in my SD and it transforms the car's driving characteristics.