GDE fuel economy

LibertyCRD · **Posted:** Sun Feb 14, 2010 4:01 pm

OK, so that tank worked out to 20.49 MPG. That's about 0.0-0.5 MPG better than what the previous 3 tanks were. This tank is a "fresh" tank of Flying J truckstop diesel...and judging by the EVIC I'm down to about 19 MPG right now, despite more highway driving than average so far! (My typical drive is 50/50 city/highway and very conservative) :shock:

It's still early...but it appears that this tank is going to be even worse than the Walmart diesel.

After I try the Flying J...I'm going to try some BP diesel.

RJM · **Posted:** Sun Feb 14, 2010 5:38 pm

geordi wrote:

vtdog wrote:

My experince over the 5 winters I have had the car is about 2-3 mpg down in winter. Some of the drop is due to the blend, but some is due to cold temps not allowing engine to get to full operating temp. In mild-hot weather my temp gauge shows 11:58. In cold temps it is down around 11:55 no matter how far/long I drive.

Mine too, and I have been toying with making a grille blanket as a test to see if that helps get the engine warmed up any further. Without towing to load the engine... I don't think it is working hard enough to get to its most efficient temps. And my MPG hasn't been that great this winter either, down around 20 or so. Part of that should be b/c of the air sensor... But that is still a huge drop.

I have winter grill inserts, makes no difference mileage wise, no noticable change in engine /cabin heat

flman · **Posted:** Sun Feb 14, 2010 7:14 pm

RJM wrote:

I have winter grill inserts, makes no difference mileage wise, no noticable change in engine /cabin heat

x2, had them on my 1992 E-350 van many moons ago, they did not make a difference. Just help keep the road salt out of the radiator.

geordi · **Posted:** Sun Feb 14, 2010 7:53 pm

Is it a screen, or a solid vinyl blocking panel?

I was thinking about a solid panel.

RJM · **Posted:** Sun Feb 14, 2010 8:50 pm

geordi wrote:

Is it a screen, or a solid vinyl blocking panel?

I was thinking about a solid panel.

Solid block S.S. covering all 5 grill openings and the long one on the bottom. Looks good does nothing.
An old beer box and two zip ties will do the same.

LibertyCRD · **Posted:** Thu Feb 18, 2010 10:45 pm

I did some more calculating and figuring today, and this is what I came up with: The GDE HOT tune actually appears to be increasing my fuel economy by 10-15%. Once I factored in odometer error before and after my tire size change, and took into consideration the typical 2 MPG lost with non-stock tires, it appears that I've actually gained about 2 MPG with the tune if not just a little bit more. So in the real world...I've actually picked up 10-15% in fuel economy.

I would guess that in warm weather this Summer, the increase could be a little more. In any case...I'm still testing but for now it appears that my increase was a little more than originally thought.

dgeist · **Posted:** Thu Feb 18, 2010 11:06 pm

LibertyCRD wrote:

I would guess that in warm weather this Summer, the increase could be a little more. In any case...I'm still testing but for now it appears that my increase was a little more than originally thought.

Feeling better about the investment, I assume :wink:

NIce to know that when it's all on the line, we can always depend on math for the truth.

Dan

LibertyCRD · **Posted:** Fri Feb 19, 2010 11:47 am

dgeist wrote:

LibertyCRD wrote:

I would guess that in warm weather this Summer, the increase could be a little more. In any case...I'm still testing but for now it appears that my increase was a little more than originally thought.

Feeling better about the investment, I assume :wink:

NIce to know that when it's all on the line, we can always depend on math for the truth.

Dan

Absolutely. What happened was, my speedometer was 1 MPH too fast stock. After my tires it was 1 MPH too slow. So when I went back into my spreadsheet and subtracted 2% before the tires, and added 2% after the tires to compensate...it changed things around some. Also, I'm going on the assumption that I lost 2 MPG with the tires. No hard evidence there...but generally that is the loss so I'm using 2 MPG as an assumption.

So, if I lost 2 MPG with the tires, and then adjusted for odometer inaccuracy...what I come up with is that my mileage is exactly the same with tires+GDE as it used to be with stock tires+stock ECU. Therefore, GDE isolated by itself was probably responsible for at least a 10% increase in mileage.

Still really want to get this thing in some warm weather and see how it does. Very anxious...

evolDiesel · **Posted:** Sun Feb 21, 2010 2:48 am

I've only run 2 tanks since getting my GDE Hot tune ECU back, but I'm up 4 MPG, its spools and responds faster, fuel guage gives me nice linear results now, and CEL.. goodbye (yes!). You really notice it between stop lights. You won't find a better CRD improvement for $550. Its crime not to sell these rigs with this ECU.

BVCRD · **Posted:** Sun Feb 21, 2010 12:45 pm

evolDiesel wrote:

I've only run 2 tanks since getting my GDE Hot tune ECU back, but I'm up 4 MPG, its spools and responds faster, fuel guage gives me nice linear results now, and CEL.. goodbye (yes!). You really notice it between stop lights. You won't find a better CRD improvement for $550. Its crime not to sell these rigs with this ECU.

DC was just trying to save the vehicle from repairs. If they baby this thing, maybe it will last longer....that sort of thing. Dollars and sence.

LibertyCRD · **Posted:** Sun Feb 21, 2010 5:02 pm

This tank of "fresh" Flying J truckstop diesel returned 19.45 MPG.

I filled up at a BP this time...going to give it a try. If I was doing 90% city driving I'd be OK with that. But realistically I spend quite a bit of time on 55 MPH highways.

I checked both front brake calipers...took them off and checked to make sure they are greased up good. No signs of dragging so far.

StanCRD · **Posted:** Tue Mar 02, 2010 1:23 am

Your mileage was almost identical to mine when I had a leak in the intake system and was losing boost. Power seemed to be good but the mileage was crap.
Maybe you should have a really good look at the hoses, connection points and the intercooler. One member on the board had a defective intercooler that was leaking. On my CRD the CAC hose was not connected properly from the factory and created a leak only under a good load. my mileage went from 18mpg to almost 27mpg when I fixed the leak, and this is with freezing temps right now, I expect it to improve as our weather warms up.

LibertyCRD · **Posted:** Tue Mar 02, 2010 11:44 am

StanCRD wrote:

Your mileage was almost identical to mine when I had a leak in the intake system and was losing boost. Power seemed to be good but the mileage was crap.
Maybe you should have a really good look at the hoses, connection points and the intercooler. One member on the board had a defective intercooler that was leaking. On my CRD the CAC hose was not connected properly from the factory and created a leak only under a good load. my mileage went from 18mpg to almost 27mpg when I fixed the leak, and this is with freezing temps right now, I expect it to improve as our weather warms up.

How does one go about checking that?

evolDiesel · **Posted:** Tue Mar 02, 2010 12:40 pm

StanCRD wrote:

Your mileage was almost identical to mine when I had a leak in the intake system and was losing boost. Power seemed to be good but the mileage was crap.
Maybe you should have a really good look at the hoses, connection points and the intercooler. One member on the board had a defective intercooler that was leaking. On my CRD the CAC hose was not connected properly from the factory and created a leak only under a good load. my mileage went from 18mpg to almost 27mpg when I fixed the leak, and this is with freezing temps right now, I expect it to improve as our weather warms up.

I stumbled on some truly amazing math here guys...

1984 Mercedes 190D
401,000 miles
41 MPG average

2005 CRD
49,800 miles
22 MPG average

Apparently we lose approximately 1 MPG for every production year.

Someone please show this to the "greenies" and let them know that emissions is not solving the problem. It's only making us burn more fuel

BVCRD · **Posted:** Tue Mar 02, 2010 1:02 pm

If we ran as dirty as the 190D, we could get 41 also.

http://cgi.ebay.com/ebaymotors/1984-Mer ... 3caaa4d81b

GreenDieselEngineering · **Joined:** Sun Jun 07, 2009 5:10 pm **Posts:** 1111

The discrepancy relates more to the rolling mass of the vehicle, the merc is most likely around 1000lb. less than the jeep, no 4WD system, street tires and a better coefficient of drag. If you compared the merc with a new VW Jetta diesel (roughly same engine size), then the fuel economy is about the same.

From an emission standpoint, lower regulated emissions equals more fuel usage. In the US our main issue is CO2 is not regulated and it is virtually everywhere else in the world. Once America's new fuel economy laws are enforced (2014+) we will start to see a shift in the types of vehicles produced. The problem with that is how many people really want a little car and less utility??? In the future we may all have little commuter vehicles for the work week and our big haulers for the weekend.

BVCRD · **Posted:** Tue Mar 02, 2010 2:58 pm

I doubt that it is costing us 20+ mpg to haul around an additional 1000 pounds. We loose some through aerodynamics, and 4x4 like you said. The rest I believe is taken away by the brains.

CATCRD · **Posted:** Tue Mar 02, 2010 4:03 pm

The Mercedes is also running about a 22:1 compression ratio, making it more efficient. The EPA won't let you do that anymore.

evolDiesel · **Posted:** Tue Mar 02, 2010 6:06 pm

The MB 190D is lighter, tires have lower mass & lower rolling resistance, RWD, no turbo (90Hp when it was new), 5 speed transmission... but the CRD has 20 more years of technology? So, does it seem reasonable, even when comparing apples (MB) to oranges (CRD) do we get a vehicle with 1/2 the fuel economy as one from 20 years ago (not to mention 350,000 more miles on her).

I guess what I'm saying is that "22 MPG" would taste good if it were a truck, but this is a 4-cyl diesel. This thing should do better. I bet if Toyota has a 4-cyl tacoma it gets 30+.

BVCRD · **Posted:** Tue Mar 02, 2010 6:18 pm

evolDiesel wrote:

The MB 190D is lighter, tires have lower mass & lower rolling resistance, RWD, no turbo (90Hp when it was new), 5 speed transmission... but the CRD has 20 more years of technology? So, does it seem reasonable, even when comparing apples (MB) to oranges (CRD) do we get a vehicle with 1/2 the fuel economy as one from 20 years ago (not to mention 350,000 more miles on her).

I guess what I'm saying is that "22 MPG" would taste good if it were a truck, but this is a 4-cyl diesel. This thing should do better. I bet if Toyota has a 4-cyl tacoma it gets 30+.

Maybe if Cosworth had developed our heads.......just maybe.

GDE fuel economy

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