GDE fuel economy

LibertyCRD · **Posted:** Fri Mar 19, 2010 9:20 am

http://www.fuelly.com/driver/wxman/liberty

I joined Fuelly. Looks like a good resource. From checking other CRDs...looks like my mileage is pretty common. Makes me feel a little better.

DOC4444 · **Posted:** Fri Mar 19, 2010 2:12 pm

BVCRD,

My experience is that below 45 degrees F, the viscous heater simply runs continuously and eats 2-3 MPG. You can see this for yourself by simply removing the VH relay. (It does not affect anything else and does not throw any sort of code.) My version of the GDE HOT shuts off the VH after about 5 min of running and it does not restart until the Jeep has sat for several hours in the cold. (Combined with a FIA blanket, this works very well in terms of quick warmup and maximum MPGs in cold weather.)

BTW, we are getting 28 MPG on winter fuel (30% kerosene) in 50/50 highway/local driving. I expect it to go back up to 31-32 with summer fuel/temps.

DOC

BVCRD · **Posted:** Fri Mar 19, 2010 2:55 pm

DOC4444 wrote:

BVCRD,

My experience is that below 45 degrees F, the viscous heater simply runs continuously and eats 2-3 MPG. You can see this for yourself by simply removing the VH relay. (It does not affect anything else and does not throw any sort of code.) My version of the GDE HOT shuts off the VH after about 5 min of running and it does not restart until the Jeep has sat for several hours in the cold. (Combined with a FIA blanket, this works very well in terms of quick warmup and maximum MPGs in cold weather.)

BTW, we are getting 28 MPG on winter fuel (30% kerosene) in 50/50 highway/local driving. I expect it to go back up to 31-32 with summer fuel/temps.

DOC

I see that it runs off the belt, but that it also shuts off if passeger compartment demand is gone. So, if you can do without heat in the passenger compartment until the coolant warms up from the engine, it never does come on.

evolDiesel · **Posted:** Fri Mar 19, 2010 4:03 pm

DOC4444 wrote:

BVCRD,

I expect it to go back up to 31-32 with summer fuel/temps.

DOC

Those are some seriously impressive numbers. I have to ask, what tires are you running? How are you calculating your MPG?

Jack

DOC4444 · **Posted:** Fri Mar 19, 2010 5:59 pm

Evol,

Stock size Dunlop Radial Rover ATs @ 38 PSI, cold, hand calculated, multiple tanks.

DOC

evolDiesel · **Posted:** Fri Mar 19, 2010 6:43 pm

Sure would be nice to verify those numbers will a GPS. I have always said these rigs should get beyond 30MPG with mixed driving, but I can't seem to get much beyond 24MPG (even after the GDE Hot Tune brought me up by 3MPG).

I hand calculate and account for the additional circumference on my 20's. I verify against my Garmin and they both hit about 3.5% increase in distance traveled. And when I'm crusing on the highway the CRD will say 60 but the GPS will say 62.x

The GDE Hot tune has got me back in the 400's (miles per tank). I wish I was in the 600's like I was with my 2006 Jetta TDI :wink:

Jack

CRD Joe · **Posted:** Sat Mar 20, 2010 5:50 pm

When I bought my CRD I drove from Nashville to Seattle. The truck was very well taken car of, save some pretty balt tires. I think it was those bald tires that helped me get 746 miles on 19.7 gallons. 37.86 MPG. I folded in the mirrors and took off the antenna. I had an XM set up I was listening to. Thank tank was driven at 60 MPH on cruise for 12+ hours. On that trip had four tanks of fuel. Only one (28mpg) was bad going thru the Colorado rockies. All the other tanks were in the mid 30's.

BVCRD · **Posted:** Sat Mar 20, 2010 8:55 pm

Antenna??? 1st for me.

CRD Joe · **Posted:** Sun Mar 21, 2010 4:36 pm

Anything to try and cut the drag coefficient...... Lol

kapalczynski · **Posted:** Mon Mar 22, 2010 4:06 am

LibertyCRD wrote:

Finally got the CRD out on the Interstate to see just how high I can get the MPG to go. Check this out:

Previous '05 CRD Sport - bone stock. Bought new in May '05. Not even a Provent or EHM...BONE stock. Grabber AT2 tires. 23-24 MPG on my normal driving routine. 26 MPG on the Interstate.

Current '05 CRD Limited - EHM, GDE HOT tune, Grabber AT2 tires. So far 19-21 MPG on my normal driving routine. 26 MPG on the Interstate with A/C off, windows up, cruise set at 70, sunny and 50s outside.

It appears that my mileage isn't improved significantly over a stock CRD. Everything else is awesome....but the mileage hasn't improved much. And I truthfully drive more conservatively now than I did 5 years ago. Age does that to us. I may be seeing 10% improvement at very best if you account for cold weather lately...but I won't know for certain until after the weather has been warm for a while.

All these numbers are hand calculated. EVIC is 2-4 MPG too high with each tank.

Just curious, where are you sitting on your coolant temp gauge after engine is warmed up and you are moving at a constant speed with torque converter locked?

Engine Temp is significant to economy. I live in Colorado Springs, CO where it is routinely 20F* - 40F* outside on my commute (winter) and have been around 20-22mpg to work and back at ~55-65mph mostly highway with cleaned MAP sensor and a brand new intercooler (replaced due to leak). My coolant gauge is usually 154F* according to scanner (roughly 3/8 on the gauge) so I KNOW my thermostat is bad. I am replacing thermostat/waterpump/timing belt next weekend and also getting GDE hot tune so curious to see where I end up.

Keith at GDE recommended I try a 192* thermostat for efficiency when I get my housing design complete.

After waterpump/timing belt replacement and GDE tune, I think I will run the bad thermostat (probably opening at 140-150*), then the 180*, the 192* and post all the temp numbers according to the scangauge and the tank economy results with different thermostat on each tank.

If you can hook up a scan gauge for actual numbers it would be cool to see where exactly you are at, but you can guestimate with the gauge.

The painted in needle is where I am usually at:

Thx GDE for image -

DOC4444 · **Posted:** Mon Mar 22, 2010 8:17 am

Kap,

Please make your thermostat change the last move you make after GDE HOT, etc. This will be much more helpful to many of us who believe higher coolant temps will help mileage. However, the OEM unit appears to be a "two-stage" which makes it all a bit more complicated.

I expect you should see 4-5 MPG improvement with a GDE tune alone.

DOC

BVCRD · **Posted:** Mon Mar 22, 2010 9:34 am

kapalczynski wrote:

LibertyCRD wrote:

Finally got the CRD out on the Interstate to see just how high I can get the MPG to go. Check this out:

Previous '05 CRD Sport - bone stock. Bought new in May '05. Not even a Provent or EHM...BONE stock. Grabber AT2 tires. 23-24 MPG on my normal driving routine. 26 MPG on the Interstate.

Current '05 CRD Limited - EHM, GDE HOT tune, Grabber AT2 tires. So far 19-21 MPG on my normal driving routine. 26 MPG on the Interstate with A/C off, windows up, cruise set at 70, sunny and 50s outside.

It appears that my mileage isn't improved significantly over a stock CRD. Everything else is awesome....but the mileage hasn't improved much. And I truthfully drive more conservatively now than I did 5 years ago. Age does that to us. I may be seeing 10% improvement at very best if you account for cold weather lately...but I won't know for certain until after the weather has been warm for a while.

All these numbers are hand calculated. EVIC is 2-4 MPG too high with each tank.

Just curious, where are you sitting on your coolant temp gauge after engine is warmed up and you are moving at a constant speed with torque converter locked?

Engine Temp is significant to economy. I live in Colorado Springs, CO where it is routinely 20F* - 40F* outside on my commute (winter) and have been around 20-22mpg to work and back at ~55-65mph mostly highway with cleaned MAP sensor and a brand new intercooler (replaced due to leak). My coolant gauge is usually 154F* according to scanner (roughly 3/8 on the gauge) so I KNOW my thermostat is bad. I am replacing thermostat/waterpump/timing belt next weekend and also getting GDE hot tune so curious to see where I end up.

Keith at GDE recommended I try a 192* thermostat for efficiency when I get my housing design complete.

After waterpump/timing belt replacement and GDE tune, I think I will run the bad thermostat (probably opening at 140-150*), then the 180*, the 192* and post all the temp numbers according to the scangauge and the tank economy results with different thermostat on each tank.

If you can hook up a scan gauge for actual numbers it would be cool to see where exactly you are at, but you can guestimate with the gauge.

The painted in needle is where I am usually at:

Thx GDE for image -

So, according to your gauge, the stock setting is around 196*. I can only imagine that as cold as you are running now, with the engine in a constant state of trying to warm itself, you would save a load on fuel costs by getting the thing heated up.

LibertyCRD · **Posted:** Mon Mar 22, 2010 10:09 am

According to that picture...mine runs at 176 when it's a warm day....and just barely below 176 when it's in the 40s and 50s outside.

BVCRD · **Posted:** Mon Mar 22, 2010 10:13 am

LibertyCRD wrote:

According to that picture...mine runs at 176 when it's a warm day....and just barely below 176 when it's in the 40s and 50s outside.

I though that too, but upon looking carefully, mine is at 196. Hard to say since there is 40* in difference between the 12 o'clock mark and the first one to the left.

canlib · **Posted:** Mon Mar 22, 2010 10:25 am

Mine runs at 176 ...just left of 12:00 ....summer and winter (with the Fia Winterfront on)

Rixram · **Posted:** Mon Mar 22, 2010 11:06 am

Hiya fellas.

Quick question:
I'm looking at the GDE Tuners for my "new to me" 2006 KJ CRD (Bought it this past Saturday). The Hot and ECO tunes cost the same, but I'd like some owner feedback as to how going to the Hot tune over ECO, and whether or not there is much of a mileage hit. I need to make sure I get the best mileage possible, and am a fairly conservative driver (speed limits or close, and cruise control, usually).

If the mileage is identical for the Hot and ECO tones, I might as well go with the Hot tune, but if it sacrifices much, then it doesn't make financial sense to go hot.

Your help please? Thanks in advance.

BVCRD · **Posted:** Mon Mar 22, 2010 11:15 am

Rixram wrote:

Hiya fellas.

Quick question:
I'm looking at the GDE Tuners for my "new to me" 2006 KJ CRD (Bought it this past Saturday). The Hot and ECO tunes cost the same, but I'd like some owner feedback as to how going to the Hot tune over ECO, and whether or not there is much of a mileage hit. I need to make sure I get the best mileage possible, and am a fairly conservative driver (speed limits or close, and cruise control, usually).

If the mileage is identical for the Hot and ECO tones, I might as well go with the Hot tune, but if it sacrifices much, then it doesn't make financial sense to go hot.

Your help please? Thanks in advance.

There are other benifits to the GDE tune, but since you mainly mentioned mileage gains, doing the math, (IF) you get 3-4 more mpg, it will take you 30,000 miles before you break even on the fuel savings.

evolDiesel · **Posted:** Mon Mar 22, 2010 11:43 am

Rixram wrote:

I'm looking at the GDE ... and whether or not there is much of a mileage hit.

Rixram,

1.5 months of GDE Hot tune has shown me a repeatable 3MPG gain over prior (21 to 24). I would say my driving mix is close to 50/50.

Good luck,

Jack

Rixram · **Posted:** Mon Mar 22, 2010 12:39 pm

BVCRD wrote:

Rixram wrote:

Hiya fellas.

Quick question:
I'm looking at the GDE Tuners for my "new to me" 2006 KJ CRD (Bought it this past Saturday). The Hot and ECO tunes cost the same, but I'd like some owner feedback as to how going to the Hot tune over ECO, and whether or not there is much of a mileage hit. I need to make sure I get the best mileage possible, and am a fairly conservative driver (speed limits or close, and cruise control, usually).

If the mileage is identical for the Hot and ECO tones, I might as well go with the Hot tune, but if it sacrifices much, then it doesn't make financial sense to go hot.

Your help please? Thanks in advance.

There are other benifits to the GDE tune, but since you mainly mentioned mileage gains, doing the math, (IF) you get 3-4 more mpg, it will take you 30,000 miles before you break even on the fuel savings.

That math works in my favor. I drive 16-17K miles/year and keep vehicles usually for 4-6 years. Being this one is my first diesel, I will likely kept it at least for the 6 years, possibly more.

Rixram · **Posted:** Mon Mar 22, 2010 12:42 pm

evolDiesel wrote:

Rixram wrote:

I'm looking at the GDE ... and whether or not there is much of a mileage hit.

Rixram,

1.5 months of GDE Hot tune has shown me a repeatable 3MPG gain over prior (21 to 24). I would say my driving mix is close to 50/50.

Good luck,

Jack

Thank you for your response.

I may not have phrased myself right. I know there will be a mpg gain with both the ECO and HOT tunes, but what I'm wondering if the mpg gain is about the same for either tuner, or if the ECO provides a significantly better mpg gain than the HOT tune.

GDE fuel economy

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