GDE fuel economy

LibertyCRD · **Posted:** Thu Mar 04, 2010 9:15 am

The weather here now is *slightly* nicer. And I just posted my best tank!! 21.6 MPG hand calculated...~24 MPG EVIC. Woohoo!! Improvement is good!

BVCRD · **Posted:** Thu Mar 04, 2010 9:43 am

For kicks and grins, I took along my GPS out of town last weekend on that 543 mile run. I got 24.7 all highway with speeds from 55 to 75. All stock, no special tune and winter gas. 10 ounces of power service added to the fuel. Temps ranged from 22 at the start to 55 in the afternoon. That's with my new Grabber AT2 tires. I had just Seafoamed the fuel the week before to clean up the combustion chamber and injectors. Change in elevation was from 8000 feet at start, down to 5000 feet, then back up to 8000 feet and home. Soooo, we're all good here.

StanCRD · **Posted:** Thu Mar 04, 2010 10:20 pm

LibertyCRD wrote:

How does one go about checking that?

Best way I can think of is to rig up some plugs for the intercooler and use an engine leakdown tester to check it. For the hoses you could do a visual after removing and cleaning them.
Mine had the "woosh" sound that appeared to come from under the driver side dash so it was easy to know that I had a leak.

Drewd · **Joined:** Mon Feb 06, 2006 12:24 pm **Posts:** 902

Well, so far even with highway driving with speeds between 70 to 80mph, I'm getting 20.8 mpg with the tune.

I'm happy with the tune but its a shame that my Grand Cherokee gets 24mpg in the same highway driving.

dthdcrd · **Posted:** Sat Mar 06, 2010 11:45 am

I purchased the CRD for the all round abilities, towing, fuel economy, and being a daily driver. I have a Striker1 power module (came with the vehicle) I plan to purchase the GDE tune. I have run the power module in fuel economy mode and different power levels. I have never experienced MPG better than 24, and that was a steady 70MPH on an 8HR trip. I have been dissapointed with the over all MPG. I drive conservatively and usually let the trans shift between 2200 and 2500 RPM, and doing this yields 19 to 21 MPG combination city highway driving. I see others with similar mileage, but then see the ones with 19-20 towing 22-24 city and 30!!! highway? What gives?? I have been over the sticking brake issues, and tried everything in between to make the Jeep roll free?

Why is there such a discrepancy??

Thanks

RJM · **Posted:** Sat Mar 06, 2010 11:57 am

For hwy driving, I get the best mpg at 1800rpm. Also fuel quality appears to be a bit of an issue, I can get 27mpg on average with good fuel, but it will drop to 22-23 with crappy diesel. As far as the claims people make with extremely high figures, take it for what it's worth. I take it as BS.

flash7210 · **Posted:** Sun Mar 07, 2010 10:24 pm

dthdcrd wrote:

I drive conservatively and usually let the trans shift between 2200 and 2500 RPM...

Hmmm, not conservative enough.
Try letting it shift between 2000 and 2200 rpm.
Try maintaining 2100 rpm until you reach 4th+ lockup (i.e. 50mph).
Its not unreasonably slow, see how that works for ya. :wink:

grywlfbg · **Posted:** Mon Mar 08, 2010 2:06 am

Hmm. I have the latest GDE Eco-tune (supposedly they made the EVIC more accurate but have not hand-calc'd to verify) and the EVIC displays 25mpg for my wife is hellish stop-and-go Bay Area traffic and can easily get into the low 30's on the highway. This is running B100, A/C almost always on, etc.

You will not find another SUV w/ 335 ft lbs of torque getting that kind of mileage. 4-cylinder Tacoma is EPA 20/26 and only has 180ft lbs of torque. The V-6 is still only 260 ft lbs and drops to EPA 14/18. 4-Runner w/ the V-6 is 270 ft lbs and EPA 17/23. 4-runner is close but this is comparing the 2010 model w/ our 2005's - Imagine if Jeep had spent 5 years improving the CRD. Also, the new 4runner is also WAY more expensive than a CRD was when new.

-<shrug>- at the end of the day I don't know of another vehicle on the market with this combination of performance, mileage, and durability (and the ability to run biodiesel is an extra bonus). I plan to keep this beast for long time.

Joe Romas · **Posted:** Mon Mar 08, 2010 8:02 am

grywlfbg wrote:

Hmm. 4-runner is close but this is comparing the 2010 model w/ our 2005's - Imagine if Jeep had spent 5 years improving the CRD.

They have and it's now 400 foot pounds :BANANA:

But the anti diesel carb and epa folks won't let us have them here :ALONE:

evolDiesel · **Posted:** Mon Mar 08, 2010 2:09 pm

Joe Romas wrote:

grywlfbg wrote:

Hmm. 4-runner is close but this is comparing the 2010 model w/ our 2005's - Imagine if Jeep had spent 5 years improving the CRD.

They have and it's now 400 foot pounds :BANANA:

But the anti diesel carb and epa folks won't let us have them here :ALONE:

A 4-cyl TDI Tacoma would be S-I-C-K!

LibertyCRD · **Posted:** Tue Mar 09, 2010 9:51 am

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.

BVCRD · **Posted:** Tue Mar 09, 2010 9:55 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.

I'm not too surprised. You will start getting another 2-3 mpg in a month or so when the summer syrup starts to flow. Course, you'd be getting that with a bone stock flash anyway.

ac5501 · **Posted:** Tue Mar 09, 2010 11:32 am

A Few weeks ago, I got my GDE tune updated to the latest version which shuts off the viscous heater at a lower temp.

This appears to have given me about 1 - 2 mpg pickup over what I was getting before. Before the update my winter MPG's were about 24 - 26 (I say about because I went through a stretch after Christmas where I was pumping fuel 10 - 20 dollars at a time). Since getting the tune my avg has been fairly steady around 27.5. This includes a bit of 4wd and a lot of running the floor heat (turns on AC compressor).

I may try their suggestion about the air intake duct but its a little late in the season for that.

BVCRD · **Posted:** Tue Mar 09, 2010 11:47 am

ac5501 wrote:

A Few weeks ago, I got my GDE tune updated to the latest version which shuts off the viscous heater at a lower temp.

This appears to have given me about 1 - 2 mpg pickup over what I was getting before. Before the update my winter MPG's were about 24 - 26 (I say about because I went through a stretch after Christmas where I was pumping fuel 10 - 20 dollars at a time). Since getting the tune my avg has been fairly steady around 27.5. This includes a bit of 4wd and a lot of running the floor heat (turns on AC compressor).

I may try their suggestion about the air intake duct but its a little late in the season for that.

But doesn't the viscous heater turn off once the engine is warm anyway? It probably saves you fuel because it gets the engine temp up quicker.

ac5501 · **Posted:** Tue Mar 09, 2010 12:05 pm

BVCRD wrote:

But doesn't the viscous heater turn off once the engine is warm anyway? It probably saves you fuel because it gets the engine temp up quicker.

Yes, that sounds correct. I think Chrysler just set the cutt off temp a little too high

My theory for improved mpg is this: Since getting the GDE (july 09) tune i've noticed the normal operating temperature is much more sensitive to the outside air temp. For days with temps say 25f or lower, the coolant temp would not rise high enough to shut off the viscous heater. I believe stock, the heater cuts off at 165f. My jeep was not reaching that temp, or taking an awful long time to get there during the winter. I think the GDE guys lowered the cut off temp to 131. I'm still running the same temps, but now the viscous heater is off.

BVCRD · **Posted:** Tue Mar 09, 2010 12:30 pm

ac5501 wrote:

BVCRD wrote:

But doesn't the viscous heater turn off once the engine is warm anyway? It probably saves you fuel because it gets the engine temp up quicker.

Yes, that sounds correct. I think Chrysler just set the cutt off temp a little too high

My theory for improved mpg is this: Since getting the GDE (july 09) tune i've noticed the normal operating temperature is much more sensitive to the outside air temp. For days with temps say 25f or lower, the coolant temp would not rise high enough to shut off the viscous heater. I believe stock, the heater cuts off at 165f. My jeep was not reaching that temp, or taking an awful long time to get there during the winter. I think the GDE guys lowered the cut off temp to 131. I'm still running the same temps, but now the viscous heater is off.

Wow! You been real cold up there this winter? we have beem somewhat milder than normal here. Even with it off, you might want to consider a radiator blockoff of some design to get that operating temp up a tad. Your engine will thank you for it.

ac5501 · **Posted:** Tue Mar 09, 2010 1:03 pm

BVCRD wrote:

Wow! You been real cold up there this winter? we have beem somewhat milder than normal here. Even with it off, you might want to consider a radiator blockoff of some design to get that operating temp up a tad. Your engine will thank you for it.

I actually think its been a little milder then normal. We've gotten the real cold days (highs in the single digits lows below 0) just not as many. Seems like we stayed consistently in the 20's this year. Yes, getting the operating temps up makes a big difference.

I don't have an EVIC to give exact numbers, but there is a noticeable difference on how fast my fuel gauge moves during weeks when the temp is around 60 vs weeks when the temp is around 30 (same daily commute).

BVCRD · **Posted:** Tue Mar 09, 2010 1:13 pm

ac5501 wrote:

BVCRD wrote:

Wow! You been real cold up there this winter? we have beem somewhat milder than normal here. Even with it off, you might want to consider a radiator blockoff of some design to get that operating temp up a tad. Your engine will thank you for it.

I actually think its been a little milder then normal. We've gotten the real cold days (highs in the single digits lows below 0) just not as many. Seems like we stayed consistently in the 20's this year. Yes, getting the operating temps up makes a big difference.

I don't have an EVIC to give exact numbers, but there is a noticeable difference on how fast my fuel gauge moves during weeks when the temp is around 60 vs weeks when the temp is around 30 (same daily commute).

I'm hoping slower around 60*?

ac5501 · **Posted:** Tue Mar 09, 2010 1:49 pm

BVCRD wrote:

I'm hoping slower around 60*?

Yeah, I got that backwards. The fuel gauge definitely moves slower at 60 as opposed to 30

BVCRD · **Posted:** Tue Mar 09, 2010 1:55 pm

ac5501 wrote:

BVCRD wrote:

I'm hoping slower around 60*?

Yeah, I got that backwards. The fuel gauge definitely moves slower at 60 as opposed to 30

That's normal. In comparison, my 2007 Mustang GT gets way, way better fuel economy up here at 8000 feet and cool (45-65) rather than high humidity and 85-90 when we visit family back in Missori. Like.... 27-30 highway (here) vs 21-23 in the sweltering heat.

GDE fuel economy

Who is online