crd mileage

flash7210 · **Posted:** Fri Dec 07, 2007 1:06 pm

I finally did it! Got better than 26 MPG!

Yesterday I calculated 27.33 MPG at fill up.

I dont have the EVIC.

I'd like to thank all the people here on LOST KJ's and at GasSavers.org
whos knowledge and input made this possisble.

Contributing factors to this feat:

Ambient temps dropped to low 70's
Tire pressure @ 47 psi- stock tires
No muffler
ORM
Clean MAP sensor
Home made Provent-like thingy
Blocked off 60% of grille
8 oz. of PowerService (gray bottle) for every 20 gallons
New Mopar air filter
33000 miles on the odo (F37 performed at 30K miles)

I'm being a little bit sarcastic here. I know this isn't much of a FEAT, but its
the first improvment I have seen.

Still waiting to install the SEGR and Facet lift pump.

DarbyWalters · **Posted:** Fri Dec 07, 2007 1:20 pm

It is amazing what increased tire pressure and grill blocking (especially in the colder months) will do for fuel mileage. Now just get the Amsoil EaA201 Air Filter and you will be set for 100,000 miles...better air flow too.

mark2m · **Posted:** Fri Dec 07, 2007 1:43 pm

I agree on most of the fuel saving tips giving here but I wouldn't go to 50psi on tire pressure. While granted the rolling resistance is greatly reduce but you are increasing your tire wear. With your tires over inflated, factory setting is 33psi based on tire size and weight you will be wearing the centers down quicker. It may not be that much of a concern for some but I'd rather have a better contact patch and save on not having to replace my tires as often.

Cowcatcher · **Posted:** Fri Dec 07, 2007 4:46 pm

With respect to the NEUTRAL shifting issue discussed by Darby, if you have a ScanGuageII you can monitor the "engine load" which typically ranges somewhere between 14 at idle in neutral and 75 WOT uphill. I note that the difference at idle in neutral versus idle with the foot on the brake in drive at the light goes from 14 to the 40 to 60 load range. I will be speeding more time sitting in neutral as load is a strong indicator of fuel consumption.

clday25 · **Posted:** Fri Dec 07, 2007 5:57 pm

I do the same thing Cowcatcher

but i also look at the GPH (Gallons Per Hour) gauge. You can really see the difference in engine load and fuel flow with it being in drive, neutral, A/C on (all settings but panel), Heat on high, engine cold, warm, ect.....

I've also noticed that load and fuel flow are their lowest when coasting in Drive, not neutral. Its a trade-off, travel farther in neutral or use less fuel in drive.... now, if i could just get my Jeep to coast down a hill like the wife's 06 Jetta TDI

chrispitude · **Posted:** Fri Dec 07, 2007 6:51 pm

clday25 wrote:

I do the same thing Cowcatcher

but i also look at the GPH (Gallons Per Hour) gauge. You can really see the difference in engine load and fuel flow with it being in drive, neutral, A/C on (all settings but panel), Heat on high, engine cold, warm, ect.....

What are the typical GPH numbers for neutral and stopped in drive? We can translate that directly to the amount of money it costs to sit at a red light for 30 seconds in drive versus neutral...

- Chris

Cowcatcher · **Posted:** Fri Dec 07, 2007 8:29 pm

It will typically drop to "0" because you are not moving on MPG! :lol:

When you coast downhill in neutral/idle it will pin out to 999 if I recall correctly.

I haven't tried GPH

clday25 · **Posted:** Fri Dec 07, 2007 9:39 pm

I can't remember what the GPH numbers are and i'm not sure it my Inmotion tune messes with those or not.... i'll have to take some notes here soon and report back.

Regardless of what the actual flow and load numbers are, its still giving you some type of feedback that you can use to drive more economical if you chose.

later,
Chris

Cowcatcher · **Posted:** Sat Dec 08, 2007 1:02 pm

OK, I turned on GPH on the ride home last night. On a cold engine (31F) there was about .4 GPH difference between idle/drive versus idle/neutral. On a warm engine it increased to about .5/.7 GPH range. Actual on warm was around 1.1 GPH in drive and about .4 in neutral. This was with the heater lights and radio but not defrost (I believe defrost activates the AC pump).

DarbyWalters · **Posted:** Sat Dec 08, 2007 1:45 pm

Yep...that correlates with the 2.5x CFR (Calculated Fuel Rate) gmctd and I got on my CRD. That also adds to the benefits of "grill blocking" to get to operating temps faster and hold them.

So if you were stopped and idling (1.1gph) in "Drive" with 20.5 gallons of diesel...you would last 18.64 hours.

Stopped and idling(.4gph) in "Neutral" with 20.5 gallons of diesel...you would last 51.25 hours.

KJMedic · **Posted:** Sun Dec 09, 2007 1:42 pm

As far as the od. reading I was sitting at a light the other day and the Od. went up 1 mile while I was sitting still. :shock:

Cowcatcher · **Posted:** Sun Dec 09, 2007 2:38 pm

Another find. If you have your foot on the brake will stopped the GPH also increases several tenths. Lowest GPH consumption is neutral with no brake.

Neutral coasting downhill on the other hand may increase GPH reading. In drive coasting the GPH will often register "0" while it will register .4 in neutral.

groovin1 · **Posted:** Tue Dec 11, 2007 1:19 pm

Darby:
Thanks for the info - I have been following the thread. I feel a bit better because I finally was able to get on the highway and check the od, and sure enough 10 miles by the mile markers was 9.5 on my od. Therefore my mileage is a little better than what I was figuring.
I brought my tires back up to 40psi as they went down when it got cold here in NY. I have been using the Standyne additive and I have a K and N air filter installed. Next I will get a grill insert. However, I do keep it in the garage so it never goes below about 58 degrees in there, but I am sure the insert will help.
groovin1

groovin1 · **Posted:** Wed Jan 16, 2008 3:19 pm

I wanted to post a follow up.
I took a trip to Vermont a few weeks ago, temp. between 20 and 40. I got 25.3 mpg, and that included 1 hour in 4x4 hi and 1 hour in bumper to bumper traffic. Other than that, mostly highway between 63 and 70 mph.

This was calculated, not from the computer.

Excellent....

DarbyWalters · **Posted:** Thu Jan 17, 2008 12:51 am

Now keep speeds to 64 or so in the final OD...about 1800 rpm...you will hit 30+ most likely

groovin1 · **Posted:** Thu Jan 17, 2008 7:22 am

I try to stay at 64ish because of that. Sometimes conditions warrant a bit faster. Also, the time in 4x4 hi was in a snowstorm, so 25+ on this trip was excellent. I noticed that since then I have been getting better mileage around town also, like 20 and 19. Is this because the long trip on the highway cleared things out?

DarbyWalters · **Posted:** Thu Jan 17, 2008 7:27 am

Probably due more to a slight change in driving style. EPA City is 19...Combined is 21...If you really are careful you can get 22 City. Make sure when you are stopped you are in neutral...not drive (burns 2.5x less fuel) and keep tire pressures in check.

groovin1 · **Posted:** Thu Jan 17, 2008 7:40 am

I thought it was 21 city, 26 highway.
I have been putting it in neutral at stops, and also coasting in neutral when feasible, which is more often than people think. There are spots you can go for a mile or more in neutral even locally.
So I guess these have really helped. I am trying to get my wife to do this stuff in her Maxima - can't hurt there either I would guess. Don't worry - no arguments looming!

Jim Friese · **Posted:** Fri Jan 18, 2008 1:13 am

I went to Dayton OH. last DEC. and it was a 930 mile round trip with local driving there in Dayton. My MPG was 21. not to bad for driveing 65 to 75 MPH depending where I was. MY Liberty spent 2 weeks at the dealer getting a new CCV TCM and rear window driver's side motor control and moter. My brakes moan like you know what and I am still trying to get them to fix it. anyway 21 MPG seem OK for how I was driveing. Have a nice day all.

Red CRD
Provent:
Drove ORM

DarbyWalters · **Posted:** Fri Jan 18, 2008 2:11 am

The new EPA Ratings are 19/21/23. Pretty realistic and easy to beat with very little effort. The Old Epa was 22/23/26.

http://www.fueleconomy.gov/feg/findacar.htm

The Grand Cherokee Diesel is 17 city/22 hwy

crd mileage

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