Important

Zuki-Ron said:
Well, Mac, I'm going to have to take back my comment in the EarthDay post about these new trucks getting better Milage than a 1975 Chevy Pickup. I ass-u-me'd that the EPA figures of 20mpg Hwy were to be believed.

You would have to break 17mpg to beat the 16mpg of my old 351-EFI powered Bronco with a 5K race car and trailer combo behind it at the Gas Pump.

Zuki "Why do people buy gas guzzlers then complain about their milage?" Ron
Click to expand...


We are pulling 18.5-20mpg on the 99 VP44 truck.

I run 5w-40 T6 or Syntec in the jeep and the Miata. Didn't see any drop in MPG going to it from whatever the PO had in it. My biggest MPG killer has been the tires, bumper/winch, and the lockers. Spending half its time in 4Low also doesn't help fuel consumption much.... :)

Once this engine dies, I'm strongly considering a Perkins Diesel or VW TDI engine (4bt is just too expensive!)
 
Last edited:
chpmnsws6 said:
We are pulling 18.5-20mpg on the 99 VP44 truck.

I run 5w-40 T6 or Syntec in the jeep and the Miata. Didn't see any drop in MPG going to it from whatever the PO had in it. My biggest MPG killer has been the tires, bumper/winch, and the lockers. Spending half its time in 4Low also doesn't help fuel consumption much.... :)

Once this engine dies, I'm strongly considering a Perkins Diesel or VW TDI engine (4bt is just too expensive!)
Click to expand...

Not sure what a VP44 is. I googled it and its a injector pump for a Cummings :banghead:

Aerodynamics are a killer on a Cherokee. The stock trim is pretty efficient, and going with a bigger tire or a locker doesn't make that much difference I think I noticed 1 mpg drop. The big killer is lift. Once you get that puppy off the ground, it migh as well be a brick on wheels to the wind. I noticed a 2 mpg difference going form 3" to 4.5" with no other change to the Jeep other than the height. Of course it all adds up. Bigger tires (more unsprun weight), lift height, rack... it all adds up and pretty soon you get the gas mileage of a 1970 Pontiac Bonneville with the lifters ticking away like a swiss watch ;)
 
A VP44 is a Bosch injection pump. It's a hybrid pump, partly mechanically controlled, partly electronic. My 99 CTD (VP44) running at 70mph on my daily commute is getting right around 19 mpg. On a 60mph run, I can get 22-23 mpg. On the run to/from WF11 at 65mph, loaded down to around 14.5-15k lbs., I averaged 14.5 mpg over 1,100 miles.
 
Interesting. I wonder how that compares to a gas engine in the same application?

For example: A 1500 with a 5.7 V8 is EPA rated at 20 Hwy. It's just about the same body style, just the 2500 has beefier chassis and axles. If my 82' Dodge 1 ton Extended van could get 18mpg while towing, an EFI setup with better aerodynamics and fancy electronics should be able to do better than 20 unloaded/ 14.5 loaded, wouldn't ya think?
 
Zuki-Ron said:
Not sure what a VP44 is. I googled it and its a injector pump for a Cummings :banghead:

Aerodynamics are a killer on a Cherokee. The stock trim is pretty efficient, and going with a bigger tire or a locker doesn't make that much difference I think I noticed 1 mpg drop. The big killer is lift. Once you get that puppy off the ground, it migh as well be a brick on wheels to the wind. I noticed a 2 mpg difference going form 3" to 4.5" with no other change to the Jeep other than the height. Of course it all adds up. Bigger tires (more unsprun weight), lift height, rack... it all adds up and pretty soon you get the gas mileage of a 1970 Pontiac Bonneville with the lifters ticking away like a swiss watch ;)
Click to expand...

Cummings diesel? C'mon Ron!!!! :doh:








:D
 
I got that. But from the fuel pump model you can tell me what size the truck is, and what size engine is in it?

Maybe we should start refering to our Cherokees by model and fuel pump model, since everything else is about the same ;)
 
Zuki-Ron said:
Well, Mac, I'm going to have to take back my comment in the EarthDay post about these new trucks getting better Milage than a 1975 Chevy Pickup. I ass-u-me'd that the EPA figures of 20mpg Hwy were to be believed.

You would have to break 17mpg to beat the 16mpg of my old 351-EFI powered Bronco with a 5K race car and trailer combo behind it at the Gas Pump.

Zuki "Why do people buy gas guzzlers then complain about their milage?" Ron
Click to expand...

I bought a diesel cause its supposed to get good fuel economy. Are all these mpg's hand figured? The lie-o-meters...lie. Everyone has a cummins that gets 30 mpg towing 30k...but I have yet to see that. My megacab was an 06 that got 10.5 with a 30ft enclosed and 13 mpg with a single place and 11mpg with my two place...and had shitty seats.

The f450 was killed by gears and emissions...the govt has really screwed anything that's 07.5 and up with the dpf crap. Thats making them run cleaner...but worse fuel economy and hurting these motors.

The f350 has 4.10s. Before deletions and tunes it was 11 to 12 on the lie-o-meter. With the mild tune, at 60 its showing 20mpg+ and at 70 16mpg with no load. I always hand figure and will report back.

The 'hot' tune on this turner is insane. You floor it, it will spin the tires shifting into 2nd and 3rd...I left four black rubber marks on the country road where I was getting the feel of the truck and trying to get the transmission to learn me...it started to walk sideways...on dry pavement...an 8k dually truck... ridiculous...and getting better than stock fuel mileage...


ChiXJeff said:
A VP44 is a Bosch injection pump. It's a hybrid pump, partly mechanically controlled, partly electronic. My 99 CTD (VP44) running at 70mph on my daily commute is getting right around 19 mpg. On a 60mph run, I can get 22-23 mpg. On the run to/from WF11 at 65mph, loaded down to around 14.5-15k lbs., I averaged 14.5 mpg over 1,100 miles.
Click to expand...

I've been grossing out at 25 to 27k...

mac 'and black smoke!' gyvr
 
macgyvr said:
Everyone has a cummins that gets 30 mpg towing 30k...but I have yet to see that.
Click to expand...

I hear crap like this all the time. Unless you're towing a small boat, I'm talking a 14ft. Jon boat like my dads, you're gonna lose MPG's. I even hear this from fellow employees. Sorry but you cannot get 20 MPG towing anything with a light duty diesel truck. We make good motors but they aren't that good! :shhh:
 
I think I am going to like my new shoes. :D

100_1256.jpg


100_1255.jpg
 
FlexdXJ said:
I hear crap like this all the time. Unless you're towing a small boat, I'm talking a 14ft. Jon boat like my dads, you're gonna lose MPG's. I even hear this from fellow employees. Sorry but you cannot get 20 MPG towing anything with a light duty diesel truck. We make good motors but they aren't that good! :shhh:
Click to expand...

I agree Flex! Also I agree with Mac about the Lie-o-meters.

The EPA has been killing the fuel economy. I think it's more about putting money in their pockets, but I know for a fact diesels pollute much less even burning more fuel.

The real numbers for the Cummins <---notice no G...

Original 6bt trucks could get 21-23 on average. Anyone on the high side of that normally has a 2wd w/stick ALSO! they probably have the timing adjusted properly.

The "ISB" "24 valve" "vp44" trucks get 18-20mpg

The "common rail" trucks get 15-18mpg

The "VGT w/DPF" trucks are 13-16mpg

Put a trailer and one jeep behind any of these trucks and you can usually subtract 5mpg.

And as Mac knows choosing a gearing that puts the engine in the sweet spot for your average driving style is key.
 
Big Hank said:
And as Mac knows choosing a gearing that puts the engine in the sweet spot for your average driving style is key.
Click to expand...

So these 5.57's I've got aren't good for highway economy? NO WAY!


I don't think it matters. We're going to get 10 MPG no matter what I do. I have located a 4.30 3rd member though, so at least we'll be able to do the speed limit.
 
Well, i own a Comanche now.........its stuck in his yard. I got stuck trying to pull it out.I have the title and hes gonna bring it to me now that his tow rig is fixed........when its not in a soupy mess!
 
Gas mileage is giving me a headache. Fuel is $3.90/gal and that just sucks. So glad the 2dr XJ gets 18mpg to and from work, and 24 on the open road.
The 4dr, not so much. I need to work on that. The trip to and from WF yielded 12mpg; and I thought the Wrangler got lousy mileage :wierd:

Speaking of that unit: The front diff seal leaked when I got it, and I polished the yoke seal surface and was hoping to save myself a seal. No luck. I replaced the gear lube and filled it up to the fill hole. Since then, it's been worse, so I ordered up a seal. I pulled the yoke today and the fluid just poured out. I yank the seal, and the floodgates open ;) Seal install went like a breeze. I was wondering if I should add more lube and I got to thinking, why so much lube loss? Then I look at the SOLID diff cover. They located the fill hole ABOVE the axle tube, not below like the stock cover.

I guess I have to tap in a new plug so I don't have to think too hard when I do the front service... I bet my gas mileage would improve :)
 
while we are on the fuel mileage debate...

I have owned 3 xjs that ran and I daily drove...

around down i got 12-14...hwy maybe 18...

this was from stock to not...all three were 4.0/aw4/4dr/4x4

mac 'I have never seen over 20 mpg out of an xj' gyvr
 
You must log in or register to reply here.

Similar threads

1
New here, but not to Jeeps
Replies
1
Views
164
macgyvr
macgyvr
C
Delete my info
Replies
3
Views
452
Numbers
Numbers
A
Power window issues, all 4 were working but no longer
Replies
5
Views
433
maxbraketorque
M
‘
‘91 XJ Crank no start
Replies
5
Views
234
94RHDCherokee
9
M
Disconnected cable identification
Replies
6
Views
76
Miamitj
M
Back
Top