500 miles on one tank.

spoonyG · **Posted:** Thu Jun 08, 2006 12:37 pm

Longest range I've dared was 450. It was on a highway trip to Austin, TX and my EGR was failing at the time. Can't wait to try that trip with a healthy rig.

Goglio704 · **Posted:** Mon Jun 12, 2006 8:51 pm

How many MPG do you think the air conditioning sucks down? I made a trip this weekend of 350 miles, mostly highway and only got 22.1. Cruise was set on 70 or less most of the way, and I took it easy when I was off the highway. Really expected to get better mileage than that, and the AC being wide open is the only thing I can blame it on. At 6000 miles on the clock I'm starting to lose patience waiting for the mileage to come in. Something is not right.

bbo · **Joined:** Fri Sep 30, 2005 5:17 pm **Posts:** 382

Goglio704 wrote:

How many MPG do you think the air conditioning sucks down? I made a trip this weekend of 350 miles, mostly highway and only got 22.1. Cruise was set on 70 or less most of the way, and I took it easy when I was off the highway. Really expected to get better mileage than that, and the AC being wide open is the only thing I can blame it on. At 6000 miles on the clock I'm starting to lose patience waiting for the mileage to come in. Something is not right.

6000 miles is not really a lot on the motor .. I am just getting to 20k and it's starting to come into its own right now ... I just made a 290M trip and averaged just a hair over 30 on the way here ~70MPH or so ... no A/C , but I think the biggest thing is getting miles on the CRD ....

Joe Romas · **Posted:** Mon Jun 12, 2006 10:01 pm

oldnavy wrote:

mcompound wrote:

Just some FYI on getting more than 20.5 in the tank. I was an automotive engineer in the aftermarket until my plant was closed. All fuel tanks are designed with vapor space. On a gasoline vehicle, in my experience, a fuel tank has about 20% vapor space in the actual volume of the fuel tank. If the temperature is not very warm you can actually "force" more fuel into the tank than it was designed for. I don't recommend it as it may start splashing on the roll over valve, the vent valve, and it could hold the filler neck valve open - but it can be done.

Never drove a diesel VW or some other vehicle have you. :wink:

We always do something called venting to be able to fill that void on vehicles that use the same tank for gasser as their diesel. A4 VW's would hold about 17 1/2 gal in a 14.5 tank and the VW B4 wagons would hold about 26 in an 18 gal tank, allow those B4 wagons to go 1100 to 1300 miles on a tank. Nice thing about diesel is no vapor expansion like gassers.

I owned a 96 B4 wagon and once went 1000 on one tank. I guess I had a lot left! The wife was going to make ME walk when I ran out. The last tank of fuel I bought at Meijer didn't foam at all. Not one bit. My CRD was even quieter. Any way to ven the tank on a CRD. Also anyone had to use the prining pump? I haven't seen on of those since a 77 rabbit :shock:

oldnavy · **Posted:** Tue Jun 13, 2006 10:01 am

Goglio704 wrote:

How many MPG do you think the air conditioning sucks down? I made a trip this weekend of 350 miles, mostly highway and only got 22.1. Cruise was set on 70 or less most of the way, and I took it easy when I was off the highway. Really expected to get better mileage than that, and the AC being wide open is the only thing I can blame it on. At 6000 miles on the clock I'm starting to lose patience waiting for the mileage to come in. Something is not right.

Remember these are 4x4 vehicles and rather low geared (3:73 rear axle ratio) and diesels are very throttle sensitive.

The power to pull the a/c is non existant compaired to the air brake effect of driving 70 mph with windows down.

Quality of fuel has a very big effect on fuel mileage, as does driving habits. I have a friend with a VW Passat gasser and he never can break 26 mpg and is very disappointed in the car. I took a short trip once with him and he was always speeding up and slowing down, mainly when someone passed and when he was passing a tuck he would hit 80 to 85 mph to hurry and get away from being beside the semi truck. The point is he would say he had the CC on 70 mph all the time, but he forgot about the sudden speed ups to pass or reacting to someone passing (that really bugged me) him. He also will not inflate his tires (52 PSI max rating) to anything above 28 psi because he is still stuck in the 70's with his tire knowledge. I run 40 psi in our Jeep with it's 44 psi rated tires and have a high mpg of 33.7 mpg with only 10k miles on the Jeep.

Other things that can lower mileage is weather, road conditions and just the differences that can be in two vehicles.

Goglio704 · **Posted:** Tue Jun 13, 2006 10:08 am

Old Navy,

Didn't you see a mileage increase after a reflash? I'm running my tires at 35 so I'll bump that up. As for the speeding up and slowing down, I was watching that on that trip. I was also very easy on the throttle when accelerating. When accelerating I'd just ease into it and hold in the 1500 to 2000 RPM range and let the torque do its thing. Don't get me wrong, I don't think my mileage is terrible, but it is nowhere near 30 either.

oldnavy · **Posted:** Tue Jun 13, 2006 10:17 am

Maybe you were not letting it get into top gear soon enough or at all on some of the low rpm cruising.

But as I said no two cars are exactly alike and yours could just be a little out of adjustment. It could be injection pump timing is off a bit or the tranny programming needs adjustment. Heck who knows they could have even given you a lower rear end ratio by acciddent and how would you know.

RTStabler51 · **Posted:** Tue Jun 13, 2006 10:36 am

I got 29.5MPG on my second tank on my trip from Fort Wayne back to DC on #2. I usually drive around 75-80mph

Goglio704 · **Posted:** Tue Jun 13, 2006 7:54 pm

RTStabler51 wrote:

I got 29.5MPG on my second tank on my trip from Fort Wayne back to DC on #2. I usually drive around 75-80mph

EVIC or hand calculated?

RTStabler51 · **Posted:** Wed Jun 14, 2006 11:03 am

Goglio704 wrote:

RTStabler51 wrote:

I got 29.5MPG on my second tank on my trip from Fort Wayne back to DC on #2. I usually drive around 75-80mph

EVIC or hand calculated?

I believe both, I know at one point the EVIC said 29.5, and i have an excel spreadsheet to, and I believe it came out to 29.2

retmil46 · **Posted:** Wed Jun 14, 2006 11:29 am

When I changed oil yesterday, I put in Amsoil Synthetic Diesel 15W40. I wanted to test out how this might affect oil in the intake and see what effect it might have on MPG.

When I checked everything out yesterday, after 4000 miles since cleaning the CAC hoses, the Provent outlet hose and the CAC outlet hose to the intake was bone dry and clean. The stock CCV hose was also bone dry. I checked inside the stub tubes on the intercooler, also dry and no oil.

The intake hose and turbo discharge outlet, however, did have another coating of black crud inside them. Intake hose wasn't bad, mainly at the elbow at the discharge of the turbo, with one thin streamer that had worked it's way down the hose.

I don't know if this was residual oil from the stock CCV hose and turbo inlet elbow that finally flushed it's way thru (never cleaned them out), or possibly slight leakage past the turbo seals, or maybe the Provent filter needs a really good coating of oil on it to really become effective.

This beast has been knocking down 25.5 MPG consistently on the drive to work for the past 3 months now with 5W40 Rotella. I'm going to give it 3000 miles befoe changing oil again to see how much of a hit, if any, using the heavier oil gives to MPG. If the hit on MPG is negligible, and the intake oiling and what is collected by the Provent goes down or goes away completely, I'll be tempted to stick with 15W40 synthetic.

500 miles on one tank.

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