Highest MPG

[dieselsnowmobile]

Just curious what the highest MPG you guys have seen in your diesels. With my mostly highway commute, I slowed to a top speed of 58mph and have been getting low 60's (over the course of 5 tank fulls) on my 89 (1.6 NA with AOP tranny). Personal high was 63.32 mpg over 740 miles. My longest tank was 844.8 miles at 62.1 mpg (I added 1.0 gal after the click, 13.6 gal total).

Curious if anyone has been able to get higher and what they did. My mods are tires at 50 psi, self alignment that is dead on, keeping speeds low, accelerating slow, and trying to limit braking as much as possible. It seems that getting into traffic helps, I'll lug along just above idle if I can. I've tried tapping the grill (yes I kept a close eye on temp), but that didn't seem to help. I thought about a engine belly pan, but haven't yet. I tried shutting the engine off whenever possible on a tank but it was negligible difference, so I stopped figuring it is probably harder on the engine anyway and the risk of running out of vacuum for the brakes puts a risk to it as well.


PS - Please don't debate my tire pressure, yes, I know it is above the VW recommended tire pressure but within the tire specs. I know it might cause a bumpier ride, and wear my shocks and joints out faster. The stock PSI wore my outsides, so don't really care out it wearing the insides now. This did help me get solidly in the 60 mpg consistently, before, I was consistently high 50's with a tank just above 60 mpg.

[TylerDurden]

Impressive.

Best I've done is 53mpg in my caddy with oversize tires.

My 89NA Jetta with AOP tranny gets 45mpg in mixed use driving. I rekon on steady highway it would exceed 50mpg. No real engine tweeks, but the base model Jetta is pretty light.

What tires are you using?

[Tac]

Mixed driving and a couple of rushing to work days gets me a 45 with one tank and 47 the week before. Tire size is stock (sticker in the door) and normal tire inflation.

Tom

[bscutt]

I drive mine like it's a GTI and get 42-44 no matter what. Driving it real easy gets me about 45-46 and that's it. FF 5 speed with the .76 top gear (older version)

[dieselsnowmobile]

I'm just running 175/70R13s. My 91 has the silly AWY tranny with 185/65R14s and can only do low to mid 50's with it right now. Alignment is an 1/8" off though, I need to fix that.

[Tac]

Something I thought of. If you put larger tires on, your speedo will be off. I don't think by very much. I used a larger size tire for a very short period of time (tried buying used tires). My speedo was off by a little when I looked at my GPS. If you figure out the difference between the two you would have the right MPG. Bigger tires will certainty get you a little better mileage.

Tom

[TylerDurden]

I do correct for tire size by validating speedo and odo with stopwatch and mile markers, using large samples. (Not yet convinced GPS is accurate.)

[damac]

pretty steady 43 in my 79 rabbit with 1.6td, fn tranny, 175/70/13 tires

i drive the hell out if it pretty much all the time. my freeway runs in the am have me in the fast lane going 85-90mph for long stretches.

oh gosh i can't wait until i get healthy and can do a tdi swap, i am sick of this car

[vwtyp133]

The '80 Dasher wagon(1.6n.a., "2M" 5-speed, 195/60-14) shows similar results in surface street/freeway crazy commuting traffic: consistent 43mpg, corrected. Actually the 195/60-14 tires corrected the slightly optimistic oem speedo/odo readouts.

Why is our a.m. commuting traffic so insane (One can get run over at less than 80-100+ mph!), while the same #%*&ing drivers in the evening, commute back home at a pace that keeps me rowing between 2nd & 3rd gears much of the time? Are they all late for work in the morning & yet abhor returning back home 9 hours later? Weird.

For comparison, when speeds were somewhat slower, my '79 Dasher sedan(1.5n.a., 4-speed, 175/70-13) got 45mpg (corrected) for the same basic commuting trips, but at 65-70mph freeway speeds (yeah... cruising slightly above the rpm of the 1.5's peak torque).

For straight long road trips averaging 60-65 mph on highways, the 1.5 sedan got 56-58+ mpg, while the 1.6(with the wagon's added aero drag at its rear) only gets 52-55+ mpg. Wagon with oem 1.5n.a. towing a 2400 Lb utility trailer (3700-mile trip) returned an actual 33.6 mpg, at speeds probably averaging somewhere in the 50-60mph range.

Looking forward to using 5th gear more, once I can get the 1.6 td finished & installed in the '80 wagon. Hopefully, once the rings have seated, that will enhance its overall MPG, with some careful adjustment of the nut behind the steering wheel.

Other comparos... Our '77 Rabbit "Bronze Edition" (the stripped model!) regularly hit 60-62 mpg on long highway cruises, and the '80 Rabbit (5-speed) was at 62-64, dropping to only 52-55 mpg with a full roof rack of skis and front tires in snow chains.

[bscutt]

ditto on the insane commuter speeds. Even at 5:30 AM they all think they are running the indy 500. How late can you be at 0530? Afternoons vary since I leave at 4 pm, sometimes it's a race, other times running pretty consistent 55-60 in the 50 zone. Thus I get 42-44 most of the time.

[air-cooled or diesel]

'86 mk2, im getting 45-47mpg, i could get a little more if i put the stock size fuel line back on; ive been trying to find an adaptor for fuel line to inj pump; i run 205/60/13's at about 30psi. then again i have suspension mods,.