Auto FE - It's all about driving style

[jcp123]

Hmm, I should update that sig. The bike's been gone for about 5 months now, but it was really easy on fuel - my commutes actually averaged around 47mpg, highway trips were pretty consistent at 52-53mpg! Fantastic for an 1100cc, but the dated design of the Shadows really comes through. Right now I'm saving up for a Harley Sportster to build a bobber bike out of as my fuelsaver - the big, heavy flywheel allows these torque monsters to cruise at low RPM's with bigger throttle inputs, reducing pumping losses and yielding pretty impressive mileage. My Dad and I are also working to get a '61 Mercedes 190b roadworthy for a family grocery getter. With a 1.9l SOHC four and a four-on-the-tree, it should be pretty decent in the mileage department.

After I'm done with school and move out, space permitting, I'd love to get a late '65 Mustang with the 200ci I6/3-speed stick combo - they're capable of touching 30mpg on the highway weighing in at only around ~2600lbs. The other option would be a '58 Chevy Biscayne 2-door post, Chevy's base model, with a 235 I6 and 3-speed overdrive. It's physically a large car, the same size as Chevy's Bel Air and Impalas, but weighs in at only about 3400lbs since it's a no-frills, radio-delete kinda car. Chevy's 235 is arguably a better-designed engine than Ford's 200, and with overdrive is able to push the extra 800lbs along at 30mpg as well.

The only problem with carb'd cars is that a lot of the little hidden tricks like DFCO and neutral at stoplights don't work on them. Other than that, they're capable of fine mileage, but automatics hold them way back, much more so than modern auto'd cars.

[theholycow]

Originally Posted by jcp123

The other option would be a '58 Chevy Biscayne 2-door post, Chevy's base model, with a 235 I6 and 3-speed overdrive. It's physically a large car, the same size as Chevy's Bel Air and Impalas, but weighs in at only about 3400lbs since it's a no-frills, radio-delete kinda car.

1980 Buick Lesabre is 3400 lbs too, not quite as no-frills, and has a trunk big enough to park my VW in. Mine's got a 252 (4.1l) v6. I hope to eventually change it to fuel injection, but I think it's a bigger project than I originally anticipated. I originally thought I could throw a TBI, ECM, a few sensors, and maybe a fuel pump on it and it would work. I've come to realize that it seems I'll also need to change the gas tank and all the gas lines, and maybe some other stuff I've missed.

[theholycow]

The engine has to do a little more work to push against the torque converter compared to if you're in netural. If you've got approximately the same RPM either way, then it's feeding a little more fuel in.

I've setup a fuel rate gauge (see the "realtime monitoring for pre-obd2 cars" thread), and the difference in my 2002 GMC is miniscule but definitely there.

[palemelanesian]

On my Odyssey V6, it idles at about .05 gph in gear, and in neutral it flips back and forth between .04 and .05. The resolution is really rough with numbers that low, but at least it shows that neutral uses less fuel.

[GasSavers_RoadWarrior]

Noticed something today on Marvin, he has a 3 speed hydraulic torqueflite derived transaxle....

Below 2000 rpm, if I put it into neutral for a second or two, then put it back in drive it appears not to engage drive until I press the gas again... thus you can be "neutral coasting" while still having instant access to acceleration should you require it... it appears to stay out even when you brake to a stop, and only engage when you touch the gas again. It does seem however to go back into drive fully when over 2000 rpm, guess that's because the tranny can still push the engine. Seems to need a certain amount of push from either side to engage, and lacking that stays out.

However, I think I remember one time a while back, I shifted into N, then went back to D and coasted down to a stop without brake use... and it sat there 5-10 seconds and then engaged drive slowly and began to crawl again. I didn't make any connections then about it staying in N though.

[theholycow]

P&G (using N but not EOC) definitely works in an automatic. Proof is in the latest gaslog entry for my truck. I haven't gotten this kind of mileage in years, since the truck was brand new and I was driving 100% highway with the cruise control at 65. 18.31mpg!!!

I've been pulsing at 2000 to 2500 rpm, using as much throttle as I can while staying in third or fourth gear. It may not be as good as if it was manual, but it's sure better than nothing.

[philp100]

I've noticed on my '05 Passat that if I use the cruise control going over hills that it holds a higher gear longer than if I try to drive it myself. I even tried putting it in tip-tronic mode to hold top gear but the computer makes it down shift. I have been having lots of fun with coasting in N on the downhills. It does not seem to be making a big difference in my FE though.


jcp123- A newer tranny with OD and lockup would probably give your Mustang great highway mileage.


Phil

[Scott_in_Tulsa]

phlp100,

You might try gradual acceleration downhill and then coast in N going uphill. You just need to accelerate enough to get about 5 or so over the speed limit and then coast to about 10 under the speed limit if you can.

I have tried this with great success. It takes some experience to fine tune the driving style and when to accelerate and coast but is well worth it. If you had a ScanGuage, you would probably learn on this faster than I have (haven't been willing to shell out the money for a SGII yet).

You can look at my Gaslog chart and see the gradual improvements over the past few months with neutral coasting up hill. I am now seeing about 39 mpg when I started with only 32.

Good luck!

[jcp123]

Originally Posted by philp100

jcp123- A newer tranny with OD and lockup would probably give your Mustang great highway mileage.

I don't doubt it. 2500rpm @ 60mph isn't a recipe for huge MPG. Maybe someday...getting the crossmembers and other hardware along with a shortened driveshaft is a bit much to contemplate at the moment...especially when the trans I have now only has 4800 miles on it.

[theholycow]

Vag-Com may be able to adjust your transmission behavior. Check on vwvortex.com or a Passat forum.