D-FAS: High speed hypermiling technique for the very few …
 

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Re: D-FAS: High speed hypermiling technique for the very few …
 

I tried this a couple of times on my way back home from Oklahoma. It works really well. So well, in fact, that even on a very slight decline, I was accelerating toward the truck in front of me, under no power. A couple of short taps on the brake helped, but I have to say it was quite scary going 70+ mph with my motor off and still gaining speed!

Lucky for me, I don't do much highway driving at all, so I don't have many opportunities to submit myself to the high-stress techniques involving extreme proximity to large, fast-moving vehicles. ;)

Re: D-FAS: High speed hypermiling technique for the very few …
 

Hi Doppler:

___I too had that down hill acceleration happen a few times and when I couldn’t pull to the side, I tapped the binders just enough to maintain the gap. I sure wish this Accord had a simple IMA start or even GM’s upcoming 42 V BAS as it would make it so much easier on this semi-lux 4-door sedan’s gear reduction starter and 12V battery :(

___Good Luck

___Wayne R. Gerdes
___Waynegerdes@earthlink.net

Re: D-FAS: High speed hypermiling technique for the very few …
 

While I don't resort to FAS at cruising speeds very often, I don't worry about restarting after an FAS... since I drive a 5-speed, I just restart the car (IG III as you call it) while still in neutral, select the appropriate gear, rev up and let the clutch out.

That said, I'm sad to hear that '06 Hondas will not be available in MT trim... the few times I've push-started the HCH at high speeds (~35-40mph from 0rpm in 5th gear), I've thought "oh ****! that doesn't sound good!"

Maybe you CVT owners can pipe in with your experiences of "push-starting" your cars at high speeds?

--edit-- Wayne: ah. It just occured to me why you might pine for an IMA or similar starter mechanism :) You are restarting your non-hybrid with the 12V starter after an FAS, no?

Re: D-FAS: High speed hypermiling technique for the very few …
 

Hi Doppler:
___Unfortunately, that is exactly the case :cry:

___Prior to the above, I was FAS’ing ~ every 10 miles on average over the past 3 months with relatively decent traffic conditions throughout the summer months. Last weeks Chicago Interstate traffic nightmares brought that down to 1 every 5 - 6 miles or so on average. This new found technique is bringing her average distance between a regular FAS or D-FAS to ~ every 4 + miles … An IMA start and a completely freewheeling Auto tranny would really come in handy about now ;)

___Good Luck

___Wayne R. Gerdes
___Waynegerdes@earthlink.net

Re: D-FAS: High speed hypermiling technique for the very few …
 

You are obsessed with drafting, although I can understand why. Phoenix had a gas shortage 2 years ago, exposing how easily our supply can be disrupted. I am NOT about to get caught with my pants down again and have to wait in gas lines if/when we run out again due to the current refinery shortages.

I topped off on Sunday, and have been driving my absolute most conservative and as much as it pains me, I've been drafting almost whenever possible.. even close drafting a semi truck almost my entire freeway drive home today. Zero A/C use since Sunday, too. The result? 95.1 miles on 1.767 gallons, and that was with clicking the pump two more times after the auto-shutoff where I normally stop! My previous best ever was 47mpg but this calculates to 53.8. Even my ScanGauge was showing a tank average of 48.5mpg, which is probably the "true" figure, and again still my best on record. I'm still not a fan of drafting for safety reasons, but it becomes child's play to get hypermileage tanks when you do so.

Re: D-FAS: High speed hypermiling technique for the very few …
 

Hi AZCivic:

___Easy there … The Insight was never a good draft vehicle because she didn’t have the power in lean-burn to maintain the proper distance. All but traffic side and everybody receives those. Tbaleno’s HCH did not receive any draft assistance its first time out and she showed me some pretty worthwhile numbers around town. The highest FE segment in GreenAndBlue’s AH video came from the first 15 minutes without a straight draft of either type to be found IIRC … Krousdb’s Prius II did not receive any draft assistance in its run back and forth in the Pittsburgh area earlier in the month ;) The Ranger didn’t receive any kind of a draft while towing the Landscape Trailer and gear around the subdivisions and driving around town over the last 108 miles either. Take a look at the Ranger’s last (2) fills for proof of concept! I use whatever opportunity is availed to me depending on the automobile I am driving. Tiring, yes. Child’s play? Not a chance or everybody would get it.

___What I am finding is a D-FAS cannot be performed as much of the time as I had hoped unfortunately. The targets just weren’t lining up with the descents properly while in heavier traffic tonight. When sitting in the usual Chicago traffic nightmare tonight gave way to much less “Drafting”, “DWL”, and “Fast Climbing” technique(s) and much more traffic jam and FAS technique(s) … A dropping tank average is the result as the TC is showing just 55.0 mpg after almost 400 miles now :(

___Good Luck

___Wayne R. Gerdes
___Waynegerdes@earthlink.net

Re: D-FAS: High speed hypermiling technique for the very few …
 

Wow. I think that redefines pushing the envolope. Now that I hit that 3K milage boost, I've given up drafting to get good MPGs, and I don't think I'd ever consider doing D-FAS.

No wonder you mentioned in that other thread that you could get Prius milage with a FEH.

No offense, but this isn't my cup of tea, I'll stick to driving rather normally, but still getting 33 MPGs. To me, that's the goal of the hybrid driver, to get fantastic MPGs without radically changing how they drive.

Re: D-FAS: High speed hypermiling technique for the very few …
 

but what happens if you change the way you drive but still technically arrive in the same time as the "normal" driver? ;)

you save a lot of gas! Hybrid mileage without the hybrid ;)

Re: D-FAS: High speed hypermiling technique for the very few …
 

Tailgating, at highway speeds, is a great idea. It's both legal and safe.

Re: D-FAS: High speed hypermiling technique for the very few …
 

foo monkey. It is niether legal nor safe. Unfortunately neither is going over the speed limit weaving in and out of traffic. But its rare you hear anyone complain about that or even make the realization that what they are doing is unsafe. At least people that do drafting and fas are aware of their surroundings and make an effort to be safe while doing it. Thats more than I can say for some of the high speed drivers I see on the road.

Re: D-FAS: High speed hypermiling technique for the very few …
 

Hi Wayne,

An interesting approach. In 1972, I had a '66 VW MicroBus an in a trip to the west coast over the high plains, I had to draft to maintain safe speeds on the Interstates. I could cruise at 65-70 MPH if I stayed 'tucked in' and 'between the buffet walls'. If I got into buffet, I knew I was getting too far and could 'loose the bubble.'

What I remember was three distinct states:

1. Smooth - you are completely in the draft bubble but generally within a very short distance, 15-20 ft. of the truck. You have to back off of the throttle our risk running into the truck. You have to steer to stay in the bubble.
2. Buffet zone - about the length of my van where it would rock but auto-steer behind the truck. A rougher ride, there was more space but this is the limit. But you need to put on the accellerator and get back into the smooth zone.
3. Too far - when even maximum accellerator could no long keep up.

In your technique, are you pulling into the 'smooth' zone and coasting?

This weekend, I commuted 650 mi. from Huntsville AL to Kansas City KS and back. I had Murphy head winds the whole way with my Prius. Not wanting to suffer and traffic-stop delays, I would pull into the 'buffet zone' and use my fingers to monitor the auto-steer. The Prius cruise control allowed me to adjust in 1 MPH increments up and down. This really helped keep the MPG 'less bad' but I wasn't trying for maximum MPG.

I noticed the bus seems to do a better job of keeping speed going up hills. The tandom-trailer seemed to do OK too about keeping constant speeds. But I realized that having an accurate distance and relative speed instrument would have made this a lot easier.

Have you tried using any electronic instrumentation to monitor either distance or speed to the vehicles ahead?

Have you tried 'tuff' testing to see what the turbulence and laminar flow areas look like around your vehicle?

With my Prius, I'm loath to turn the ICE off due to reports that above 42 MPH, it is needed to avoid overspeeding MG1. But the ICE will 'idle' down very nicely so I don't feel the needed to perform the 'forbidden experiment.'

Working just in the buffet, auto-steer zone gave me about a 5+ MPG advantage and off-loaded some of the steering tasks. The ride was a less smooth but I didn't feel I was risk of being stopped for traveling too close. Basicly, I was trying to mitigate the 43 (F) temperature and direct headwind.

Bob Wilson