HyperMile

[Bror Jace]

My 1995 Civic DX had no power steering ... thing was fine with skinny OEM rims and tires but a bit of a bear with the wider, high-performance tires I put on it ... especially in paved parking lots.

My 1968 Camaro had no power steering and no power brakes (4-wheel drums) ... but I loved driving it anyway.

If only it had a manual transmission.

 

[glennc]

Originally Posted By: Shannow
Checked my E30 (early '80s model, leaded fueled, open loop injection system), and it's definitely fueling on over-run.


That is sort of interesting. Mine, which is an '89 325i, does cut fuel when off the gas. The fuel-economy gauge goes to the stop at infinity, and if I reset the trip computer it'll read 99.9mpg. In fact, as I'm coasting in gear and the rpms change around the cutoff point, I can watch the gauge go from near the stop to the stop, or vice versa, whenever it changes.

The difference must have to do with the engine management system, as I recall having read that the E30s switched from an older Bosch system to a newer one not long before the '89 models. I think they went from Jetronic to the first Motronic around the mid '80's, and then to a second iteration of the Motronic system around '88 or '89.

 

[rationull]

Originally Posted By: glennc

The difference must have to do with the engine management system, as I recall having read that the E30s switched from an older Bosch system to a newer one not long before the '89 models. I think they went from Jetronic to the first Motronic around the mid '80's, and then to a second iteration of the Motronic system around '88 or '89.


Interesting. The car I was commenting about in my earlier post that did not do the cutoff except at high engine speed also used the Bosch Jetronic EFI system. So seems like for the BMWs as well, the change in fuel injection system did include the fuel cutoff feature.

 

[twentynine]

If you got an auto tranny and you take your foot off the gas (zero throttle position) don't you coast on down like you were in neutral?

 

[Shannow]

glenn,
mine is a leaded version (Oz didn't get rid of lead until 1987 MY, leaded fuels lasted beyond that), so there's no O2 sensor or closed loop operation.

Haven't even been able to find a throttle position indicator/switch, so I doubt that the computer is ever going to "know" that there's an over-run.

Definitely fuels on over-run, as engine braking increases when on overrun, and pops badly when ignition is turned on

 

[daves66nova]

Originally Posted By: twentynine
If you got an auto tranny and you take your foot off the gas (zero throttle position) don't you coast on down like you were in neutral?
I don't think so.The trans is still connected inside the t.c. ,I THINK.you'll notice a good drop in revs if you go downhill with the trans in drive and in neutral.

 

[dwendt44]

Some of the newer computer controled transmission unlock when coasting. My last two cars didn't seem to want to slow down very fast when I tap the brakes to drop out of cruise.
Got a ticket a few years ago for just that reason; car didn't slow as I entered town (a known speed trap).

 

[ericthepig]

My first result from hypermiling (Mazda 323).

Before HM - 26 mpg city.
Applying HM techniques - 32.5 mpg city.

Nothing to exactly write home about. Presently I'm doing the coast method (engine on - whereas before I was turning it off every chance I got).

 

[harry j]

Originally Posted By: ericthepig
My first result from hypermiling (Mazda 323).

Before HM - 26 mpg city.
Applying HM techniques - 32.5 mpg city.

Nothing to exactly write home about. Presently I'm doing the coast method (engine on - whereas before I was turning it off every chance I got).



Looks good Eric, I think evveryone should give this technique a try.

 

[Buffman]

Originally Posted By: dwendt44
Some of the newer computer controled transmission unlock when coasting. My last two cars didn't seem to want to slow down very fast when I tap the brakes to drop out of cruise.
Got a ticket a few years ago for just that reason; car didn't slow as I entered town (a known speed trap).


based on my tuning experience from my car, converter will unlock when coasting. A simple check box keeps mine locked until under a certain speed at 0 % TPS. I will also be playing with the DFCO (deceleration Fuel Cut Off) settings to try and optimize it as best as possible.

 

[Audi Junkie]

Big difference coasting with my a/c on and off. Without air, it seems to unlock for a good deal of distance of coasting.

 

[Drew99GT]

Coasting and timing stoplights is the easiest way to gain a few mpg in town. Look far enough ahead - if the light is turning red or is red, lay of the gas and coast - you'll coast right through after it turns green. If you see it just turned green, bump your speed up a bit so you won't hit the light. Great way to save brakes as well.

I've never understood why people haul a$$ up to redlights. I swear some people look no further than their hood when they drive - I routinely see people focusing more on passing someone. Once they pass and are going 10 over the speed limit they realize the light right there in front of them is red (they have no clue it's been red the entire time) and JAM on the brakes. Idiots.

 

[mpvue]

since I've been driving more conservatively ( I hesitate to cal it 'hypermiling') I've noticed others' bad habits, much like I realize I was driving too fast, 'keeping up w/ traffic'. I set my cruise at 60 (on a 65mph interstate) and people will pass me only to hit the brakes, cut right back in front of me to get off an exit ramp! also, on a new bypass opened up recently, the limmit is 45mph, heavily patrolled, so I set my cruise at 45 or 50. the road has about 5 traffic lights on it. the whole crowd the speed past me, only to get hit at the next light; I cruise up behind, only need to stay stopped for a few seconds, then whoosh! they are off again!
I'm happy to say, even w/ using AC now (I can't drive w/o it, sorry) my mpg is still around 30, from a 'used to be' avg of low 25's, so I'm happy.

Originally Posted By: Drew99GT
Coasting and timing stoplights is the easiest way to gain a few mpg in town. Look far enough ahead - if the light is turning red or is red, lay of the gas and coast - you'll coast right through after it turns green. If you see it just turned green, bump your speed up a bit so you won't hit the light. Great way to save brakes as well.

I've never understood why people haul a$$ up to redlights. I swear some people look no further than their hood when they drive - I routinely see people focusing more on passing someone. Once they pass and are going 10 over the speed limit they realize the light right there in front of them is red (they have no clue it's been red the entire time) and JAM on the brakes. Idiots.

 

[firemachine69]

Originally Posted By: Audi Junkie
Big difference coasting with my a/c on and off. Without air, it seems to unlock for a good deal of distance of coasting.



A/C in my Yaris enhances the DFCO 'experience' quite a bit more... I use it more often than brakes sometimes! Free A/C *and* less pad wear!

 

[bob_ninja]

Well I'll jump in although I missed most of older msgs:

Civic CX 1995 1.5L I4, manual
This is a perfect machine for HMing. The commute pattern before:
80% hwy, speed range 60-75
occasional anticipation of red lights, easy/slow accel
typical 18 km/l, 42 mpg

This was fine except prices kept climbing, so I decided to try some HM methods:
1) lower speed range now 56-62
2) mild version of P/G with aggressive anticipation of traffic and light ahead
3) trailing trucks, distance 10m-15m (estimate)
5) kill engine at lights for 30+ seconds (average around 1 min)

Now I am getting average 21 km/l, 50mpg
However, when I manage to trail trucks a lot I get even better results. The last tank was:
430km 17L = 25km/L = 59mpg
This one was rather strange. Still I do manage to go over 50mpg often.

The bottom line is I see significant improvements and I like it. Also, nice side effects:
1) much less stress in right lane
2) much less breaks use since I am slower than most everyone else
3) less lane changes, less hassle
4) can relax more as I work less driving

Regarding trailing trucks and safe distance, I adjust my spacing based on traffic conditions. When I see/anticipate heavy traffic then I don't follow trucks or keep more spacing. Sometimes trucks kick up dust which is annoying. Then again my car is 13 years old so I don't care

Next I'll try this on my other vehicles. In winter I switch to a Protege which has a 2L I4 and CRV also 2L I4. I am especially interested in CRV since it has a horrible drag with big body and winter tires. I may try even lower speed range to 50 mph.

 

[Kestas]

There was a time where I used to downshift for high rpms while coating to a stop. This allowed the (free) energy to go to the a/c compressor and keep me cool.