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Old 06-18-2007, 01:15 AM   #1
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o/~ I feel goood o/~

Firstly, I'd like to personally thank each and every member of Gassavers for both your advice and just being yourself as a member.

So, up till the 16th of June, most of my trips have been local within the city and it's highways. Well, on the 16th of June, I had the opportunity to do some inter-city driving to see if I've learned enough hypermiling thus far.

So the segment from home to the destination started out like any other regular merging onto the on ramp to the highway. Then, to help my focus, I punched 55 mph into my cruise control. I used a consistent RPM of around 1800ish RPM on the climbs and the flats, then coasted down hills. When my speed dropped too much below 55 mph, I would apply a little gas to help maintain 55 mph down the hill. Unfortunately, there were like at least three major pockets of traffic on the way, the third was due to a bottleneck caused by a clean up crew trying to tow what looked like a small four door sedan with it's rear trunk opened up, no windows, and heavy charring which suggests the car was burned. I have to say that when the traffic got heavy on the highways, instead of the road rage I used to feel, I switched mental modes from "highway driving" to "city driving" to include things like popping the gear from D to N when the car in front of me has stopped for a relatively long time. The mental switch from "highway driving" to "city driving" helped me remain relatively calm to the point it was almost as if I had "negative road rage." It was almost like I was in a meditative state. Even though I ended up like an hour late to the destination, I felt a certain sereneness that seems to be coming from knowing that my mpg was probably high that washed over any sense of guilt for being late.

On the way home, once again I hit heavy traffic but once again, switching mental modes from "highway driving" to "city driving" helped me retain my sanity through it. As before, traffic permitting, I punched in 55 mph into my cruise control. Since it was really late night driving, in order to avoid too much boredom that may lead to sleepiness at the wheel, I tried to practice some "pulse & coast." Man that helped keep my mind alert because as I've read already, it takes quite a lot of concentration to pull it off. I'd have to agree with that statement. Eventually, I made it home safely.

The day after, after doing a few errands, I faced the gas pump to be the judge of my performance. So after swiping my card, putting the nozzle into the gas tank filler neck, pulling the trigger, and engaging the trigger lock, I awaited the gas pump's verdict. The gas pump's verdict was 9.850 gal of gas filled up. As shown in my gaslog, that works out to be _28.32 mpg_! Based on my Old EPA Combined FE of 20 mpg, that's a 41.6% above EPA! That's the reason for this thread's title and opening sentence in this post. To sound suggestitive, that was the best darned Saturday night I've had in a long time. :P

So, as an enthusiastic member of GasSavers, if there was ever an infomercial for GasSavers, I would be one of those "Actual client with NO compensation" folks giving their testimony. USE the advice found here because they work, even for a non-hybrid car like mine.

Ok, since I'm still a relatively newbie here, I've got some questions:
  1. I noticed while driving with cruise control set to 55 mph, that when I am going down a gentle hill, the RPMs drop a little, but when I'm going down a relatively steep hill, the RPMs spike like higher than 2500 RPM. Why is that?
  2. While climbing a relatively steep hill, the first two times I just let the RPM spike up, but the third I disengaged the cruise control and tried to hold a constant 2000 RPM and accepted whatever mph that gave me. Was that right? Would I definitely need to consult a ScanGuage to determine the rightness or wrongness of what I did?
  3. While coasting down a relatively shallow hill, I noticed that the mph decreased below 55 mph. Fortunately, since it was late at night there was not that many others around me so I "got away" with coasting at 50 mph or less. So occasionally I nudged the accelerator pedal to help maintain 55 mph. Was the addition of the accelerator a good or bad thing?
  4. As far as pulse & coast, I had the cruise control set to 55 mph, then pulsed manually up to 60 mph, then coasted down to the 55 mph cruise control setting. Was that the proper pulse & coast technique?
  5. While pulse & coasting, I'd encouter some gentle uphills. Is it better to climb at 55 mph or continue to pulse even on uphills?
  6. Upon review of pulse & coast after I got home, supposedly pulse & coast is best used on long stretches of flat. Can pulse & coast be effectively used in hilly conditions or should I stick to the basics of: 1) hold a constant RPM for climbs 2) hold a constant RPM for 55 mph on flats 3) coast down hill at idle power?
  7. Any other advice or comments?

Once again, I'd like to say, you guys and gals rock.

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Old 06-18-2007, 05:46 AM   #2
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Originally Posted by rGS View Post
  1. I noticed while driving with cruise control set to 55 mph, that when I am going down a gentle hill, the RPMs drop a little, but when I'm going down a relatively steep hill, the RPMs spike like higher than 2500 RPM. Why is that?
Our Honda minivan has something called "grade logic" where it downshifts going down hills to help control speed. Maybe your van has the same. On the Honda, it doesn't engage unless the driver touches the brake. Maybe yours has similar rules, like it only engages if you touch the brake, or if the cruise control is set.

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Old 06-18-2007, 06:20 AM   #3
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1. Not sure why your RPMs will spike that high....maybe a TC unlock??
2. In my exp., the RPMs will spike on a climb in CC. This is because the cruise is struggling to maintain the set speed. If it can't get that speed in OD, it will downshift (higher RPM spike) to reach your speed. My Jeep sometimes will downshift to 3rd for a few seconds while it climbs up to 55, then drop into 4th for a few seconds. When the speed hits 45-50, it will downshift to 3rd again (big waste of fuel, IMHO). I just disengage the CC on long/steep hills, and hold steady throttle.
3. IDK if the accelerator was good thing or not. Maybe try coasting downhill in N?? that will lower the engine RPM, and help out with your coast....
4. I've got no idea....I'm trying to figure out the proper way to P&G with my Jeep currently.....(damn auto trannies!!)
5. Same as above
6. I like your suggested approach, instead of P&G on the hills. Steady throttle on flats and uphills, coast downhill in N if possible. Here in IN, there's not much for downhills.....I usually coast 1/2 way down in N, then hit drive and the skinny pedal to get up to my hwy. speed. Taking a little advantage of the downhill + gravity effect.....

I guess a lot of this is kind of an open debate, at least until we get some "accurate, unbiased" opinion....from Scangauge or SuperMID, I'm thinking.....
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Old 06-18-2007, 06:58 AM   #4
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First: congratulations, rGS!

I have my doubts that pulse & coast will work at highway speeds in an unaerodynamic vehicle (CD & A). The coasts will be too short to make up for the penalty of the pulse. Sub/urban driving is another story, however.
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Old 06-18-2007, 07:02 AM   #5
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You've got a good gaslog!

Stick around, you've made great progress!
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Old 06-18-2007, 11:58 AM   #6
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I totally agree ! Some great progress has been made .What other have said about the rpm spike is real close to correct - you just need to learn to take advantage of it . I've not had any vehicle that has done that so tweak the technique ! I found that the cruise (while consistant ) a bit to aggressive for the roads I drive and am having quite a bit of success without it . As far as your pulse & glide technique - keep trying it for a tank or two , you just may need to tweak it a little. example:Make your maximum speed 55 and glide down to 45 or 40 (if traffic allows) then pulse back up very slowly to 55 . It takes me a 'good' half mile+ to get back up to my max speed . Try to glide as far up hill as possible before using throttle to hold or gain speed . If you can keep the SG under 35-40 LOD uphill it really helps (I aim for 30-35 LOD) ...Keep up the good work and keep experimenting most definitely !
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Old 06-18-2007, 12:05 PM   #7
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You should feel good! Seeing your gas log go from a pre-hypermiling 18.56mpg to 28.32mpg is really motivating.

The only other thing I've done besides adjust my driving style is take extra weight off of my vehicle. I've experimented with things like Acetone, which may or may not be helping.

The greatest advance came from slowing down.

Keep it up!


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