trends in gaslogs, come discuss...

[mjswan]

Originally Posted by Project84

Here's what I notice. I notice those of you getting 50+ mpg, have similar trends in the gaslogs, where in the "notes" section, I've even seen 30mpg averages and then someone will write "began hypermiling" and the average for that tank will be like 38mpg.

Or I'll see baseline tanks and notes like "pre-hypermiling" with averages in the 30's and then an upward trend to the 50's.

How is it that one day you people just "decided" to start hypermiling and the gas mileage goes through the roof? I'm not calling you liars, but damn, I have seen TINY improvements thus far and I've drastically altered my driving habit (although my car is inheritly not a gas saver (dohc + automatic)).

My scangauge is on the way, will I be happier when it shows up?

Also, my mileage is generally about 70% city and 30% highway. I only drive 6miles to/from work each day, barely enough to let the car warm up.

I haven't done any mods really other than strict maintenance and 50psi in tires. Saturn owners please chime in!

Not a bad question, but to be fair all my mileage is based on an 85 mile commute each way, nearly all freeway. And, I am going the opposite way from all the other poor folks sitting in traffic headed in toward L.A. I have the opportunity to drive as fast--or as slow--as I choose. I choose to have the majority of the drivers irritated at me as I cruise at 58-60 mph in the slow lane. And I don't use my air conditioner. My mileage has increased nearly 10 mpg as compared to my previous commutes which involved dealing with traffic. You can see from my mileage logs--on either car--that initially my mileage increases were significant, but they have gradually decreased.

[palemelanesian]

In my log, see that I was getting low 40's when I started hypermiling. That first spike was due to a short fillup.
You'll see there's a big jump when I got the Scangauge - my first 45+ tank.
There's another big jump when I started doing serious P&G - my first 50 tank.

This last March I drove 4,000 miles across the country with 5 of the best hypermilers around, including Wayne Gerdes. Gaining from their collective knowledge pushed me up over the 60mpg mark these last 4 tanks.

I wasn't logging mileage before hypermiling, so I put in one tank at "about" what I was getting before.

[R.I.D.E.]

I read a lot on this site which caused me to buy a super low mileage VX that was rear ended and stored inside for 13 years.

My previous car, a Del Sol was good practice, but it took a while to get the hang of the VX. Lean burn and low differential ratios caused me to rethink my strategy, and make some significant changes.

The most important was to avoid high speed, unless it is necessary to keep from being a rolling roadblock. Then I look for a drafting source, like a big rig and just follow my 3 stripes behind, and people dont try to pull over in front of me as much as they normally would. This is on the interstate which around here means cars tailgating 3 or 4 lengths at 65+ MPH. I am much safer behind a truck because people dont tend to tailgate quite so bad.

I also have to maintain a minimum speed or risk getting out of the traffic light timing. I tend to pulse and glide somewhat less, I think at 52 MPH it becomes a wash if you can't draft. The light timing controls the speed, if I slow down any more I start catching yellow lights, then red.

Instead I focus on DFCO and use it almost exclusively when I need to slow down. In most cases I end up in exactly the gear I need to accelerate with RPM around 1200. Understanding the tactic of DFCO is the critical part of my recent jump in FE.

I did a coast today that lasted for almost 7 tenths of a mile. Another one ended with a DFCO after close to 6 tenths. These are mostly slight downhill grades where I can coast down 15 MPH.

My last two tanks were excceptional, 68.5 and 65.6 MPG. I dont turn my engine off in traffic, only to coast the last 3 tenths to my house.

I did notice a difference in idle speed due to my WAI. I shut it off on a 90 degree day and my idle speed went up about 100 RPM. With it on my idle is very low, which reduces idling fuel losses.

My goal with this VX was 60 MPG. I think I have the tactic down pat to get to that point. I could go somewhat higher but it would certsainly be a lot more work with a small benefit, concentration I need for situational awareness when traffic is heavy.

regards
gary

[Project84]

Pale, reading your gaslog is what triggered me to post this thread.

opelgt73, thanks for the smack in the face, but in reality, this engine is known for blow-by (which mine has a terrible case of) and constant problems with Engine Coolant Temp sensor, making the computer go crazy and think your running cold when you're actually overheating. That being said, like pointed out before, this isn't the ideal car for hyeprmiling. It's "finicky" as I like to put it.... and yes, your 6cyl gets the same mileage as my car, and I don't find that astounding, my parents have a '92 Bonneville w/ a 3.8L V6 and automatic that averages 28mpg and my g/f drives an '04 Grand Prix 3.8L auto that averages 27mpg. These are the things that annoy me!!! lol

I don't see why I shouldn't be able to find 35mpg city though.... I've went from 27 to 30 thus far, hoping my fill up at the end of this week will be in the 30's again. I just ((feel)) like I'm trying really hard and concentrating and I'm very aware and conscous of what I'm approaching, what I'm around, who I can draft, etc, and it seems like there's little pay off so far.

Perhaps w/ the scangauge I can reshape my recently changed driving habits into even better ones.

also like to make note that, since joining this site and keeping better track of mileage (I've always checked mileage, but just recently kept the log) I do drive more consciously and I think it is paying off a bit.

Also, I know I don't drive much but I've been searching like a mad man trying to find a SOHC Civic, mostly due to feeling so guilty about not getting 40+mpg in such a non-rewarding car. I mean, my Satty has no resale, no aesthetic appeal, no creature comforts... its pretty sad!

[palemelanesian]

Overall, the upward trend is all about learning. I'm still constantly trying to refine my technique and optimize everything about my driving. I'm not one go to halfway into something.

I think the instant feedback from a scangauge will be hugely beneficial for you.

[Zvolen]

Project:
I am in almost the exact situation as you, SOHC AUTO Saturn with a relatively short 5-6 mile commute which is all I really drive. The same was true for me as I found it hard to get over 30MPG in the city even with my concerned driving. However when I drive on the Freeway/Highway that is when I see larger gains with my new driving style.

I have tried various things to help but like others have stated it is tough to improve much on such a short interval so instead I have found ways to not drive at all. For instance since I live so close to my work I use to drive home everyday for lunch and since staying at work I have found I save much more gas and my MPG as actually improved since I am sometimes in a hurry during lunch.

This gives me the same effect as improving my MPG since effective it is doing the same thing, decreasing my monthly bill and using less gas with all of the benefits that provides.

**Edit**
I do however need to update my gas log with all the current info

[Project84]

Zvolen, you make me feel good... for once in this thread! If you were having trouble getting 30mpg in your sohc saturn, and I'm hitting 30mpg in my DOHC, I feel a bit better. Not to take away from you but, if you look over my detailed gas log and vehicle description, you can see that I recently took charge and preventive maintenance and really gave my Satty all the goods it needed to return positive FE results. Perhaps your Saturn needs some maintenance. You may find it helpful to sign up at www.saturnfans.com (saturnalia) where I honestly learned quite a bit, and someone over there, I forget his name, has posted TONS of DIY videos on youtube showing you things like replacing the water pump, replacing engine mounts, replacing coolant temp sensor, etc.

I was SO serious about buying a bicycle this year, and I've put it off because about 3 miles of my commute is on a two lane road w/ a VERY small shoulder, effectively leaving no room to safely ride w/o being in the way of traffic. That being the case, I've given even more thought, recently, to buying a used Ninja 250. The downside, the 250 costs a lot more, and returns no health benefits and is possibly more dangerous than riding a bicycle those 3 miles on the road.

I'm really looking forward to the scangauge... my g/f's '04 Grand Prix has a monitor in the dash that shows instantaneous MPG and I was recently able to get her tank average from 27.3 up to 33.7 during a trip to Tennessee and back. I think being able to read the live results will help me a lot!

[Project84]

also, I'm running 205 wide tires, factory spec I believe is 185, but at the time of tire purchase a year ago, I was REALLY into SCCA and thought if my Camaro ever broke down, I could still race my SAturn, so I wanted the widest foot print possible. How do I calculate the MPG difference w/ the wider tires? That should help me be even more accurate.

[Hateful]

http://www.miata.net/garage/tirecalc.html TheHolyCow put this link into a prior thread; may help

[slurp812]

It does take quite a bit of work to keep the numbers up. some days I just start to get frustrated and just drive like an idiot. But then its back to it...