trends in gaslogs, come discuss...
 

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!

Look at my log. You will note that the highway drives get way better MPG using hypermiling techniques than city.

I was able to get 42 mpg on a long highway drive - I was shell-shocked. Using the same techniques on my commute to work (mixed highway and city), I get about 32.

Without any hard data, my super-simplistic explanation is that the fuel flow rate is largely the same for any given RPM...so in slower city traffic (i.e. lower gears) for a given fuel flow rate you get lower mileage. That same flow rate at highway speeds nets you a much better MPG number.

I think partly the difference is that it takes a lot of faith, guts and to be honest, a huge pair to cut your engine off for engine off coasting (EOC) the first time you do it. once you see that it won't hurt your vehicle and will yield better mileage, you find more and more places to do it.

I am not recommending that you do it but that is what I have found. think about it. if you take your last tank and add 10, 20, or 30 gas free miles to the tank (because that is essentially what EOCing is doing for you) then yes your mileage will shoot through the roof.

also the scangauge will help out a lot because you can instantaneously see when you are using a lot of gas and when not.

*edit* I am not saying not to EOC, I am saying to make sure that it won't hurt your vehicle first, knowledge is power.

I EOC when possible, but on my daily commute, there just isn't much possibility for it. 6 miles, all of which the car isn't even warm yet, so if I try EOC it just dumps fuel on startup, and, my car is an auto, so EOC isn't as easy as just clutch starting from a roll.

I EOC'd on a few highway commutes on my first 30mpg tank as seen and read in my gaslog, but I can only roll about 3 miles at any given EOC spot, as here in hilly KY, once you're rolling down the hill, its not long before you're climbing another.

What are more techniques I should incorporate?? I realize the WAI will help a lot, and I've been putting off fabbing one until I got a scangauge so I can monitor air intake temps... same is true for grill blocking. After those two mods, what's left?

it also depends on the car and what the baseline numbers are as to how radical the change is. 35-50 mpg is what? 30% gain? now what's a 30% gain on a 20 mpg baseline? 6 mpg. it's not just the peak mpg but how much they've improved it. look at my truck, I've been very unscientific about changing things around (just add them in whenever) so it's been a very gradual increase and it started low but still over 25% (gas log average is lowered by the history... boo)

basically, you don't have to wake up and decide one day to hypermile. just gradually do it more and more. it has the same results even if it does take longer

For me; I started logging here after a couple months of a different Hypermiling site, but political differences cause me to leave that one. Once I had my ScanGauge I drove some just to test my techniques for a couple tanks, but now just drive when I actually need to go somewhere. I kept experimenting with Aero mods as the winter weather set in, so it was like paddling up stream. I didn't lie, but my cars nose still kept growing.

Many of us kept gaslogs before starting here, which is why you see pre-hypermiling in the notest for some, and for others they have tried out a few things first that helped before taking the plunge to things like EOC. This may be a couple of the reasons you see this.

Some only track highway miles, as their city driving can be measured in full tanks and so can their highway.

Some of this is placebo and self-fulfilling prophesy too. When one gets a scangauge they are usually happier (I hope you are too) and they also can start fixing the worst driving habits - so the addition of a scangauge will nearly instantaneously help them fix their bad driving.

When you start posting your gaslogs chances are you start to watch them more closely too, so you drive more carefully. Basically the more you try to save mileage, the better you will get at it, and it will keep increasing. The more you show it to the public, the better you'll want your numbers to be, sort of "keeping up with the Joneses" but on the internet scale.

Plus you'll feel more relaxed with saving money & fuel, so you will not need to hurry so much, meaning you'll start keeping speed down - all of these things will coalesce for you and you'll have a LOT better mileage!

Take a look at my logs. Mine have gone up steadily like yours.

I suspect that for your 6 mile commute won't be able to gain much -- and I doubt that WAI and grill blocking can help in such a short ride. You might need some crazy mods to get it to warm up for your commute, or a block/oil pre-heater system that lets you warm it up on mains power before you start the engine.

Really, though, you aren't putting on many miles so your gas budget is pretty small regardless of how many MPG you get.

quick response...

let's assume a 40% increase over pre-hypermiling.

20% increase via driving tech is reasonable, then figure another 20% via SEVERAL other mods.

any combo of overinflated tires, grill block, synthetic fluids, EOC, weight reduction, tune-up/fuel cleaner, aero mods, etc could TOGETHER be significant.

I've been keeping track of my mileage since I was 16. I never used any hypermiling techniques until recently.

With some cars you can get better results than others. I generally average 28 with my 6cly BMW which is much higher than EPA but no matter what I do I can't seem to average any higher than that unless it is a road trip where there is 99% highway. Then I might be able to hit 30mpg.

On the other hand I was averaging 16mpg in my SUV mixed and just by driving the speed limit and avoiding jack rabbit starts I get 18mpg consistently in mixed driving. It's no fluke either, I consistently get 18mpg tank after tank after tank. I think with a little bit of weight reduction and a grill block I could easily push past 20mpg.

I gotta tell you though, I looked at your gaslog and thats pretty abysmal. I easily average higher than that and my car is a 6cly. You either have something seriously wrong with your drive train or you need to make a more radical change in your driving habits.

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.

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.

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

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!

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.

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

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!

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.

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

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...

https://www.google.com/search?q=%22vehicular+cycling

For such a short commute, with no highway driving, why not a scooter? For that matter, an electric scooter or motorcycle. Me, I'd buy the cheapest (after necessary parts to repair it) beater scooter or motorcycle I could.

You could also try to find a more bicycle-friendly route.

The DIY fuel rate monitor link in my sig might help if your budget is too small for a ScanGauge right now.

scan gauge is on the way, but I REALLY appreciate the input from everyone... are there any more tips out there for driving style??

I think the best advise I have heard is to drive like there is an egg between your foot and the accelerator pedal.

I would check your plugs to see if the car is running rich too. I don't know what after market stuff is available for that car but you may be able to have the FI re mapped.

plugs have less than 10k on them and I just had them out and cleaned/regapped them less than 2k mi ago and they looked fine.

I don't think my car has seen 3,000 rpm, or half throttle, in nearly 6 months. Today's commute was typical, I did about 30mph when possible on my way to work where the speed limit is 45, and I take high speed turns and know which lights to coast up to, to give them time to change before I come to a complete stop. Like I said though, if a SOHC auto was having trouble getting 30mpg mixed, I'm feeling better about my achievements.

I just did the math and on a 12.5 gallon fuel tank, to get 300 miles each tank, I need 24mpg or better. I think I'll just drive to 300 from now on, each and every tank, and watch the mileage to see what's happening.

Try this list for ideas: https://ecomodder.com/forum/hypermili...ecodriving.php

Glad I could be of some assistance and make you feel better. Although I guess I should clarify when I was attempting to get 30MPG it was during the winter season and I did not use any of the P&G/EOC methods. Now that I have the summer blend fuel and am being more careful I am starting to see those 30 MPG mostly city trips.

Oh and I am a member over at SaturnFans as well and like you find it very informative, Thanks.

I just realized after reading the 105 MPG tips that I've been P&G'ing all wrong... I haven't been placing the trans into neutral, or shutting off the engine. I was just pulsing to 55mph, then slowing to 40mph in gear, then pulsing back to 50mph. Today on my drive home from work, I put the car into neutral and was surprised to see the idle was like 1300 RPM w/ engine fully warmed. At a stop, I idle at 750rpm, set per owner's manual about 3 months ago, but even in neutral at any speed, the RPM is above 1,200, what gives?

It's easy. People that have huge fluctuations either because they changed where they drive or they manipulate the numbers to try and justify what changes they have made to the car.

:rolleyes:

What changes in where I drive? I'm still driving from the same house to the same office every day.

What changes to the car? It's a tire pump and a scangauge away from being bone stock.

And Project - that saturn is one of the cars whose auto-trans can handle EOC and be happy all day long. Just another option to think about.

I had the same revelation in my Saturn as well, which is why I stopped doing it. Considering I could just keep the car at 40MPH and be somewhere around 1500 RPM's. However you could turn the car off, but being an automatic like mine you also might find that to be excessive as well. To each his own...

Take that thing out and ride on it a little bit! Engines aren't built to be idled around all the time.

Engines need to be run-in every once in a while or carbon buildup in the chambers and on the valves(in non-E85 and propane engines) start to hurt performance and economy. It also leads to poor injector spray patterns and the bad fuel spray can lead to accelerated cylinder wear and other issues. Usually, by the time the buildup has gotten to where it'll hurt performance it's too late to 'blow it out' and the engine needs professionally cleaned.

My 88 Toyota had over 200k on it when I sold it and passed a leak down and compression test with flying colors(within 5% of factory specs). Anyone that knows me and how I drive can tell you it saw WOT for about 20% of its life and got revved to the red line daily. My injectors sprayed like they were new and the bearings were actually in very good condition(inspected at 185K) which I attribute to not lugging the engine and pounding the bearings to death.

So far I have noticed that the best thing I can do to get my mileage up is to change throttle position little and drive slower.

It's looking like this will be another 30mpg tank!!

I'll probably fill up sometime over the weekend and then spend some time working with a test-HAI and test grill block... my SG should've been in already but USPS didn't recognize my address so I had to give an alternate and it just shipped today. :(

I have been EOC'ing where ever I see the opportunity to get at least 1/2 mile out of it, less than that and I don't think there is any benefit (just my opinion). It's too bad I don't travel more highway, around here the highways are very hilly and I know of at least 3 spots where I can and have EOC'd (before I even knew what it was....) just for the hell of it and rolled 2 1/2 to 3 miles for free!

Also, not that it's terribly needed, but I've been searching for a Civic to replace my Saturn and hopefully, I can just find a clean rolling shell so that I have my choice of engines!

I couldn't be bothered to read all the replies in this thread, so forgive me if this has already been pointed out. But couldn't the reason you're not getting good FE is because you are P&G in gear?

To me the assumption that the fuel savings of DFCO engine on do not outweigh the extra fuel used to make up for the engine braking during the glide. Either put it in neutral during the glide or don't use P&G. How far down do you depress the gas pedal when you accelerate or when you do your pulse?

One thing I learned recently is that--at least in my car which is a 5 speed with lean burn--is it's more beneficial to let the revs go a little higher and maintain a gentle foot on the pedal than to be shifting as early as possible and have the pedal near the floor. The other thing I noticed is that the power difference between flooring it and a gentle foot (say 1/4 pedal depressed) is not very big! I can only guess that the fuel use is considerably less when 1/4 pressed despite the small difference in power. So my hypothesis is that revving to 1500-1800RPM with a low throttle opening instead of always shifting at 1400RPM with the a wider throttle opening is saving me more gas (this flies in the face of Monroe's hypothesis, which I briefly agreed with but am now questioning, that it's better to floor it all the time and be at low RPM as possible.)

Anyway, that was a bit sidetracked from your issue. If you haven't already stated it in this thread, detailed info on how hard you press on the gas pedal when accelerating, how you handle hills, and at what RPM your car is shifting would be helpful.

One other thing to consider when P&G. This might seem obvious but when I P&G I always try to get as long glide as possible, but there are situations when this causes more detriment than help to your fuel economy, and that is when approaching hills. Much better to start accelerating again before you get to the hill so you have at least some momentum to carry you up the hill, otherwise you are going to need a wide open throttle setting to get up the hill. Though this is fairly obvious, I still find myself making the mistake of overextending my Pulse.

Hope some of this info might be of help. I'm very curious to know as specifically as possible details on your driving habits and the conditions you are driving in--the length of your trips etc.

I have no idea who the 5 best hypermilers around are, but that statement is very intriguing! Would they be the likes of who got 100+mpg in a Prius?

Maybe you could school the rest of us? You are getting better gas mileage than me despite all the EOCing I do and the car I have. What's the secret?

Yeah, I think since you skipped through a bunch of the posts you missed all that info! hehe

I drive w/ the "egg under the pedal" idea, I think 90% of the time I'm probably only giving the car 5-10% throttle.... never much more. The car shifts on its own when cold around 2200 RPM, when warm I can keep it around 1800 RPM. On my daily commute I don't approach any hills really, none that are significant. When I do approach hills though, I've done one of two things, either use CC to help me get up the hill, or follow semi's who have their hazard lights on and travel at 45-50mph up the hill, where I try to stay in 4th gear but the car hates and it generally goes to 3rd. If it goes to 3rd, I pull around the trucks and throttle until it goes back to 4th.

I didn't know P&G meant neutral or EOC before, but since learning that a few days ago, I've tried it a few times and I don't mind it and I'm not in fear or it, but its not very convenient and I worry about my trans takin the beating. I'd' rather stick to EOC when I see a good opportunity to roll up to at least 1 mile.

Look at the rankings in the HybridFest mpg competition, and look at the top of the gaslog charts at Cleanmpg. Wayne Gerdes and some of those others.

One of the biggest things I adjusted after that trip was using even lighter acceleration from a stop, and anticipating even farther ahead. Traffic light 1/2 mile ahead? Watch the cycles and time it. Also, being ready to loop into a parking lot when the light does turn red, and loop back out as it turns green - moving the whole time. Lots of little things like that.

And I do EOC all the time. It's probably about 50% of my drive. I'll do it if the glide is more than about 20 seconds. Shorter than that and I'll just engine-on neutral coast or keep a light, stead cruise.

It's just a hypothesis, and I can imagine all sorts of reasons why it might be wrong, especially under certain conditions. So I'm very interested in hearing about any theory that might work better.

I wouldn't be shifting at 1400 rpm - that's a bit too low. Shifting INTO 1300-1400 is what I do, and then take it up to 1800-2000, all depending on terrain and conditions.