trends in gaslogs, come discuss...

[dkjones96]

Originally Posted by Project84

I don't think my car has seen 3,000 rpm, or half throttle, in nearly 6 months.

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.

[friz]

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.

[Project84]

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.

[Project84]

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!

[1993CivicVX]

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?

Originally Posted by Project84s Gaslog

Trying to pulse and glide a lot, but speedlimit in city is 40mph and if I pulse to 45mph and glide to 35mph the car wants to shift back to 3rd which I'm sure doesn't help at all.

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.

[1993CivicVX]

Originally Posted by 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.

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?

[Project84]

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.

[palemelanesian]

Originally Posted by 1993CivicVX

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?

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.

[monroe74]

Originally Posted by 1993CivicVX

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.)

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.

[palemelanesian]

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.