Care to lend a hand?

[bowtieguy]

sounds like you're are limited to what you can do. but, here's the same motor, similar driving, different car...

http://www.gassavers.org/garage/viewgaslog/775

[Ford Man]

Harbor Freight has a trio gauge set (oil pressure, water temperature and amps) for under $20. I have a set of them on my '88 Escort and they're accurate.

[Philip1]

add a vacume gauge if you keep it reading as high as possible you will see better milage.

[theholycow]

Wouldn't high vacuum indicate a lot of pumping loss?

[palemelanesian]

Correct. I like to accelerate at around 12 psi MAP, or very low vacuum. It's somewhere around 75% throttle. Low rpm, of course. Then I glide, glide, glide.

If you're aiming for steady speed, then high vacuum is good, as it correlates to high instant mpg.

[GasSavers_RoadWarrior]

Yup, granny accelerating really doesn't help FE. Marvin liked enough throttle to take him to about 2500rpm and keep him there until up to speed. BUT having said that, still drive as if your brakes have failed, accelerate briskly but no more than required at any instant in time, if the traffic is speeding up slowly, that might be a kind of spurt and coast regime. It's not smooth, but it works.

"Jackrabbit" starts killing FE is something of a myth, going too fast kills FE because you have to brake. If you've read the road ahead and are sure that the speed you're aiming for is appropriate, then you're just wasting gas not to be at that speed.

Wile-E is proving something of a tribulation with this at the moment, especially when cold the transmission is changing too early and he's pinging a little as it slogs. This is partially due to having to be gentle with the pedal due to winter conditions. I'm wanting to pull to at least 2500 but he's changing at 1500 and struggling ... I guess I should stay out of OD until he's warm.

[theholycow]

Don't go getting shift points and acceleration rate involved...we were just talking about throttle. Once you attach shift points to throttle (as in an automatic), the game changes entirely.

Now that I have my SG I'm finding that my auto GMC surprises me. I have been watching the instant MPG readout and I thought it would squarely confirm what I've observed in my manual VW with tank-average MPG experiments.

In the VW it definitely saves gas to use the tallest gear possible and lay on the gas. I learned that by experimenting for tanks of gas at a time. I drove it with the SG for a few days and didn't notice anything to raise any doubts.

In the GMC with the torque-beast V8 and 4 speed automatic, my strategy (which has been pretty successful) has been to lay on the throttle as much as possible within the confines of keeping RPM low and gears high. However, the SG is reporting interesting information about higher RPM and power -- if I let it kick down a gear or two and rev up to 2500, 3000, or more...I get one hell of a lot of acceleration without paying much more loss of MPG. I might lose 20% to 60% of my MPG but it seems like I gain more speed. As the RPM and speed climbs, the MPG stays steady or even improves. The downside is that my glide starts sooner and therefore ends sooner (unless I pulse higher). I'm not sure just how much of this is due to OBDII lag, but when I can get a steady baseline MPG average going again, I'm going to experiment with it.

[amizcuz]

Originally Posted by theholycow

Welcome! The Lesabre is a nice car, even if yours is a beater, and that generation of Lesabre still looks cool to this day (IMO). The 3800 has a reputation as a robust, long lived, and efficient engine. Can you post a picture of your car?

I would definitely add a temp gauge snip

There's probably a lot of aftermarket support snip

I don't know if it would be difficult (probably would) but if your car revs high while cruising snip

You probably don't need a scanner snip

In my sig, there's a link for a fuel rate meter; in the linked thread, there are links to similar/better ideas. You may be able to pull a DIC (Drivers Information Center, the factory-installed MPG gauge) from a similar car in a junkyard.

snip

- No coasting rules out Pulse & Glide and downhill coasting snip

- No drafting snip

- You already conserve your momentum and limit your top speed.

- You can't do any grille blocking or install a warm-air intake because of your fear of overheating.

- You can'd do aerodynamic modifications because you need to look respectable when you arrive (and your car doesn't leave much room for improvement without making it look bad) snip

Increased tire pressure may be a worthwhile experiment. You sound like you're decided on your tire pressures without having experimented and actually tested to see how it affects traction. snip

I could post a picture eventually - right now I just have a picture of a beflowered door handle. Within a few days of owning it I let someone sit on the hood and the trunk and they had something metallic and scratchy, so I have a few rusty scratches on my hood, but I like to think that they add to the car's "character", like a scar or something.

Aftermarket parts (at least newer technology) are a great idea, and those jobs are relatively simple and cheap

The engine is great to drive - just basing this off of how it sounds like it's revving, it likes cruising between 55 and 65. I feel like there's a greater delay between my accelerator and an increase in revs than other, newer vehicles (98 f-150 triton, 00 taurus, 96 cavalier, 05 focus), but other than having to learn how to adapt my driving to this I don't know if it helps ya'll.

I'll look into scanners again.

How would I read the output of the DIC?

I've tried coasting in neutral (both engine off and on, different tests), and the engine always either ends up stalling or doesn't turn back on if I do it as often as it benefits me. I can and sometimes do cruise in neutral, but only on short trips along paths that I already know well. I wonder if my issues with neutral stem from a less-than-effective fuel pump or some other blockage (I'm not so great on diagnosing problems yet).

Since I posted, I retried drafting, but with a different (06 cavalier) car, and noticed lower rpms at the suggested distance, and I think I'll give it a another try in my car. I won't be sure if the increased FE will offset my annoyance at having to adjust to the trailer's speed changes until I install the fuel rate monitor (or one of the similar/better ideas).

I could probably block the grill in the winter, at least. And what's an air dam? The area beneath the grill and bumper?

My car still has every external badge (really surprising considering the condition I bought it in), which is why I haven't sold my original wire hubcaps for something cheaper, lighter, and less of a ***** to get on and off (my dad ground down a socket to fit the lock on my hubcaps - it works, but I haven't spent the time to mark exactly how it fits on each hubcap, so I have to figure it out each time I want to take off a tire. I understand that every little bit of decreased drag helps, but I agree that it would be a shame to take off the hood ornament.

When I wasn't concerned with traction (I've driven at least 50 miles through nearly every major winter storm in the northeast in the past two years, foolhardy, but successful each time) I keep the tires inflated and check them at least every two weeks (usually before I notice anything visually). My new tires are properly inflated and I plan to keep them so

I have noticed that my car seems to decelerate faster when I shift it into neutral than when I just drop off the gas, and the rpm (I'm doing this purely via sound btw, no tach) sound about the same. I'm not sure which saves more fuel, but a guess that's based purely on my experience (not noticing an especially different FE when I originally tested, but my methods could have been better) tells me that if the engine is on, the difference between neutral and my foot off the pedal is very small.

Pale - I make mistakes like that all the time. It's best when they're minor, inconsequential and someone notices

About the torque converter - my auto experience is based purely on this car (not a bad car to learn on, thus far), my dad's only really taught me things as I've needed to know them. I can double flare brake line (as well as other repairs), but I have just the faintest idea of what the idea of a torque converter (something that converts torque, and I'm assuming it has to do with shifting between drive and neutral) is, and no idea of what it looks like.

Actually, I do have one of those combination sets of three sensors, but what's holding me up from installing it are: where to put the gauges (more an excuse to procrastinate, but I also don't want to slam my knee on them), the fact that they're not electric, and it's cold outside right now

[quote=roadwarrior]"Jackrabbit" starts killing FE is something of a myth, going too fast kills FE because you have to brake. If you've read the road ahead and are sure that the speed you're aiming for is appropriate, then you're just wasting gas not to be at that speed. [quote]

Isn't there a point where aerodynamic drag cancels out the benefit of speed (more miles per time) because the drag increases to a point where the engine is fighting it more than other frictions? And could you elaborate just a bit more on the jackrabbit starts? I assume that people who jackrabbit probably burn more fuel because they overshoot their cruising speed and have to brake harder than otherwise, or because they spin out their tires.

Thanks everyone! I got a lot more responses than I expected.

[amizcuz]

Also, I sort of live out of my car so I bet I'd get better gas mileage if I packaged my stuff better and took it out whenever I could. But then again a lot of my stuff is stuff that would make me really happy to have if I ended up stranded somewhere (either no other place to sleep or repairs that I couldn't do with the tools I have in the car and I can't get cell signal to call roadside assistance) - and while the roads I drive are usually major, I usually travel them when there's as little traffic on them as possible (late at night/early morning).

What does acetone do to improve gas mileage? I read the gas log of the car that someone posted, and the driver mentions acetone...

[theholycow]

Originally Posted by amizcuz

How would I read the output of the DIC?

If you can find one that's compatible and manage to get it installed, it will just display the information.

http://www.gassavers.org/showthread.php?t=4258

I've tried coasting in neutral (both engine off and on, different tests)

Don't make a habit of coasting in neutral with the engine off. That can destroy an automatic transmission, which requires the engine to run its oil pump.

I wonder if my issues with neutral stem from a less-than-effective fuel pump or some other blockage (I'm not so great on diagnosing problems yet).

If it was something like that, it would probably also stall when in Park or stopped.

I could probably block the grill in the winter, at least. And what's an air dam? The area beneath the grill and bumper?

Yes, that's what the air dam is. It's usually a plastic piece hanging down, either as an extension of the bumper or separate.

Here's a separate one:


Here's an integrated one that's been extended by adding a second one from a junkyard:

(That's user Jay2theRescue's truck.)

I have noticed that my car seems to decelerate faster when I shift it into neutral than when I just drop off the gas, and the rpm (I'm doing this purely via sound btw, no tach) sound about the same.

That is not normal. I wonder if it could be related to your stalling in neutral. It should coast further and decelerate less when in neutral unless your engine is idling very fast. What speed did you try it at? I can imagine at 30mph the engine could continue to power the car at idle.

I have just the faintest idea of what the idea of a torque converter

That's an easy one. It fits between the engine and transmission, where a clutch would be, and does approximately the same job as a clutch. The TC is essentially two fans blowing oil at eachother. When you come to a stop while in D, it doesn't need to disengage like a clutch; the engine side keeps spinning and the transmission side stops. The transmission remains in gear and the oil in the TC gets thrashed/sheared while it waits (that sounds bad but it's fine).

The TC allows the engine RPM to not match the transmission RPM; the engine can go slower if it's not applying power or it can go faster if it is applying lots of power. Modern TCs can lock and are called Torque Converter Clutches; when locked, they cease to allow any slippage and act just like a fully engaged clutch. Locking on modern TCCs is controlled electronically by the computer.

Here's what a TC/TCC looks like:


There's a nice disassembled view at:
http://www.tciauto.com/Products/Tech..._explained.asp

Isn't there a point where aerodynamic drag cancels out the benefit of speed (more miles per time) because the drag increases to a point where the engine is fighting it more than other frictions?

Aerodynamic drag increases as a square of speed rather than directly proportional, so at 50mph you might have about 4x as much aerodynamic drag as you do at 25mph.

Someone else should post about the transition from Laminar to Planar (did I get the terms right?) airflow, because I don't know anything about it except that it happens at a different speed for each car (between 50 and 70mph on average) and reduces drag at that speed.