I drive an '88 Buick LeSabre with the 3800 V6, automatic tranny, and FWD.
I do nearly all the work on it to keep it running (in a driveway - when it rains, I cover what I can with tarps and suck it up), and I'll be doing whatever mods I decide to do myself as well. I change the oil regularly (between 5k and 10k miles) and use "older vehicle" oil. I'd use synthetic but I feel like the benefit would be less than the cost difference, which in turn allows me to buy more gas... Oh, and I normally keep my tires properly inflated but come winter time I let that slide a little because the extra traction is WAY more important to me than a slightly improved FE.
There isn't much I can do to better my driving - I can't coast in neutral, not habitually, anyway (engine stalls out if I do it too much, rather not push the tranny too hard else I have to fix it), the majority, or what feels like the majority, of my driving is highway, and I drive between 55 and 60 mph (the speed limit is 65, 90% of people do 70 or higher) on cruise control, I never use the AC (plus, it's $80 minimum parts alone to fix it lol), unfortunately because I drive an old car and want to keep it running and don't have a coolant/oil thermometer (not one that I have access to, anyway) I always drive with the heat on, often on high, I accelerate as slowly as I think drivers around me can live with, I brake gently and well in advance of stops, I otherwise try to conserve my momentum as best I can while not driving in a manner that would piss me off if I was following, and I'm otherwise a very observant driver.
I probably do more subconsciously, but I'd like any suggestions. I'd draft, but everyone drives faster than me and I prefer to be lazy and slow, and safe(r).
Mostly, I'm interested in mechanical mods that won't anger my poor old engine and tranny, and won't turn my classic car of the era into an ugly clown car. Sooooo, yeah, there are limits, but I am very keen on anything that saves me some cash and doesn't make my lazy commute much more difficult (just a thumb on the wheel and open eyes for over 60 straight miles). Remember, I have an OBD-I connection that's damn near impossible to find a reader for, and thus monitoring my engine block's temperature (rather, in my case, doing whatever I can to keep it from overheating) is very important to me. Being forced to replace a transmission for a FWD vehicle without a lift in a driveway by myself is what I do *not* want to have to do any sooner than I have to already.
Right, so if you skipped all that, find me a few mods that don't involve making my engine hotter than its regular cruising temp. I checked out a few on the site but I'd rather just listen to your unbiased replies before narrowing anything down.
(edit: if someone notices that I didn't use an acronym, please correct me, I'm too lazy to learn them by myself )
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 to the car. They're not expensive. JC Whitney sells a gauge with sender for $32. I'm sure you could get into one for under $20 if you spend more time looking than I did (and I only spent 90 seconds on it). This would allow you to feel more comfortable with your car's condition, as well as not sweating your butt off in the summer.
There's probably a lot of aftermarket support for the 3800, and you may be able to upgrade the fuel injection, ignition, and maybe even the computer. I don't know how much there is to gain by doing so, but you may be able to do it cheaply with junkyard parts from newer vehicles.
I don't know if it would be difficult (probably would) but if your car revs high while cruising you could change the differential ratio. At least you can do that when the weather is nice.
You probably don't need a scanner to pull codes, but I wouldn't be surprised if you could find one to give you sensor data. However, you can probably get much of your data using DIY methods and contraptions, using gauges, meters, and LEDs that tap the sensor's wire.
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.
Most real improvements that people get are from driving techniques, not car modifications. Unfortunately, it sounds like you're already doing almost everything you can, and can't do most of the useful modifications. The usual things that would help are ruled out by various conditions you posted...
- No coasting rules out Pulse & Glide and downhill coasting. My 1987 FWD Cadillac's transmission took over 200,000 miles of awful abuse without ever complaining but that's no assurance that yours will survive thoughtful and careful usage of neutral. However, in my experience, the fear of the 'N' is mostly superstition; some vehicles won't cool the transmission sufficiently in 'N' but other than that it's no problem as long as you rev-match when putting it back in 'D'.
- No drafting -- well, would it bother you to draft tractor trailers at a lengthy 3 second following distance? Most people follow much closer than 3 seconds, but results posted by members here show that 1.5 to 3 seconds is the most effective drafting distance. It's not hard to find tractor trailers driving at your speed.
- 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). You might be able to experiment with an extended air dam. You might be able to remove the hood ornament (that would be a shame) and replace the likely wire-spoke hubcaps with interesting smoothies but they'd probably look too out of place on your car.
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. Your car is probably pretty light with relatively large tires, so you may not be able to safely run maximum pressure in the summer, but it's almost certainly necessary to run the car's recommended pressure in the winter. Running less than that is just begging for a blowout on the highway, even at 55 to 60mph.
That transmission already coasts automatically as soon as you lift your foot. One of the best out there for that - lift off the gas and it immediately releases and drops to idle. On the highway, don't let it downshift when climbing a hill - turn off the cruise and use your foot, allowing the speed to drop slightly as needed.
Just keep it rolling - standing starts are killers. Drive as if your brakes have failed. (but use them when approaching a light that's about to go green, so you can roll through without stopping)
A friend of mine with a 2002 Regal has done 40 mpg on highway trips, by simply driving a little slower, smoothly, and with higher tire pressure.
Do you have a Scangauge? You should buy one. It includes a temperature readout, and the feedback it gives you WILL pay for itself in gas savings. I saved over $500 last year.
Lots of people think that automatics go into neutral when you lift off the gas, but I have yet to see credible documentation or hard data that convinces me. With the torque converter unlocked lots of cars will allow the engine to simmer down some, but most won't go to idle.
Pale, you have my respect as someone who does a lot with hard data and credible documentation, and as someone who produces real results. Do you have anything to back that statement up?
Sorry about the scangauge thing. I didn't read the year model closely enough.
Driving with my friend in his Buick, scangauge and tachometer equipped. As soon as you let off the gas, the rpm drops down below 1,000. It may not be exactly the same as idle, but aside from the technical details it's pretty darn close.
In contrast, my Honda Odyssey will stubbornly hold it in gear when you let up. It gives you massive engine braking unless you manually shift into neutral. The two vehicles behave very differently.
In addition to higher RPM than idle, it also does some engine braking. It's not the massive amount you get from a foreign automatic or any manual, but it's still some. I'm not confident that it would produce good results, though I can't say for sure that it won't.
What was the speed where you observed the behavior in your friend's Buick?
Doing it in my truck with RPM at ~800 uses about twice as much fuel as putting it in neutral and reduces the distance I can go before having to apply power again. I don't feel the engine braking but the distance is far shorter. I'll have to gather some hard data the next time I drive.
Interesting. I believe you. You have more time in that truck that I do in the buick, for sure. We were driving around town, so somewhere in the 30-40 mph range. He just traded the buick for an Odyssey last week, so I can't do any further research with it. I'll defer to your experience.