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Poor mileage acceptable to Toyota - READ ONLY

69 messages,  Last post on Jun 24, 2003 at 5:04 AM

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What is this discussion about? Toyota Tacoma, Fuel Efficiency (MPG), Truck

Messages Page 7 of 7

#60 of 69 rlafaver's mileage is probably from driving style by dieselbreath

May 10, 2003 (2:46 pm)

So far I've read:
- you're driving really easy, shifting under 2000 revs
- your 4-cyl truck has a 4-valve-per-cyl. engine
- you're not getting suitable mileage in town, but doing good on the highway.
This is perfectly logical. You're only mistake is thinking that mileage is inversely proportional to REVS when it is proportional to EFFICIENCY.
Small displacement engine designers increase power by reving the engine faster (to draw in more air & fuel). To increase efficiency at high revs, they've added more valves to let the engine breath. And they've likely optimized the engine timing, cams, etc. for a tradeoff between peak HP (good for marketing) and peak torque (good for acceleration).
Now shifting at 2000 revs is fine if you're driving a V8, but your engine is just starting to wake up. Its almost the equivalent of shifting a V8 at 1000 revs when you shift your 4-banger at 2000 revs.
On March 11th you wrote that the engine is turning 2200 RPM on the highway. And you're exceeding the rated MPG. Bingo! Try this:
- keep your engine OVER 2000 revs for one tank of gas. I'll bet your mileage is almost the same, maybe even slightly better.
- on the following tank, keep it over 2000 when accelerating (shift around 2500), but let it run below 2000 when decelerating before you downshift.
- eventually, with experimentation you'll find engine speeds that work.
But remember that with 4 valves, low RPMs will cause some fuel/air to blow right out the exhaust valve during the intake/exhaust overlap because the engine is designed to rev.
Let it run in the range the engineers designed it for and it will:
- run smoother
- be less stressed (lower torque required)
- last longer
- get better mileage.
If you really want good mileage at low REVs you'll need to change cams. Get an "RV cam" designed for torque instead of high-rev power and then its OK to drive like you do now. (that cam will have much less overlap) But I'd advise against it because you won't recoup your expenses and you may void your warantee. Your engine if begging to spin faster. Make it happy!
That's just one engineer's opinion.
What do the rest of you think?
(PS: My favourite truck was my Landcruiser Diesel Wagon...great MPG and built like a tank!
If you're serious about economy go to your VW dealer and ask for a Transporter Van with Diesel and 5-spd ... expect 34+ MPG in the city. My brother's friend just bought a used one with over 300,000 on the odometer and it gets over 30 MPG still. Just be careful on the highway because they are s-l-o-w

#61 of 69 dieselbreath by rlafaver

May 11, 2003 (5:50 am)

Thanks for the input. I got sort of the same advice earlier. I have since tried using 2200 as a rule for accelerating from a dead stop and I have tried 2500, which feels a bit much like a race. You are correct that the mileage was about the same. 2100 to 2200 seems to get something less than .5 mpg improvement. Keep in mind that I am usually driving without hinderance of traffic, so I can try these things for city driving. I feel for those folks who face "real" city traffic.
Changing cams is drastic, but synthetic oil is something most people can afford and seems to generate improved mileage in all driving situations.
89 octane gasoline boosts highway mileage enough to actually save money, but it does nothing for city mileage. Along with the oil, however, it does render the valves completely silent, which seems to me should decrease engine wear. Someone out there might have a more scientific opinion on the 89 octane stuff.
I have decided to change to a K&N air filter in an attempt to get more benefit from the higher octane in the city. It seems logical that boosting air intake has to help, and the K&N should help combustion even when idling.

#62 of 69 dieselbreath, I should have added by rlafaver

May 11, 2003 (5:54 am)

Everyone in my family considers me lead-footed. I only tried the low-rev thing as an experiment, knowing I would never stick to it, even if it improved mileage. It did not, so I am happily driving as I always have. Ordinary accelleration is usually under 2500 when unhindered, but I now allow the engine to exceed 3000 when turning onto a major highway in traffic. I have even pushed 4000 just to see how the engine reacts. It is good.

#63 of 69 Your mileage is probably OK by dieselbreath

May 11, 2003 (2:44 pm)

I think that if you're an "average" driver you normally won't get the rated MPG, unless you live somewhere rural where you drive a lot on secondary roads with 50 MPH limits. Keeping up on the freeway demands performance outside of the scope of the EPA fantasy-world.
And the lead-foot tendencies play a huge factor, of course. That's one of the reasons I really like diesels ... they are built to drive foot-to-the-floor and still return good MPG. (and its harder to get into trouble with the law!)

#64 of 69 dieselbreath by lagitane

May 15, 2003 (12:02 pm)

So what deisel do you drive, and what would you recommend for someone on a very moderate budget. My step Father drives a big honking Ford Deisel and loves it, but price is way over my head. Any decent moderate priced ones out there you'd recommend? Toyota doesn't even make one that I'm aware of.

#65 of 69 Diesel recommendations by dieselbreath

May 15, 2003 (10:31 pm)

Well, you're almost out-of-luck in the US for a couple more years. Once the lower-sulphur diesel fuel is available (in 2006 ? I think) there should be more choices. I drive a VW New Beetle TDI, mostly because I'm 6'5" and it has more headroom than any other car on the market, but also because I was driving between Vancouver BC and Seattle WA at least 4 times a month when I bought it. (it has over 150,000 on the odometer now) ... 50+ MPG at 80+ MPH is hard to beat! (none of the hybrids can do that) I also have a big Chevy 5-ton truck with a CAT V8 diesel, and I had a Toyota Landcruiser Diesel in the past. The Landcruiser is a phenomenal rig ... but I don't think they've sold the diesel ones for several years now.
But the Jeep Liberty is avail. in a diesel (for 2004) and the VW Passat (sedan and wagon) also for 2004. But I haven't heard of any small pickups yet. Your current rig is probably almost as good as it gets!

#66 of 69 Sheesh, TOyota has spoiled it's clientelle by eharri3

May 19, 2003 (8:45 am)

IF Toyota owners have nothing better to do than post about 2-3 mpg gas mileage discrepancies, maybe they dont realize how lucky they are.

#67 of 69 Mileage and re #65 by moparbad

May 19, 2003 (9:34 am)

I have 2003 Tacoma V6 4WD Xcab and my last tank of fuel provided 21 mpg. As I get more miles on the truck the mileage has improved. Strange is the fact that this truck gets better mpg when it is driven a little hard.
 
re #65 the Liberty will not be available until 05 model year and as of last week VW is stating Passat TDI in sedan only initially and even then not until Feb. 04 at earliest. What is Toyota doing to improve MPG on it's trucks? I see no plans for hybrids and Toyota has no plans on bringing a diesel for it's Tacoma or Tundra. Even though Toyota already offers multiple excellent diesels for the Tacoma outside of North America.
 
Until something better shows up the Tacoma is the best option available in compact light truck and Tundra is a competitive choice in full size.

#68 of 69 eharri3 by rlafaver

May 21, 2003 (8:22 pm)

Toyota might have spoiled some body, but they haven't spoiled me. This is my first. When I buy a new vehicle, any new vehicle, I expect the truth on the sticker mileage. I paid for it, and I want every dime's worth. As far as all the other smoke is concerned, the only reasons so far that I can say the truck is worth the cost is the handling, the quietness, and the power (considering it is a 4 cylinder). The handling is the best I've experienced on a pickup. However, the mileage sucks, the seats suck, the paint flakes off like it was painted with moisture on the truck, the paint is orange peeled as badly as I have ever seen a new vehicle, and on and on. I bought the thing, and I will live with it, but I just got back from a business trip tonight, and my back hurts too badly to get in bed. Guess I will have to drop another $700 for after-market seats. Where is the spoiling, eharri3?

#69 of 69 Now I'm Spoiled by rlafaver

Jun 24, 2003 (5:04 am)

I got Recaro seats for this Tacoma, and they look and feel like they were made for it. What an amazing seat. Firm, comfortable, and absolutely silent (NO SQUEAKS). The down side - $1770 for driver and passenger, and that is the low side on pricing for Recaro Trend seats. There should be a law that Toyota refund the money for the crappy seats they stick in Tacomas. I would ship them back in a heartbeat.

Messages Page 7 of 7

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