Is it true you "adjust" a car to get much better gas mileage?

I heard that the factory can set something different so that a car will get double or more the gas mileage it does now. I don't have a news source or anything, but a friend of a friend said they had a Cadillac that got over 60 mile per gallon. It was just a normal big-boat Caddy that you would have thought low 20s for gas mileage. Someone that might know told him that the factory screwed up and didn't set something right and that was responsible for the superb gas mileage. Of course this is second hand info. Can anyone tell me anything about this??

driving slower.
The slower you drive the better your mileage.

Don't believe friends with conspiracy theories unless they can show you irrefutable documentation, I say. :D
Don't you think a 60 mpg Caddy would sell like freaking crazy?

Cletus

but I thought I might as well ask.

:)

High school friend of mine had an old camaro with a straight six that had a quarter inch caking of dried oil all over it. It didn't get great mileage, but for some reason, it had zero emissions -- it never failed a state inspection.

I'm only sure of two things. One is that, like everywhere, there are hucksters, so don't believe everything you read. The other is that the American automobile industry has shown near zero interest in really developing genuinely attractive high mileage products. Only now that Toyota is kicking ass with the Prius are things starting to move.

At certain "flukey" points in the transmission shifting cycle, timing and mixture cycles, etc., such as when you have just gone over the crest of a gentle hill, and are "coasting" down hill, at the right outside temp and humidity, no a/c, windows closed, etc., etc., etc. -- if you have an "instantaneous" miles per gallon display - it might "indicate" exceptional mileage -- but that is just a briefly lived, transient "artifact" of the on-board microprocessors -- that indicated mileage is neither sustainable nor even real.

I've seen 80+ instantaneous on a Grand Prix. I'm sure it would get 1000 if you drop it off a cliff but that wouldn't mean anything.

but "average 50" in a full size car-- might be doable with the same block -- digital valve lifters, digital injectors, digital sparks, digital transmission shifter, all tied together through the "Automotive Data Bus" with a Pentium or PowerPC and the right firmware/software.

That's the "teaser" at the annual IEEE-SAE "Automotive Electronics" joint meeting each fall at the Hyatt Fairlane Town Center in Dearborn (that's where are the guys who are both "computer geeks" and "gearheads" get together).

who can put in a better chip or adjust the fuel maps for better economy...but even that would cost $$$$ and net a minor gain of maybe 5-10 percent mileage improvement

they said something about a chip. It had the wrong chip in it and got outrageous gas milage. As my thrid-hand story went, anyway.

to get worse gas mileage. But no, not better.

Cadillac mad a car that could run on 4 6 or 8 cylinders. My grandmother had one. this may be what your friend has.

That's what it was called.

Only lasted a couple of years in production as the damn things wouldn't work right half the time.

Seems like a few companies are trying it nowadays to better results.

was an idea WAY ahead of its time...(too bad they couldn't make it work properly in that era)

It is possible to get better mileage from your vehicle. I'm in the construction buisness and therefore have driven p/u trucks for the last 15 years. The gas milage SUCKS! I've never gotten anything like the caddy but I have made some signifigant gains in economy. This was easy to do w/carb engines and no computers but has gotten much harder with new cars. Best ever- '85 ford f150 w/351ci. motor, 14mpg. to 20mpg with $16 worth of parts from thew hardware store. I can explain it, was very simple and required minimal tech knowledge. Note-I've been researching this for years-

My dad has a 75? Ford Tiltcab and a 78? Chevy Tandem for hauling grain. Could it work on that? Paying $2 for 5 miles a gallon hauling $1.80 corn is a bitch. What's the basic process? Any links?

The original info came from a co. called eagle research, they have a site but you have to buy their manuals. The basis setup is cake, bend a 3" piece of 1/4" copper tubing into a hook shape,put hook in carb bowl vent about 3/4", connect piece of 1/4" fuel line to copper,run fuel line to intake manifold, cut in small brass shutoff valve in middle of fuel line.

Materials list
1/4" copper pipe
3' 1/4 fuel line
brass shut off valve
tee to go into int. man.hose (usually pcv line)

This just sucks vapors from carb bowl that would be escaping into the air and uses them to run engine. Open valve until motor revs up,then set idle back.

...is a vacuum leak.

Fuel vapors vented from the carb are ingested by the engine as designed. The fuel bowl vent is exposed not directly to atmosphere but internally to the air cleaner housing. Airflow through the air cleaner housing into the carb venturis will carry fuel vapor from the vent tube(s) with it. Plumbing a line from the vent to manifold vacuum will result in a vacuum leak. air will be drawn into the tube and into the added line, as there is insufficient evaporated fuel vapor at the entry point to completely satisfy the draw through the tube. The result is a leaner cruise mixture.

Carb and ignition tuning on a chassis dyno would have gotten the result you desired, and more.

The valve is to control the amount of vacuum from the manifold so the mix will be rich. I think this system mainly saves the fuel by using vapors at idle and allowing the idle to be set back. As far as a chassis dyno, I'm certainly not a mechanic and wouldn't know how to operate that kind of equipment even if I had access to it.

You will not ingest any additional fuel. With the connection you describe, you only would have a choice of "no change" (valve closed), or varying degrees of lean above the whatever ratios the carb is set to provide.

As I stated, the carb vent is designed to vent into the air stream through the air filter inside the air cleaner housing. Any additional attempt to draw fuel vapors into the engine will not not result in any change other than a leaning of the cruise or idle mixture.

chassis dyno be used on new vehicles? If so, who would have one? I've tried everything to make my '02 dodge get better mileage but it just refuses.

Most are performance shops, but some old tune up shops have them.

Computer controlled vehicles are a bitch to tune unless the tuner has a way to make changes to the fuel map in the computer. Factory cars are set to provide a generally sufficient mixture that will work well for most altitudes, and then some models for high altitudes have special tuning. All fuel metering systems, carb or FI, have some ability to adjust for altitude.

The general mixture is not optimized for any particular region, and not for any particular engine. All engines have certain variations that can be adjusted for by careful tuning. But, unless you do your own work, you may find that the cost of labor exceeds the retun in mileage. 351Ms in trucks are often running rich and can respond easily to tuning, but a late model computer car is another thing.

Me, I'm looking to diesel. I know I won't get my Crown Vic's mileage to improve above it's 18 MPG it gets currently.

I pull trailers a lot, the dodge goes from 12.8mpg down to about 11.2 with a big trailer. I've been waiting for years to switch because I can't take all the noise. Now they seem to be a lot quieter so next truck will be a diesel. The price tag will be the only issue.

There are many variations/additions to this but just this will make a difference in mileage. Also beacuse the engine is burning these vapors you may be able to lean the fuel mixture a little bit and set the timing up just a little. It requires some adjusting but once you've done it it's maint. free.

on edit: all the manuals say make these mods at your own risk, but I have tried many of them and hade no problems.

I gave it (1997 RAV 4) to my daughter and son-in-law, as they needed another car. I now ride this 80 mile per gallon fun machine:

Year 2000 50 cc Honda Elite:

What's the weight limit on those?

Mine is the old style that only carries one person, about 200 lbs.
The newer ones carry two people, and have a bigger engine, 80 cc's.
Check them out here at my neighborhood fun store:
www.hondaofhouston.com
:hi:

you can bet your ass it is.

Redstone

Would be wonderful, in fact you could be a rich man with that Tech.

1997 Corolla. In a city, use public transportation, walk or bicycle.

adjust the valves to make your car get a few more miles per gallon

Be VERY!suspicious if it's "a friend of a friend."


http://www.kliljedahl.net

There are lots of things you can do to boost economy, but most are very minimal. Chips from specialty manufacturers, special camshafts, silly gadgets of various kinds. Water injectors were all the rage back when. Driving style makes the most difference. But in any case, 18 years of experience as a line mechanic has convinced me that significant gains (100+ %) are purest BS. There is only so much energy in a gallon of gas. An internal combustion engine is able to convert that energy at a certain efficiency. There's a limit. Why would Toyota build the Prius(sp?) when all they needed was a chip to do the same thing only better?

Yes, there are some tweaks here and there that can be done to boost the MPG numbers a bit, but only in the low to mid single digits, nothing more, and certainly not double or more.

And any kind of modification that you do in today's modern autos is going to be detrimental in the long run, since the various computers and sensors are factory set for certain ranges. You change those, and you're going to seriously mess up your car. The best bet for doing these kind of modifications is on older, non computerized cars.