Mods to increase gas mileage

i own a 92 olds 88 royale, and with the recent rise in gas prices, simple maintenance is not enough. i want to increase my mileage with a cheap fix. any ideas?

No cheap fixes. One thing you might be able to do is have someone burn you a custom chip. The factory left the fuel curve a little rich and the timing curve a touch conservative. You could maximize those two and gain 1-2 mpg, but you'd have to burn 91 octane or better which defeats the purpose.

The cheapest fix would be to trade your car straight up for a Tercel, Civic, or Metro.

The manufacturers of cars have to meet some pretty tough CAFE (corporate average fuel economy) standards, so they've already done about as much as they can with sqeezing the last mile out of each gallon with the 1992 technology they had.

Vice grips on the fuel line.


I mean um.. yeah what Curtis said.

if you have a timing light or can get one you can advance the ignition timing a few degrees. advance it in intervals of 2 degrees until you hear knocking, then back off 1 degree until you dont hear it. it won't gain you much but it's a start.

If you want more gains you'll have to spend more money, like curtis said you can tune your ecu or get a new one made. you can get intake, exhaust, ignition upgrades but those are more expensive. ignition can set you back around $150, and it only gets more expensive for the other mods.

Some simple fixes to reduce fuel consumption is

1. Check tire pressure. Higher pressure means a lower friction loss.
2. Car weight. Don't carry around luggage that you don't need. Running without a spare tire might save you some additional fuel but if you get a flat...
3. Drag. Remove all external devices that you doesn't need. Run with the windows closed and so on.
4. Engine and tranmission lubricants. A thinner lubricant will reduce the friction loss so use the thinnest oil specified for your engine. Use a lubricant that is specified as energy conserving, for example ILSAC GF-4.
5. Drive without the A/C and other energy consumers such as electric heaters. This might be dangerous though.
6. Learn how to drive economic; use high gears/loads, avoid unneccasary braking/acceleration, use engine braking.
7. Check spark plugs and general engine condition.

By doing 1-7 you will save more fuel at a lower cost compared to the other ideas mentioned in this thread.

you want to get exceptional mileage?

Here's the ticket. (depending on your fabrication ability) its very cheap to setup too!

http://www.utterpower.com/10hp_chevy.htm

Clean or replace your air filter regularly. Or better yet, replace it with a cold air intake.

Clean or replace your air filter regularly. Or better yet, replace it with a cold air intake.

No offense intended, Tonto, but why is this such a widely held notion? Decreasing the temperature of the incoming air raises its density, which forces the computer to inject more fuel. In fact it can have the opposite effect. It can increase power, but it most certainly will also increase fuel consumption.

you want to get exceptional mileage?

Here's the ticket. (depending on your fabrication ability) its very cheap to setup too!

http://www.utterpower.com/10hp_chevy.htm
That's pretty sweet, if you turbocharged that thing and shoved a bit more fuel in it you could have a nice little off-highway machine, or on highway depending on how much you could get. i wonder how many miles per gallon they get.

That's pretty sweet, if you turbocharged that thing and shoved a bit more fuel in it you could have a nice little off-highway machine, or on highway depending on how much you could get. i wonder how many miles per gallon they get.

my thoughts also. The bueaty is, the motor is so cheap, maintenance cost would be near $0, and I was also disappointed they didn't list MPG, but I bet its near 100mpg.

The stock 1.0L metro engine gets about 45-50mpg, and has a peak HP of 55. With a high efficiency turbo diesel engine, say 20hp peak, you could probably get at a minimum of 70-80mpg and be "capable" of driving it on the freeway....although you sure ain't passing anyone.

But if you want to talk about serious fuel efficiency....a diesel motorcycle would be the ticket. Kawasaki is making a diesel KLR650 for the military (a on/off road enduro) that gets over 100mpg, but they have yet to make one for the public. I bet they will eventually

I'd say just get a small diesel engine and stick it on some old sportsbike. then get the gearing correct because a 3000rpm engine is not going to use the same gearing as a 12000rpm bike engine.

the sport bike thing has been done. They were going for performance though, not focusing on MPG (although I'm sure it was pretty decent....but again, they never mentioned what it was)

They used a European spec TDI 1200cc 3 cylinder out of a VW Lupo. 120HP and 250 ft/lb's at 450 pounds. Would probably be a fun ride.

http://thekneeslider.com/archives/2005/02/25/thunder-star-1200-diesel-by-star-twin/

Decreasing the temperature of the incoming air raises its density, which forces the computer to inject more fuel. In fact it can have the opposite effect. It can increase power, but it most certainly will also increase fuel consumption.

Curtis,

Sorry Incorrect. Yes the increased density will probably make the ECM add more fuel per VOLUME of air. However, you will open the throttle less to achieve the same amout of work. This vastly offsets the injected fuel. The ~14.7 a/f mixture is based upon mass, not volume. And this mass is what makes the HP.

Jim
SR Racing

Curtis,

Sorry Incorrect. Yes the increased density will probably make the ECM add more fuel per VOLUME of air. However, you will open the throttle less to achieve the same amout of work. This vastly offsets the injected fuel. The ~14.7 a/f mixture is based upon mass, not volume. And this mass is what makes the HP.

Jim
SR Racing

unless it improves the efficiency, its pretty mute how much power you have at what throttle opening.

If you want to split hairs, in general, an engine is more likely to have better mileage at higher throttle openings for a given load.....this is one of the reasons small engines typically get better mileage. Although, as with everything involving this complexity....its not that simple. But there's a simple example of why its not necessarily cut and dry

Curtis,

Sorry Incorrect. Yes the increased density will probably make the ECM add more fuel per VOLUME of air. However, you will open the throttle less to achieve the same amout of work. This vastly offsets the injected fuel. The ~14.7 a/f mixture is based upon mass, not volume. And this mass is what makes the HP.

Jim
SR Racing

The engine must produce a certain amount of power, so if air density increase less throttle will be used. This will increase pumping losses and fuel consumption per produced kW will increase. The difference is most like to be very small though. But during high loads a lower intake temperature will be good.

Bottom line here is we're talking about things like pumping losses, combustion efficiency, and air consumption.

At WOT, hotter air will use less fuel period, and make less power. There is less mass, fewer molecules, and therefore less fuel gets injected. That is not to say however that it will change MPG. That is a part throttle phenomenon that is tough to quantify, but the IMEP map will tell you.

However, having said that, cool air intakes can help MPG but NOT because of the cool air. If they remove a significant restriction from the intake tract they can reduce pumping losses, but cold air alone does not increase fuel efficiency. It CAN improve combustion efficiency which is a completely different animal.

Its true that if you reduce the intake air temperature it will take less throttle opening to maintain cruise. Its also true that the computer will maintain a stoich mix regardless. That is to say, the net amount of air and fuel molecules ingested will remain the same regardless of air intake temperature. Let's not forget however that a cooler intake air signals the IAT to richen the mixture. There are also modestly increased pumping losses like SaabJohan talked about.

It may be a widely held notion, but its generally wrong. Hot intake air helps MPG. It is still quite common to heat the intake manifold with exhaust gas and coolant, as well as source hot air from under the hood to help MPG. Hotter thermostats were also used for the same reason. Sorry to disagree with you on this one guys, but saying cold air intakes help MPG is simply regurgitating propaganda that the cold air intake manufacturers feed you. Its BS.

to add a small bit to that....one thing you can always note is the current trend of the manufactures. They have changed designs many times over the years. As Curtis mentions, it used to be very common to channel some/all of the intake air through a heat exchanger off the exhaust....this was particularly common on carb'd engines. The reason might surprise some, it wasn't for performance, obviously, it was actually to help negate temp changes effecting jetting. The control valves that operated teh flapper in the snorkel, would attempt to maintain 100*F intake temp, or something around there.

Modern cars though, are going further and further away from those types of ideas though. Now with modern engine management systems, there is no need for hot intake temps anymore. No worries about carb freezing, or AFR issues. Most of the intake systems these days are plastic, which disapate heat very effectively. Throttle bodies may or may not have a very small coolant line going to them, but its only there to prevent throttle freeze. Air intakes are more intelligently placed, and no modern car worth mentioning draws in hot engine air anymore. Which is why I've always kinda smirked when someone mentions the "cold intake"s. They look cool and sound cool. Thats about it. Very little gain with any decently engineered engine, which is most these days.

......................................

It may be a widely held notion, but its generally wrong. Hot intake air helps MPG. It is still quite common to heat the intake manifold with exhaust gas and coolant, as well as source hot air from under the hood to help MPG. Hotter thermostats were also used for the same reason. Sorry to disagree with you on this one guys, but saying cold air intakes help MPG is simply regurgitating propaganda that the cold air intake manufacturers feed you. Its BS.

You get carried away with the hot air idea and some one will mention the Pogue(sp?) carb craze...woops guess I just did........I got the plans for it around here somewhere.........


JD

I want to edit the censor on this forum to eliminate the word "pogue." Have it show up as something like p**ue. Kinda like f**k and s**t.

By the way, unclebob; good call on the hot air and jetting consistency.

Which is why I've always kinda smirked when someone mentions the "cold intake"s. They look cool and sound cool. Thats about it. Very little gain with any decently engineered engine, which is most these days.
.

I may stand corrected re: the amount of fuel used per gallon with cold air. :frown: (However when testing fuel consumption with these units no changes were noticed.), But logic seemed to indicate to me that it would have been better. I will have to go back and try some of these tests.

However there is no question that cooler air (and cold air systems provide more HP (at WOT), and these gains are significant. We have probably installed 15 or 20 K&N etc. aftermarket systems and another dozen fabricated systems for race cars. Before and after and (after and before) RWHP dyno runs show gains in the 3 to 6% area. As a matter of fact, I think our web page has some graphs of before and after runs on it. As you point out, steady state eddy current loaded may runs show no fuel consumption changes, but the HP is improved.

We do dyno testing here for the manufacture of Granitelli MAF's etc.
BTW, We do NOT sell any of the above systems and are not associated directly with GMS or K&N so we have no bias either way. We only build and maintain race vehicles with the intent of getting the most performance available from a given engine.

As I mentioned in another post we are now doing a series of tests (as a contracted independent) on "MPG-CAPS" from "Fuel Freedom International".
They make some pretty wild claims which will be of interest to verify or negate.

Jim
SR Racing

its a bit off topic, but the effectiveness of a cold air intake depends greatly from the make of the system. I've seen more than a couple that actually routed the intake to consume MORE hot engine air.

IMO, it doesn't so much as drop the intake temp (in general), as reduce restrictions. This again, will vary from engine to engine. Some are more free-flowing than others. You could make the same claims with exhaust of course.

Hot air vaporizes fuel more effectively. This doesn't work for high performance because heating the air reduces its mass, reducing the amount of Oxygen in a given liter of air at WOT, but when you're trying to improve fuel economy, I'd say hot air with minimal restriction is the way to go. You won't any see phenomenal gains unless you add to it one of the 200+ patents claimed to get over 100mpg spanning all the way from the 1930s to the present day.