Master list of 65+ proven mods for increasing MPG

[Formula413]

I do know that some makers of aftermarket TCs for performance applications will offer one free re-stall (change of stall speed) to anyone purchasing their converter. So it can be done, at least on some aftermarket converters, not sure about run of the mill OEM TCs.

[whitewiz]

in another thread someone estimated the leach load of power steering at .21 gph
get the electric power steering pump out of a Toyota MR2
you turn maybe 20% of your total drive time, why does the booster need to run 100%
electric brake booster too... don't know any cars with these

i know the die-hards just convert to manual steering

[Christ]

I don't think the brake booster uses any of your efficiency at all, since you're at neutral or negative throttle when you're hitting the brakes.

If you really wanted - you could add an electric vacuum pump for your brake booster. It would negatively impact your efficiency though, b/c it would have to drain electrical energy that would put more load on the engine via the alternator.

The electrically driven power steering pump would be better suited with a position switch (which I also believe the MR-2 has). That would make it so the pump was only moving while you were steering.

[Curly1]

I think underdrive pulleys should be added to the list of 60 things to do to improve effeciency.
I have not done and tested it yet but it appears to me that it will mean the alternator, water pump, air conditioner, power steering and anything ran off of the crank pulley to use less energy. The factory on many new cars is already doing some of these things but they still have a more powerful alternator, water pump, air conditioner etc to allow for worst case scenario. So I think most could get away with underdrive pulleys.
That is a trick I used on my drag race car that should help to increase the effeciency and mileage.
Eliminate all sources of horsepower (mileage) robbing parasitic drag and decrease the amount of drag they have on the ones you have to keep.
On my drag car I completly removed the factory water pump and fabricated a small electric water pump. I also found the smallest radiator and used smaller diameter water hoses cutting about 60 lbs off of the front wheels. Got rid of the power steering and manual fuel pump and put a underdrive crank pulley AND alternator pulley. Then I used two batteries and charged them between races.
Some have done a alternator delete on your cars. I think you need one to run the lights at night and creature comforts. A underdrive pulley system should allow you to have your cake and eat it to.
In many ways drag racers and other forms of racing do the same thing we are. Trying to get the most out of the car by eliminating the things not absolutly required and reducing the drag of the ones that are required.

[JohnnyGrey]

You guys can't quantify TC losses like that. The reason it's called a torque CONVERTER is because it converts some of the RPM on the input shaft to additional torque on the output shaft. It doesn't do this as efficiently as a set of gears, but the power loss isn't as dramatic as the apparent RPM loss. You gain some torque at the wheels.

[Intrigued]

Originally Posted by JohnnyGrey

...The reason it's called a torque CONVERTER is because it converts some of the RPM on the input shaft to additional torque on the output shaft.

Only when it isn't locked in! By far the most of them lock in pretty quickly, and while I haven't taken the time to look up the studies, the Big Boys generally will try to make pre-lock slippage occur at a fairly efficient RPM. (other modders insert arguments at will...)

It seems to me that trying to mess with slippage won't gain you much, unless you spend most of the time in Stop-and-Go driving. If you have the money, those fancy take-apart re-stallable TCs would be about the only way to take matters to the nth degree.

Originally Posted by JohnnyGrey

...It doesn't do this as efficiently as a set of gears,

Whew! I ain't touchin' that can of worms...

[Andyman]

Originally Posted by JohnnyGrey

You guys can't quantify TC losses like that. The reason it's called a torque CONVERTER is because it converts some of the RPM on the input shaft to additional torque on the output shaft. It doesn't do this as efficiently as a set of gears, but the power loss isn't as dramatic as the apparent RPM loss. You gain some torque at the wheels.

Yes, that's true some of the time, but I doubt that it's true when I'm climbing that hill at 32 MPH. I know that when the car is stopped and the throttle is applied, the torque converter can at least double the torque in most cases. It has something to do with the stator redirecting fluid flow inside the torque converter. As the car goes faster, at some point the overrunning clutch allows the stator to turn with the rest of the torque converter. When that happens, there is no more torque multiplication, so any slippage is just generating heat and not contributing to additional torque. I took a look at the "HowStuffWorks" web site. It says that the stator will begin freewheeling at about 40 MPH. I think that this is for a heavy load in high gear. At lighter loads the stator should freewheel at lower speeds. There is probably a formula to calculate when the torque converter is multiplying torque. It probably happens when the output speed of the torque converter is less than a certain fraction of the engine speed. What that fraction is I don't know. There is probably some variability according to the type of torque converter.

Here is where I read the basics of the torque converter.

HowStuffWorks "The Stator"

[gascort]

I did a new mod on my car that would be a fair benefit for most average drivers; I insulated the low pressure parts of my air conditioning system under the hood with foam pipe insulation and fiberglass insulation around the accumulator. I had over 2 meters of uninsulated pipe under the hood between the expansion valve and the compressor. This could be very significant for compressor clutch cycling on someone's car where the a/c is used 100% of the time during 4-6 months of the year.

[Intrigued]

Originally Posted by gascort

... insulated the low pressure parts of my air conditioning system under the hood with foam pipe insulation and fiberglass insulation around the accumulator.

Good catch there! Doing JUST the low side is key to gaining efficiency, since the idea of keeping the car cool depends on how cool your refrigerant is. Insulating the low side, which has COOLER than ambient contents, helps keep it even cooler, which then results in less A/C needed.

The high pressure lines, which are smaller in diameter than the low pressure lines, will run hotter than ambient temps when the A/C is operating, (because of the pressure AND the heat pulled out of the cabin of the car) and therefore should be left uncovered, to help cool off the refrigerant a tad.

Oh, by the way: better than 40 percent over EPA on your car, Gascort! Excellent! My car is there temporarily... I turn in my last Final project for the semester today, so maybe I'll get started with the blog on my success on the trip to KC in the heat for the meet!!!

[gascort]

Originally Posted by Intrigued

Good catch there! Doing JUST the low side is key to gaining efficiency, since the idea of keeping the car cool depends on how cool your refrigerant is. Insulating the low side, which has COOLER than ambient contents, helps keep it even cooler, which then results in less A/C needed.

The high pressure lines, which are smaller in diameter than the low pressure lines, will run hotter than ambient temps when the A/C is operating, (because of the pressure AND the heat pulled out of the cabin of the car) and therefore should be left uncovered, to help cool off the refrigerant a tad.

Oh, by the way: better than 40 percent over EPA on your car, Gascort! Excellent! My car is there temporarily... I turn in my last Final project for the semester today, so maybe I'll get started with the blog on my success on the trip to KC in the heat for the meet!!!

I was surprised to find that my expansion valve is very close to the radiator and condenser, maybe 25 cm away, more forward than my battery!
To find the low pressure lines for sure, I just ran the a/c for about 45 seconds and shut the car off, then felt the lines. I didn't notice before, but I had a low pressure line right next to the whole length of my exhaust manifold! That part will probably see the most improvement of them all. I'm definitely doing this mod on my wife's car and my brother's car - they use the a/c very often and I think it would help.

Thanks for the congrats! BTW, I'm actually doing even better - haven't used enough fuel since the Kammback to reflect in my logs, but I don't think I've had a tank average under 44.4 mpg since installing it.