Master list of 65+ proven mods for increasing MPG

[MetroMPG]

Speed doesn't matter.

Because:

Making the surface smooth only works for bodies with very low Cd, say in the neighborhood of below 0.1.

[Frank Lee]

It'll help the same way adding .5 psi to a tire will help: sure, it's a step in the right direction; too bad it's undetectable.

[SOUL-DRIFTER]

Ok here is one for ya.
How about dimpling the surface of the car body?
Ever wonder why a golf ball is dimpled?

[2000mc]

Originally Posted by SOUL-DRIFTER

Ok here is one for ya.
How about.....

.....generally shouldnt be in a thread called "Master list of 65+ proven mods for increasing MPG"

might find a more receptive audience in a new or different thread

[Frank Lee]

^... threads of the sort that many exist of already.

Search function. Use it. Love it.

[rollercoaster]

Originally Posted by SOUL-DRIFTER

Ok here is one for ya.
How about dimpling the surface of the car body?
Ever wonder why a golf ball is dimpled?

Mythbusters did this already - go to Discovery dot com.

They also did clean vs dirty car and a few other mileage myths. - For instance they did the tail gate up vs. down scenario and the truck with the tailgate up went an additional 30 miles.

Unfortunately they did not do them all in one show, so you have to poke around a little to find them.

[mja1]

about the warm air intake. If the vehicle has a MAF, a more efficient flow of air to that MAF "cold air intake" will net a greater lb/min, gram/s or lambda based on AFR (whatever you personally measure MAF readings with from Hz). Measured target AFR will be 5-15% over the actual, meaning you'll be running slightly lean. If this lean event is not enough for the ECM to add enough fuel to noticeably effect long term fuel trims, you'll net slightly better mpg. The only way to change this is to tune the MAF tables while driving or on a load dyno.

This is how K&N and others can advertise a '3%' gas mileage increase or whatever we've seen out there. It isn't because the cold air is creating this efficiency, its the reduced constriction to the MAF from the design of a CAI. Mail order tunes are not going to be accurate to change this at all.

Most cars a few years older that are being used for super mpg use speed density, without a MAF. In which case warmer is better, to a point. Check to see what style tune you have on the ECM and go from there.

[Daox]

If your engine leaned out 5-15% your O2 sensor would see that and correct for it.

[mja1]

Originally Posted by Daox

If your engine leaned out 5-15% your O2 sensor would see that and correct for it.

What's happening is the AFR measured at the O2 sensor is around 10% or less, likely less on a much smaller engine (I said 15% so people wouldn't get on my butt as they have on here for some little discrepancy) over the base air volume/time tables given by the OEM air box MAF. When we throw in a CAI that increases the volume of air to the MAF at the same time, the MAF actually reads the same in measured Hertz for larger volume. Unless the long term fuel trims can be changed enough by the O2 sensors to warrant dropping out of closed loop for part throttle driving, the Hz measurement from the MAF to the ECM will continue to be the main fuel adder map. It runs lean.

Edit - If I didn't explain this well just let me know, the O2 sensor reading and the actual AFR are different. The ECM commands a certain AFR to the O2 sensor, which is what the sensor will show. The actual ratio of air/fuel will be slightly lean.

[Daox]

Sorry, no that doesn't make sense. What it seems you're saying is that modern EFI systems don't compensate for variations in temperature. This is not true.

A CAI or HAI should have absolutely no effect on AFR unless the engine is in open loop. Ecodrivers virtually never operate in open loop so basically the exception doesn't even apply to us.