Archives

I commute from Virginia to North Carolina every day over the Blue Ridge Mountain. My commute is very hill to say the least.

I was wondering for constant up and down is a short FAS costing more gas than a NICE coast? I'm thinking for some reason it may use more gas to start frequently than to idle?

Any ideas? Also how does the short FAS coast compare to coasting in gear (automatic) and letting the injectors shut off fuel?

Thanks!

Travis

Sorry, I got in a hurry and I will check my spelling better next time, I promus

You should not use FAS in your vehicle if it is equipped with an automatic transmission UNLESS it can be flat towed (pulled on all 4 wheels).

If this is the case, you'll send about 7s worth of idling fuel to start your fully warmed up engine. Any coast longer than this time frame will benefit you more than coasting NICE-ON. This is especially true of vehicles equipped with a manual transmission because a bump start uses even less fuel.

Fuel cut is very nice when you need to slow down -- but not for coasting (unless you can maintain speed with it going down a really steep hill). Fuel cut only triggers when you are in an engine braking mode -- you will slow down. Most of what we call coasting is for reducing consumption without slowing down much. Fuel cut isn't good for this.

Fas will save gas over nice-on coasting.
I have read that there is a 10 second rule for turning off your engine at a stop. If you will be stopped for more than 10 seconds you will save gas by turning your engine off.
I apply that to my coasts. If my coasts is not going to be close to 10 seconds I don't FAS.
I am still a rookie and still getting use to FASing, so I am probably wrong. Can't wait to see the other replies though.

Travis, a good resource to see if FAS is safe on your auto tranny, is at http://www.motorhomemagazine.com/din...uide/index.cfm and look up your vehicle on the Dingy Towing Guide for your model year. I checked on 2005 Element, and it appears to be fine, unless you FAS for more than 8 hours straight (like FAS-ing down Everest!), but if you have a different model year you should check to be sure it is safe.

As far as, FAS -vs- NICE-on goes, I found PaleMelanesian's advice on another thread very helpful, based on gal/mile comparison --> http://www.cleanmpg.com/forums/showthread.php?t=11270. In a nutshell, fuel savings is almost nill at highway speeds coasting with engine off versus on, but a huge savings at low speeds. So at highway speeds, I usually NICE-on, expect for long descents and/or less than 50 MPH. The advantages are no loss of power steering, no loss of power brakes (after 2 pumps), and less wear on the starter. But, like Joe, I am a newbie, too.

I also found that refining my DWL helped a lot. Here's a very lengthy, but useful discussion on DWL strategy on big hills -->http://www.cleanmpg.com/forums/showthread.php?t=11657. Good luck to you!

Thank you for all your input, I just checked my mileage today, and using the techniques I have been using I got a record high 34mpg, BUT, it very hot here and I just used a gallon, will expansion throw me off that much?

I hope to be get my scanguage in the next few days so I can really have fun.

I wouldn't worry about expansion but you really should fill up more than that. Normal pump variations can be a quarter gallon or so -- that's a huge percentage of your total fill!! The more you fill with the less such variations will cause your results to deviate from actual.

I wouldn't worry about expansion but you really should fill up more than that. Normal pump variations can be a quarter gallon or so -- that's a huge percentage of your total fill!! The more you fill with the less such variations will cause your results to deviate from actual.

Yea what he said. :D

I wouldn't worry about expansion but you really should fill up more than that.

Ditto, and check out the pic on PaleMelanesian's post under http://www.cleanmpg.com/forums/showthread.php?t=11631, which shows how factory-recommended PSI wears quicker/uneven, compared to at or near Max sidewall PSI. Some folks here venture beyond Max without problems.

Cool,

I try to fill up at the same pumps in the same position, but I hear what you are saying. Its just so hard because I want to see how I did with the differnet techniques I try each trip. I just ordered a scanguage in the last group buy, and I can't wait to start using it.

Travis