[Infidel]

On my commute in this morning, I managed to squeeze out 86.0mpg over 40.7 miles. The outdoor temp is currently 47 degrees, my tires are at 50#, I have the radiator block in place, traffic was about as close to ideal as physically possible (left the house at 4:30am).

My morning commute (each way) consists of about 10 full stop/starts, 15 miles on surface streets going 40-45mph, and 25 miles in the freeway avg 55-62 mph or so (maintaining lean-burn 100% of the time, except for purges). There are hills on the freeway every exit and I'd say they're about 30-50 ft high. There can't be more than 2-300 feet of total elevation change between my house and work.

I guess my question is, under these conditions, what is the absolute best that I can expect on a regular basis? Will I get any more FE with the Hot-Air mod? I don't have a problem holding lean-burn, so what does "extending the lean-burn window" mean? Does it mean lean-burn is easier to get into/hold, does it mean that at the same speed, lean-burn is more efficient, or both?

 

[Insightful Trekker]

I don't have a problem holding lean-burn, so what does "extending the lean-burn window" mean?

IMO the former. In moderately cold weather it makes the speed range available for lean burn slightly wider.

Your MPG achievement in such weather conditions definitely puts you in the hyper miler category :!: Congratulations. Don't want to get your hopes unrealistically high, but from what you've written (and have almost achieved myself, once ) 100MPG should be within reach for you in warmer weather.

HTH!

 

[Infidel]

Excellent!!

Unfortunatly, the 2-3 times I've tried cruising with the A/C, it seemed like I was taking a 10-15mpg hit, skimmed off the top. I'm not sure how I'm going to handle our 110 degree days without A/C.

For you AZ guys, does using the A/C totally cancel out any hot weather FE gains? My experience was that A/C seems to be a bigger FE hit than background charging.

 

[sno779]

I live in Gilbert, AZ by the Chandler airport and work at the Phoenix Sky Harbor airport, 28 miles. It was about half and half, city/highway, but now is more freeway as more and more of the 202 is finished. Last summer I averaged 92.3 MPG over more then 5000 miles. The last 3 tanks have been 86, 80, 84, and the current tank looks like it will be around 84. The 80 tank was a trip to the mountians so it's not really fair to include it, but anyway you could say I get 92 in the summer and 84 in the winter. I never use A/C or the heater so the change you see is due to a few things. 1. Winter gas. 2. More traffic. 3. More driving with head lights on. 4. "cold" weather. So you could expect an increase of about 8 MPG in the summer if you don't use A/C. That makes 94 MPG - about 20 MPG if you do use A/C, for about 74 MPG.....Louis

 

[Subterfuge3927]

Excellent!!

Unfortunatly, the 2-3 times I've tried cruising with the A/C, it seemed like I was taking a 10-15mpg hit, skimmed off the top. I'm not sure how I'm going to handle our 110 degree days without A/C.

For you AZ guys, does using the A/C totally cancel out any hot weather FE gains? My experience was that A/C seems to be a bigger FE hit than background charging.

I use a pulse AC technique. Basically, I turn it on for down hill and regen segments of my trips. With the AC set to the off, but the fan still blowing on flat and uphill, it will continue to blow cold/colder air for several minutes. Takes a lil practice, but it didn't affect my milage all that much. I am going to refine the technique this summer.

 

[Dougie]

Keep in mind that there is a thermostat in the A/C system. The compressor only runs when needed, so the higher you set the thermostat the less it runs. My approach in summer is to use the A/C but set it as high as I can stand...

Also be aware that hot air is significantly less dense than cold air, and aerodynamic drag is directly proportional to density. So you can expect to get pretty good mileage on the highway on those 110 degree days. Here in Colorado it's been getting up into the 40s in the day, but still in the teens at night--I could use a 110 degree day right about now!

 

[Infidel]

I managed to break a new record on my one-way commute this morning. I pulled off 98.7mpg over 41.3 miles. Yesterday I increased my tire pressure up to 58#, so that clearly helped. I think the temp this morning was in the mid 50s or so, and there was a significant amount of traffic on the freeway.

Ironically enough, some traffic actually improves my FE as long as it isn't stop & go. It's nice when traffic is in that special "plasma-like" state where you tool around at 30-35mph indefinately getting 125-130mpg... :twisted:

 

[The Citrus Smoothie]

Yesterday I increased my tire pressure up to 58#

:shock: :!: :shock:

 

[Insightful Trekker]

AFAI remember, and its posted in here somewhere, xcel used to run them at 60# :shock: :shock: :shock:

One sharp road hazard and _expect_ a blowout :!: I just hope their not going too fast when it happens.

HTH!

 

[Infidel]

One of the benefits of hypermiling is that you never really go all that fast.

Besides, you only live once.

 

[Billy]

Very excellent job, Infidel! Keep it up. I will pass your acheivement on to Wayne in Illinios, he will be pleased to hear it........

 

[Guest]

Hi Infidel:

___Excellent FE, simply excellent!!! You are oh so close to the 100 mpg club and with another 10 + degrees, you are there

___Insightful Trekker, a heads up. Bridgestone’s burst pressure is > 5X’s max sidewall … Something you really need to know and understand I only wish I would have been running 60 #’s from day 1 instead of for the tank records just before she was retired

___Good Luck

___Wayne R. Gerdes

 

[Insightful Trekker]

I was quite sure that _burst_ pressure was 3x or more of sidewall rating before you clairified. Thanks However a propensity to "blowout" always increases with pressures over the sidewall rating. Yup its highly dependent on all the factors that can cause it. Overpressurization only being one factor.

 

[Infidel]

Yet another new record for my commute in! 101.0 over 41.3 miles. It was a bit warmer this morning (58 degrees) and I dropped my average speed by a couple mph, but I'll still take it.

I've found that you can't always trust the up-shift light if you really want to push the envelope of FE. For example, if your on a mild uphill grade (like a freeway overpass) and going between 40-50mph, the upshift light is *always* on in 4th.

In this situation, you're better off hillclimbing in 4th, in lean-burn, consuming around 70mpg than you are in fifth. Sure, you may hold 75mpg in fifth, but you're loosing speed while your doing it, while the same situation in 4th will actually accelerate mildly (1 mph every 4-5 sec) at a mere cost of an additional 5mpg. Far better than dropping out of LB...

Of course a lot of this is highly dependant on your route, your entrance speed of the hill, etc, but I think the basic idea is that once you can hold LB in any gear, you are ALWAYS better off dropping a gear (assuming you can shift without losing LB) rather than losing LB in a higher gear, REGARDLESS of what the shift light tells you.

BTW: I've hit some pretty nasty potholes at 58# and still no problems, so looking pretty good so far.

 

[Subterfuge3927]

True, very true! Excellent work Infidel!

Xcel, I only wish I could find someone in my area with Nitrogen gas for tires with the balls to blow my tires up that high! I finally found one that would inflate to sidewall, and anything over I have to add straight air. I don't particularly like the moisture content in straight air compression. I haven't tried 58+ psi... I may just try 60lbs this summer and go for my record.

I have long ago joined the 100mpg club on a segment... my goal this summer is a 1k mile single tank 100+mpg. Will be tuff since my comute is always changing, but it is my goal non the less. :badgrin: