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Kodak 04-04-2011 11:53 AM

So close to highway rating
 
Today's fill yielded 23.978mpg. I know 24 is within reach for this 'around town' commute.

The pros: I can use 5th in one segment of my commute where previously 4th was used. I used neutral to traffic lights when coasting in gear would have caused too much engine braking. I'm getting better at shifting by ear.

The cons: A few lights were timed rather poorly. Construction zones made me lose a bit of momentum. This tank included some A/C and blower use. I know this summer will mean only more A/C use, but hopefully the warmer temps will cancel out that factor.

When I filled up, the number of gallons seemed unreal. I had to go to a second click to verify that I was truly on full. Had I not done that, this might have been a 24mpg tank.

I am hoping that the warm summer weather (less dense air, better start-up temps) will mean 24 is right around the corner.

Even so, today was a personal record if I set aside the highway roadtrips that I've logged and only count around town fills.

Over the course of just 3000 miles, 24mpg versus the 20mpg combined rating, will mean 25 gallons saved - or about $91 at the current national average price.

bestclimb 04-04-2011 10:36 PM

I think you are there. 24 I mean. something about significant figures, how accurate your fill is, and .022 mpg being pretty well inside the "noise" of .25 gallon fill errors, your odometer error, heck even fuel expansion.

gone-ot 04-04-2011 11:27 PM

...always "round" to integer numbers!

...hence, anything between 23.5 and 24.4 is 24!

Kodak 04-15-2011 05:22 PM

Well, today sealed the deal pretty much. 24.8mpg on this fill.

The only variable was the fact that last tank fill I went to click #2 (see above story), so it's like I got a free 'bonus' amount of fuel but I know that wouldn't have given me an extra 8/10ths of an mpg.

I've also been filling much slower after having read the thread about fill speeds - maybe that's helping a little.


With the nicer weather, there are a lot of pedestrians, so I'm trying to be very conscious about not turning the engine on until it's clear. If I had passengers, I'm sure they'd be curious.

This tank, I learned that on flat terrain 5th is good for as low as 48mph or so. It can probably do 45, but it would require an extremely steady foot, and I don't want to chance lugging.

I am probably going to up my tire pressure from 33 to 35psi this weekend and see how it feels. No intent to approach max sidewall (44ppsi), just a little extra air.

My goal is to hit a very consistent 24 this summer without trying and wean myself almost completely off the speedometer. All by ear baby.

gascort 04-15-2011 10:29 PM

Congrats! Are you using instrumentation yet? I'm guessing no based on your "by ear" comment. I did the same for a bit, but saw HUGE gains once I got my MPGuino. Since your truck is new, get a SGII - it will pay itself off fast.
Read around here more on the pressure thing; most of us split the difference - the manufacturer tire psi is a minimum for safety. I fill to a bit above that on all our cars - sometimes you go a few weeks or a month without checking. Going from 38 psi to 32 is no big deal for FE or safety. Going from 33 to 27 is not as safe (although not awful) and WILL hurt FE.

Kodak 04-16-2011 09:47 AM

A Scan Gauge is something that I've really thought about. I know that would answer a lot of my questions when there is more than one seemingly effective ways to do something (like a certain segment of my commute).

But I'm afraid that I will become too reliant on instrumentation, and my driving safety would suffer. That's my hold up.

Your take on tire pressure is interesting. So rolling resistance does not have a linear relationship with pressure, but more of a diminishing return?

euromodder 04-16-2011 10:43 AM

Quote:

Originally Posted by Kodak (Post 231981)
So rolling resistance does not have a linear relationship with pressure, but more of a diminishing return?

That's right.
You can't keep cranking up the tyre pressure and hope to get big gains every time.
The biggest gain is when you increase tyre pressure from car manufacturer specifications (and in real life, often below) to say 10 psi above that value.
The results of doing so will be readily noticeable.

euromodder 04-16-2011 01:35 PM

Quote:

Originally Posted by Kodak (Post 231889)
Well, today sealed the deal pretty much. 24.8mpg on this fill.

The only variable was the fact that last tank fill I went to click #2 (see above story), so it's like I got a free 'bonus' amount of fuel but I know that wouldn't have given me an extra 8/10ths of an mpg.

Always fill up the same way, or you're introducing even more variables.


I always insert the fuel nozzle so that the copper-ish part lines up with the side of the car, and don't add more fuel after it shuts off automatically.

http://www.mischacoster.com/wp-conte.../03/foto-3.jpg

JRMichler 04-16-2011 02:48 PM

I have Nokian WR tires on my Canyon. There is a very noticeable difference in rolling resistance between 37 and 47 PSI. I have not tried higher pressures.

The Canyon responds very nicely to DWL. Either a vacuum gauge or a Scangauge is necessary because the throttle plate does not have a consistent relationship to gas pedal position.

I find it possible to hold 5th gear down to about 22 MPH on a smooth, level road. It will even accelerate from that speed, although only at about 1 MPH per city block.

Kodak 04-16-2011 03:11 PM

Quote:

Originally Posted by euromodder (Post 232015)
Always fill up the same way, or you're introducing even more variables.


I always insert the fuel nozzle so that the copper-ish part lines up with the side of the car, and don't add more fuel after it shuts off automatically.

You're definitely right. It was kind of a weird fluke that day. My mileage was significantly better than usual, so I didn't trust the first click. I was wrong.

--

JR, 22mph and no signs of lugging? That's impressive. What rpm is that? I can do 47mph at around 1500 rpm in 5th - any lower and it doesn't feel right.

I've been winging the DWL. Gain speed before the ascent, and bleed off speed by the peak. Naturally, it's not terribly specific.

Maybe I'd consider a vacuum gauge, but my safety hang-up is still there.


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