Hugely dissapointed with hypermiling results

[Christ]

Originally Posted by 99metro

Those short trips are killing you. My diesel pickup only gets about 12mpg over 6 miles, yet I can get over 28mpg over 55 miles.

My 99 Metro can just get 40 mpg over 6 miles, but can get over 60 mpg over the same 55 miles.

I believe hypermiling techniques can be realized over longer distances, rather than short trips. Don't idle and let it warm up - just get in, seatbelts on, start it and go. Use light throttle to use the least amount of horsepower. A heavy foot at low RPM is very wasteful.

If you have a Phillips 66 gas station around, I believe most all DO NOT use alcohol/oxygenated fuel (check the pump sticker). Use the lowest octane.

Do you have proof that high throttle angles at low RPM are wasteful? You've pretty much just contradicted the laws of fluid and thermal dynamics, and the basic theory of engine operation. Those are giant shoes, my friend.

Carb'd or not, the engine will only get enough fuel (given a proper tune) to compensate for the air in the cylinder, which means that at low RPM, using more throttle to reduce pumping losses and make slightly more than normal HP will get you up to cruising speed much faster, with only slightly more fuel being used. It's more efficient that way.

If you've ever accelerated in a manual at 80% throttle, shifting around 2k RPM, and then do the same thing at 25-30% throttle, you'll notice a HUGE difference in the time that you're spending getting from 0-40MPH. Like nearly double the time for the latter, or more.

I'm not going to go through the formulae and do the math for this here, but basically, the engine can only suck in so much air, and by widening the path that it sucks in air through, you're just lessening the vacuum load on the pistons, which means the engine doesn't have to use as much of the generated work (torque) to keep spinning, and has more capacity for moving the vehicle.

In simpler terms - The engine can only produce 100% power per throttle/speed, for the amount of fuel introduced. Of that 100% (Theoretical max), normally, at 30% throttle, 25% of that tM power is being used just to keep the engine running. By opening the throttle (which acts like a big choke) to 60% the engine can breathe easier, meaning that maybe now only 15% of tM is being used to keep the engine running, leaving 85% tM for moving the vehicle, as opposed to 75%.

(This assumes that tM remains constant based on throttle angle, which just isn't true. You'll get more power if you open the throttle more, except in the case where the engine can't inject any more fuel to match the incoming air - you may lose power in that case.)

[chipsndukes]

Originally Posted by 99metro

Those short trips are killing you.

That's true, too.

I averaged 15-18 mpg during the last period of short trips with the same truck that was capable of 40+ mpg when warmed up and moving.

Maybe as simple as that...

Chipsndukes

[Frank Lee]

Originally Posted by 99metro

Use light throttle to use the least amount of horsepower. A heavy foot at low RPM is very wasteful.

If you have a Phillips 66 gas station around, I believe most all DO NOT use alcohol/oxygenated fuel (check the pump sticker).

Wrong

and wrong.

[Christ]

Originally Posted by Frank Lee

Wrong

and wrong.

I was getting to that, as well... I can't find the thing I was looking at, but any station that dispenses fuel which does not contain the Federally Required amount of Ethanol (min 10%, IIRC) can be fined and shut down, with no renumeration for expenses or lost fuel as a result.

What they'd be selling is basically no longer legal for on-road use as a mass-produced fuel.

[Frank Lee]

I've linked it before, I don't know if it's still here, but I found a university study that agrees with my ethanol experiences, and that is with up to 40% ethanol blends, several models of cars tested did not experience any fe drop, or it was negligible, and in fact one got better fe.

I generally figure my fe is unchanged by mixes of E85/regular up to 50/50 and above that, yes, the fe drop becomes noticeable.

And of course there is the basic hypermiling technique of short shifting and going deep into the throttle, which I think needs no further explanation here.

[cfg83]

sn0w3n -

I agree with 99metro. Short trips are killing you (but not a bad way to live your life). After you establish a baseline, maybe you should plan a field trip to a place you'd like to go that has a lot of highway travel. That might give you an idea if your Saturn is operating normally or needs some repair TLC. Top off your tank before the trip, at the destination, and when you get back, with odometer measurements at each fill.

CarloSW2

[Christ]

I enjoy the "joyride maintenance check", personally.

Get on Google Maps, find yourself a 150 mile route that ends near a gas station, out in the country somewhere, preferably with nice twisty roads that go up over/around mountains.

Get there, have lunch, fill 'er up, drive home.

I'm probably crazy, but I enjoyed driving from Harrisburg, PA to Niagara, NY and back in one day (about 14 hours, the whole way back I had an engine in the trunk and a complete CRX dash and several other goodies in the back seat, my wife in the passenger side, who didn't have a license at the time. Drove there, loaded the engine, grabbed a snack and drinks, and drove home, all in a 1.5L 1988 Honda Civic.)

The whole trip, I averaged about 40MPG.

[99metro]

I guess I should have clarified.

Phillips 66 stations in non-attainment areas don't have oxygenated/alcohol blend fuels. It is not federally mandated that all stations in the US use oxygenated/alcohol blend fuels - only in certain areas. I live in a mostly non-attainment area - I was not thinking about the city folks. I feel so stupid for not mentioning that.

Areas Participating in the Oxygenated Gasoline Program

I always thought that the more horsepower you use to accelerate or maintain speed, the more fuel you use. I thought wrong. I stand corrected. I try not to make my hobby complicated.

[sn0w3n]

ok in a few days I'll have a baseline of regular driving. Will post results soon.

[jonathan150cc]

Originally Posted by Clev

Wow, that's awesome. Sounds like you'd be a perfect candidate for a Forkenswift.

Man, you have no idea how awesome that would be. I have a 1976 MG Midget sitting in my basement right now waiting on some money so I can drop an electric drive system in it.