Am I on to something?

[AeroModder]

When a section of pipe came off my exhaust, I had to drive a lot softer to avoid being obnoxiously loud. I noticed that if I get up to speed relatively quick, then just barely add enough gas to go, the exhaust stayed pretty quiet. The trouble was, I was very gradually slowing down. Any more gas and it was a bit loud.

I ended up driving half the tank with the exhaust open, then went on the freeway up to the local drag strip. I drove faster than usual on the freeway and made a couple passes at the strip. I was going to test some intake setups and have quantified results, but something didn't sound right after the second run, so I called it a day. Haven't heard that sound since, but I didn't want to risk breaking something.

Even after all that, I got 26.4 MPG, matching my last best tank. When I got the pipe back on, I didn't concern myself with working the throttle that carefully, but the other day, I decided to try it again, bringing it up to a little above 55, then letting off te gas enough so it's decelerating at a very slow rate. I noticed the needle on the gas gauge didn't move much at all after the usual 20-mile commute to the nearby city.

I'm thinking of this as a modified "pulse and glide," since I'm using very little power to keep the car going on the "glides."

It's been a little over 200 miles this tank, and I still have just under 1/3 of my fuel left. I'm wondering if this is going to be a record tank!

So, am I on to something here, or just discovering on my own what everyone else already knew?

[MadisonMPG]

You're pretty much P&Ging.

[hummingbird]

I tried this technique to much benefit recently. The weather was unbearably hot, and I had to go some 200 miles at a stretch. I was forced to keep the AC on, and therefore EOC coasting was not possible. I just decided to 'micro-P&G' - get up to 80 kmph, let the car come back to 75 on DFCO, then add a gentle burst of power to push it back to 80, DFCO to 75, rinse and repeat.

I got 47, without shutting off engine at all, at a respectable speed of 80 kmph.

Since then this has become my fallback option if I cannot do EOC coasting. (the entire summer months are 'fallback', with some exceptions).

[Nevyn]

Over on CleanMPG, this is known as "Hang Time" and it's VERY effective.

[AeroModder]

No wonder my last 3 tanks were around 25 or better. XD

Thanks guys!

[MadisonMPG]

Originally Posted by AeroModder

No wonder my last 3 tanks were around 25 or better. XD

Do you have an automatic transmission?

[gasstingy]

I use my AC a good deal in hot weather too. What I've started doing is to get the car cool, make sure the recirculate button is on so I don't start miing the hotter outside air, turn off the AC button and turn up the fan speed. For my 20 mile commute, this cuts my AC usage by about 1/3 and I stay relatively comfortable the entire time.

[AeroModder]

Madison: Yes, it's a 3-speed auto, and I can barely stand it. Though I can get it to short-shift by itself if I barely touch the throttle, but I'm crawling forward with all the speed of a slug. I only do that if there's no one behind me. This tranny makes the engine spin at 3K RPM around 60 MPH.

gasstingy: I actually removed the AC compressor at the same time I removed the power steering.

[ac6404]

hang time, haha i like that. I drive a manual and just pop it in neutral to do the same thing. Do you put it in neutral to glide when you do this on an automatic? you said 3000rpms so I gues not. If you can, I feel like shifting in to neutral on your automatic for coasting would get you even better FE, as you should coast farther if your wheels arent turning your engine.

[AeroModder]

I'm not actually coasting for this, but barely touching the gas so it's just barely slowing down, maybe a half a mile per hour every 10 seconds, and I hold that throttle position until it drops to around 50.