Pulse & Glide Shifting for 04 Civic VTEC

[euromodder]

Originally Posted by VegasDude

My engine produces a healthy amount of torque and so my goal is always shifting around 1-1.2k rpm.

What does it drop down to after shifting ?
Must be way down low !

Definitely not something you can do with every car.

I'm into 5th by 25 mph

OK, so I had heard about short-shifting, but never about anyone shifting that early

That's about idling speed for me ... in 4th (of 5) gears !
(FE around idling speed is horrible for me)


Surely our driving environments are vastly different, but you're getting about the same mpg from a petrol engine with more than twice the displacement of my lowly diesel !

[PaleMelanesian]

VegasDude has a V6.

I aim for each shift to land in the next gear at about 1300 rpm. Give or take depending on the terrain - higher rpm for uphill.

Yes, it is slow acceleration. That's good for mileage. Anything in a hurry will use more gas.

I have recently been tweaking my shifts - I was keeping the rpm TOO low. By that, I mean I'm now running 1300-2000 rpm instead of 1100-1800. That's about the upper limit, though. Any higher, and the glide cannot make up for the fuel used in the pulse. I watch the trip average mpg like a hawk, and focus on making it go up with each cycle.

[PaleMelanesian]

low rpm better:
Showdown: testing RPM vs. MPG at a fixed speed - MetroMPG.com

[VegasDude]

The truth is even tho I take my foot completely off the gas, the revs usually go up close to 2k when I push in the clutch to shift. The only way to keep this from happening is to take my foot off the gas for ~3 seconds before shifting, not usually practical.

I often overshoot going from 1st to 3rd since 1200 rpms comes pretty fast. An ideal situation would be timing the lights well enough to rarely need 1st, since it's geared so low it's almost not nessesary.

Yes, even 18 mph into 5th is no problem, but at that speed I'm only idling around the neighborhood. Things change with hills, but having a higher displacement engine helps keep the revs low around town.

[euromodder]

Originally Posted by VegasDude

The truth is even tho I take my foot completely off the gas, the revs usually go up close to 2k when I push in the clutch to shift. The only way to keep this from happening is to take my foot off the gas for ~3 seconds before shifting, not usually practical.

Strange.
Tho I've always driven manuals, I've never experienced anything like that.

Unless I get off the throttle a tad too late, the revs start dropping instantly - I even keep a bit of throttle on when shifting up to counter that drop.

But then, I've never really explored the low-revving territories before

Yes, even 18 mph into 5th is no problem

I'm amazed !

but at that speed I'm only idling around the neighborhood.

Your comment and PaleMelanesian's link have triggered me to re-try the near-idling trick again in a 20mph (actually 18.6 mph here ) zone, but in 3rd and on cruise control this time.

Amazingly, I got 58 mpg going 20mph in 3rd around idling rpm !
Thanks guys !
I used to be happy with anything slightly better than 32 mpg in 2nd using CC
Controlling the throttle myself, anything better than 25 mpg used to be fine - hence 20 mph zones were killing my overal FE.


Now, if this works at 20mph in 3rd, there's no reason why it won't work @ 30mph in 4th (rather than 3rd), maybe even @ 45mph in 5th (instead of 4th).

More experimentation coming up

[VegasDude]

Yeah the revs only go up when shifting when you shift at low revs. If you shift around 2.5k the revs only go down when you push in the clutch.

[euromodder]

Originally Posted by euromodder

Now, if this works at 20mph in 3rd, there's no reason why it won't work @ 30mph in 4th (rather than 3rd), maybe even @ 45mph in 5th (instead of 4th).

20mph in 3rd, and 30mph in 4th work on level roads or downhill, but FE plummets on the slightest incline.

45mph in 5th doesn't work at all, not even on slightly downhill roads - the engine is struggling and simply can't take this load efficiently.

[ChazInMT]

So I drove to Ohio from Montana & back and averaged 37 MPG in the Civic that's rated 34 MPG hwy. I stayed at around 70 Max, 65 when the law. My tanks ranged from 41.2 to 34.6 MPG. Question...How much does the AC kill mileage?? I'm guessing a 8-10% hit (3-4 mpg to me), what is the general rule of thumb on this? I had to have it on half the time cause it was freaken hot out. My fuel log showed this difference.

[VegasDude]

It really depends on the car. In a big SUV, it's already burining a lot of gas just to move down the road, so as a percentage of the fuel burned, the A/C isn't adding much. I believe a smaller and more aerodynamic car will suffer more. It also depends on the temperature outside and how cool you want it inside. The A/C compressor usually isn't running 100% of the time, but enough to keep the evaporator cold. The less cold air you need, the less it runs. Although, in some vehicles, the compressor might run 100% of the time.

I drove a Civic for a few years and I remember using the A/C generally dropped my mileage by 5-6 MPG, that was well before I cared about improving my mileage.

[euromodder]

Originally Posted by ChazInMT

Question...How much does the AC kill mileage?? I'm guessing a 8-10% hit (3-4 mpg to me), what is the general rule of thumb on this?

That won't be far off the mark.
When using CC, I'm instantly using 10% more fuel when switching the A/C on.
When left on, the FC drops down again to slightly above previous amount - until the time when the AC comes on again (like when setting a colder temp).

When I switch it off when its running full blast (think defog) it's an instant 10% increase in FE.

The weird thing is I only saw this happening after I had CC installed.
Before that, I didn't believe it could make such a big impact as I wasn't seeing any, but apparently it does.

With the ScanGauge, it also shows up in the engine load.