Shifting habits? mini P&G?
 

I got my MPGuino installed a couple days ago and using it has made me wonder about shifting. I can't help but notice the instant mpg shooting up while shifting. Has anyone tried spending more time between gears coasting as a sort of mini P&G?

It's only happening because you lift the throttle and the engine rpm drops ... as does the load on the engine (as it's going to idle).

At speed, you're obviously using less fuel when coasting than while accelerating.
If you want to continue accelerating, don't interrupt the process, as you'll lose speed again, and need to re-accelerate to make up for it.

What you say does happen. If I am at high RPM and push in the clutch and take my foot off the gas, the overrun kicks in, and I have infinite MPG until the rpm gets down to idle speed. Then I am at normal engine on coasting.
I have found that engine on coasting MPG is very dependent on your speed. This is because you are using idle fuel. More speed means more miles while burning that fuel.

Coasting in neutral my Altima got 60 MPG for every 16 MPH. 48 MPH was 180 MPG.
The Insight got 150 MPG at 16 MPH. 48 MPH was 450 MPG.

You can also calculate your coasting fuel consumption.
The Altima was just under .25 GPH 16/60 GPH
The Insight was right at .11 GPH 16/150 GPH

Coasting fuel consumption may be the same as idle consumption depending on the vehicle

regards
Mech

I saw the same thing when I hooked up mine. Every time you push in the clutch you get great mileage, I first thought "why not spend more time there?". But like Euromodder stated, you'll use all your fuel savings taking longer to accelerate to speed. Coasting downhill with my clutch in gets me around 120 - 150 mpg @ 55 - 65 mph. Downshifting is giving me an infinite reading. Does anyone know if the Ford Ranger cuts fuel when decelerating in gear or if this reading could be bogus?

Yes, you'll have to re-accelerate through what you just did, but P&G is constantly reaccelerating. Don't worry about it.

When traffic and road conditions allow, I'll stretch those changes. I was going to be out of gear anyway so I might as well make it a glide.

I do it when there is traffic in the way:
http://ecomodder.com/forum/showthrea...ift-17489.html

I just concentrate on shifting smoothly until it gets to cruising speed. That way I can rev-match it and not have to blip the throttle before putting it back into gear.

I try to rev match my cobalt, I tend to skip gears because the blasted thing cant be throttled to any paticular RPM (one of the big disadvantages of drive by wire) This means that I have to wait a relatively long time waiting for the RPMs to slowly hang and drop. I also would love to have an autotragic idle on the MT since to me its just a waste having it idle at 1k when the auto is usually around 600rpms.

I have often thought of buying an HP tuner for the 010 cobalt XFE just to force DFCO to happen instantly when gas pedal TPS=0 and RPMS are above some point. This would speed my shifting, reduce clutch wear (when I am forced to be in a hurry) and it would allow a mini P&G as I shift from 1->3->5.

Anyone have such a device there are a couple things I would love to tweek on the cobalt but I can't justify $500+ to attempt it.

Cheers
Ryan

Hmmm Megasquirt 2 standalones are less than 500 but they don't have sequential injection...I think they might be able to control the throttle though. Obviously would be a lot of work to adapt.

The 010 has a variable geometry motor which is why I can lug along at 800rpms if I want and not buck like a bronco, that would be darn hard to program from scratch, there are HP tuners out there for it but they, in my mind should be cheaper for non-turbo cars (since no one in their right mind would ever buy an HP tuner for one anyway) but I digress.

Really, when up shifting you want to shift as quickly as possible. This captures the kinetic energy stored in the fly wheel and moving parts of the engine and transfers it to forward motion. Otherwise if you let the rpms drop to match the gear your shifting up into you allow all this energy to be dissipated and get nothing in return.

Unless I need to get up quickly, I'll let the flywheel's KE die out while I ride the car's.

thus wasting all the energy your fuel has put into the Flywheels KE.

Yep and I will glad for it since the clutch turns much of the kinetic energy into heat and powder.

I rather not replace a $500-$1500 clutch job (depending on who and when) in 150k when I can replace it after 300k.

I have an HP-tuner and got the good one the extra $150 was worth not needing a laptop in the car to scan. I might be selling it after I review the tune on my wifes car but only since I got rid of my bonneville.

I just downloaded a stock tune of your car and here are some things that you can change.
Idle (stock is 800 warm and 1000 max cold)
Cam angle for intake and exhaust based on rpm and load
DFCO Cutoffs
Enrichment point
Cat heating (also adjusting cam for cat heating)
Spark based on load rpm and cam angle
Fan speed based on coolant temp.

I wish that I lived closer to you so I could help tune it as I think that it would be fun since i have not got to tune on a car that you can controll the cam with. The great thing is there is a lot of room for improvement in the stock tune and you can enable EGR in low load by adjusting the cam timing.