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[MetroMPG]

CO - was there also a temperature difference between the 2 runs?

[cfg83]

CO ZX2 -

Originally Posted by CO ZX2

New coasting info. 3/15/07
...
Don't you think everyone should be Engine Off Neutral Coasting at every available opportunity? Even if you have to make your own opportunities.

Yes, but I had to deal with this today :

Attachment 266

This was probably under 35 MPH on the flat.

When I get my injector fuel cutoff switch installed (eventually), I will be able to use Engine Off in 5th gear to help me deal with this traffic.

EDIT : In urban traffic, where I think power brakes are necessary to avoid accidents, EOC in 5th means that I can save gas and have 100% working brakes. A (momentary) fuel cutoff switch will be perfect for this strategy.

CarloSW2

[CO ZX2]

Originally Posted by MetroMPG

CO - was there also a temperature difference between the 2 runs?

Metro. Temps were 3 degrees F. colder than first tests, 26 degrees vs 29. I had driven 20 miles to the test site so drivetrain would have been plenty warm. All else very much the same conditions. I have coasted down this same stretch many times and never made it over the rise mentioned.

Engine was shut off for the test so wouldn't have mattered there.

[ELF]

I don't know how cold it gets in the rockies but, around here when it gets sub zero temps the cars just won't roll as good, there is a pretty big difference too.
I don't know if its the tires or frozen grease in the bearings or a combo of the two.
I think thats why Metro wanted to know if there was a temp diff.

But ya, I agree with what you said ..


""Don't you think everyone should be Engine Off Neutral Coasting at every available opportunity? Even if you have to make your own opportunities.""

[BeeUU]

I have been getting braver at creating "opportunities". I dont necessarily slow traffic, but I allow people to approach and trail for a few seconds before I bump start and gather speed.

I have been fortunite lately, most people have turned off the road soon after an approach or I get back up to speed.

I have been testing out EOC in many places now, and have found that I can coast in many places that I never would have thought possible. I definitely am getting familiar with moving slowly and the strange feeling in the steering wheel when the power steering pump kicks in.....

[DRW]

BeeUU wrote:" I definitely am getting familiar with moving slowly and the strange feeling in the steering wheel when the power steering pump kicks in."
Be careful here. I got a suprise when I was learning EOC on twisty roads. I was going a bit faster than I was comfortable with around a downhill turn, so I let the clutch out and bumped the motor to use engine braking. Anyone care to pause here and guess what happened?

The high effort unpowered steering suddenly became low effort power steering, and the wheel jerked quickly into the turn. Luckily I caught it, otherwise I would've spun the car.

I also want to thank CO ZX2 for this thread. Message received.

[BeeUU]

Originally Posted by DRW

Be careful here. I got a suprise when I was learning EOC on twisty roads.

Yep, the first time was interesting, I thought it was the snow tires loading up, plus it was wet, I thought it might have been ice, it was a bit of a surprise. But it seems to be the pump starting. I am fairly lucky, the effort level is not that much different at speed, at least with snow tires. I am not sure what it will be like with the autocross tires installed.

Originally Posted by DRW

I also want to thank CO ZX2 for this thread. Message received.

Yes, for sure!! Good to hear the aero work is paying off!!

[rh77]

Originally Posted by DRW

Be careful here. I got a suprise when I was learning EOC on twisty roads. I was going a bit faster than I was comfortable with around a downhill turn, so I let the clutch out and bumped the motor to use engine braking. Anyone care to pause here and guess what happened?

The first time you have to re-start in a corner is a bit of a surprise. There's a long downhill where traffic loads-up before an on-ramp. I can usually EOC for quite a while on the downhill (usually having to brake as traffic loads-up).

Then, on the ramp itself is when I have to start back up. The first time went from effort to a quick jerk in the wheel (mid-ramp). Luckily the suspension is pretty neutral, so it just slid and corrected :whew: I usually start-up before the turn begins, now

[MetroMPG]

Originally Posted by CO ZX2

Metro. Temps were 3 degrees F. colder than first tests, 26 degrees vs 29.

That's good to hear. If it had been warmer, I would have wondered how much the different rolling resistance from the drivetrain (temperatures of wheel bearings, CV joints, transaxle oil, tires) had contributed.

[VetteOwner]

Originally Posted by skewbe

Yah, on some cars (i.e. mine, apples if you like) the scangauge reports base fuel consumption during overrun/EOC in gear, even there isn't any, which is not a big deal IMHO.

CO reported zero fuel used at the end of his first test leg so I assume his doesn't do that.

Just a thought, A carbureted car very likely would still spew fuel into the engine when coasting with in-gear coasting with the ignition off , and make a nice backfire when you turned it back on

yup it will, especially if you have a mechanical fuel pump (like my vette) since its run off the distributor, if th eengine is turning the fuel will spray, flood the engine possibly hydrolock