the slip: shifting without using the clutch

[j12piprius]

Originally Posted by ShadeTreeMech

When upshifting, you would ease off the gas while pulling out of gear. In one movement, pull out of gear and try to put the stick in the desired next gear. The stick won't engage the gear until it is time. Wait for the engine to coast down, and when the revs match, with you putting gentle pressure on the stick in the direction of the desired gear, you'll feel it start to engage. Give it the push needed to fully engage, and there you go.

By upshifting, I take it you mean going from 2nd, to 3rd, to 4th, to 5th etc.

Upshifting is a bit trickier. It involves disengaging the current gear, revving the engine past where it needs to be for the next highest gear, then following the above mentioned step of allowing the engine to coast down to the correct rpms.

Don't you mean downshifting is tricker without using the clutch?

[ShadeTreeMech]

Originally Posted by johnlvs2run

By upshifting, I take it you mean going from 2nd, to 3rd, to 4th, to 5th etc.



Don't you mean downshifting is tricker without using the clutch?

LOL, ok, my dyslexia kicked in again. I got it backwards. Upshifting is the easy one, downshifting is trickier, I'll edit it.

[ConnClark]

Once again I fail to see how it saves fuel.

lets say I'm driving and its time to up shift from second to third. I start out with the engine at a high rpm. After I shift, my engine is at a lower rpm.

Shifting with the clutch I take some of the high rpm rotational energy and, even though the clutch slips some, use it to generate torque to move the car forward. The rest of the energy gets turned to heat.

Shifting with out the clutch I pop it out of gear at a high rpm and let the engine spin down (wasting energy that could be used) until the syncros line up and pop it into the next gear.

[user removed]

Learn it in a 38 Ford truck with straight cut gears and no synchros, and you will have it down pat.

1st to 4th back to 1st in my M22 4 speed 59 Corvette with no clutch. Heck I drove it to work with the steering gear failing and it would only turn right. Left turn, you went through the intersection and backed up with the wheel to the right then foreward.

regards
Mech

[ShadeTreeMech]

Originally Posted by ConnClark

Once again I fail to see how it saves fuel.

lets say I'm driving and its time to up shift from second to third. I start out with the engine at a high rpm. After I shift, my engine is at a lower rpm.

With a modern engine, while the engine is coasting down, you would use no fuel since DFCO would likely cut off the fuel

Shifting with the clutch I take some of the high rpm rotational energy and, even though the clutch slips some, use it to generate torque to move the car forward. The rest of the energy gets turned to heat.

Shifting with out the clutch I pop it out of gear at a high rpm and let the engine spin down (wasting energy that could be used) until the syncros line up and pop it into the next gear.

The fact that a modern engine uses no fuel when coasting negates your argument. But regardless, the amount of fuel saved for that simple method of changing gears would be crazy small compared to the driving style shifting without the cltuch encourages compared to the driving style of the clutch fiend.

[moorecomp]

DFCO only works when decelerating with the clutch engaged. If you shift to neutral or as soon as you push in (disengage) the clutch, fuel has to flow or the engine would quit.

[Frank Lee]

I know how to clutchless shift but I don't do it regularly- except when tossing it into neutral for glides- and I don't see any potential for fuel savings either. On the "Pro" column it forces the driver to be more consciencous and smooth; on the "Con" column I do believe, even when smoothly executed, trans wear would be increased while fuel saved would be nothing.

[jmf]

I use clutchless shifting when I'm using my left knee to steer because I'm eating and texting with my hands. It is very important to know how to do.

[ConnClark]

Originally Posted by ShadeTreeMech

With a modern engine, while the engine is coasting down, you would use no fuel since DFCO would likely cut off the fuel

I'm talking about the fuel already used to accelerate the engine to the high rpm before the shift. The fact that no more fuel is used does not recover any energy that has been expended. Just letting this useful energy dissipate is a waste.

The fact that a modern engine uses no fuel when coasting negates your argument.

Hogwash!

But regardless, the amount of fuel saved for that simple method of changing gears would be crazy small compared to the driving style shifting without the cltuch encourages compared to the driving style of the clutch fiend.

No utilizing all opportunities to recover energy saves fuel. Popping the clutch burns the clutch not the fuel. The clutch was designed to wear, gears are not. Save fuel and your transmission by using the clutch.

[j12piprius]

Originally Posted by ConnClark

I'm talking about the fuel already used to accelerate the engine to the high rpm before the shift.

That would only occur shifting down.

The shifting without clutch would be primarily used shifting up and then EOC.

Popping the clutch burns the clutch ... The clutch was designed to wear, gears are not. Save fuel and your transmission by using the clutch.

So you're saying don't use the clutch, use the clutch?