What makes a shift "sporty"?

[dcroasmu]

I'm trying to define "Sporty" as a target for AT shift feeling. What, in your opinion, are the characteristics of a "sporty" feeling shift?

Thanks

 

[MechanicalChef]

Speed of the gear-change, and firmness of shift. That would be my criteria. Once again, "sporty" is a highly subjective feeling. What would be firm to one person would be rough-and jerky to another.

 

[patprimmer]

With a sporty shift the shift should be so fast at full throttle that you feel a kick in the pants as it changes, even possibly chirping the tyres.

With modern controls it is entirely possible to have a very fast firm change at full throttle but an imperceptible change at say half power or less, possibly controlled by manifold pressure.

Regards

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[oab]

With an auto, while the transmission computer cuts the torque, during the change, it will always be slow. To have the change made faster, the torque cut can be deleted, but you have to ensure that the Trans computer does not lower the line pressure during the change, as most do, or a catastrophic dismantling of the transmission will take place.

Harvey.

 

[NormPeterson]

Perhaps the intended usage, or range of same, should be defined. Shift speed isn't particularly at issue, but the firmness is. Shifting that's appropriate for dragstrip use is almost certainly too harsh for something like autocross or road course use, to say nothing about use under low friction conditions.

Personally, I find automated up/down shifting in such daily driving situations as highway onramp cornering/merging unsettling enough as it is, never mind if they were made still more intrusive.


Norm

 

[JayMaechtlen]

" I find automated up/down shifting in such daily driving situations as highway onramp cornering/merging unsettling enough as it is, "

?? what kind of vehicle produces such unsettling upshifts? Is this some kind of sporty beastie, or were you accustomed to early Dynaflows?

(well, it could be unsettling when my old Dodge Aspen would grab first gear on a rainy freeway cloverleaf, and the rear would slide out...)

cheers
Jay

Jay Maechtlen

http://home.covad.net/~jmaechtlen/

 

[OP800]

Having 3 different Ford tensmissions with shift quality changes, it is still subjective, application based and what the driver expects from it.
In my C4 with a shift kit mod, at low power loading the shifting is just precision but under heavey throttle the shifting becomes very firm and to the point the tires will break loose on a 1 to 2 shift as well as burn them from a dead stop.
On my AOD with valve body mods taylored to the use of a Kenne Bell supercharger, the shifting is set up to respond to throttle control for shifting under high power but will still auto shift in normal driving. The changes are still quite firm and will accentuate drive lins slop if there is any. In this type transmission there is no overdrive accumulator so the OD up shift is harsh unless the throttle is used as a buffer loading.
In my 4r70w (AODE)with valve body mods, the shift is just percieved as firm and quick by intent. The truck is in a weight class of about 5600 pounds and used for heavey towing. I run a program tuner that can also change the shift firmness but don't run anymore than what the valve body gives because it gets way to harsh running both methods. The AODE is an electric control where the 2 previous are hydraulic with two different methods of shift control. So I end up with three different transmission control systems but all respond to valve body modifications is about the same manner.

 

[NormPeterson]

"?? what kind of vehicle produces such unsettling upshifts? Is this some kind of sporty beastie, or were you accustomed to early Dynaflows?"

Mostly it unsettles me more than it does the car. But I probably notice it more than do most folks as I haven't owned an auto-tranny car since about 1972. So when a shift occurs that I did not specifically request, it comes as a mild surprise.

Some of the vehicles that I have been (un)fortunate enough to have driven have hunted between gears under certain conditions of load and road speed, and I never feel that I'm driving very smoothly when that happens.

There were a couple of 1960s Dodges with the 3-speed Torqueflite transmission that were firmish to slightly harsh on the upshift - that part being mostly OK. But they were matched to rather poor downshift logic that was overly abrupt when you finally did get it to happen, and it always did seem that the ensuing upshifts came too quickly if you lightened up on the throttle even a little.

Still earlier was a 1950s Pontiac with the 4-speed automatic that was nearly as unobtrusive in its shifting as such a thing could get without actually being a Dynaflow. I was not even aware of just how many discrete gears it had until I installed solid-core spark plug wires, after which I could clearly hear it all happen over the AM-only radio.


Norm