VSA on/off driving experience

[SteveSRT8]

Originally Posted By: Hokiefyd
Steve said something a while ago about these new 6-, 7-, and 8-speed transmissions and I think it applies to driving with VSA-type systems as well. You used to be able to control your transmission with the throttle. You could induce an upshift by letting up on the gas, then power back down when it upshifts. Steve made the comment, and I agree with it completely, that these newer transmissions react best to a steady foot. They don't seem to respond well to you trying to "drive around" the logic in the software. Simply give it the throttle you want and let the software handle it.

I find this to be the case with stability control systems as well. I feel that they're less effective when drivers try to "drive around" the logic. As one who grew up with old school RWD vehicles, I can completely sympathize with those who would rather drive the car than let the car sort out all the sensor inputs, but after owning multiple vehicles with stability control systems (the first really good one I had was a Cadillac with StabiliTrak), they seem to work the best when you tell it where you want to go (with the wheel) and how fast you want to get there (with the throttle) and let it get you there.

There is obviously still a measure of skill and caution needed when conditions are poor, but modern vehicles are remarkably capable of using sensor inputs and brake system outputs to keep the car on the intended line.

For better or for worse...


Great comments, and exactly right with many systems. My car will completely ignore a quick stab at the throttle when moving, absolutely nothing happens. In our new 2013 3500 van the throttle response is extremely dependent on what gear you are in and whether or not you are in 4 cylinder or 8 cylinder mode. And you can really confuse a modern car by having a foot that can't pick a throttle setting and keep it steady.

These are all SOFTWARE related issues and are precisely why many of us report such dramatically different behavior despite the vehicles all pretty much monitoring the same parameters. They are also many times tuneable with aftermarket stuff...

 

[dparm]

Originally Posted By: SteveSRT8
Actually at a Skip Barber event I attended they taught me that you can use the stability control system to be a better driver. By learning to drive smoothly and NOT actuate the system you could go faster around the course even with the system on.

One of the best things about my aftermarket tune is the way it pushed back the thresholds of intervention. Most stability control systems do NOT go completely off when you push the disable button, they simply move the threshold further away.



I think that varies from car to car. Performance cars, like BMWs and Porsches, are going to be more forgiving, whereas something like a Camry is going to be more intrusive and abrupt so the driver knows they were pushing too hard.

In M Dynamic Mode, mine will smoothly back the power off and smoothly add braking so there isn't a massive loss of momentum. In normal mode, there is a brief but noticeable interruption in pretty much everything.

 

[MCompact]

My MS3 has a fairly low intervention threshold as well.

 

[rjundi]

Looks like the engineers (at least Acura) have a blast working on VSA(and SH-AWD) in the winter esp with their all-season equipped tires. Lots of "inputs" likely from VSA.

 

[gofast182]

SH-AWD is undoubtedly an electronically-controlled system, however the VSA program can be turned off and the functionality of the SH-AWD will remain (up to 70% of power to the rear, of the 70% up to 100% left or right, and an acceleration factor of 1.7% of the vehicle speed on the rear wheels) without brake intervention.

 

[Hokiefyd]

Originally Posted By: gofast182
SH-AWD is undoubtedly an electronically-controlled system, however the VSA program can be turned off and the functionality of the SH-AWD will remain...


The same is true of our MDX with VTM-4. VSA can be turned off, but I don't think there is a way to disable the VTM-4 system, short of removing the propeller shaft. Not sure why one would want to, but...

 

[gofast182]

Originally Posted By: Hokiefyd
Originally Posted By: gofast182
SH-AWD is undoubtedly an electronically-controlled system, however the VSA program can be turned off and the functionality of the SH-AWD will remain...


The same is true of our MDX with VTM-4. VSA can be turned off, but I don't think there is a way to disable the VTM-4 system, short of removing the propeller shaft. Not sure why one would want to, but...

Correct.

 

[Hokiefyd]

I'm going to bump this thread, even though I participated in it quite a bit in the past.

I don't know if the OP is still around, but I've been doing a lot of experimenting with my 2009 Ridgeline (which I didn't own a number of years ago when this thread was current), and I have the same observations as the OP does. When VSA is on and the gear selector is in D5, the transmission programming will moderately pulse the torque converter clutch immediately after the 1-2 shift and immediately after the 2-3 shift. You can see it on the tachometer, you can feel it slightly in the rate of acceleration, and you can really hear it in the Ridgeline -- the tone of the intake and exhaust changes as the engine goes under slightly more load. I generally drive with a fairly light foot, and this behavior can be annoying. If I use enough throttle, it's as if the computer switches to a different program, and the transmission doesn't pulse the torque converter at all -- it's completely smooth acceleration.

The other two ways to "defeat" what I will call this "economy" mode is by turning VSA off or by using the D3 button on the shift selector (the Ridgeline is column shift, and has only D5/2/1 with a D3 button on the end of the stalk). If VSA is manually off, or if D3 is engaged, it doesn't matter how light you are on the throttle, the transmission will NOT pulse the torque converter clutch in at lower speeds. It'll still lock in right after the 4-5 shift, as it normally does, but it doesn't try to further load down the engine in the lower gears.

I think this is what the OP is describing in terms of his car driving differently when VSA off vs. on.

My guess is Honda are targeting the EPA's emissions testing program with this software. They know the precise rate of acceleration that the EPA testing program requires, and they program their engine and transmission control software to be on its best behavior at those lower rates of acceleration, when it can. If you give it enough throttle (probably more than required for the EPA testing, at least in many cases), the software won't artificially try to pull more out of the engine with pulsing the converter clutch. If you do something not done during the EPA testing, like disabling the VSA or taking it out of D5, it will also revert to not artificially putting more load on the engine.

To be clear, VSA being on doesn't directly intervene with your driving in the sense that it's constantly trying to control wheel spin. But I think it has an indirect impact by allowing the computer to use this "economy" mode when it can, at lower rates of acceleration. Enough people with Hondas report improving their drive by disabling VSA that I think there's something to it. I guess it's not all that unlike my dad's Mercedes SLK350. By default, it starts in this "eco mode" (says so right on the dash), which softens throttle response and allows the car to automatically start/stop I think. Every time he gets in, he hits the button to disable that mode. Maybe Honda have given us the same type of option, but it's more or less an undocumented feature. The vehicle very clearly drives just a little different if VSA is off or if it's not in D5.

It's not dramatically different. The difference is small, but it's very tangible, and it's very repeatable.