No kick down lag in Gen I because there is no kick down. The Gen II gives you a kick in the pants. Not sure how it does this as they are both 1 speed transmissions and didn't notice any lag, was too surprised when it happened.

 

The Gen 1 Volt is capable of full performance in all operating modes using only the larger electric motor, MGB. The smaller motor, MGA, is clutched to the drivetrain only when overall efficiency can be improved by doing so (in Electric Mode, 70 mph is often used as the example speed for doing this). IOW, the Gen 1 Volt remains in single-motor configuration even as torque demands increase.

The Gen 2 Volt’s two motors are closer in size, and because the Gen 2 has added a second planetary gear, the two motors are more frequently used together for better efficiency. Even at low speeds, high torque demands will take the Gen 2 Volt from one- to two-motor configuration. See the following article for more information on the Gen 2's one and two motor CD ev modes:

http://gm-volt.com/2015/02/20/gen-2-volt-transmission-operating-modes-explained/

 

I've only driven a Gen 1 Volt once and I floored it from zero to 70 and it was absolutely smooth. My 2017 is also absolutely smooth when I do this. So real question here, what is this "kick down" and when does it occur?

 

When cruising at a steady speed for a while, then suddenly floor it for a burst of speed. Sometimes there is a delay of about 1 second before you feel any acceleration.

 

This.

It surprised me because I was driving
a decent speed, 59 or so, and needed to accelerate quickly during emergency maneuver.

Hit the pedal and absolutely nothing happened for a noticable delay.

Then it took off like a rocket. But the delay was weird.

 

Thanks Barry. I do this occassionally but have never noticed any lag. I wonder if you need to be near the "switchover" speed between the MGA and MGB motors. And remember, I'm coming out of a stick shift where I was used to no lag between throttle input and vehicle response. Granted that response was sometimes lethargic if I was near lugging the engine but it was there. My Volt responds so much faster than that that I hadn't noticed.

My wife's Clarity definitely has a lag unless its in Sport mode. I've taken to switch it to Sport mode on two lane roads when I'm getting ready to pass just to avoid this delay. It's a little too jerky to leave in sport mode all the time even though I know it won't impact overall efficiency.

 

I worked my way thru the above detailed article - interesting stuff. But I couldn't find any particular reason for the lag - unless it is inherent with two gear boxes. and I couldn't find anything I could do to reduce/help. I start driving in Sport but didn't notice any difference. But one day might be a little soon to see the difference. One nice thing about the dual motor is sporty feel- which is undercut by the lag. Any thoughts?

JIM

 

Many have noticed the lag, but it is rarely seen as a major problem. I wonder if yours is normal or worse than what others are experiencing. Since you had a Gen 1, you should be very familiar with what to expect, in general. I don’t know if the lag is supposed to be more noticeable in the Gen 2. If you can figure out a reliable way to duplicate it, you could have it looked at by a technician.

 

The lag is MUCH more noticeable for Gen two. It is easy to duplicate and seems to be when the second engine is brought on line. What is behind the idea of driving in Sport mode as it seems both engines operate in either mode - based I assume on torque requirements?. Any idea if the problem is mechanical or electrical - I would respond differently depending.

Thanks much for taking the time to respond.

JIM

 

The lag is MUCH more noticeable for Gen two.

I assume you mean more noticeable in your specific Gen 2 vehicle. I was wondering if all Gen 2s are like that, or if the problem is specific to your car. I know my Gen 1 does it, but it is not annoying. During the week I drove a Gen 2, I don't remember noticing it being a problem. If it is specific to your car, a trip to the dealership might get it fixed.

 

Have you tried switching off the traction control?

Also, when accelerating from a stop the Gen2 Volt will briefly limit power and torque to the drive wheels to minimize wheel slip. This is true even when traction control is off.

 

The lag is not noticeable from a standing start - but more often from say 30 MPH when U want to pass. The addition of sport seems to make no difference which is unexpected. last night drove all around town in Sport - and kept it in two engine with a regular punch every few minutes - and was wow. later in the evening out to the car - gentle driving and lag returned - as always. It might seem that from a standing start it works well and as long as I keep punching all is fine. Let it relax in peaceful mode for about say 5 minutes. Then punch and the huge lag returns. The two engine mode seems to be there - but once your start limousine driving - big lag in getting two engines running together again. The two motors are no longer friendly - takes a few second to get them working together. When both engines are on line (what ever that means) amazing car. But something happened within a few minutes of one motor only - and the big lag returns. Again thanks for the advice.

 

This is a stretch but maybe the Volt limits power and torque based on the battery SOC and battery temperature. Those impressive track times logged by Tesla Model S Performance vehicles only happen when the battery pack is near fully charged. Tesla owners have posted that their vehicles seem a bit sluggish when the battery is only partially charged as compared to the acceleration they experience with a full charge.

 

It's literally a kickdown in the traditional sense. Above around 40 mph, the transmission shifts from single motor operation to dual motor for better efficiency. This is seamless because you're under light load and it blends the torque during the transition. However when you floor it it now needs to bring motor A to a stop, accelerate motor B to proper speed and apply a clutch to hold the ring gear of the planetary. (all clutch speeds are matched by the motors before apply) Once the clutch is fully applied full torque is allowed on motor b and away you go. This shuffling takes about a second or two.

You'll learn to stab the gas pedal a few times to initiate the kickdown before you take on a fast merge. I've argued to the moon that "Sport" mode should leave motor B fully engaged for best response and the few miles dual motor is worth be damned, but GM won't listen.

https://youtu.be/AX5ZwzNwTc4

 

More information. This is type two set up. If driving using battery all is fine. When U are driving using ONLY gasoline - the lag kicks in and does so with relatively big lag. Practically - around town it is fantastic. But if you have driven enough so that the batteries are tired and you are ONLY on gasoline (as GM has used a safety factors - ONLY on gasoline takes some patience) ...……. now try and pass someone and U will be in for a surprise. Two second maybe more. if you instead give give the car a gentle nudge forward and all is fine. It seems to be somewhere in the gasoline engine set up or transition as mentioned above. Once you have kicked it down - and the trip continues for say the next few minutes - no lag. Beautiful Then about 5 minutes (or so) the motor and engine no longer like it each (think first date) and the lag returns just once. Motors make nice with each other. But drive for say another five minutes and it returns. Drove from Dulles to Delaware - lag and then no lag and then lag and then no lag. etc. So two questions - why the lag in the fuel side of the equation. And why does the lag restart about five minute into the marriage - and every five minutes? Recharge and all is fine. Did I explain it well? By the way, during the time the two motors are friendly - WOW - is it some car.

 

Part 2. If you have gotten the motors friendly and are driving slowly - the lag returns more quickly - if you are driving at Interstate speeds it take a bit longer than 5 minute. I guess that as you drive only in gasoline - some energy is sneaking over into the battery side giving a mini recharge. Short trip - kicks to all gasoline more quickly. Longer trip or at higher speed, it stays in a version of battery mode a little longer. Key seems to lag only with depleted battery. Just a guess.

 

I'd say this is not much different than most 'gasoline' cars, whether auto or manual......

On Electric, of course you get an
almost' instantaneous drive........I think, driving electric has made the initial gasoline spin up (kick down) more apparent than ever.....no matter which car I am driving (manual or auto)
IE For me, I THINK the 'lag' has probably always been there , the same......but driving electric=instantaneous.....as close as possible acceleration has only highlighted the inevitable 'gasoline' delay....if this make sense !!

( Even riding my gas powered bikes.....I'm 'noticing' not only the revs as the engine spools up, but also the (almost) instantaneous gearchanges MORE now than ever ......Its only mildly annoying on the bikes, but in a 'gas powered' car, its.......more pronounced !)

 

Visited the dealer to see what they knew - which was a lot. One person above said - given all the gears that need to come up to and down to speed - you might expect a lag. Dealer said the same. The amount of lag depends a bit on where the various components are. If you just finished a high torque something - passing a car - the two motors are pretty much in sink. Little lag. If you have been coasting along listening to violin music - will take a few second for the gas engine to make nice with the electric motor. Dealer says - yep - that is the way it is. Depending on how much stuff needs to come up to speed or down to speed (electric often slows as well as gas engine comes up to speed) will change the nature of the lag. The word they used was "inherent" in the design.

During all this, another question came up - what does Sport actually do. Change the suspension but not much with regard to the engine - or so it seems. Lot of wrong information out there - anyone know for sure.

 

During all this, another question came up - what does Sport actually do. Change the suspension but not much with regard to the engine - or so it seems. Lot of wrong information out there - anyone know for sure.

It remaps the accelerator pedal curve a little bit to make a light press a lot more like a good stomp. There's no performance difference between completely flooring it in Sport and flooring it in Normal. No change whatsoever to suspension or braking. The latter is what L is for on the shifter.

 

Seat of pants,pretty much what I just said, lag is inherent, in most propulsion designs, but much less noticeable in Volt than most......

I STILL think you are experiencing 'heightened' senses Re gas v electric torque delivery

As for Sport, as far as I know, and seat of pants again, it seems that the throttle travel/response is somewhat reduced IE 'Quick action throttle' on a motorcycle......same HP, same Torque, but a QA throttle only has to rotate a fraction of your normal one, to increase the engine revs/speed/torque delivery...so your bike SEEMS to have more power delivery......but its just the same 'power', delivered a fraction quicker, really

 

After driving my car's battery to exhaustion last weekend I can say for certainty that my 2017 LT doesn't have a lag when I punch it. My wife's Clarity PHEV, on the other hand, has a terrible lag unless you've put the car in sport mode. Then it responds quickly, but not nearly as quickly as my Volt.

 

And here I thought I - and the dealer and GM technical - had it all figured out. Damn

 

Strange - I noticed more lag in my 2012 then my current 2017. The Gen 1 under 2 motor operation would lag if you punched it during this time. I've never noticed any lag in my 2017.

 

The gen2 is almost always in dual motor operation. It never goes to single motor under hard acceleration.