MG4 2 speed gearbox?

[bobtherock]

Hi,

I always assumed the MG4 (trophy LR) was single speed but got new tyres installed a few weeks and now i notice foot down acceleration from junctions, at 35/40mph there is a clear step/gear change.

Im confident it isn’t slip. Is the Trophy 2 speed gearbox?

Edit; just found a forum post mentioning it in a johny smith review from 2022. No insight though. MG 4, 2 gears? ?

 

[mg4mc]

Nope

 

[bobtherock]

Nope

Any insight into what the step might be?

 

[webhiker]

Nope unless you have a MY2027 ??

 

[siteguru]

Any insight into what the step might be?

It'll be the torque curve. I've noticed the same thing in my SE (with the original tyres).

 

[bobtherock]

It'll be the torque curve. I've noticed the same thing in my SE (with the original tyres).

Thats not how a torque curve works though? It would just taper off. This reapplies the torque after the step.

Interesting, as long as its not a sign the transmission is about to explode ill relax.

 

[Koomi]

I can't say I've ever noticed it either.
What drive mode are you in? Maybe some electronics adding more power if in sport?
But again, not noticed on my 23 plate trophy.

 

[BingBong]

I know what you talking about, its the TRC system trying to avoid wheel spin. Try to disable TRC (BE CEARFUL KEEP THE STEERING WHEEL CENTERED) and you will probably feel that its a wheel slip.

I got my car with trash tyres (not the original Conti) and it also happened in some scenarios

 

[bobtherock]

Both sport and normal. I can’t say i noticed till i changed tyres to cross climates. Im on a 23 trophy too.
Slide side note, what were your factory tyres. My car is secondhand and not sure if the tyres were swapped before delivery.

I know what you talking about, its the TRC system trying to avoid wheel spin. Try to disable TRC (BE CEARFUL KEEP THE STEERING WHEEL CENTERED) and you will probably feel that its a wheel slip.

I got my car with trash tyres (not the original Conti) and it also happened in some scenarios

That’s interesting. I had mismatched comtis with very different tread originally. Now running cross climate 2’s.

Ill give it a boot without TRC but at 40mph i’d be surprised if it had the torque to spin the tyres?

 

[siteguru]

Thats not how a torque curve works though? It would just taper off. This reapplies the torque after the step.

I didn't say it was the peak of the torque curve, just the shape of it. ?‍

 

[tsedge]

Yes, it is software limiting torque to control wheelspin - which is of course dependent on which tyres you have and how grippy they are.

 

[Coulomb]

Any insight into what the step might be?

It could be the onset of flux weakening, which I believe is at around the 60 km/h speed (37 mph).

I've mentioned it in a ZS post here. It's sort of where the "electronic transmission" kicks in; torque is traded for speed, same as with a mechanical gearbox.

Only EVs with the highest speed ranges have a mechanical gearbox. The original Tesla Roadster came out with a 2 speed gearbox, but later models did away with it, and earlier models were upgraded to the no mechanical gearbox drivetrain.

 

[Barrie]

Only EVs with the highest speed ranges have a mechanical gearbox. The original Tesla Roadster came out with a 2 speed gearbox, but later models did away with it, and earlier models were upgraded to the no mechanical gearbox drivetrain.

Not true. My MG Marvel has a two speed gearbox and would not class it as a high speed model !

 

[tsedge]

It could be the onset of flux weakening, which I believe is at around the 60 km/h speed (37 mph).

I've mentioned it in a ZS post here. It's sort of where the "electronic transmission" kicks in; torque is traded for speed, same as with a mechanical gearbox.

Only EVs with the highest speed ranges have a mechanical gearbox. The original Tesla Roadster came out with a 2 speed gearbox, but later models did away with it, and earlier models were upgraded to the no mechanical gearbox drivetrain.

That's a good point, I have forgotten about flux weakening.

2 speed gearboxes were originally due to limitations on motor RPM but modern motors have a wide enough range for single speeds.

 

[Barrie]

2 speed gearboxes were originally due to limitations on motor RPM but modern motors have a wide enough range for single speeds

My MG Marvel motor spins to 9k with a 2 speed gearbox !

 

[tsedge]

My MG Marvel motor spins to 9k with a 2 speed gearbox !

20k is not unheard of.

 

[Coulomb]

My MG Marvel has a two speed gearbox and would not class it as a high speed model !

Are you sure? You would presumably know better than me, but I only see P, R, N, and D:

Things could of course have changed since that photo.

 

[Barrie]

That's a Cyberster image not a Marvel. You can't "select" the second gear. When you floor it you feel it change gear around 100kph. It's surreal for an EV and the surge is addictive.

 

[Coulomb]

That's a Cyberster image not a Marvel.

Duh! My bad.

The Marvel must be one of the few EVs with a top speed of 125 mph or less that has a two speed gearbox. Thanks for the data point.

 

[jds686868]

Hi,

I always assumed the MG4 (trophy LR) was single speed but got new tyres installed a few weeks and now i notice foot down acceleration from junctions, at 35/40mph there is a clear step/gear change.

Im confident it isn’t slip. Is the Trophy 2 speed gearbox?

Edit; just found a forum post mentioning it in a johny smith review from 2022. No insight though. MG 4, 2 gears? ?

Were you going around a corner or on a slippery road and accelerated? I have the XP and the nanny aids (traction and stability control) are not very refined let's say. It ramps up power out of corners in "increments". Feels like an old school turbo. Not sure why it is programmed that way, would be nice to have it a little more refined and progressive. There is no 2nd gear.