MG4 SE motor upgrade from 125 to 150 kw?

[Bassiavet]

It's just a theoretical question, is it doable? I know It might affect the warranty, and greatly reduce the range, but I'm just curious if anyone did something similar.

 

[TBay]

It would definitely affect the warranty.

 

[AndyL61]

MG have done it . The SE LR. ?

 

[Bassiavet]

MG have done it . The SE LR. ?

Yes, of course , but wondering if anyone did it with the LFP 51 kwh battery.

 

[AndyL61]

It would be quite quick as a fair bit lighter.

 

[Tig170]

... whilst its theoretical, why would you want to, for such a small power increase?, it wouldn't suprise me if the rear motors are the same on all models, there are a few breaking on ebay.co.uk and all look the same irrespective of model. - I do remember from 30-40 years ago the adverts of Duracell v's EverReady Blue : I'm not sure its much difference now?

 

[kiwi]

Totally software.

 

[siteguru]

Reduction gearing may be different for the 2 motors?

(The LR has slower acceleration 0-30 mph, but is faster 30-60 mph than the SR).

 

[BingBong]

Reduction gearing may be different for the 2 motors?

(The LR has slower acceleration 0-30 mph, but is faster 30-60 mph than the SR).

No, this because they both have the same toureq (250nm)

 

[Bam Bam]

It would be quite quick as a fair bit lighter.

Aren't the models all about the same weight because the LFP battery is less energy dense?

 

[Rolfe]

I think the SR is actually a tad heavier because the LFP battery isn't so energy dense. Or it might be as Bam Bam said, that they're much the same. It's certainly not lighter.

 

[Tig170]

Reduction gearing may be different for the 2 motors?

(The LR has slower acceleration 0-30 mph, but is faster 30-60 mph than the SR).

Maywell be - but back in 2022 my overiding comment from the dealer was that there were no optional extras, you can only choose the colour - it was a basic model with a slightly different battery - I still have rear tinted windows which apparently slipped through - was just checking my tyres today (as have had the need for snow mode in recent times - stuck in mud on the nearside, where more power appears to be focussed) - tyres were made in week 19, 2022 (w/c May 9, 2022)

 

[siteguru]

Build date of my car was 28-Aug-22 (I think) ... mine is also one with the rear tints.

The SR is marginally faster than the LR 0-60, but that's because the 0-30 time is more quick than the LR's 30-60 time advantage. Given that the weight of the SE SR vs SE LR is essentially the same, what this tells me is that the gearing of the SR is different ... power is lower so the only way the SR can be faster from start is with lower gearing ( = limited top speed); the LR has more grunt but higher gearing, so that tells when the car is already moving - slightly harder to get going, but once going it pulls better.

All IMHO of course.

 

[Tig170]

Build date of my car was 28-Aug-22 (I think) ... mine is also one with the rear tints.

The SR is marginally faster than the LR 0-60, but that's because the 0-30 time is more quick than the LR's 30-60 time advantage. Given that the weight of the SE SR vs SE LR is essentially the same, what this tells me is that the gearing of the SR is different ... power is lower so the only way the SR can be faster from start is with lower gearing ( = limited top speed); the LR has more grunt but higher gearing, so that tells when the car is already moving - slightly harder to get going, but once going it pulls better.

All IMHO of course.

IMHO, is that do EV's have mechanical gearing? - I assumed that it was litterally a battery & motor (with a sprinkle of software?) - there is about 1litre of gearbox reduction oil that goes somewhere (hopefully not on your driveway )

 

[Rolfe]

There is a "reduction gearbox", a very simple single-ratio thing, that just brings down the rotation speed from the motor to a speed that can be handled by the drive train.

 

[Tomg4]

You don't want to spin your wheels around with 15.000 rpm

 

[Tight Git]

IMHO, is that do EV's have mechanical gearing? - I assumed that it was litterally a battery & motor (with a sprinkle of software?) - there is about 1litre of gearbox reduction oil that goes somewhere (hopefully not on your driveway )

Some do - Porsche Taycan apparently has 2 gears as you feel the change.

 

[siteguru]

IMHO, is that do EV's have mechanical gearing? - I assumed that it was litterally a battery & motor (with a sprinkle of software?) - there is about 1litre of gearbox reduction oil that goes somewhere (hopefully not on your driveway )

As @Rolfe said, there's a reduction gearbox the converts the motor speed to wheel speed. This has a gear wheel on the motor shaft and another gear wheel on the drive shaft; the gear ratios (i.e. number of gear teeth on each wheel) are what determine the traction effect. My supposition is that the LR models have a different gear ratio, so the higher power has a bigger inertia to overcome, but once rolling that higher power can have more effect (vs the gear ratio/motor power in the SR).

 

[OriginalBigAl]

In the refit/remove manual as supplied by Monsieur Siteguru it appears that the motors and final reduction gearing, are the same. Page 83 . These are shaft A models , shaft B are slightly different and are for the rear motor for the ER and X power. They just have different BMS,s to complement each battery size.

 

[siteguru]

If that's the case then I guess the power is software-limited, and each type has different "torque curves", hence why the SR has better low down acceleration.