Handling of the E93 M3 Convertible

[PRS]

Having owned my E93 M3 convertible for a few months now, I've noticed that the handling is better with the top up. (for context, I have a lot of track experience and am an 'advanced' driver and have multiple Porsches)

With the top down, the car has a tendency to understeer and needs a lot of trailbraking to help it turn. I assume that this is largely because putting the top down shifts the weight balance towards the back of the car, thus less grip at the front.

With the top down, I've also noticed that the handling of the car isn't great when braking hard and late and then trailbraking, as one would do on a race track. This could partly be due to the understeer, but I think that twisting of the car under that transient load could also be a factor, resulting in the dampers getting confused (I have EDC) and the front of the car not staying planted. It seems like putting the top up would stiffen the car, since the roof is metal and locks into the A-pillars.

What are your experiences with the handling of the car, top up versus top down?

Does the car have adjustable sway bars, so that the balance can be made more neutral with the top down? (yes, I know that may make the car slightly understeery with the top up)

How does the handling of the convertible (top up) compare with the coupe/sedan? I know the convertible is more than 400 pounds heavier and likely not as stiff, but most of the extra weight should be at the bottom of the car, so the convertible may not have much of a penalty in terms of center of gravity height, and acceleration of the convertible is plenty fast for me.

[roastbeef]

An alignment could help, and would be cheapest. Next, I'd add camber plates, but that might not align with your comfort and drivability goals.

Swaybars are not adjustable, and you'd want to add stiffness to the rear to help with what you're describing. Changing the rear sway bar is a labor intensive job that requires dropping the rear subframe.
If you do this, add solid subframe bushings while you're at it.

[CamasM3e93]

Mine was lowered on H&R sport springs and aligned to factory specs. I always thought it handled better top down on the streets and in canyon carving. HOWEVER I've had a single hpde and don't have the skillset to describe what you are picking up and relaying in your experience. That said, top up track driving at Portland international raceway the car was noticeably top heavy in the corners and to my feel, eliminating that with top down was a bigger gain than problem.

[kolosy]

i do wonder if the car becomes stiffer with the top up, but i'd imagine the weight transferring further back is the bigger contributor.

[PRS]

Originally Posted by roastbeef

An alignment could help, and would be cheapest. Next, I'd add camber plates, but that might not align with your comfort and drivability goals.

Swaybars are not adjustable, and you'd want to add stiffness to the rear to help with what you're describing. Changing the rear sway bar is a labor intensive job that requires dropping the rear subframe.
If you do this, add solid subframe bushings while you're at it.

Hmm, surprised they made it so difficult in such a sporty car which is often tracked.

[roastbeef]

Originally Posted by PRS

Hmm, surprised they made it so difficult in such a sporty car which is often tracked.

german engineering... they'll tell you its perfect as-is.

[torrque]

Originally Posted by PRS

Having owned my E93 M3 convertible for a few months now, I've noticed that the handling is better with the top up. (for context, I have a lot of track experience and am an 'advanced' driver and have multiple Porsches)

With the top down, the car has a tendency to understeer and needs a lot of trailbraking to help it turn. I assume that this is largely because putting the top down shifts the weight balance towards the back of the car, thus less grip at the front.

With the top down, I've also noticed that the handling of the car isn't great when braking hard and late and then trailbraking, as one would do on a race track. This could partly be due to the understeer, but I think that twisting of the car under that transient load could also be a factor, resulting in the dampers getting confused (I have EDC) and the front of the car not staying planted. It seems like putting the top up would stiffen the car, since the roof is metal and locks into the A-pillars.

What are your experiences with the handling of the car, top up versus top down?

Does the car have adjustable sway bars, so that the balance can be made more neutral with the top down? (yes, I know that may make the car slightly understeery with the top up)

How does the handling of the convertible (top up) compare with the coupe/sedan? I know the convertible is more than 400 pounds heavier and likely not as stiff, but most of the extra weight should be at the bottom of the car, so the convertible may not have much of a penalty in terms of center of gravity height, and acceleration of the convertible is plenty fast for me.

I stand to be corrected... but if you own multiple Porsche and AMG... acceleration of your unlimited head room M3, which is slower than a coupe should be obviously less.. and sway bars will NOT help with that handling.
Sorry but you bought the wrong M3 if you wanted handling.

[Dpc2u]

As an E93 owner (not my only M), I will say this.

She isn't the most athletic in the stable, has a little too much junk in the trunk, but loves to go topless and is still a fun ride.

[PRS]

Originally Posted by torrque

I stand to be corrected... but if you own multiple Porsche and AMG... acceleration of your unlimited head room M3, which is slower than a coupe should be obviously less.. and sway bars will NOT help with that handling.
Sorry but you bought the wrong M3 if you wanted handling.

Have you driven both the coupe and convertible? If so, what's your experience of the handling differences?

I'd consider getting a coupe, but advantages of the convertible are:

- Sound with the top down
- Open air experience with the top down
- Ability to put the top up to get the handling closer to the coupe

[neilum]

Originally Posted by PRS

Have you driven both the coupe and convertible? If so, what's your experience of the handling differences?

I'd consider getting a coupe, but advantages of the convertible are:

- Sound with the top down
- Open air experience with the top down
- Ability to put the top up to get the handling closer to the coupe

The weight penalty is ~450lbs and has its roof cut off. It's an entirely different car and not close in performance.

Getting the e93 closer to handling to an e92/e90 is like saying I took 300 lbs of unnecessary weight out of my Acura MDX so its now closer in handling to my e92 m3. It means nothing, a fixed roof e9X traps about 4-5 mph faster and would smoke a vert around a track.

Enjoy the vert for what it is but I don't see the point of making it a performance discussion, its the wrong tool for the job.

Some cars like the S2000 and 911's dont suffer a huge vert penalty performance wise, but in this case 450 lbs is a LOT and offers little to compensate other fundamental differences in the chassis and related components

[CamasM3e93]

I think everything you say is true - but adding viewpoint that the extra weight of the vert actually came in handy when I added a Harrop supercharger. I didn't have nearly the traction issues on stock tire sizes (255/235) that others in the lighter e90 and e92 face with that torque-focused induction unit. That, in addition to the DCT, gave me 0-60 speeds reliably at 4.0 seconds that I can't come close to matching in the Harrop e90 6MT. A lot of that has to do with the slower shifting of the MT compared to the DCT, but I definitely struggle more with traction in that off the line experience in the harrop e90 on a wider tire setup 265/245. That SC unit adds 80 pounds to the engine compartment and I wonder if part of my experience that top down driving was so good is in part because of that counterweight to the roof in the trunk.

Acknowledge that OP's track observations and my street performance observations are two different scenarios.

[PRS]

Originally Posted by neilum

The weight penalty is ~450lbs and has its roof cut off. It's an entirely different car and not close in performance.

Getting the e93 closer to handling to an e92/e90 is like saying I took 300 lbs of unnecessary weight out of my Acura MDX so its now closer in handling to my e92 m3. It means nothing, a fixed roof e9X traps about 4-5 mph faster and would smoke a vert around a track.

Enjoy the vert for what it is but I don't see the point of making it a performance discussion, its the wrong tool for the job.

Some cars like the S2000 and 911's dont suffer a huge vert penalty performance wise, but in this case 450 lbs is a LOT and offers little to compensate other fundamental differences in the chassis and related components

Again, have you driven the E93 and directly compared to the E90/92?

Extra weight isn't necessarily a big problem if the F/R balance is good and CG is kept low; Tesla Model S is heavy, but the batteries are at the floor and the handling is excellent.

Acceleration is unrelated to handling, and I think the acceleration of the E93 is amply strong for a road car. I'm not tracking the E93 because I have Porsche GT cars for the track which are much faster than any E9x.

[kolosy]

Originally Posted by PRS

Again, have you driven the E93 and directly compared to the E90/92?

Extra weight isn't necessarily a big problem if the F/R balance is good and CG is kept low; Tesla Model S is heavy, but the batteries are at the floor and the handling is excellent.

Acceleration is unrelated to handling, and I think the acceleration of the E93 is amply strong for a road car. I'm not tracking the E93 because I have Porsche GT cars for the track which are much faster than any E9x.

i sold my E93 to get a carbon roof E92. they're completely different cars, top up or not. If you have a proper track car though, why do you care? The pluses you list for the cab are for real -- top down WOT that noise is hard to beat.

[PRS]

Originally Posted by kolosy

i sold my E93 to get a carbon roof E92. they're completely different cars, top up or not. If you have a proper track car though, why do you care? The pluses you list for the cab are for real -- top down WOT that noise is hard to beat.

I care because this generation of M3 is an outstanding and fun car, and if I can improve the handling of my E93 by reducing the understeer, I'd like to do that.

If I can get an E92 with relatively low miles at a decent price, I may buy that and keep the E93. A bit redundant, but if they're really noticeably different cars, it could make sense.

[kolosy]

Originally Posted by PRS

I care because this generation of M3 is an outstanding and fun car, and if I can improve the handling of my E93 by reducing the understeer, I'd like to do that.

If I can get an E92 with relatively low miles at a decent price, I may buy that and keep the E93. A bit redundant, but if they're really noticeably different cars, it could make sense.

as multiple people have said, they're noticeably different cars. my e92 is massively stiffer when driving, on top of overall handling characteristics. the e93 is a top down cruiser, not a track car.

[CTMike]

Not sure why it offends certain folks that some people want their E93 to handle as well as possible. Whether or not that’s “better” than an E92 is irrelevant. It magically becomes a track car the moment it’s driven to a track.

[PRS]

Originally Posted by CTMike

Not sure it offends certain folks that some people want their E93 to handle as well as possible. Whether or not that’s “better” than an E92 is irrelevant. It magically becomes a track car the moment it’s driven to a track.

Yep, odd to say don't try to make the car I have better because it won't be as good as some other car I don't have. Understeer/oversteer balance can be changed in any car.

And I strongly suspect that the factory balance of the E93 was conservatively set to have very slight understeer with the top up, resulting in more significant understeer with the top down. I want to dial out the understeer with the top up, which will reduce the understeer with the top down.

[kolosy]

odd to infer that someone's telling you what to do when you get answers to your direct question. ¯\_(ツ)_/¯

Originally Posted by PRS

Again, have you driven the E93 and directly compared to the E90/92?