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      10-09-2017, 05:48 PM   #67
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I found on my last track day that when the outside wheel spun the inside just didn't have enough to hold the car in the turn. Oversteer would happen, I don't see how the an LSD would help or make the situation work.
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      10-09-2017, 06:20 PM   #68
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Quote:
Originally Posted by zinner View Post
I found on my last track day that when the outside wheel spun the inside just didn't have enough to hold the car in the turn. Oversteer would happen, I don't see how the an LSD would help or make the situation work.
The inside generally won't have enough to hold the car in the turn because it isn't loaded. An LSD will allow you to accelerate forward in a slight oversteer situation provided you counter steer a bit. With an open diff, you'll have to wait until the car settles before you get any meaningful acceleration.

A bit more context would be helpful. Was this on entry or exit?
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      10-10-2017, 10:42 AM   #69
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Quote:
Originally Posted by Polo08816 View Post
However, I think we need to frame this around the fact that the MP LSD is an OEM stock 1.5 way unit and not an aftermarket 2 way LSD for race applications.

For regular street driving with DSC fully on, it will still intervene despite the car having an LSD and save the driver from him/herself.
granted, but then you are relying on the abs and not the lsd for traction. to use the lsd to it's full potential (track, snow, etc) you need to turn DSC off. otherwise the car will continue applying the brakes to spinning wheels and you're not really seeing a benefit at all.

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Originally Posted by zinner View Post
I found on my last track day that when the outside wheel spun the inside just didn't have enough to hold the car in the turn. Oversteer would happen, I don't see how the an LSD would help or make the situation work.
the idea is the limit where the outside wheel would lose grip is higher, so you can apply throttle sooner and go faster. it's not that it would prevent you from oversteering.
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      10-12-2017, 08:14 AM   #70
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Have you tried the dinan shockware? Quick and cheap. Did wonders for my car. I have all the m performance items also
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      10-12-2017, 08:36 AM   #71
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Quote:
Originally Posted by dr.roro View Post
2015 F32 435i M Sport, RWD, 8AT, Adaptive M Suspension
Daily driver, occasional autocross, maybe once/yr track in future

Debating M Performance LSD vs. KW Street Comfort coilovers. Both are about $2000 + $500 install (rough numbers).

Which is the better bang for buck? Which will make the greater difference in overall handling and feel?
Coilovers cause you feel it everyday of the year
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      11-10-2017, 09:19 AM   #72
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Quote:
Originally Posted by Polo08816 View Post
The inside generally won't have enough to hold the car in the turn because it isn't loaded. An LSD will allow you to accelerate forward in a slight oversteer situation provided you counter steer a bit. With an open diff, you'll have to wait until the car settles before you get any meaningful acceleration.

A bit more context would be helpful. Was this on entry or exit?
I think I had that backwards (which wheel was spinning part), but I was referring to exit on a tight corner. But I think we covered it in another thread somewhere.

OP
I think my first track day was ~2000 bux without spending anything on mods. My take away from the track day was I spent a lot of money on unneeded power mods.

Costs
tires - 800
hotel - 250
inspection/alignment/mount tires/brake bleed - 650
school fee - 450

Ultimately you are in charge of your own budget. I think once I get my input and car control into a better state I can start trying to understand suspension issues, tracking a car is a progressive learning process if you stick with BMWCCA schools. Since I had all the bad habits, I spent my first school just trying to break those.
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      12-25-2017, 09:09 PM   #73
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Quote:
Originally Posted by Red_Baron View Post
This is quite a colorful discussion with some good and other parts not so good. A fresh perspective may help.

Since I recently had an M-Performance differential installed, I though that I would chime in with some initial impressions. My car also has Dinan springs/bump stops/adaptive damper tuning. I think that this collectively tuned solution is close enough to coil-overs for discussion purposes here.

My car also was ordered with the track and handling package. The stock suspension is the weakest point of the car. I found it to be simultaneously under-sprung and under-damped. Comfort mode was the most egregious. Excessive dive/squat under braking/acceleration as well as body roll during cornering were evident. The excessive softness also degraded perceived predictability. I could feel the car load and unload wheels in spirited driving, loosing mechanical grip. I suspect that the very progressive rate of the springs are the biggest issue here.

Another big gripe of mine is that the car does not put the power down effectively/efficiently. Very careful/timid throttle application on the street was how I dealt with this. The large torque of the B58 is both a blessing and curse here.

Shockware came first. This is a +15% damping rate increase in each mode roughly. Secondary motions were removed. (overshoot and ringing after a bump) A slight improvement in the faults above was observed. A band-aid really.

Matched springs and bump stops came next. This was truly transformative. All controls from driver inputs became much more linear/predictable. Mechanical grip was noticeably better as the tires' available grip was actually used since the tires followed the road much better. Moreover, the car put power down better accelerating. The ride is still very comfortable. Passengers do not know that the suspension is not stock.

Finally, the M-Performance LSD came last. It really helps put the power down predictably. This is most noticeable in tight corners. No surprise here. What is left out of the everyday usefulness is that every single right/left turn to merge into traffic is clearly improved in both dry and wet. Those that say an LSD is wasted outside of a track event is not something I agree with. The net effect is improve linearity in the car behavior and higher driver confidence. I smile much more driving the car now. It was worth the $2600. Traction control still cuts power, but the intervention point is much higher and forward momentum is maintained. All chirping of the inside (right usually) wheel is gone. The throttle is now a much more predictable tool. Now I finally understand why RWD cars are revered for their driving dynamics.

After all that background, the suspension change was definitely more transformative. My vote is to do that first. Without the suspension improvements, my car would have been sold and replaced with something else. In retrospect, I should have just gotten and M3 instead since all the issues that I fixed are addressed stock there. My 340i is everything I hoped for now without an F80 M3's burden of way too much power for the street. (my opinion of course)
Great overview of your experiences and spot on with mine. I went LSD first (only because of the rebate timing as I was committed to do both from the start) and then i went full coilover change with a set of Bilstein B16 PSS10... I love the LSD and would do it again in heart beat but the coilovers completely changed the car for the better. I didnt have the m sport version (had the sport line) and I felt the stock suspension was awful. Car felt gushy and heavier in the nose, the steering felt worse also. The car became so tight and go-kart like after the Bilstein coilovers yet comfortable for commuting. Coilovers would be my first mod on an F30 for sure.
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      12-25-2017, 10:32 PM   #74
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In my case the stock suspension is so floppy it's untenable. The suspension is so surprisingly bad it must be removed (today) way before any driveline discussion.(I have the xdrive so haven't really got the need for the diff, though I believe the same part can be added and would help with throttle add out of a turn).

I have the arc8 18x8.5 et38 and PSS 255/40/18 in the mail for as soon as it stops snowing. I'll figure out the coils soon, I'm just not sure if that is all it will take (sway bars and I fear changing bushings may happen).

The stock brakes are also too soft and spongy even. I may try a better fluid soon. But when the brakes are near end of life equipment changes there will be made. (I did not get the track pkg). Then we'll see about driveline (diff /mounts etc).. and finally a few extra hp. There's usually a logical order to fixing a car. I never would consider a diff a wear item....

Last edited by B58 parts; 12-25-2017 at 11:11 PM..
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      12-26-2017, 12:50 AM   #75
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Quote:
Originally Posted by ejn1 View Post
Quote:
Originally Posted by Red_Baron View Post
This is quite a colorful discussion with some good and other parts not so good. A fresh perspective may help.

Since I recently had an M-Performance differential installed, I though that I would chime in with some initial impressions. My car also has Dinan springs/bump stops/adaptive damper tuning. I think that this collectively tuned solution is close enough to coil-overs for discussion purposes here.

My car also was ordered with the track and handling package. The stock suspension is the weakest point of the car. I found it to be simultaneously under-sprung and under-damped. Comfort mode was the most egregious. Excessive dive/squat under braking/acceleration as well as body roll during cornering were evident. The excessive softness also degraded perceived predictability. I could feel the car load and unload wheels in spirited driving, loosing mechanical grip. I suspect that the very progressive rate of the springs are the biggest issue here.

Another big gripe of mine is that the car does not put the power down effectively/efficiently. Very careful/timid throttle application on the street was how I dealt with this. The large torque of the B58 is both a blessing and curse here.

Shockware came first. This is a +15% damping rate increase in each mode roughly. Secondary motions were removed. (overshoot and ringing after a bump) A slight improvement in the faults above was observed. A band-aid really.

Matched springs and bump stops came next. This was truly transformative. All controls from driver inputs became much more linear/predictable. Mechanical grip was noticeably better as the tires' available grip was actually used since the tires followed the road much better. Moreover, the car put power down better accelerating. The ride is still very comfortable. Passengers do not know that the suspension is not stock.

Finally, the M-Performance LSD came last. It really helps put the power down predictably. This is most noticeable in tight corners. No surprise here. What is left out of the everyday usefulness is that every single right/left turn to merge into traffic is clearly improved in both dry and wet. Those that say an LSD is wasted outside of a track event is not something I agree with. The net effect is improve linearity in the car behavior and higher driver confidence. I smile much more driving the car now. It was worth the $2600. Traction control still cuts power, but the intervention point is much higher and forward momentum is maintained. All chirping of the inside (right usually) wheel is gone. The throttle is now a much more predictable tool. Now I finally understand why RWD cars are revered for their driving dynamics.

After all that background, the suspension change was definitely more transformative. My vote is to do that first. Without the suspension improvements, my car would have been sold and replaced with something else. In retrospect, I should have just gotten and M3 instead since all the issues that I fixed are addressed stock there. My 340i is everything I hoped for now without an F80 M3's burden of way too much power for the street. (my opinion of course)
Great overview of your experiences and spot on with mine. I went LSD first (only because of the rebate timing as I was committed to do both from the start) and then i went full coilover change with a set of Bilstein B16 PSS10... I love the LSD and would do it again in heart beat but the coilovers completely changed the car for the better. I didnt have the m sport version (had the sport line) and I felt the stock suspension was awful. Car felt gushy and heavier in the nose, the steering felt worse also. The car became so tight and go-kart like after the Bilstein coilovers yet comfortable for commuting. Coilovers would be my first mod on an F30 for sure.
Indeed agree with what he said as well;

Not to get off the original topic but to complement, I'd throw in some caster/camber correction too, using eccentric bushings or equivalent:
It will improve steering feel, reduce the center dead zone and providing greater agility for a few hundred bucks.
Lowering in itself will provide a bit of both, but not nearly enough as these car come from factory with 0deg camber (could even be positive) and a caster designed to make steering feel light as opposed to communicative.
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      12-26-2017, 07:29 AM   #76
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Quote:
Originally Posted by YuminNuman View Post
In my case the stock suspension is so floppy it's untenable. The suspension is so surprisingly bad it must be removed (today) way before any driveline discussion.(I have the xdrive so haven't really got the need for the diff, though I believe the same part can be added and would help with throttle add out of a turn).

I have the arc8 18x8.5 et38 and PSS 255/40/18 in the mail for as soon as it stops snowing. I'll figure out the coils soon, I'm just not sure if that is all it will take (sway bars and I fear changing bushings may happen).

The stock brakes are also too soft and spongy even. I may try a better fluid soon. But when the brakes are near end of life equipment changes there will be made. (I did not get the track pkg). Then we'll see about driveline (diff /mounts etc).. and finally a few extra hp. There's usually a logical order to fixing a car. I never would consider a diff a wear item....
Since the labor was the same for new springs vs coilovers, I just went with the coilovers. I was looking at the Dinan spring set but decided to just go all the way and do the complete change. All I can say was my 340i was a new car with the B16 coilovers and all of that floppiness was gone.

Since you mentioned it, I have my brakes being changed tomorrow I really wanted to put the Brembo GT BBK on but couldn't justify the cost and decided to go with the M Performance kit. I actually don't think the stock BMW brakes on the sport line are that bad and certainly not a day 1 type of upgrade for me but got a steal on a M Performance set so I'm doing it.
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      12-26-2017, 07:39 AM   #77
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Quote:
Originally Posted by Lancelot View Post
Indeed agree with what he said as well;

Not to get off the original topic but to complement, I'd throw in some caster/camber correction too, using eccentric bushings or equivalent:
It will improve steering feel, reduce the center dead zone and providing greater agility for a few hundred bucks.
Lowering in itself will provide a bit of both, but not nearly enough as these car come from factory with 0deg camber (could even be positive) and a caster designed to make steering feel light as opposed to communicative.
Thanks for this. I was surprised also at the change in my steering feel that occurred with the coilover change. I wasn't expecting really much of a change in that area but it was a big improvement also. Good to know it can be further improved per your suggestion above. I'm also a little worried about camber correction as won't it eat through tires more quickly and unevenly? Dinan makes some camber plates for the F30 that look good also.

I'm finding my biggest issue now is keeping the tires stuck on the road when I accelerate quickly. I'm running the stock OEM run flats which need to go soon !!!!
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      12-26-2017, 08:30 AM   #78
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Quote:
Originally Posted by ejn1 View Post
Quote:
Originally Posted by Lancelot View Post
Indeed agree with what he said as well;

Not to get off the original topic but to complement, I'd throw in some caster/camber correction too, using eccentric bushings or equivalent:
It will improve steering feel, reduce the center dead zone and providing greater agility for a few hundred bucks.
Lowering in itself will provide a bit of both, but not nearly enough as these car come from factory with 0deg camber (could even be positive) and a caster designed to make steering feel light as opposed to communicative.
Thanks for this. I was surprised also at the change in my steering feel that occurred with the coilover change. I wasn't expecting really much of a change in that area but it was a big improvement also. Good to know it can be further improved per your suggestion above. I'm also a little worried about camber correction as won't it eat through tires more quickly and unevenly? Dinan makes some camber plates for the F30 that look good also.

I'm finding my biggest issue now is keeping the tires stuck on the road when I accelerate quickly. I'm running the stock OEM run flats which need to go soon !!!!
I wouldn't worry too much about uneven wear, i have yet to go through my first set of Michelin PSS but no sign of this;
IMHO we need -1 to -1,5 degrees of camber which isn't a lot but a good compromise.

To stay straight under acceleration i think we need in addition to a better suspension
- good tyres (for me that means switching to Michelin Pilot Alpin 4 for the season, PSS have as much grip as a bar of soap these days)
- good alignment too to ensure straight thrust
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      12-26-2017, 08:39 AM   #79
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Quote:
Originally Posted by Lancelot View Post
I wouldn't worry too much about uneven wear, i have yet to go through my first set of Michelin PSS but no sign of this;
IMHO we need -1 to -1,5 degrees of camber which isn't a lot but a good compromise.

To stay straight under acceleration i think we need in addition to a better suspension
- good tyres (for me that means switching to Michelin Pilot Alpin 4 for the season, PSS have as much grip as a bar of soap these days)
- good alignment too to ensure straight thrust
I don't have the snow issues that you have
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      12-26-2017, 09:04 AM   #80
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Normal negative camber will not cause tire wear. Toe causes tire wear. As long as you are not stanced yo with -6 camber you'll be fine. -1 or -2 camber is good and your tires won't notice. Get your toes checked though.
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      12-26-2017, 11:23 AM   #81
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Quote:
Originally Posted by Lancelot View Post
I wouldn't worry too much about uneven wear, i have yet to go through my first set of Michelin PSS but no sign of this;
IMHO we need -1 to -1,5 degrees of camber which isn't a lot but a good compromise.

To stay straight under acceleration i think we need in addition to a better suspension
- good tyres (for me that means switching to Michelin Pilot Alpin 4 for the season, PSS have as much grip as a bar of soap these days)
- good alignment too to ensure straight thrust
I just checked my alignment stats from a few weeks ago.

Camber LF= -0.7, RF = -0.6, LR = -1.6, RR = -1.5 degrees

When you say -1 to -1.5, do you mean all the way around or just the rears?

Thanks
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      12-26-2017, 11:29 AM   #82
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I meant all around
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      12-26-2017, 11:31 AM   #83
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Quote:
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I meant all around
Got it, thanks.
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      04-27-2018, 11:14 PM   #84
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What did OP go with?
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      04-28-2018, 08:00 AM   #85
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Now that winter is (finally) over around here, I'm going with new wheels and Michelin PS4S tires first.
Then DP/FMIC/CP and bootmod3 later this summer.

Still haven't made a firm decision on coilovers vs. LSD yet, but will probably not happen until next year. I'm hoping Bilstein will have their B16 DampTronic available by then, in which case I may choose those over the LSD first.
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      04-28-2018, 08:02 AM   #86
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LSD first !
More fun with the car
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      05-02-2018, 06:49 AM   #87
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LSD first !
More fun with the car
No question LSD gives you additional capability in the chassis.
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      05-02-2018, 01:00 PM   #88
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Just add 1.5 more and get bags
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