[Detailers Domain]

good to know

[eeyang92]

Originally Posted by chris719

I am not a suspension expert, but my understanding from physics / calculus is that there is going to be a spring and damper combination that results in a setup that is a slightly underdamped system, which appears to be what you want for a non-race-car.

http://www.kaztechnologies.com/wp-co...m-Kasprzak.pdf

I would have thought a critically damped system would be ideal but I'll defer to experts.

I don't know why we have to result to blind mix / match of "knob clicks" and random spring rates to guess at a setup. Too bad there isn't a more data driven approach taken by most tuners.

According to the paper, you only want critical damping if you have some ground effect areo going on - makes sense, ground effect areo loses almost all effect if you're airborne, so more ground time = more consistent in the corners.

On a normal racecar, if you're too critically damped, then the car will tend to "hop" (imagine if your car had a solid bar in place of your shock, it would be extremely harsh and bounce off of bumps). Thus, your wheel will constantly be losing traction.

The same happens on the other end of the spectrum - if your compression is too low, then the wheel wont reset fast enough, so on bumps it will spend a lot of time in the air, thus losing traction.

[dmk08]

Originally Posted by hellrotm

KW is the manufacturer, so they can't be that bad.

KW V3 are some of the most overrated coils I've ever run. Give me a set of Ohlins R&T cheaper any day.

[M-Pilot]

Originally Posted by dmk08

KW V3 are some of the most overrated coils I've ever run. Give me a set of Ohlins R&T cheaper any day.

I was planning to get Ohlins but was recently told that they require a rebuild every 19K street miles or 10hours of track time. I can't imagine getting them rebuilt every year.

[carl44]

Used to run Nitrons S.A on my Exige S 34000 miles 10k of it on track, they were sill perfect. The make them in single,double and triple adjustable. carl


http://www.nitronracingshocks.com/BM...PER_c_468.html

[hellrotm]

Originally Posted by cntzl

I was planning to get Ohlins but was recently told that they require a rebuild every 19K street miles or 10hours of track time. I can't imagine getting them rebuilt every year.

That is the one big advantage of the Mperf coilovers. Get them installed at dealer and they are covered under warranty. Plus you can get them for $2k, about $1k less than R&T.

[dmk08]

Originally Posted by hellrotm

That is the one big advantage of the Mperf coilovers. Get them installed at dealer and they are covered under warranty. Plus you can get them for $2k, about $1k less than R&T.

My r&t for my m4 were $1950.

[hellrotm]

Originally Posted by dmk08

My r&t for my m4 were $1950.

Where from? I don’t see them listed for less than $3k.

[chris719]

Originally Posted by eeyang92

According to the paper, you only want critical damping if you have some ground effect areo going on - makes sense, ground effect areo loses almost all effect if you're airborne, so more ground time = more consistent in the corners.

On a normal racecar, if you're too critically damped, then the car will tend to "hop" (imagine if your car had a solid bar in place of your shock, it would be extremely harsh and bounce off of bumps). Thus, your wheel will constantly be losing traction.

The same happens on the other end of the spectrum - if your compression is too low, then the wheel wont reset fast enough, so on bumps it will spend a lot of time in the air, thus losing traction.

You can't be "too critically damped". You might mean overdamped though. Sounds roughly correct, but I think the reason for race cars running closer to critical is just for comfort. Too bad there isn't anything from DSC Sport available for BMWs.

https://www.dscsport.com/porsche/#981

[swifty]

Its coming for f8x.

I wonder if the tractive coils for the F80 will work on the M2. Then you can install the DSCsport with it.

[swifty]

Originally Posted by chris719

You can't be "too critically damped". You might mean overdamped though. Sounds roughly correct, but I think the reason for race cars running closer to critical is just for comfort. Too bad there isn't anything from DSC Sport available for BMWs.

https://www.dscsport.com/porsche/#981

Its coming for f8x. 

I wonder if the tractive coils for the F80 will work on the M2. Then you can install the DSCsport with it.

[phil_m2]

I have got the m performance coils on my m2c.
With my setup and adjustments they are not as stiff as the stock suspension in the lowspeed fraction but when the dampers need to work fast, it is stiffer and firm.
Exactly what I want.

[bluebro]

Are you using the bmw recommended bump/rebound setting Phil?

[Bee Pee]

Originally Posted by phil_m2

I have got the m performance coils on my m2c.
With my setup and adjustments they are not as stiff as the stock suspension in the lowspeed fraction but when the dampers need to work fast, it is stiffer and firm.
Exactly what I want.

Are you using OEM ride heights 595/600 F&R and any photos ?

[phil_m2]

Originally Posted by Bee Pee

Are you using OEM ride heights 595/600 F&R and any photos ?

I have shown pics of the lowest settings on my Instagram (@phil_m2)

[Bee Pee]

Originally Posted by phil_m2

I have shown pics of the lowest settings on my Instagram (@phil_m2)

Not an Insta user

[UltraMagneticAL]

unless you're a pro racer, the difference between ohlins r&t and kw v3 will not be felt by the average driver. they are basically in the same class. m perf coils also fall into this category, but there's a limit to how low the height can be set, most likely to preserve warranty if installed by bmw.

i had the v3 on my m2 base, but will be getting the ast 3 way setup with a little stiffer front spring for the m2c (also a true coilover in the back). the dampers on the v3 were good enough for a occasional track days, but the spring rate was a little too soft for the track. ohlins rt, kw v3 and m-perf coils are all tuned for street-first, track secondary use. they're great for spirited canyon carving and the occasional track day, while being able to live with them on the daily commute. however if the ohlins do require rebuilds every 30,000km, that seems pretty poor for something labeled "road and track".

[Bee Pee]

Originally Posted by UltraMagneticAL

unless you're a pro racer, the difference between ohlins r&t and kw v3 will not be felt by the average driver. they are basically in the same class. m perf coils also fall into this category, but there's a limit to how low the height can be set, most likely to preserve warranty if installed by bmw.

i had the v3 on my m2 base, but will be getting the ast 3 way setup with a little stiffer front spring for the m2c (also a true coilover in the back). the dampers on the v3 were good enough for a occasional track days, but the spring rate was a little too soft for the track. ohlins rt, kw v3 and m-perf coils are all tuned for street-first, track secondary use. they're great for spirited canyon carving and the occasional track day, while being able to live with them on the daily commute. however if the ohlins do require rebuilds every 30,000km, that seems pretty poor for something labeled "road and track".

If going full coilovers at the rear how will you reinforce upper damper mounts to cope with spring loadings ?

[UltraMagneticAL]

Originally Posted by Bee Pee

If going full coilovers at the rear how will you reinforce upper damper mounts to cope with spring loadings ?

https://f87.bimmerpost.com/forums/sh....php?t=1410589

seems ast provides a plate to disperse the force to the body. the 5200 rear design looks similar to the front top hats, but with three bolts.

[M Fifty]

That plate looks thicker than the stock cast item - but not actually any bigger?

[Zabi]

Originally Posted by UltraMagneticAL

seems ast provides a plate to disperse the force to the body.

Nope, the stock top shock mount is with three bolts. The AST is just a top mount adapter for their spherical end shock. Its best quality is the road noise.

[Bee Pee]

Originally Posted by UltraMagneticAL

https://f87.bimmerpost.com/forums/sh....php?t=1410589

seems ast provides a plate to disperse the force to the body. the 5200 rear design looks similar to the front top hats, but with three bolts.

I'd want to know if the oem damper mounting points - top and bottom - have enough meat on them to take body weight and spring loads combined. Esp top mounts may need re-inforcing as oem damper forces into that area would be much less than loadings from coilover set up....