[Izzy559]

I enjoy my KW v1. Love the ride and I got a great deal on them.

[Matt335is]

Originally Posted by Yngvejos

The ride is very nice. I think the m-sport suspension felt harsh/underdamped compared to h&r. I have had some different setups with adjustable dampers from koni and spax on other beemers I had earlier and never found the optimal settings.

What h&r suspension did you use?

[Go Horns!]

Originally Posted by NiNeTyOne

Absolutely not. First, these are linear springs, not progressive rate, so you're not comparing apples to apples as you might think. Second, once you've set up race cars a few times you learn that as the level of damping improves, particularly when going from monotube to something like a 4-way TTX damper, that your spring rates have to climb, and they climb quite a bit. The dampers are just that good. My last Ohlins setup car had 750 rear, 650 front linear rates on an AWD car that weighed 3130 lbs wet and put down 440AWHP.

So I actually find the base R&T rates a bit soft. They will be generally no stiffer than Eibach Pro progressives. If they made an X drive setup (dampers need to be shorter in the front to clear the draiveshaft) I would have them and add 50lbs to the rates.

The rough ride is created not by the stiffness of the springs. It is the effective rate of the front compared to the rear. You want the rear effective rate to be greater than front to maintain a flat ride, which is important for a car driven on the street. On an e92, if your front spring is 343 lb/in, you will need a rear sping rate of 1250 lb/in to maintain a flat ride.

When the front effective rate is greater than the rear, and you go over a bump, the rear can never catch up to vertical motion of the front, so you get pitching. And the pitching creates a rough uncomfortable ride. To combat the pitching you need excessive dampening force, which leads to an even stiffer shock, which leads to a very stiff and uncomfortable ride.

And generally, when designing a suspension, you match the shocks to the springs, not the springs to the shocks. You should only use a shock stiff enough to control the oscillation of the spring. Any stiffer, and you are not letting the springs do their job.

[tlow98]

Originally Posted by NiNeTyOne

I'll repeat, for ~1700-1800 this kit from PSI is the best kit you can buy under ~4000.00.



Ohlins Road & Track coilover suspension BMW 3-series

KW, Koni, Bilstein aren't even close to the same league. For the price PSI sells these things for, they are a screaming bargain.

The website says $2k - what am I missing? Thanks for the link.

[Yngvejos]

Originally Posted by Matt335is

What h&r suspension did you use?

On the receipt it says:
H&R mono-tube coilover kit - 29177-5

Note that this part number is for the touring.

[NiNeTyOne]

Originally Posted by Go Horns!

The rough ride is created not by the stiffness of the springs. It is the effective rate of the front compared to the rear. You want the rear effective rate to be greater than front to maintain a flat ride, which is important for a car driven on the street. On an e92, if your front spring is 343 lb/in, you will need a rear sping rate of 1250 lb/in to maintain a flat ride.

When the front effective rate is greater than the rear, and you go over a bump, the rear can never catch up to vertical motion of the front, so you get pitching. And the pitching creates a rough uncomfortable ride. To combat the pitching you need excessive dampening force, which leads to an even stiffer shock, which leads to a very stiff and uncomfortable ride.

And generally, when designing a suspension, you match the shocks to the springs, not the springs to the shocks. You should only use a shock stiff enough to control the oscillation of the spring. Any stiffer, and you are not letting the springs do their job.

You are partially correct, as the chassis geometry and the power of the vehicle are also critical factors, however, with lower tier shocks, you often have springs that must compensate for inadequate damping performance, particularly with compression and high speed rebound (which is where many consumer targeted adjustable shocks fall short). This is why many of these shocks are matched to lower rate springs. Add in swaybars, which also act as variable rate springs during cornering and the problem is further exacerbated. This is why most upper tier suspensions use linear rate springs (and just initial body roll alone is a good reason to ditch progressives of your shocks can deal with it).

Dual-rate springs also go out of the effective damping range as they are pushed dynamically into higher or lower rates.

Higher end damper systems with dual circuits or independent high and low frequency damping control have much better performance in this area, because of this the rates almost always climb.

[NiNeTyOne]

Originally Posted by tlow98

The website says $2k - what am I missing? Thanks for the link.

Call them, that's MSRP. You won't pay that if you call them up. I believe the street price is somewhere between 1700-1800 now.

[Jarrod]

Originally Posted by NiNeTyOne

It's a complete replacement, and honestly, the M suspension is total crap compared to this setup. This is as good as it gets before you get into VERY serious money.

This, along with all new bushings (Strongflex) and a better rear bar would totally transform an 335is. Don't even worry about the soft rear shock bushings, go with the "race" ones. The dampers will work even better.

Well this is very interesting to read. What about using that on the E93, with the added weight in the trunk when driving top down?

The ride on our bumpy roads with the 335is sport suspension is harsh, especially with 19" rims and RFTs. While not as "bad" as the M3 suspension, it still beats the crap out of you. Counterintuitively (and UNLIKE the M3 suspension), when you go over a hump a relatively high speed, the rear end feels under-damped, and there seems to be a fair bit of unwanted lateral movement as well.

On a perfectly flat road it's fine, love the way it feels going into and coming out of corners. But in real life conditions, even with me knowing almost nothing about suspensions, it's clear that they screwed something up with the one on these cars...

[tlow98]

Originally Posted by NiNeTyOne

Call them, that's MSRP. You won't pay that if you call them up. I believe the street price is somewhere between 1700-1800 now.

Many thanks - I'm only 20 miles from them. Nice Auto-x course at Sonoma raceway!

[NiNeTyOne]

Originally Posted by Jarrod

Well this is very interesting to read. What about using that on the E93, with the added weight in the trunk when driving top down?

The ride on our bumpy roads with the 335is sport suspension is harsh, especially with 19" rims and RFTs. While not as "bad" as the M3 suspension, it still beats the crap out of you. Counterintuitively (and UNLIKE the M3 suspension), when you go over a hump a relatively high speed, the rear end feels under-damped, and there seems to be a fair bit of unwanted lateral movement as well.

On a perfectly flat road it's fine, love the way it feels going into and coming out of corners. But in real life conditions, even with me knowing almost nothing about suspensions, it's clear that they screwed something up with the one on these cars...

With a convertible chassis flex alone.. I could go on, but it's pointless. The car is far heavier than a coupe, the chassis is a noodle, adjusting the rates top up/down is the least of your concerns. If that was really a consideration you should have bought a coupe.

One of the many reasons why the Ohlins are superior is how they deal with setting ride height (which alone makes them perform better than Bilstein, KW or Koni):

"When adjusting ride height on coilover units, it’s worth comparing how it’s done. On many inferior designs, height is adjusted by raising or lowering the lower spring platform. This has the effect of compressing or extending the spring, which can limit the suspension travel that may cause topping out. The Öhlins method is to leave the spring seat in its perfect position, whilst the lower flange spins easily on the threaded body, to allow you to adjust with absolute precision whilst maintaining the perfect characteristics that we took so long to design in! Once you’ve set it all up, the adjuster simply locks off to maintain your exact settings."

You should read a bit about Ohlins DFV technology. Here's a link.

[Ozzie335i]

2 grand for coil overs for a 325? Really? Sell it and get a 911. Seriously, I wouldn't spend that much on coil overs for any 3 series.

[Jarrod]

Originally Posted by NiNeTyOne

As for your top, dude, you bought a convertible. Chassis flex alone.. I could go on, but it's pointless. The car is far heavier than a coupe, the chassis is a noodle, adjusting the rates top up/down is the least of your concerns. If that was really a consideration you should have bought a coupe.

It's not, really. But I've read they can be made to handle better. Why wouldn't I want to make it better?

[Matt335is]

I did find an H&R set for my 335is CPE I am just not sure of the quality of it and if it might lower my car too much. Here's the link and lowering specs. Does anyone know if this would be a good buy? Also looking at the eibach pro sus kit as well.

https://www.ecstuning.com/b-h-and-r-...-kit/39177-11/

Average lowering of 1.25"-2.5"F 0.75"-2.0"R

[unrealii]

Originally Posted by Jarrod

Well this is very interesting to read. What about using that on the E93, with the added weight in the trunk when driving top down?

The ride on our bumpy roads with the 335is sport suspension is harsh, especially with 19" rims and RFTs. While not as "bad" as the M3 suspension, it still beats the crap out of you. Counterintuitively (and UNLIKE the M3 suspension), when you go over a hump a relatively high speed, the rear end feels under-damped, and there seems to be a fair bit of unwanted lateral movement as well.

On a perfectly flat road it's fine, love the way it feels going into and coming out of corners. But in real life conditions, even with me knowing almost nothing about suspensions, it's clear that they screwed something up with the one on these cars...

I went with KW V3's for my E93. I had Koni FSD and one shock failed. Also, the Konis aren't designed for the extra weight of the E93 and the rear was under dampened.

The KW v3 kit for the E93 is the same as the E92 kit with stiffer springs in the rear. KW V3 also has a dual dampening technology. You adjust low speed dampening and rebound. High speed dampening is left to KW.

"The exclusive KW patented system has dual-level valves to provide the adjustment of the rebound damping (comfort) and the compression damping (driving dynamics) in the low-speed range. High-speed settings for driving comfort are preset by KW engineers."
source: https://www.tirerack.com/suspension/...l-Over&make=KW

[max_330i]

Originally Posted by NiNeTyOne

As for your top, dude, you bought a convertible. Chassis flex alone.. I could go on, but it's pointless. The car is far heavier than a coupe, the chassis is a noodle, adjusting the rates top up/down is the least of your concerns. If that was really a consideration you should have bought a coupe.

Originally Posted by Jarrod

It's not, really. But I've read they can be made to handle better. Why wouldn't I want to make it better?

Don't want to step on anybody's toes here, but I think his point is that the convertible chassis was a compromise the second it rolled out of the factory. You simply can't make a drop top with the rigidity and stability of a coupe. Wicked fast, absolutely, and very fun to drive-- but not a track machine.

I'm sure you could replace your 'is suspension with a better aftermarket kit, and unfortunately I wouldn't know which one. But he is right that stock for stock, E92 will blow away E93 in terms of handling.

[PBoutique]

KW's are amazing if you can afford them. Ive bought a few set used and they seem to be great, but a few friends have had bad luck and have had to get them rebuilt shortly after purchase, which can be pricey. If youre looking for something more on the budget side, I highly recommend BC Racing BR series. For the price you can't go wrong. Especially with custom spring rates.

[Eagle1oh7]

Lots of good info here! Thanks for the inputs, I feel like the OP does. I'm considering KW Clubsports so I have duality when it comes to DD and tracking.

[NiNeTyOne]

Originally Posted by unrealii

The KW v3 kit for the E93 is the same as the E92 kit with stiffer springs in the rear. KW V3 also has a dual dampening technology. You adjust low speed dampening and rebound. High speed dampening is left to KW.

This alone should tell you that the rear KW's would need re-valving, I don't care what they say. With a rate change in the springs you'd need to re-valve them to make them as good as a kit that was properly matched.

I have driven on road and track with both the KW's and the Ohlins, including running linear potentiometers to capture telemetry on both. The KW's can't even be compared to the Ohlins. The Ohlins are just that much better. Less harsh on the street and way more composed on track.

Lap times backed it up. The Ohlins are SECONDS a lap faster on the same car. At hundreds less than the v3's there's no choice whatsoever.

[tlow98]

Originally Posted by Ozzie335i

2 grand for coil overs for a 325? Really? Sell it and get a 911. Seriously, I wouldn't spend that much on coil overs for any 3 series.

Yes, 911s are cheap and suspensions are not the most enjoyable part of a 3 series, especially a 325/328.

[Eagle1oh7]

Originally Posted by NiNeTyOne

I have driven on road and track with both the KW's and the Ohlins, including running linear potentiometers to capture telemetry on both. The KW's can't even be compared to the Ohlins. The Ohlins are just that much better. Less harsh on the street and way more composed on track.

Lap times backed it up. The Ohlins are SECONDS a lap faster on the same car. At hundreds less than the v3's there's no choice whatsoever.

Ohlins is also on the radar. The price is really attractive as well.

[NiNeTyOne]

Originally Posted by tlow98

Yes, 911s are cheap and suspensions are not the most enjoyable part of a 3 series, especially a 325/328.

$1700 in suspension and another $5-600 in bushings will change your opinion quite a bit. It'll still never be a Cup car, but for a daily, they can be made MUCH better. Especially once the interface between the subframes and the chassis is tightened up and you put some real dampers on them.

For anyone who's not driven an Ohlins clad car, they need to. Your idea of what suspension can do for your car's performance will totally change.

These Renault Megane's are damn good out of the box, in some ways, better than any 3 series, but look what the r&T's do for them. Add io that a proper set of bushings throughout..

[tlow98]

Originally Posted by NiNeTyOne

$1700 in suspension and another $5-600 in bushings will change your opinion quite a bit. It'll still never be a Cup car, but for a daily, they can be made MUCH better. Especially once the interface between the subframes and the chassis is tightened up and you put some real dampers on them.

For anyone who's not driven an Ohlins clad car, they need to. Your idea of what suspension can do for your car's performance will totally change.

These Renault Megane's are damn good out of the box, in some ways, better than any 3 series, but look what the r&T's do for them. Add io that a proper set of bushings throughout..

Fwiw, I was being sarcastic.

90% of the time quality suspension upgrades are the best thing a person can do to maximize bang for buck.

I'm with you on these Ohlins