[ajaypjayaraj]

Originally Posted by akshay1234

Not trying to argue. But the F30 does bob on the rear suspension. In fact at speeds over 100, if you go over a larger undulation it feels as though the rear is in the air for a fraction of a second (which is unnerving) even though grip is not lost at all.

True that. And this video explains why it feels so. The valve seems to be too small for a planted ride.

[Diesel_convert]

One worn out shock vs a new one, its not an accurate comparison.

[issigonis]

>>>

The Koni FSD seems to give the best of both worlds - under real, 'Indian' road conditions.

I get the feeling, after having driven Akshay's wonderful E90 with the M Power kit, fleetingly and my stock F30 (and even after the ZF auto re-map) over six months, that the rear of the F30 is softer- and hence needs to be fixed for greater stability, especially over twisties and at high speeds. As to comfort, I am fine with the current ride quality, even with the stock RFTs; my understanding is that after switching to normal tubeless, the ride will improve a bit.

The steering wheel is definitely not what it might have been with a hydraulic unit.

Meanwhile here's something to sink our teeth into for our E90 vs F30 pundits :
[The E90 was a 335i and the F30 a 328i, though]

"
* The 328i has better weight distribution (49.2 percent front/50.8 rear) than its immediate predecessor (50.5/49.5), but the older 335i’s center of gravity, at 20.0 inches high, is an inch lower than the 328i’s

* The 328i’s wheel rates (overall suspension stiffnesses) are 2 percent softer in front and 10 percent softer in back, which helps explain the new 3-series’s smoother ride

* The 328i’s anti-roll bars are slightly larger in diameter

* Roll centers, both front and rear, are an inch higher in the 328i. (Suspension geometry defines theoretical points—one in the front, one at the rear—about which the body rolls when subjected to cornering forces.) The *imagi*nary line connecting the front and rear roll centers is called the roll axis. For a given center of gravity and cornering rate, a higher roll axis (closer to the center of gravity) yields less body roll

* The 328i and the 335i both roll 3.4 degrees per g during cornering. This is the net result of findings two through five (as above)

* There’s significantly more braking anti-dive built into the F30’s front-suspension geometry and slightly more anti-lift designed into its rear axle. Both characteristics are advantageous to braking performance

* The 328i’s steering is 8 percent quicker than the 335i’s and has significantly less ratio change as the steering wheel sweeps lock-to-lock. This may be attributable to an improved steering-column design with reduced universal-joint angles

* The slip angles producing cornering forces at the tire patches create what’s known as aligning torque—essentially, the tire trying to return to straight-ahead running. This aligning torque is fed back through the rack-and-pinion steering gear to the steering wheel. It’s part of the information the driver uses to learn what’s going on where the rubber meets the road. The K&C machine reported that aligning torque is 64 percent lower in the 328i than in the 335i. While the switch to electric power steering may improve mileage, it’s a bummer for Bimmer driving satisfaction

In summary, the most significant change from the E90 to the F30 results from the switch to electric power-steering assist, which diminishes feel. Body roll in the two cars is identical, but the use of rear-suspension understeer instead of  larger tires in back may be why the new 328i feels less agile turning into corners. All of  it adds up to a softer, tamer 3-series that’s more about luxury than fun"

More info about the differences between the E90 and the F30 can be found here ( all copyrights acknowledged) :

http://blog.caranddriver.com/a-tale-...-so-different/

>>> The Koni FSD is still in front :-)
Regards

[ajaypjayaraj]

Originally Posted by Diesel_convert

One worn out shock vs a new one, its not an accurate comparison.

Well, more than the comparison, the time the stock shock takes after the compression does not look like it would help much with the ride remaining planted on an uneven surface. It is a known fact that F30 ride is not settled. World over. Me as an owner feels it. Fellow owners have upgraded to Bilstiens already including people on the forum. There has to be a reason. Cant be that everyone is giving a wrong feedback. I do agree with the lot, with my own experience using the car for more than 3 years now.

Coming back to the topic - not if F30 ride is settled or not but which among Koni FSD and Biltien...

Well people love FSD as well as people hate FSD. The problem with it is, it tries to be best of both worlds. Which it does pretty well. But when you want the best of just one, either sport or comfort, it would face challenge atleast in one of the areas. Like say if you want the best of sport, its Bilstien. It wont act anything less, but then at the cost of comfort. So while FSD might take care of comfort, it is slightly giving up on the sport front as compared to a purely sport tuned suspension. FSD sounds interesting but somehow I am more inclined towards a purer equipment in favour of the sporty ride which would be B6.

[issigonis]

Here's a link to a comparo between an OE set up, a Koni Sports set up and a Koni FSD set up.
Same car, same tyres for a comparison as exact as possible.

Take a look :
http://www.tirerack.com/suspension/tests/koni_fsd.jsp

[ajmat]

I think it is all down to personal preference. FSD's are known to have a higher than normal failure rate on our roads and service is not too good.

Ride comfort or hard edged dynamics - choice is yours and yours only

[novice]

Since you are not happy with the stock suspension's handling which in fact is quite good compared to many other cars in its segment, you should go with Bilstein. FSDs probably won't satisfy you. Also many say that FSDs lose their adaptive damping after few years.

My car is running with Bilstein B6 and Run Flats. I expected the car to ride very stiff with this combination but actually it turned out to be far better. It is kind of firm but offers very controlled movements. Overall I would say both ride and handling definitely improved for the better.

BTW, mine is not a BMW.

[quickdraw]

Very interesting thread, just wanted to ask OP if he has considered the BMW M Adaptive Dampers? They should be covered in factory warranty at install? I'd reccomend these over aftermarket ones simply because of very high chance of failure due to bad roads here.

Also slightly OT, F30 owners here. Is it possible to have steering in comfort while rest of the car is in Sport +?

Originally Posted by akshay1234

In fact at speeds over 100, if you go over a larger undulation it feels as though the rear is in the air for a fraction of a second (which is unnerving) even though grip is not lost at all.

Yeah I've seen the traction control light at speeds of over 130 km/h and absolutely agree with what you see, it feels like just the rear bounces off!

Originally Posted by coolboy007

Do not want to compromise a lot on that front keeping pathetic roads around north India, love the butter smooth ride right now on 16" wheels.

The ride is quite decent even with 18' rims. Which I keep demonstrating to my friends when we cross the Sai Baba mandir near Lodi Road.

[Akshay1234]

Originally Posted by quickdraw

Very interesting thread, just wanted to ask OP if he has considered the BMW M Adaptive Dampers? They should be covered in factory warranty at install? I'd reccomend these over aftermarket ones simply because of very high chance of failure due to bad roads here.

Also slightly OT, F30 owners here. Is it possible to have steering in comfort while rest of the car is in Sport +?

Yeah I've seen the traction control light at speeds of over 130 km/h and absolutely agree with what you see, it feels like just the rear bounces off!

M adaptive dampers will not be easy to add. It will involve a lot of wiring, a new ecu which will have to be added and integrated into the car. And the cost will be at least 3 times that of just upgrading the dampers.

It's not possible to have steering in comfort with the rest of the car in sport.

[novice]

Originally Posted by novice

Since you are not happy with the stock suspension's handling which in fact is quite good compared to many other cars in its segment, you should go with Bilstein. FSDs probably won't satisfy you. Also many say that FSDs lose their adaptive damping after few years.

My car is running with Bilstein B6 and Run Flats. I expected the car to ride very stiff with this combination but actually it turned out to be far better. It is kind of firm but offers very controlled movements. Overall I would say both ride and handling definitely improved for the better.

BTW, mine is not a BMW.

Also Bilstein B6 dampers with stock springs hardly make any negative impact in ride quality for cars that come with stiff suspension setup from factory. It would be a different story with B8 with lowering springs. Similarly B6 would make the ride stiff on cars that come with spongy OE kits. So for the the car in discussion I would anyday choose B6 without any hesitation.

[issigonis]

Originally Posted by ajmat

I think it is all down to personal preference. FSD's are known to have a higher than normal failure rate on our roads and service is not too good.

Ride comfort or hard edged dynamics - choice is yours and yours only

>>> It is personal preference. Plus inputs from gurus.However, it is difficult to make a reasonably objective assessment without real experience driving both the set ups on the same car. Which is near impossible. So one has to decide imperfectly and then live with one's decision.Much like buying a turn table basis one's perception of how it will sound and how it will match with the rest of your hifi.

However ajmat, I don't think it is a zero sum either-or with the Koni FSD; it is both. In fact I saw some posts in a Corvette forum recount how the Koni FSD could track the changes in frequency-road surface quicker than a Bilstein B6 to provide the exact blend of handling and ride. It is hearsay of course.

I read somewhere that Koni offers lifetime warranty - that will have to be checked. The FSD technology (without any electronics is certainly interesting).

Originally Posted by novice

Also Bilstein B6 dampers with stock springs hardly make any negative impact in ride quality for cars that come with stiff suspension setup from factory. It would be a different story with B8 with lowering springs. Similarly B6 would make the ride stiff on cars that come with spongy OE kits. So for the the car in discussion I would anyday choose B6 without any hesitation.

>>>
novice,

So I should expect the ride to become stiffer all round with the B6, as the F30 is not stiffly sprung at the rear? Ok.
I can live with that, and once I change from RFTs to normal tubeless I guess that B6 will provide adequately good ride, better than that with the RFTs.

How about warranty? After market service in case something goes wrong? Any idea?

Its head to head again now.

Regards

[novice]

Actually I don't consider 320 or for that matter any BMW softly sprung. To me cars like Accord, Camry etc are softly sprung. B6 dampers would stiffen up such cars more but on a BMW the difference in ride quality would be negligible especially when compared to the gains on handling front.

I purchased my B6 set from Pete's 2 years back and they clocked 30k kms so far. I inspected my struts when I recently dismantled them to replace top mounts. Even after 30k kms these struts still remain stiff as new. But I don't know how things would work out if any defects develop.

Sorry for asking the obvious...

Are you experiencing this softness in your suspension only recently or has it been like this from beginning? If it's a recent development getting it thoroughly checked would be good before installing new dampers. Adding stiffer dampers won't give any improvement if there is even a slightest slack in other suspension components. In fact adding stiffer dampers in such a scenario would accelerate the wear on other components.

Also springs are primarily responsible for that feeling of floatiness at rear while going over major undulations. Stiffer dampers would control that to some extent but not going to remove it completely. That's my personal experience.

[issigonis]

Originally Posted by novice

Actually I don't consider 320 or for that matter any BMW softly sprung. To me cars like Accord, Camry etc are softly sprung. B6 dampers would stiffen up such cars more but on a BMW the difference in ride quality would be negligible especially when compared to the gains on handling front.

I purchased my B6 set from Pete's 2 years back and they clocked 30k kms so far. I inspected my struts when I recently dismantled them to replace top mounts. Even after 30k kms these struts still remain stiff as new. But I don't know how things would work out if any defects develop.

Sorry for asking the obvious...

Are you experiencing this softness in your suspension only recently or has it been like this from beginning? If it's a recent development getting it thoroughly checked would be good before installing new dampers. Adding stiffer dampers won't give any improvement if there is even a slightest slack in other suspension components. In fact adding stiffer dampers in such a scenario would accelerate the wear on other components.

Also springs are primarily responsible for that feeling of floatiness at rear while going over major undulations. Stiffer dampers would control that to some extent but not going to remove it completely. That's my personal experience.

>>>
novice,

> The F30 rear is softly sprung as compared to that of the E90 - I mentioned that wriggle at the back in my earlier posts in this thread. I am not comparing the former with any other car except the E90.

>> This is not a recent development, but is there in the F30 - by design, possibly to make it more attractive to rear passengers in PRC & India.

The two chief differences between the E90 and the F30 (ref: The Car and Driver report in my post above) are :

" In summary, the most significant change from the E90 to the F30 results from the switch to electric power-steering assist, which diminishes feel. Body roll in the two cars is identical, but the use of rear-suspension understeer instead of  larger tires in back may be why the new 328i feels less agile turning into corners.."

Its the rear suspension that I wish to beef up.

Its still Even Stevens - B6 vs FSD.

Regards

[super.cars]

Originally Posted by akshay1234

Not trying to argue. But the F30 does bob on the rear suspension. In fact at speeds over 100, if you go over a larger undulation it feels as though the rear is in the air for a fraction of a second (which is unnerving) even though grip is not lost at all. Compared to the E90 which really stabilizes at high speeds. There is no comparison at all.

akshay, i think what you are trying to convey is captured in this video between 1:55 and 1:59. Do you agree ?

https://www.youtube.com/watch?v=_g94hTOOJhg

[ajaypjayaraj]

Upgraded to B6. Was not planning this upgrade so soon, but it was in stock and I was at Petes garage anyways. The swap does not take much time.

So the biggest issue with F30 is taken care of. But this one wont disappoint people who are worried about losing comfort as compared to F30's stock suspension. The shocks are tuned well for comfort as well as sportiness. Initial impression is, handling has improved and surprisingly the ride comfort is a tad better. I feel that the surface is not felt inside the cabin as much as stock shocks, more so at higher speeds, but even at lower speeds I feel it has improved the ride comfort. Haven't driven it much. Will observe and update after covering more miles on it.