Best suspension for Daily Driver / Backroads Dancer 135i

[Esteban]

Originally Posted by tjswarbrick

Okay, so then, the question becomes: How much lower is M-Sport than Non-M-Sport?
And if the Swifts are supposed to bring 'er down 1" from Non-Sport, how come they brought my M-Sport down at least an inch and a half?
Am I going to worry about any of this, at all, once I get the Eibach Pro-Kit installed?

Here's BMW's description of the Performance suspension. They no longer sell the suspension for the 135i but still have this description up. When I looked it up in the past when they still were selling the Performance suspension for the 135i, it was the same description.

At the heart of performance is handling. And how well a BMW handles is directly influenced by its suspension. The BMW Performance Suspension lets you savor every curve and every corner like never before! This sport suspension set-up is reflected visually by the BMW Performance Yellow springs. This new aggressive package lowers the vehicle by 25 mm compared to the standard suspension and by 10mm when compared to the sport suspension. Spring rates are increased 48% compared to standard suspension and 34% compared to the sports suspension.

https://www.shopbmwusa.com/PRODUCT/8...NCE-SUSPENSION

So based on the numbers above, the answer to the question "how much lower is M-Sport than Non-M-Sport?" would be 15mm.

[asbrr]

Originally Posted by tjswarbrick

Okay, so then, the question becomes: How much lower is M-Sport than Non-M-Sport?
And if the Swifts are supposed to bring 'er down 1" from Non-Sport, how come they brought my M-Sport down at least an inch and a half?
Am I going to worry about any of this, at all, once I get the Eibach Pro-Kit installed?

Hm - not sure what baseline swift uses, my comment was directed at the Eibachs (sorry should've been clearer). Swift may measure from M-sport.

From anecdotal evidence the swift spec Rs are indeed lower than the Eibachs. M-sport I believe is 15mm lower than non-sport, I can't seem to find where I read that originally so take it with a grain of salt. Eibachs add another 10-15mm for a total of 25-30mm from non-sport.

The eibachs do seem to lower the front 5mm more than the rear for a slight "raked" look. The dinan camber plates are a perfect "fix" for that, my car (128i) sits level on my B12 kit. I would suggest while you're at it get the camber plates as well if you're concerned about the slight rake, it will also add a bit of front grip as a nice side-effect (albeit adding visible camber, some people may not like that).

I run 10mm spacers all around which really provides a nice "filled out" look front and rear with the suspension lowered. Stock offsets gave it a bit of a "tucked" look, which is accentuated by the added camber at the front (if you get the plates).

We're talking fine margins here - so it depends how sensitive you are to these things.

[gjm120]

This is old and you've maybe seen before...

[tjswarbrick]

Originally Posted by asbrr

Hm - not sure what baseline swift uses, my comment was directed at the Eibachs (sorry should've been clearer). Swift may measure from M-sport.

From anecdotal evidence the swift spec Rs are indeed lower than the Eibachs. M-sport I believe is 15mm lower than non-sport, I can't seem to find where I read that originally so take it with a grain of salt. Eibachs add another 10-15mm for a total of 25-30mm from non-sport.

The eibachs do seem to lower the front 5mm more than the rear for a slight "raked" look. The dinan camber plates are a perfect "fix" for that, my car (128i) sits level on my B12 kit. I would suggest while you're at it get the camber plates as well if you're concerned about the slight rake, it will also add a bit of front grip as a nice side-effect (albeit adding visible camber, some people may not like that).

I run 10mm spacers all around which really provides a nice "filled out" look front and rear with the suspension lowered. Stock offsets gave it a bit of a "tucked" look, which is accentuated by the added camber at the front (if you get the plates).

We're talking fine margins here - so it depends how sensitive you are to these things.

In addition to Z4 and trimmed M3 bump stops, Dinan camber plates are already in there, and iirc I'm at about -1.6deg per side up front. Have 12mm spacers up front. Had to remove the (also 12mm) rears when the Swifts were installed. If all goes as planned, I'll put those back in - as long as they don't cause any rub.

Looking forward to optimizing the ride/handling balance! If I can just get ECS to confirm status on the springs...

[tjswarbrick]

Originally Posted by gjm120

This is old and you've maybe seen before...

Sounds fun. No mention of N55 E88...
May be able to get before/afters on Swift/Eibach - but may not since the car's already at the shop.
What in the world is "bottom middle of rim flange"? Is that supposed to be the visible portion of the rim closest to the ground?

[gjm120]

Originally Posted by tjswarbrick

Sounds fun. No mention of N55 E88...
May be able to get before/afters on Swift/Eibach - but may not since the car's already at the shop.
What in the world is "bottom middle of rim flange"?

I took it to be straight down from fender well thru the center cap and at the top of the rim (at the bottom of the wheel)

[gjm120]

Oh and there is a typo on the front 18" sport suspension.

[duder13]

Originally Posted by duder13

I’ve only put a tank and a half of gas through it since the upgrades, but I expected it to scrape more. I even took some speed bumps pretty fast today to test it, and it was fine. I think you’re right about the camber plates, and the suspension still may settle a little, so we’ll see.

Stock 135i ground clearance is around 4.9”, so even dropping it 20mm isn’t crazy low and puts it in the range of a lot of stock Porsches. I used to take my Cayman to the mountain for snowboarding without many issues with snow, and it had a ground clearance of around 4.3” IIRC.

I just realized that my Cayman ground clearance was more like 3.9”, and I think the 135i’s nose is actually a little shorter, so my B12 kit should be fine at around 4.1”-4.3”. As I mentioned, I took the Cayman camping, snowboarding etc., without much issue.

[tjswarbrick]

Not accounting for the damaged left front, and with Dinan camber plates up front, I get the following measurements lower rim to fender with my Swifts :

Right rear : 21 7/16"
Left front : 21 15/16"
Left rear : 21 15/16".
The car is listing slightly to the right.

Assuming that the front/rear balance is good, but the car is offset to the left due to sagging on the right, but in equal amounts, let's call it 21 11/16" from lower rim lip, through center cap, up to fender.
That's only 550.9mm, on 18" wheels.
So, provided I measured everything correctly and my assumptions are sound, those Spec-R's are a full inch lower than the BMW Performance suspension in the rear, and over 1.5" lower up front. Curious to see where the Eibach's get me when everything is back in ship-shape.

[gjm120]

Originally Posted by tjswarbrick

Not accounting for the damaged left front, and with Dinan camber plates up front, I get the following measurements lower rim to fender with my Swifts :

Right rear : 21 7/16"
Left front : 21 15/16"
Left rear : 21 15/16".
The car is listing slightly to the right.

Assuming that the front/rear balance is good, but the car is offset to the left due to sagging on the right, but in equal amounts, let's call it 21 11/16" from lower rim lip, through center cap, up to fender.
That's only 550.9mm, on 18" wheels.
So, provided I measured everything correctly and my assumptions are sound, those Spec-R's are a full inch lower than the BMW Performance suspension in the rear, and over 1.5" lower up front. Curious to see where the Eibach's get me when everything is back in ship-shape.

I'm at 575mm / 564mm front / rear. Adjusting for the fact wheels are 17" that would give 18" equivalent of 587mm / 576mm which is pretty much within 5mm of the sheets posted above (remember the front 18" BMWPS is an obvious error and should be 582mm). So you are quite dropped at 551mm.

Were the Swifts designed for an E88 or are they general E82 springs? If they were E82 one size fits all that would explain the large drop.

[tjswarbrick]

Originally Posted by gjm120

I'm at 575mm / 564mm front / rear. Adjusting for the fact wheels are 17" that would give 18" equivalent of 587mm / 576mm which is pretty much within 5mm of the sheets posted above (remember the front 18" BMWPS is an obvious error and should be 582mm). So you are quite dropped at 551mm.

Were the Swifts designed for an E88 or are they general E82 springs? If they were E82 one size fits all that would explain the large drop.

E82 / one - size - fits - all, only 1-series set.
Harold thought they'd be perfect. On the convertible, I think they are too low.

If anyone would like to try them on a coupe, drop me a message.

[tjswarbrick]

Replacement strut was delivered to my mechanic today. Getting closer. But the springs are still a couple days out.

[tjswarbrick]

Mechanic discovered 3 leaks while doing the suspension. ( oil pan gasket - known; valve cover - not surprising, unfortunately ; turbo return hose - news to me.) So I just got her back today.

Parked on uneven surface, and letting it settle in, so no numbers yet. But seems about an inch taller than Swift, while still 1/2 inch down from M Sport. Looks aggressive rather than juvenile. In other words, just right.

I thought the ride was fine, perhaps a little over damped at the rear (lots of rebound.) Over sensitive teen daughter still found it harsh.

Top down, foot down, music up, it felt pretty darn ideal indeed.

[oneBIGtoe]

Hey tj, post some pics when you get a chance.

[gjm120]

Originally Posted by tjswarbrick

Mechanic discovered 3 leaks while doing the suspension. ( oil pan gasket - known; valve cover - not surprising, unfortunately ; turbo return hose - news to me.) So I just got her back today.

Parked on uneven surface, and letting it settle in, so no numbers yet. But seems about an inch taller than Swift, while still 1/2 inch down from M Sport. Looks aggressive rather than juvenile. In other words, just right.

I thought the ride was fine, perhaps a little over damped at the rear (lots of rebound.) Over sensitive teen daughter still found it harsh.

Top down, foot down, music up, it felt pretty darn ideal indeed.

Good for you!

Did Koni make good on the strut that went out? Any idea what caused it or just a defect?

[tjswarbrick]

Will take measurements tomorrow to compare to the above. Car is in no condition to be photographed right now - and on-and-off rain expected to continue - so I'm not sure when she'll get tidied up. But it's in the list of things to do!

As far as the Koni warranty :

For advanced replacement, they charge "wholesale" cost, which is like a $30 savings over ECS or Tire Rack, and include return shipping instructions and box. I'm still on the hook for freight.
If they determine it was a failure, not caused by abuse or installation, they'll refund that wholesale charge.

Frankly, the only failure I see is stripped threads where that nut came off. Will ask the mechanic his take on Monday. Not holding my breath, but will send it in and keep you guys posted.

[tjswarbrick]

After two short drives to settle in, E88 6MT with Dinan camber plates and Eibach Pro springs: front is at 22 1/4 inches from bottom of rim to center of fender = 565mm.
Rears are 22 5/16 inches = 567mm.

Still filthy - no pics. But I think it looks great.

[tjswarbrick]

A few days in, I'm surprised at what a difference in ride and handling moving to the taller, softer, progressive springs did NOT make. She's still sharp, responsive, taut, firm and flat. Sharp roadway transitions still send shivers up the cowl, but without the hard "bam" of a bottom-out. I haven't scraped hard yet, but also haven't attempted my most problematic driveways or speed bumps. Road feel is great, though it seems to be a touch more through the body than the steering compared to the previous setup. Overall, very happy. It sure didn't turn into the FIL's Lexus!

Just sent bad Koni back for warranty evaluation. Will update when I hear from them. And if the rain stops for several days so I can snap some pics.

[tjswarbrick]

Conquered the speed bumps at the local movie house. Was able to slow-roll straight ahead in first with no scraping or crash landing. So that's a win!

[tjswarbrick]

Bad strut received at Koni last week. They said to give em 2 weeks to inspect / analyze it.

In the mean time, I decided to see where my mechanic had set the rebound on the replacement. He didn't! It was at full soft. Driver's side was about 1.25 turns in, and I thought perhaps a tiny bit over damped for the Eibachs.
Set both sides to. 5 turns in from soft.
It's a little too soft, so I'll dial em in to. 75 to 1 turn when my new M10 and M12 spring dome support bolts arrive in a week or two.

[tjswarbrick]

Car is doing great, but I stil feel I could dial in a little more rebound up front. New bolts have shipped.

Koni has agreed to honor the warranty!
I should see a refund in a couple of weeks.

[chris_flies]

Originally Posted by tjswarbrick

Car is doing great, but I stil feel I could dial in a little more rebound up front. New bolts have shipped.

Koni has agreed to honor the warranty!
I should see a refund in a couple of weeks.

I've got the front at full stiff and it feels great; well-controlled and not uncomfortable. I think the rear is too stiff, though, at 1.6-1.75 turns from soft...

I'm likely dropping the Koni's for some Ohlins soon...