[Tambohamilton]

Yeah, that's weird! I can't see how the rate can be anywhere near 145lb/in+ with 11.5 wire. Unless there are fewer than 5 total coils? It's just weird, because all the other rates approximately match up to the reported rates...but this one is way off!

[1275]

Love the car and this thread. Great work tlow. Your seats are a nice touch.

Could you elaborate on the modification needed for the whiteline inserts? I've just ordered b14's, new mounts all round and these inserts.

Thanks for documenting your build!

[tlow98]

Originally Posted by Tambohamilton

Yeah, that's weird! I can't see how the rate can be anywhere near 145lb/in+ with 11.5 wire. Unless there are fewer than 5 total coils? It's just weird, because all the other rates approximately match up to the reported rates...but this one is way off!

I'll count the could and re-measure.

Originally Posted by 1275

Love the car and this thread. Great work tlow. Your seats are a nice touch.

Could you elaborate on the modification needed for the whiteline inserts? I've just ordered b14's, new mounts all round and these inserts.

Thanks for documenting your build!

Yeah, you'll see when going to put them in the rear-most mounts just do not insert no matter what you do. Cut out the part that doesn't need to be there, and you'll be good to go!

[1275]

awesome, thanks tlow.

[tlow98]

Originally Posted by Tambohamilton

Yeah, that's weird! I can't see how the rate can be anywhere near 145lb/in+ with 11.5 wire. Unless there are fewer than 5 total coils? It's just weird, because all the other rates approximately match up to the reported rates...but this one is way off!

And this is me eating crow and giving you sanity back to your spreadsheets. I tried so hard to measure that coil in The most complicated wayS the first time. Easiest = Best. Just over 12mm to my eye here. Just.

View post on imgur.com

[Tambohamilton]

Tape measure > vernier....that's a first!

I'll update it now and see how it looks

EDIT: Yes, that's much more like it!

[tlow98]

Originally Posted by Tambohamilton

Tape measure > vernier....that's a first!

I'll update it now and see how it looks

EDIT: Yes, that's much more like it!

I think its the guy behind the verniers - just don't tell my wife that. She thinks I'm perfect

[Tambohamilton]

Clearly just shoddy verniers - they're not even made in Sheffield!

[tlow98]

Built me some struts. Yee-haw

View post on imgur.com

First pic - love these spring compressors!

Second pic - all bump stops are not created equal. I bought Sachs brand fist (in the background) and they seemed incredibly hard and were not the same material I remember using in the past. Bummer, as they weren't exactly cheap ($32 for the pair). The OE BMW brand rear bump stops I bought were made from a completely different material. So, I bought OE BMW fronts to match at the dear price of $25 each which means I spent $100 on bump stops alone. Ouch, but I really want a smooth ride.

Third pic - prepping the strut mounts for Dinan Camber plates.

Fourth pic - profit.

All new rubber spring pads, and washers, etc. All OE BMW stuff. It's not cheap for all these little bits and bobs.

[Tambohamilton]

Exciting times!

Good heads-up on the 'auxiliary springs'...(wildly) differing materials is something I hadn't considered there.

[tlow98]

Originally Posted by Tambohamilton

Exciting times!

Good heads-up on the 'auxiliary springs'...(wildly) differing materials is something I hadn't considered there.

Yeah, I was pretty surprised. Especially, given Sachs is OEM for the struts. This wasn't some REIN or URO $7 units...

[GregSimon]

I have an idea to pick a family car for my wife and I very interested in BMW 3-series. This thread is great and I have more information now about what these cars inside is.

If anybody have photos with baby seats installed on the backseat - this info will be appreciated.

Thanks.

[Tambohamilton]

I've used an Axkid Minikid rear-facing seat in mine. It takes up way more space than a normal forward-facing seat, due to the headrest of the child seat leaning towards the headrest of the front seat, but my 5'8" partner was able to sit in the front in comfort (though less than normal legroom). For front-facing seats or small baby seats there is no bother, but don't expect to be able to slam the front seat all the way back with the latter installed behind! I've recently read another thread on this forum, by someone who is looking for an alternative to their e91 only because they have a 3rd child coming...

[Tambohamilton]

Originally Posted by tlow98

Built me some struts. Yee-haw

View post on imgur.com

First pic - love these spring compressors!

Second pic - all bump stops are not created equal. I bought Sachs brand fist (in the background) and they seemed incredibly hard and were not the same material I remember using in the past. Bummer, as they weren't exactly cheap ($32 for the pair). The OE BMW brand rear bump stops I bought were made from a completely different material. So, I bought OE BMW fronts to match at the dear price of $25 each which means I spent $100 on bump stops alone. Ouch, but I really want a smooth ride.

Third pic - prepping the strut mounts for Dinan Camber plates.

Fourth pic - profit.

All new rubber spring pads, and washers, etc. All OE BMW stuff. It's not cheap for all these little bits and bobs.

These on your car yet!?

[tlow98]

Originally Posted by Tambohamilton

These on your car yet!?

Actually, yes!

Got them on last weekend and was waiting to give my thoughts. I've got 250 miles on it and it seems to have settled.

Height before (measured from center of roundel to fender - i know, wonky)
FR: 370mm
FL: 373mm

Height after (measured from center of roundel and bottom of rim)
FR: 377mm 608mm
FL: 380mm 611mm

On the measuring change - When I measured a few weeks ago for the before measurement I neglected to do it the "right" way from the bottom of the rim. Le Sigh.

My stock C5 springs are ~358mm free length, FYI. So, the 30% stiffer D7 springs are 30mm shorter at full length. I then added the E30 perch to get another 10 mm to guarantee the car wouldn't go lower than stock. I also like the idea of the car NOT riding on the bumps stops all the time and don't care about the looks. So 7-10mm higher than the stock 106k mile struts.

Anyway, the delta of <10mm seems right given:
1 - You can barely tell by looking at it. Sometimes it almost seems lower.
2 - I'm well known for my measuring accuracy in this thread. Oh, wait!
3 - it was 396mm on the day of the change. Settled out some 20mm. it was looking like a 4x4 that day.

Tambohamilton What was the height of your car from the bottom of the wheel to the fender?

Notes on the ride:
1 - Set them at full soft for now.
2 - Night and day on brake dive and connected feeling in the front end - huge improvements.
3 - Very large impacts are better controlled and I'm no longer getting the solid-axle feel the M3 sway was giving me. Went back to stock sway and I'm happy I did.
4 - More lean in corners after removing the sway and upping spring rate ~30% with OE Sport D7 springs.
5 - Smaller, square-edged impacts seem slightly harsher. Shame. Perhaps the spring rate increase, perhaps the damper or a bit of both?
6 - Most impressive bit - recovery at freeway speeds from very large bottom-out type undulations. It recovers so fast. No bouncing or bobbing. No harsh bottom feel. Just takes it in stride and keeps going - very confidence-inspiring. Around town handling also not even comparable. Way more fun.

Notes on the 106k mile stockers:
1 - Stock dampers were in relatively good shape. No blown seals and worked fine.
2 - Bump stops were starting to come apart. I will update with pics.
3 - Both top strut mounts had noticeable bearing play in them and some minor cracking of the rubber. Very minor.

Excited to get the rear shocks on and lift the rear ~15mm. Not a fan of the saggy butt and could use the clearance, especially when loaded down doing wagon stuff.

Niggling thought:
- Could I have gotten that much smoother of a ride on the stock springs? Would I have been satisfied with the performance? Not sure. Those damn C5s were awfully soft tho! I'm happy enough as is.
- Koni fanboi love affair continues. There really are great shocks for the price point. But should I have gone Ohlins? Blah! Maybe for a more 'fun' car that's stick shift and not shared...

[Tambohamilton]

Nice!

My car is 603 rim-fender, with no load in it; 18" rims. Stock (non-sport) height would be 612 with load in it, but I've got Xd top mounts in there.

So basically in switching from C5 to D7/8, your ride height didn't change. But you also installed the taller spring perches, which raised it up by the ~10mm. Good to know... I've got myself in a right mess over the ride height calcs!

Glad it's working well for you so far, though disappointed that small bumps do feel harsher...can't have it all, I suppose! When do you think you'll get the rear end done? I think that will make at least as much difference again!

[tlow98]

Ok, rears are in.

Why on earth did I wait 5 years to do this? Every car I've bought I've done this within the first year and it's a remarkable change. And it was just as remarkable this time. I will not wait this long again.

You're right Tambohamilton - I think the rears actually made a bigger difference. This might make sense as the rear weighs more and now that larger mass is well controlled. The stock rears were in good shape save for the lower mounts that had been chewed up a bit and were in need of replacing. Better overall conditions than the front set up, tho.

The car is so well controlled that it's very hard to spin an inside rear tire now. Even when doing a U-turn with no T/C you get a very slight chirp and off it goes with little drama. Previously higher speed moves were ponderous and borderline unsafe. Now it just holds a line with no drama. Braking, steering, and overall agility all vastly improved.

It handles well enough now that the motor really stands out as S-L-O-W, haha.

I also took the time to apply some noise/vibration dampening butyl tape to the interior of the rear panels. The jury is still out on how effective that is - need to put on some more mileage.

Things I'm glad I did not do:
- Rear swaybar. The rear is incredibly well controlled and responds RIGHT NOW.
- Rear height raise with shim on top of the spring. After getting the springs/ perch out and placing the shim in I did not like the way the perch moved around slightly within its mount. Family car and safety is important. Out they went.

No change in rear ride height.

[tlow98]

Originally Posted by Tambohamilton

Nice!

My car is 603 rim-fender, with no load in it; 18" rims. Stock (non-sport) height would be 612 with load in it, but I've got Xd top mounts in there.

So basically in switching from C5 to D7/8, your ride height didn't change. But you also installed the taller spring perches, which raised it up by the ~10mm. Good to know... I've got myself in a right mess over the ride height calcs!

Glad it's working well for you so far, though disappointed that small bumps do feel harsher...can't have it all, I suppose! When do you think you'll get the rear end done? I think that will make at least as much difference again!

Yes, bingo on the ride height. I sort of wish I'd have kept my stock front perches as I was not confident int he safety of the rear raise and, as such, did not do it. Oh well, 10 mills won't kill me.

The ride height calcs on the sport to non-sport spring stuff is so strange and difficult to gauge. I feel like only real world examples are bank-able.

What's next for you?

[Tambohamilton]

Well, as of yesterday I have a set of d7 fronts and d4 rears sat waiting to go on...

My spreadsheet has seen a fair bit of work lately, but I've unshared it because a) it's a work in progress, and still has a fair bit of guesswork in it, and b) I've put a lot of time into it, and not sure I'm ready to let that go just yet...

Anyhow, I'm in the process of bringing bump stops into the model, to get a fuller picture of the stock setup and some sort of estimation for bump stop tuning... I won't install my new spring until I know what bump stops I'll pair them with.

I'm not 100% that I'll use the front d7 springs, partly because of their ride height, and partly because I don't think they're as stiff as I want (my 330d is pretty much the same front weight as a 335i, for reference).

My solution, most likely, will be BMW performance springs. They're around 190lb/in rate (compared with my current 120, and 150ish for the d7) - that should give me around 1.5hz nat freq ignoring bump stops, which will match the rear nicely. They should drop the front only about 0.5" lower than m sport, but I'll probably negate much of that by installing a 10mm thick camber plate to get me to around -1.8 - 2.0deg camber. I don't know why I didn't notice it before, but it was definitely a little lightbulb moment when I realised that my spreadsheet was pointing me directly at the BMW perf spring rates.

I've discounted eibach prokit and h&r springs because they seem to drop the front further than is useful, and have very similar rates to the d7 springs. I want to retain near m-sport ride height in order to keep a useful amount of bump travel (it's only about 50mm when you're in the car, at m-sport height!). I may even use e30 perches to increase the front travel.

I'll keep the rear d4, because they're very similar in rate to my current f3, but drop the rear to around m-sport ride height. When I install them, I may beef up the rear shock top mount a bit too (reduce the length of the sleeve, so the foam parts are compressed a bit further initially).

I'd like to get into the shocks a bit more, but the barrier there is dyno printouts...not much around that I can see, and without that I'm flying blind. Also, the maths for calculating desirable damping have one particular step which is a bit much for my little brain...for now at least. I think that if I eventually just have to choose a new shock without calculation I'll just go for yellows. But it would be nice if there was a similar shock with shortened bodies somewhere...?

That's awesome that you're loving your new setup! Do you think you'll lower the front, since you didn't raise the rear? Yeah, the rear top mounts are tapered - you could even just wrap them with electrical tape or similar to fill the gap from installing spacers there...it doesn't need much, and even of it was loose, the fact that it will always have spring pressure on it means it would never come to any harm. I totally agree with your decision to not use the spacers though. When you say your car is now underpowered, you mean you brake too much into turns, right?

[tlow98]

Originally Posted by Tambohamilton

Well, as of yesterday I have a set of d7 fronts and d4 rears sat waiting to go on...

My spreadsheet has seen a fair bit of work lately, but I've unshared it because a) it's a work in progress, and still has a fair bit of guesswork in it, and b) I've put a lot of time into it, and not sure I'm ready to let that go just yet...

I understand!

Anyhow, I'm in the process of bringing bump stops into the model, to get a fuller picture of the stock setup and some sort of estimation for bump stop tuning... I won't install my new spring until I know what bump stops I'll pair them with.

I went around and around on this but in the end since I am using D7 springs I just used the standard OE sport ones, albeit with a slight lift. I'm not disappointed but obviously my sample size is small and I've only tried this or blown out stock ones...

I'm not 100% that I'll use the front d7 springs, partly because of their ride height, and partly because I don't think they're as stiff as I want (my 330d is pretty much the same front weight as a 335i, for reference).

My solution, most likely, will be BMW performance springs. They're around 190lb/in rate (compared with my current 120, and 150ish for the d7) - that should give me around 1.5hz nat freq ignoring bump stops, which will match the rear nicely. They should drop the front only about 0.5" lower than m sport, but I'll probably negate much of that by installing a 10mm thick camber plate to get me to around -1.8 - 2.0deg camber. I don't know why I didn't notice it before, but it was definitely a little lightbulb moment when I realised that my spreadsheet was pointing me directly at the BMW perf spring rates.

This seems like a good way to go if you can avoid them being slammed. Did BMW issue a specific bump stop for those springs? I think it was originally released as a shock/spring kit and so I would imagine a bump stop would have been a piece of that. Tho, I'd bet they were E36 M3/Z4 units which is what I was pondering using for my set up, too.

I've discounted eibach prokit and h&r springs because they seem to drop the front further than is useful, and have very similar rates to the d7 springs. I want to retain near m-sport ride height in order to keep a useful amount of bump travel (it's only about 50mm when you're in the car, at m-sport height!). I may even use e30 perches to increase the front travel.

Yep, stay away from the slammed low spring rate units. One thing I will note about the E30 perches is that the E90 spring perch top rubber 'gasket, bushing' etc did not fit the E30 mount perfectly. It's not terrible, but it's clear that the E30 spring 'gasket, bushing, whatever' is made for that perch. The E30 gasket is much thicker (9mm, iir) and is overall quite different. Also, the E30 perch is more angular if that makes any sense? As in, the E90 perch mating point of the spring/perch interface is more parallel with the ground and the E30 is more inclined. Does the E30 perch work? Yes. Is it perfect? No, and bothers me a little. it's not unsafe, tho. Food for thought!

I'll keep the rear d4, because they're very similar in rate to my current f3, but drop the rear to around m-sport ride height. When I install them, I may beef up the rear shock top mount a bit too (reduce the length of the sleeve, so the foam parts are compressed a bit further initially).

Interesting idea here. Just don't do it so much that you shear the shaft off tightening it down. Maybe I missed but what shocks are you going with?

I'd like to get into the shocks a bit more, but the barrier there is dyno printouts...not much around that I can see, and without that I'm flying blind. Also, the maths for calculating desirable damping have one particular step which is a bit much for my little brain...for now at least. I think that if I eventually just have to choose a new shock without calculation I'll just go for yellows. But it would be nice if there was a similar shock with shortened bodies somewhere...?

Yeah, this bit is tough. And now I see you haven't selected a shock. I ended up going with OE bumps stops because it seemed the safest play. At the end of the day if you are using OE bump stop lb/in rates and are allowing a Dinan-like allowance of movement before the bump stop is being used you can be quite sure it will work out well enough to not be noticeable. At least, this was my EOD realization. They're already done the hard work of mixing/matching/designing. I just copied.

As far as shocks I was considering 3 levels. 1- Bilstein B4 sport, bcuz cheap and good. 2- Koni Yellows. 3- Ohlins, bcuz, c'mon who doesn't want Ohlins on their wagon. With Ohlins I would have spec'd 250lb/in front springs and likely 500ish rears depending on the Hz Front/Rear. The natural frequency is sadly the compromise I made when the Konis went on sale and I was able to get full set delivered for $650. Using OE sport springs it went in the right direction but still a bit off 1.5Hz. I didn't take the time to look, bc I knew I wouldn't get an answer I would like :-)

For you - BMW made performance spring specific shocks, didn't they? Otherwise if you want the best from a "set it and forget it" standpoint I would contact Shiak at Fat Cat Motorsports - he does some incredible Bilstein B8/6 based custom shocks. Always wanted a set, but they are Ohlins R&T money and not local to you. Conversely, he's in my back yard.

That's awesome that you're loving your new setup! Do you think you'll lower the front, since you didn't raise the rear? Yeah, the rear top mounts are tapered - you could even just wrap them with electrical tape or similar to fill the gap from installing spacers there...it doesn't need much, and even of it was loose, the fact that it will always have spring pressure on it means it would never come to any harm. I totally agree with your decision to not use the spacers though. When you say your car is now underpowered, you mean you brake too much into turns, right?

You know, I would like to lower it and I have kept my old stuff to do so, but well, with a 2-year-old it's hard to find time to "experiment". It would be much faster the second time around... We'll see if I can get to it. Ah well, you know what they say about the best-laid plans.

Touche about the cornering speeds - You're probably right, too! Now, I can just pin it halfway through the corner and the car goes exactly where you point it. No drama. Which I guess means I need to find the new, much higher limits haha.

[The Nightman]

You have a really well sorted suspension set up now! The Konis seem perfect for this application

[tlow98]

Originally Posted by freedomfries

You have a really well sorted suspension set up now! The Konis seem perfect for this application

Thanks! Let’s be real tho, any new shocks at 100k is likely to be a revelation :-)

So, now the only trick is to convince my wife to keep it - and I need a back up camera for that... any suggestions?

Already have Nav, but the OE solution seems above my DIY skill level. Hmmmm