The Cabrio Suspension Thread

[robrez]

Definitely need some help/suggestions here folks.

I have sort of a unique situation. Car is a 1989 cabrio with full E30 M3 suspension/5lug/S14/etc out of my '88 henna M3.

The set up I had on the Henna car was H&R Race & Bilstein sport with the old school 15mm drop hats (not e90 hats). This setup was absolutely perfect on the coupe, handled amazing, but on the vert with the added weight and lower rigidity has made the car very crashy and uncomfortable.

What I realistically need is a moderate lowering spring made for a 4cyl cabrio... which I cannot find. I see a 6cyl cabrio sport spring but I'm afraid the reduced weight of the S14 will result in a reverse rake.

Thoughts?

Ride height as it sits with no top/windows/interior currently installed. With the top & full interior it rides pretty low in the rear.

I'd run a combination of H&R sedan/coupe front springs (50406) and H& R vert/ix rear springs. Start there, it might be just right. If not, you can add e90 drop hats to lower the front a tad, or add thicker rear springs pads to raise the rear. If I hadn't scored a set of Dinan vert springs, that's what I'd be using. Even with my Dinan vert springs, I ended up adding thicker rear spring pads because I was getting a little reverse rack after I moved the battery to the trunk, the hard top on and the spare tire. I'd stay away from 4 cylinder springs, they're too soft. I'm running a Strong Strut rear brace in addition to a Mason X-brace and a front strut bar. Together, they firm up ride appreciably.

[phenryiv1]

Definitely need some help/suggestions here folks.

I have sort of a unique situation. Car is a 1989 cabrio with full E30 M3 suspension/5lug/S14/etc out of my '88 henna M3.

The set up I had on the Henna car was H&R Race & Bilstein sport with the old school 15mm drop hats (not e90 hats). This setup was absolutely perfect on the coupe, handled amazing, but on the vert with the added weight and lower rigidity has made the car very crashy and uncomfortable.

What I realistically need is a moderate lowering spring made for a 4cyl cabrio... which I cannot find. I see a 6cyl cabrio sport spring but I'm afraid the reduced weight of the S14 will result in a reverse rake.

Thoughts?

Ride height as it sits with no top/windows/interior currently installed. With the top & full interior it rides pretty low in the rear.
P1010040 by IronJoeT16S, on Flickr

You should be able to use H&R Sport rear springs from a 4 or 6 cylinder. The rear weight differences are negligible so either will work and while I cannot recall with 100% certainty, I believe that there is only one rear spring from H&R for all verts. Up front you can run whatever 4 cylinder spring you want but the Race will create rake when paired with a Sport cabrio rear.

[IronJoe]

Definitely need some help/suggestions here folks.

I have sort of a unique situation. Car is a 1989 cabrio with full E30 M3 suspension/5lug/S14/etc out of my '88 henna M3.

The set up I had on the Henna car was H&R Race & Bilstein sport with the old school 15mm drop hats (not e90 hats). This setup was absolutely perfect on the coupe, handled amazing, but on the vert with the added weight and lower rigidity has made the car very crashy and uncomfortable.

What I realistically need is a moderate lowering spring made for a 4cyl cabrio... which I cannot find. I see a 6cyl cabrio sport spring but I'm afraid the reduced weight of the S14 will result in a reverse rake.

Thoughts?

Ride height as it sits with no top/windows/interior currently installed. With the top & full interior it rides pretty low in the rear.
P1010040 by IronJoeT16S, on Flickr

[Bearmw]

I randomly inspected my rear shock mounts the other day and found both completely broken. A few years ago I replaced them using "heavy duty" stock type rubber mounts along with the bolt on reinforcement plates. The plates apparently did there job and the sheet metal was uncompromised but the rubber on each mount was completely torn. I think I may have done them in while hitting a good bump while coming down a mountain road at a good clip but I'm not sure. In any case I am going to replace them with IE urethane mounts. Lesson learned: the rubber ones aren't up to the task for my driving style.


:

[Mixedbyjairo]

I got my '92 with H&R 50404.55f the part number does not come up, I called HR and they said they are oem replacements with no change from stock but the car sits lower and feels pretty firm on 4 year old KYBs. I got the Koni Sport front inserts today finally and don't want to take the struts apart twice, anyone know the actual data on these?



The ones in back are blue, I can't see the part number on them but know he got them in a set from Pelican.

I'm running the rear set of H&R 50404 with koni yellows

[Chrisv006]

Bilstein sports, H&R coup springs, e90 drop hats, Ireland engineering street camber plates, new bushings, new brakes/pads, e38 style 5's with adapters.

https://imgur.com/gallery/cgBu3

[fporro]

ran into this about oem M Technic springs ...

BMW Germany got back to me, front springs are 3686 newton at 140mm and rear springs are 5151 newton at 122.83mm.

F=Kx

K (spring rate) for the front is 26.32 n/mm or ~150 in/lb and rear is 41.94 n/mm or ~240 in/lb.

Too bad H&R springs doesn't provide their spring rates, its hard to know if whats floating around on the internet is correct. Considering the H&R's are progressive, it would be interesting to know if the initial spring rate is less than OEM.

[Taiontrack]

Is anyone running ASTs on their convertible? IF so, feedback?

[parkerbink]

I got my '92 with H&R 50404.55f the part number does not come up, I called HR and they said they are oem replacements with no change from stock but the car sits lower and feels pretty firm on 4 year old KYBs. I got the Koni Sport front inserts today finally and don't want to take the struts apart twice, anyone know the actual data on these?



The ones in back are blue, I can't see the part number on them but know he got them in a set from Pelican.

[NeverEnough02]

Z3 rack is linear which means it is really touchy on center while a lot of the other racks are progressive so they are less touchy on center and grab more as you steer more. Z3 is better for autocross and not dongreat for highway. A good alignment should help you out though.

[phenryiv1]

One more question for you, I swapped out my steering rack for a Z3. Ever since my steering has felt light. Especially at highway speeds. Do you see the same thing?

Glad to hear no rubbing or bottoming. With 8" wide wheels I was a little worried. I didn't see a single e30 at the Vintage, besides mine, with anything wider than 7.5". I tracked down every one to see who was running what.
Maybe one or two were slammed. But I think they were on air. That's way beyond what I want for a cruiser.
For now I'm gonna see what happens with the springs and tophats. My camber is at 0.2-0.3 right now. If it doesn't go any worse than 1.5, maybe I'll leave it. I just put Monroe struts/shocks in so I'll see what happens. I've had a skid plate waiting in the garage for a while.

Sent from my SM-N915V using Tapatalk

My steering felt light after the e36 rack install but it was because both camber and toe were off. Now that I have them both where I want them the car has very predictable steering with what feels like appropriate effort.

[phenryiv1]

Hi i need some helps i just install bilstein b8 eibach pro kit + e90 drop hats...i dont see my car lowering has much! The seller told me i have to wait 1000 km to see the results..any ideas ??

Should not take more than 10-20 miles for it to settle.

Pictures?

[Saddame30]

Help !! Bilstein B8\eibach pro-kit\e90 drop hats

Hi i need some helps i just install bilstein b8 eibach pro kit + e90 drop hats...i dont see my car lowering has much! The seller told me i have to wait 1000 km to see the results..any ideas ??

[BruceJ]

One more question for you, I swapped out my steering rack for a Z3. Ever since my steering has felt light. Especially at highway speeds. Do you see the same thing?

Glad to hear no rubbing or bottoming. With 8" wide wheels I was a little worried. I didn't see a single e30 at the Vintage, besides mine, with anything wider than 7.5". I tracked down every one to see who was running what.
Maybe one or two were slammed. But I think they were on air. That's way beyond what I want for a cruiser.
For now I'm gonna see what happens with the springs and tophats. My camber is at 0.2-0.3 right now. If it doesn't go any worse than 1.5, maybe I'll leave it. I just put Monroe struts/shocks in so I'll see what happens. I've had a skid plate waiting in the garage for a while.

Sent from my SM-N915V using Tapatalk

[phenryiv1]

Another tire & wheel size for those doing research. 15x8 ET20 Rota Grid Concave Full Royal Silver with 205/55/15 Kumho Ecsta 4xII tires on H&R Sport (convertible) springs, 15mm drop hats, Bilstein Sport struts/shocks.

Outside, before settling:







And after:













This is the 4th different wheel/tire combo on the same setup so if you scroll back you get a sense for how tire size and wheel specs impacts the overall appearance.

So it's been more than a year on this combo, if you are still on it. Does it rub at all? Your wheel wells look like they aren't rolled or stretched. I'm on the same size/offset tire/wheel at stock height. Wanna drop, but.... don't want to rub.
Thanks

I am still on the Rota/Kumho wheels & tires and the H&R Sport/Bilstein Sport suspension. I also have UUC/SPC camber plates (to remedy a frame issue that was not apparent until I was already about $4-5K into this project so it was too late to start fresh on a cleaner chassis) and some unknown brand of aftermarket swaybars.

Having driven approximately 15K on everything ranging from D.C./NoVA surface roads, secondary streets, and highways to WV back roads and even gravel parking lots (ugh!), I am (knocks on wood) yet to tap my pan or to rub at full lock or during suspension compression, even when loaded with 2 adults & 2 children. And my fenders are not rolled or modified in any way. I have not even bottomed out, to the best of my knowledge, but the swaybar & spring/strut combo is slightly harsh. When I say slightly, I really mean slightly.

I have owned 42 cars, most of them modified. My last few DDs and projects have had suspension mods that range from benign to fairly comprehensive, and one thing that I have noticed is that stiffer swaybars are fine, or lowered, stiffer suspension is fine. But on every car where I do both sways and springs/struts, I find it to be a bit harsh. I bought this car on coilovers (I did not like them, though they were actually pretty comfortable) and the aftermarket sways, but I swapped in the H&Rs/Bilsteins, all before actually putting the car on the road.

All that said, I have sourced a stock convertible swaybar set and will be playing with taking one and/or the other back to stock to see if that helps with the harshness. I really liked the H&R Sport/Bilstein combo in 2 previous E30s but both were on stock sways (one was a sedan on a 'very FSB and an ix RSB) and rode better than the convertible above.

But back to your original question...no rub and no bottoming out.