Let's talk about road suspension

[stitch2k1]

Following. Want to put suspension on my 91S2 this year. Was thinking about doing a front coil over mod with GC or Paragon sleeves and Bilstein shocks (which requires a mod). I'm going to run M030 calipers (if I can find spindles and hubs!!!), I got some 2 weeks ago. Sounds like KWs are what I want though.

[Latitude48]

If you're in the KWv3 price range, you can also consider MCS and Intrax.

I had completely forgotten about MCS, I'll have to look into them.

I have a full front/rear set of MCS double adjustable... but I haven't installed them yet. I've attached a couple of pictures of the struts to show they now come with all factory attachment points. These will replace the M030 on my 951. I'll be running 300#/in front springs, so the struts are valved for this setup. I've been told they will ride much better than the same rate springs on Koni double adjustable M030 type struts I have on my S2, and while the S2 is stiff I didn't find it to be that terrible when I drove it back and forth to work for years.

Unfortunately, like most good things, the MCS is up there in pricing now. I purchased mine from Karl at Racer's Edge. I also have his camber plates on the S2 and a set for the 951. Those probably contribute most of the harshness with the spherical joints, but the handling is great.

The S2 also runs the 968 M030 30mm hollow front swaybar and adjustable rear 19mm bar; the 951 will have the new M030 solid bar in front and the same 19mm in the rear.

And both cars also have 18" wheels, so not your typical setup.

[cda951]

@crackership

What size wheels and tires does your 951 have? This is a huge determinant of ride quality. So many of the modern Porsche and especially BMW cars/SUVs that I work on for a living have horrendous ride quality, largely due to huge, heavy wheels with very thin tire sidewalls (especially in the case off BMW run-flat tires).

My 951 has been through several suspension iterations, the current one being Ground Control coilovers (torsion bar delete) with 500#F/750#R springs and almost all spherical bearings. Not street friendly.

But, I still run 16x8"rear phone dial wheels all around, with 245/45 Pirelli Trofeo R tires. The cushion of the sidewalls make all the difference in the world. I would not call it a super comfy setup for rough roads, but it is livable on some of the road rallies I do on some of narrow, rutted roads in the remote regions of California.

I plan to upgrade my front brakes for track use, which will likely require at least 17" wheels and 40-series tires, which might make the car unbearable for road use . . . .

[blade7]

Not sure I buy into all modern cars having horrendous ride quality. My daily driver SEAT Leon Cupra R wagon has 19" wheels and 35 profile tyres, and rides absolutely fine in comfort mode. My wife would soon let me know all about it, if it didn't.

[ROB III]

Run Flats have a rather stiff sidewall to begin with by design so that they can run with no air for a while ( in a demonstration by the supplier, I drove a C4 Corvette with sidewalls that had a 2" hole cut in the sidewall of each tire to demonstrate their capability), so you lose some of the impact absorption capability. I had Bridgestone run flats on my 951 on 18" RH Alurads and they were harsh on step function impact shock...the Michelins I now have, which are not run flats, are clearly better from an impact harshness perspective (but I also went from a 285/30 to 265/35 in the rear).....but not as plush as the low cost brand X I put on the original 16" rims when it went for paint. The OEM wheel/tire size were smaller and lighter with higher aspect ratio tires. There is a noticeable change in ride characteristics (increased harshness) with wider, heavier low aspect ration tires and larger rims from stock. Post impact damping is also negatively affected by heavier tire/wheel combinations.
I worked for two OEM's in dynamic vehicle evaluation and know OEM NVH groups spend a lot of time, energy, and money in tuning an overall package (tire, wheels, springs, bushings, shocks, engine mounts, etc.) for public consumption, so increasing unsprung weight, combined with lower aspect ratio tires, old bushings, and tired shocks all combine to negatively impact ride quality. Some manufacturers are willing to compromise some ride for styling trends on specific trim levels, and one way to gain some improvement back is driver adjustable shocks.
I'm just as guilty as I have 18" 3 piece cast center aluminum rims and 225/40 front and 265/35 rear tires with rebuilt Koni's on my 89 951 because I like the look, but I'm considering updating the suspension with new tech shocks, all new suspension bushings, lighter forged 17" rims, but my bank account says no for the time being.

[crackership]

@crackership

What size wheels and tires does your 951 have? This is a huge determinant of ride quality. So many of the modern Porsche and especially BMW cars/SUVs that I work on for a living have horrendous ride quality, largely due to huge, heavy wheels with very thin tire sidewalls (especially in the case off BMW run-flat tires).

My 951 has been through several suspension iterations, the current one being Ground Control coilovers (torsion bar delete) with 500#F/750#R springs and almost all spherical bearings. Not street friendly.

But, I still run 16x8"rear phone dial wheels all around, with 245/45 Pirelli Trofeo R tires. The cushion of the sidewalls make all the difference in the world. I would not call it a super comfy setup for rough roads, but it is livable on some of the road rallies I do on some of narrow, rutted roads in the remote regions of California.

I plan to upgrade my front brakes for track use, which will likely require at least 17" wheels and 40-series tires, which might make the car unbearable for road use . . . .

the car is on 18" wheels with 235/40 and 275/40, F/R. That said, I've used similar suspension with stock 16s also and honestly find the difference negligible. I'll definitely agree some of the run-flats are terrible though. By comparison, though, I drove a Cayman S on 19s not long ago and it rod infinitely better. It was comfortable and compliant but also held the road crazy well and that was, as far as I know, the factory suspension. I'd be thrilled if I could achieve that result.

[crackership]

If you're in the KWv3 price range, you can also consider MCS and Intrax.

I had completely forgotten about MCS, I'll have to look into them.

I have a full front/rear set of MCS double adjustable... but I haven't installed them yet. I've attached a couple of pictures of the struts to show they now come with all factory attachment points. These will replace the M030 on my 951. I'll be running 300#/in front springs, so the struts are valved for this setup. I've been told they will ride much better than the same rate springs on Koni double adjustable M030 type struts I have on my S2, and while the S2 is stiff I didn't find it to be that terrible when I drove it back and forth to work for years.

Unfortunately, like most good things, the MCS is up there in pricing now. I purchased mine from Karl at Racer's Edge. I also have his camber plates on the S2 and a set for the 951. Those probably contribute most of the harshness with the spherical joints, but the handling is great.

The S2 also runs the 968 M030 30mm hollow front swaybar and adjustable rear 19mm bar; the 951 will have the new M030 solid bar in front and the same 19mm in the rear.

And both cars also have 18" wheels, so not your typical setup.

I just spoke to Karl today and the MCS single adjustable sounds like a great option. I mean, I want the double adjustable just because I know it exists and it's objectively better, but even the single adjustable is a custom valved solution and I figure that "correctly valved" is the result I'm after - I'd almost prefer the professionals figure out what that is than give me a bunch of knobs so I can screw it up

[AudiSport]

Proper valving with the ability to handle high freq and low freq differently is the most important. Single adj is fine. They can be upgraded later. I have Ohlins on my Audi for the street and I never adjust them. mostly set to full soft. Lol.

[Latitude48]

Proper valving with the ability to handle high freq and low freq differently is the most important. Single adj is fine. They can be upgraded later. I have Ohlins on my Audi for the street and I never adjust them. mostly set to full soft. Lol.

I have the Stasis/Ohlins non-remote reservoir setup on my 2003 A4. I don't know the spring rates, but I think they are pretty high. The car is stiff but takes the bumps surprisingly well, even with my 19" BBS RS-GT wheels and 35 aspect ratio tires. Great shocks make a world of difference.

My MCS double-adjustables are also non-remote reservoir types. I could have selected single adjustable too, but as I recall the doubles weren't that much more expensive.

[Tom]

Proper valving with the ability to handle high freq and low freq differently is the most important. Single adj is fine. They can be upgraded later. I have Ohlins on my Audi for the street and I never adjust them. mostly set to full soft. Lol.

My KW's are set to the factory default and I've never felt the need to change them for the street either. If I were trying to shave half a second off a lap time or something, I'm sure the adjustments come in handy, but for the street I'm more of a set it and forget it type.