Can coil overs make my 3-Series ride like a 5-Series?

Keith Tanner said:

If the car is using the bumps most of the time, the solution is stiffer springs and appropriate shocks. That'll mean less time spent on the stops. It seems counterintuitive, but it works.

I can wholeheartedly agree with this.  Good dampers are huge.

I have/had two cars where I improved the handling AND ride quality with Bilstein dampers and front spring rates roughly 2x the stiffness of stock.  Granted this was going from about 100-115lb-in to 200-225, so not terribly stiff compared to many sport springs.  But the ability to not constantly crash into the bump stops was huge.

One of the worst things I had ever done was install the ipd heavy duty front bumpstops in my Volvo.  It took the bumpstop action from "progressive rate increase" to "hard hit".

I cut a half inch off the rear bumpstops and did notice a little more travel and compliance over large bumps.  But the small ripples in the road were unchanged and still killed me.

Going to order the Koni Special Actives and go from there.

Thanks all!

Slippery said:

My e39 540i with the sport suspension was one of the stiffest cars I've driven lol. 

I'd probably look for a Crown Vic or Town Car, cheaper than getting new wheels for you car. 

I was thinking exactly the same. My E36 was substantially more comfortable than my E39. I think the OP's needs are trending towards Lexus, Buick, etc. 

In reply to ShinnyGroove (Forum Supporter) :

One thing that is nice about Bilsteins is that they do not seem to play weird games with stiff initial damping to make the car "feel sporty".  They are supple on sharp hits, almost liquid.

One of the cars in question did not have HDs available for its chassis so it got regular twintubes, but fortunately they didn't have that kind of damping strategy either.

I am following to find out how nice the Special Actives are... my only experience with Konis is with yellows and they very much had trapdoor damping.

I stopped reading near the top with comments saying no.

You most definitely can if you choose a coilover that will let you choose the appropriate rates. However, I doubt you want you want to spent $2k+ for coilovers on a car approaching 20 years old.

z31maniac said:

However, I doubt you want you want to spent $2k+ for coilovers on a car approaching 20 years old.

 

2023-2016 = 7 years old ;)

In reply to Slippery :

It is still technically approaching 20 years. It just has a little way to go.

In reply to Keith Tanner :

Touche :)

Slippery said:

z31maniac said:

However, I doubt you want you want to spent $2k+ for coilovers on a car approaching 20 years old.

 

2023-2016 = 7 years old ;)

Whoops! That's my bad. For some reason, I read it as 2006. 

But the point still stands, the appropriate rates and damping can make the car incredibly comfortable without giving up performance. 

In reply to z31maniac :

The more limited the wheel travel is, the less true that becomes.

Driven5 said:

In reply to z31maniac :

The more limited the wheel travel is, the less true that becomes.

This is why you buy quality coilovers that have shorter body so it can still retain travel. Trust me I'm aware. I've owned 7 cars on coilovers and tracked another.

But quality coilovers don't come cheap.

If ride compliance is all you want, DEFINTELY get away from the 45 series sidewall Run Flats. RF tires ride harsh to start with, and only get worse the shorter the sidewall.

225/45/18 means the 17 should be a 225/50, dropping the width a little gets you a 205/55/17. gains you an additional 1/2" of sidewall and staying away from performance oriented tires will significantly improve ride quality.

bobzilla said:

... staying away from performance oriented tires will significantly improve ride quality.

I once had two sets of tires that I'd swap back and forth on a Miata. One was 195/60-14, the other was 205/40-17. The 17s rode far better because they weren't trying to win an autocross and thus had some compliance in the sidewalls.

z31maniac said:

Driven5 said:

In reply to z31maniac :

The more limited the wheel travel is, the less true that becomes.

This is why you buy quality coilovers that have shorter body so it can still retain travel. Trust me I'm aware. I've owned 7 cars on coilovers and tracked another.

While it may be as simple as using quality coilovers for some cars, it is not for others. Based on my experience custom specing an atypical set of coilovers for the preceding chassis, these cars tend to fall into the latter category. 

Shock travel is but one potential wheel travel constraint, as I've seen some owners of 'quality' coilovers find out the hard way.

Driven5 said:

z31maniac said:

Driven5 said:

In reply to z31maniac :

The more limited the wheel travel is, the less true that becomes.

This is why you buy quality coilovers that have shorter body so it can still retain travel. Trust me I'm aware. I've owned 7 cars on coilovers and tracked another.

While it may be as simple as using quality coilovers for some cars, it is not for others. Based on my experience custom specing an atypical set of coilovers for the preceding chassis, these cars tend to fall into the latter category. 

Shock travel is but one potential wheel travel constraint, as I've seen some owners of 'quality' coilovers find out the hard way.

That's true. The wheel travel thing is dependent on so many things as well. Have they gone wider and/or used an offset to push the tire closer to the fender, camber settings,  etc. 

The correct shock travel is the one that allows you to use the maximum amount of available wheel travel. Get everything else sorted, then you can specify the correct shock body length. You can't do it before that because you'll either be leaving suspension travel on the table or you'll be experiencing other effects like tire rub.

It's one of those things that some people try to make out like it's difficult rocket science, but it isn't. It's just a matter of measurement.

Keith Tanner said:

The correct shock travel and body length is the one that allows you to use but not exceed the maximum amount of available wheel and spring travel from ride height.

FTFY

Coil length (travel/bind) is a major constraint when (lack of) strut clearance pushes the lower perch to sit above the tire even for 'race' type springs. That type of measurement testing also takes more effort on strut cars.

For example, the front of my BMW has 130mm travel (slightly less than stock) shocks with 5k springs minimally preloaded and 20mm bunp stops. Ride height isn't much lower than stock sport suspension, and I wouldn't want it any lower (nor increased bump travel) for steered clearance reasons.

While I could have gone with 150mm travel (slightly more than stock) and longer bodies with my 5k springs (or even 4k with ~23mm of preload for a softer ride), there is not enough strut clearance to accept springs long enough to avoid coil bind without lifting the car above even stock non-sport ride height.  The only way to bring it back down and allow shorter coils and bodies, would be through significant factory style (extra long/progressive) bump stop tuning. That would subjectively be a large effort for little gain. And even then, if it had additional steered bump interference from increased available bump travel, that would drive at least a somewhat increased ride height too.

Those are other aspects of suspension travel/rate selection that are rarely discussed: How much steering angle vs bump travel to account for, how much bump travel as a function of static spring deflection to target, and how much preload as a function of static spring deflection is acceptable.

Whoever is doing the measurement testing also needs to not to cut the clearances too close, to account for the deflections that occur as the various dynamic driving forces affect deformable components.

It may be 'just' measurements and math, but it also takes above average knowledge and resources to understand how all the parts interact, to take all of the right measurements for a given suspension, and do all of the right math to give the right answers... And even then, plenty of knowledgeable people have failed to get it right, especially on the first try.

Edited for elaboration.