A discussion on improving ride quality

[EAGLE5]

The body is already pretty darn stiff.

[mav1178]

I'm probably doing this wrong.

I put on Ohlins. No other suspension mods, maybe some chassis bracing.
I drive all around Los Angeles with my 18" VS-XX.
I have no issues with bad roads, I've seen a ton of them.

Am I missing something here? Why the wildly differing types of suspension combinations and trial & error?

-alex

[Ubersuber]

Originally Posted by mav1178

I'm probably doing this wrong.

I put on Ohlins. No other suspension mods, maybe some chassis bracing.
I drive all around Los Angeles with my 18" VS-XX.
I have no issues with bad roads, I've seen a ton of them.

Am I missing something here? Why the wildly differing types of suspension combinations and trial & error?

-alex

Since Ohlins make some of the best and most sophisticated dampers available for a road car I don't think you're missing anything. Heck, put them on a Volvo and see what happens!

http://www.polestar.com/en-int/perfo...r-concept-car/

[RYU]

I'd love to buy you a burger for a ride in your car.

Originally Posted by mav1178

I'm probably doing this wrong.

I put on Ohlins. No other suspension mods, maybe some chassis bracing.
I drive all around Los Angeles with my 18" VS-XX.
I have no issues with bad roads, I've seen a ton of them.

Am I missing something here? Why the wildly differing types of suspension combinations and trial & error?

-alex

[pantdino]

I have been driving an E36 M3 every day for 14 years and am no stranger to sports cars, but after about a month and a half of '13 FRS ownership I think I have figured out why I find its ride uncomfortable.


I am used to having the seat bottom pushed against me when I hit a bump or travel over slightly uneven roads. What I am NOT used to is then having the car fall away from me and having the seat belt / harness pull me into the seat like I'm flying and the aircraft just hit an air pocket and dropped from under me.


With my other cars if you are on the freeway and the road surface drops half an inch the suspension allows the wheels to extend and the body then catches up a fraction of a second later, softening the shock. With the FRS it's like the body of the car INSTANTLY drops, so you are jerked downward by your seatbelt.


Honestly it reminds me of my vintage racer, which basically has a suspension so stiff it hardly functions at all. On a billiard table smooth surface that's fine, but for a daily driver its really uncomfortable.


How can the rebound stiffness be decreased on these cars?

[Trettiosjuan]

A: Drive faster (lot of people drive to slow over bumps for the suspension to get working)
B: Harder springs (but then compression will suffer, compression damping is already rather stiff)
C: New adjustable shocks (the only real solution) but unless tuned very well, you'll lose body control...

[Ubersuber]

I found the Bilsteins improved this aspect of the ride considerably.

Prior to fitting them I found myself bracing myself back into the seat when driving over frost heaving or bump strips. I noted the same phenomenon of pitching, or excessive rebound rate, as you have.

This would be why driving faster eases the symptom somewhat, mind you this has to be very fast to address the problem.

It isn't just a ride issue, this affects cornering grip in bumpy conditions also.

[wparsons]

Originally Posted by Ubersuber

These cars have insufficient power to hop a wheel otherwise.

If there is enough power to spin the tires, then you have the possibility for wheel hop. I've seen a lot of 100hp FWD cars get nasty wheel hop. There is also a few threads on here about which bushings to replace to reduce wheel hop.

Originally Posted by Ubersuber

It's possible Subaru deliberately underdamped the rear to allow a drift to be more easily provoked.

You should do your homework before stating things as fact. Stiffening rear compression or rebound will make the car more prone to oversteer, so if Subaru really did intentionally give it softer damping it was to make it more understeer biased.

[pantdino]

Originally Posted by Ubersuber

I found the Bilsteins improved this aspect of the ride considerably.

Prior to fitting them I found myself bracing myself back into the seat when driving over frost heaving or bump strips. I noted the same phenomenon of pitching, or excessive rebound rate, as you have.

This would be why driving faster eases the symptom somewhat, mind you this has to be very fast to address the problem.

It isn't just a ride issue, this affects cornering grip in bumpy conditions also.

Is the problem primarily in the rear? I hadn't really thought about it but it does seem the jerking motion comes mainly from the rear. One sits so far back in this car it would affect one disproportionately.


If so, could one start with replacing just the rear shocks?
Any specific Bilstein shock you recommend?

[Fastbrew]

I am really pleased with my FEAL 441s. I dropped just less than an inch. They have swift springs. They are 7K front 6K rear. They are 30 click one-ways with the adjustment primarily weighted to droop. I find that they are plenty "comfortable" for DD at the lowest settings and plenty stiff at the highest settings. They were 1350 for a set and Odi can service them here in the states in less than a week. There are many choices out there but I am pleased with mine for what I was expecting.

[wparsons]

Originally Posted by pantdino

Is the problem primarily in the rear? I hadn't really thought about it but it does seem the jerking motion comes mainly from the rear. One sits so far back in this car it would affect one disproportionately.


If so, could one start with replacing just the rear shocks?
Any specific Bilstein shock you recommend?

I wouldn't listen to his suggestions too much... he thinks he knows more than everyone about handling/suspension/everything.

If you want reliable advice, talk to the guys at CSG, RCE, etc. They're knowledgeable and have experience to back it up.
@CSG Mike @Racecomp Engineering @ZDan

[gramicci101]

Originally Posted by pantdino

Is the problem primarily in the rear? I hadn't really thought about it but it does seem the jerking motion comes mainly from the rear. One sits so far back in this car it would affect one disproportionately.


If so, could one start with replacing just the rear shocks?
Any specific Bilstein shock you recommend?

Check out CSG's & RCE's suspension Q&A thread for actual suspension advice from actual experts with actual testing and track experience. You'll get a lot farther with them than you will with someone who makes up contrary nonsense just to sound knowledgeable.

At a beginner level, the main problem with our suspension is that the springs are too soft for the struts, so they're being overpowered by them. RCE, Swift, Hotchkis, etc... all make springs that are a much better match for the OEM strut and work to solve a lot of the issues we have from the factory. People report a much smoother ride with just upgraded springs, because now the spring and strut are working together instead of fighting each other.

[EAGLE5]

Originally Posted by gramicci101

At a beginner level, the main problem with our suspension is that the springs are too soft for the struts, so they're being overpowered by them. RCE, Swift, Hotchkis, etc... all make springs that are a much better match for the OEM strut and work to solve a lot of the issues we have from the factory. People report a much smoother ride with just upgraded springs, because now the spring and strut are working together instead of fighting each other.

You're the first person I've seen say it that way. Why? I thought there was only a little wiggle room until the stock struts started blowing with stiffer springs. I also don't see how the spring softness is an issue. Well, I would like stiffer springs because I bottom out here and there, but these are corners where most stock cars would bottom out.

Not attacking or saying you're wrong. Just wanna know your answers.

[gramicci101]

Originally Posted by jsimon7777

You're the first person I've seen say it that way. Why? I thought there was only a little wiggle room until the stock struts started blowing with stiffer springs. I also don't see how the spring softness is an issue. Well, I would like stiffer springs because I bottom out here and there, but these are corners where most stock cars would bottom out.

Not attacking or saying you're wrong. Just wanna know your answers.

I haven't heard of the OEM struts blowing with new springs unless the springs lowered too far. And then only because there was no travel left in the strut and it would bottom out hard. I've not seen any complaints from something like RCE yellows or Swift sports. Doesn't mean there isn't anything, I just haven't heard about it.

Normally on compression the spring absorbs the impact and the strut moderates that movement by forcing oil through its valves, putting drag on the spring. On rebound, the spring expands and pushes the strut out with it. The strut again forces oil through its valves and moderates the spring's motion through drag.

With overly powerful struts, the spring can't absorb the impact as well because the strut is putting too much drag on its movement. So, the initial bump gets more firm. On rebound, the spring is not strong enough to push the strut out like it's supposed to, so the suspension stays compressed longer. This works the same where the road drops out from under you, such as potholes. All of a sudden the suspension needs to expand and it can't because the strut is holding it back. People in stock class autocross will manipulate this effect, because they're required to keep OEM springs. They get struts that are much more powerful, effectively making the springs useless and the struts are the suspension.

For us normal types, we need springs that are matched to their struts. OEM struts with RCE Yellows, or Bilstein struts with RCE Tarmacs, or something to that effect. Decent coilovers are even better, because instead of being closely matched separates, they are perfectly matched for each other.