CSG and RCE tag-team suspension Q&A thread! Ask us anything!

[nikitopo]

Originally Posted by Shark_Bait88

You might also want to check out the single adjustable coilovers from SACHS. Similar price and design to the Bilsteins, but I believe slightly stiffer spring rates. Front springs are linear and rears are progressive on the SACHS, whereas the Bilsteins are progressive in both the front and rear. I had them on my car for a year and really liked them. Felt great for daily driving, even on the garbage roads around Chicago, and performed pretty well during several track days and autocross events.

What coilovers do you have now? Spring rates?

[Shark_Bait88]

Originally Posted by nikitopo

What coilovers do you have now? Spring rates?

Just Konis and stock springs. I went back to a "stock" class for autocross for awhile. (saving for a wedding)

[n0thing]

Originally Posted by strat61caster

...

great video showing fwd vs rwd lifting wheels respectively

[nikitopo]

Originally Posted by strat61caster

Spring rate determines body roll, damping can only mask an inadequate spring rate. Even the old Ohlins were deemed too soft for most performance tires, most people running their cars on track/autox have gravitated to a 7k+ spring rate to handle <220TW tires.

Well, I like to think that springs and dampers work together as a single part and not independently. If they were independent, then why to have adjustments in coilovers? The perfect match would be just one damper setting for the specific springs.

One more information ...
The Sachs suspension in the PP option, was tested with Dunlop Direzza's ZII. These are quite sticky tires and rated at 200TW. I think the issue with most of the track/autox setups is that they are going too wide for the weight of this car (i.e. 235/245 or even more ). This starts to cause suspension geometry issues and body roll and in such cases the only option is to use stiffer springs.

[thetyrant]

Originally Posted by Racecomp Engineering

True but springs and dampers perform different functions.

I think there was a shift in focus but that shift was to move things closer to the "road" part of the spectrum rather than the "track" part of the spectrum in the Ohlins R&T name. Nothing wrong with that, just IMO they might have moved a little too far to the R.

EDIT: and this is a good discussion! I do in general prefer a somewhat softer set-up than others. Dampers can be tuned in such a way to work with that, and it can be awesome for a fast and fun street car. And bonus, it's usually a little easier to drive quickly. But with stickier tires you will have some compromises and firmer springs will be faster.

- Andrew

Yes Im thinking that's what Ohlins were working on but as you say maybe too far, Ive asked the question to my contact who is manager at German HQ so hopefully he can enlighten us and I will also mention how many people liked the previous kits spring rates as well, maybe they didn't sell enough so changed to to try and open it up to more stock cars.


Ive always preferred to run softer than most as don't mind some roll as long as car still has grip and all wheels on ground, bonus is better ride on road as well.

[thetyrant]

Originally Posted by Shark_Bait88

You might also want to check out the single adjustable coilovers from SACHS. Similar price and design to the Bilsteins, but I believe slightly stiffer spring rates. Front springs are linear and rears are progressive on the SACHS, whereas the Bilsteins are progressive in both the front and rear. I had them on my car for a year and really liked them. Felt great for daily driving, even on the garbage roads around Chicago, and performed pretty well during several track days and autocross events.

Yes others have mentioned the Sachs but when I checked prices over here is was near Ohlins money and I know what I would rather have!

[strat61caster]

Originally Posted by nikitopo

Well, I like to think that springs and dampers work together as a single part and not independently. If they were independent, then why to have adjustments in coilovers? The perfect match would be just one damper setting for the specific springs.

There are people who believe precisely that, once dampers are dialed in there's no reason to touch them. I've heard stories of custom valved Koni's having their adjusters glued down after being dynoed.

Springs and dampers are part of a system, they receive inputs and produce outputs no different than a resistor and capacitor if you're electrically inclined.

Edit: I'm too sick to make coherent thoughts about this right now... basically a spring and damper are performing two completely different tasks in a suspension.

[Gforce]

Originally Posted by Tokay444

Taking a tire off the road diminishes your traction by 25%.

You'd think so but it ain't so. Tire loading makes a difference to lateral grip (well contact patch grip technically but for roll effects are talking about lateral grip ).

[Gforce]

Originally Posted by nikitopo

Well, I like to think that springs and dampers work together as a single part and not independently. If they were independent, then why to have adjustments in coilovers? The perfect match would be just one damper setting for the specific springs.

And they do. Nobody fits a spring without a matching damper nor a damper without a spring to damp. There is a surprisingly narrow range of damper/spring combinations that will work well I need any given situation. A wise buyer considers the damper and spring to be one unit. Actually, a wise buyer considers all four springs, dampers and the two roll bars as a single component that must be engineered together.

[Purist]

Hi,

Firstly, thanks so much for offering what amounts to free consulting on suspension. It's really appreciated!

I feel that my 100% stock car is understeering on certain corners at our hillclimb track. The two corners are positioned such that I need to accelerate though them (one just after the start and one at the top of a hill, so I'm not carrying sufficient speed to warrant the hard braking which loosens the rear and helps the car to rotate). The tyres also show wear all the way to the outside shoulder, but nearly 0.5" of unused tread on the inside. The tyres are A050s.

I'm happy with the damping and rebound, I feel like it needs a couple of degrees of camber to help with front end grip on these slower corners. I'd be interested to hear your ideas.

Thanks again

[Racecomp Engineering]

Originally Posted by Purist

Hi,

Firstly, thanks so much for offering what amounts to free consulting on suspension. It's really appreciated!

I feel that my 100% stock car is understeering on certain corners at our hillclimb track. The two corners are positioned such that I need to accelerate though them (one just after the start and one at the top of a hill, so I'm not carrying sufficient speed to warrant the hard braking which loosens the rear and helps the car to rotate). The tyres also show wear all the way to the outside shoulder, but nearly 0.5" of unused tread on the inside. The tyres are A050s.

I'm happy with the damping and rebound, I feel like it needs a couple of degrees of camber to help with front end grip on these slower corners. I'd be interested to hear your ideas.

Thanks again

Yes you could definitely use a good alignment. More front camber...a lot more than stock (hence the worn outside shoulders and unused inners). I would suggest camber plates and rear lower control arms to get everything right. Those tires are pretty sticky/serious so ideally you'd add stiffer springs and bushings if that's in the budget or rules.

- Andrew

[Purist]

Originally Posted by Racecomp Engineering

Yes you could definitely use a good alignment. More front camber...a lot more than stock (hence the worn outside shoulders and unused inners). I would suggest camber plates and rear lower control arms to get everything right. Those tires are pretty sticky/serious so ideally you'd add stiffer springs and bushings if that's in the budget or rules.

- Andrew

Thanks mate. That's pretty much what I thought. I've been told that the OEM springs are too big in diameter to allow enough movement of the strut with a camber plate so looks like its going to be a set of coilovers or nothing.

[nikitopo]

Here is the testing of the Sachs dampers which appeared later in the performance package. As you can see the tires are R-spec tires 215-millimeter front and 225-millimeter rear. It looks that with these dimensions the stock spring rates are fine. Things are starting to go out of spec if you go larger than 225-millimeter.

Following is an excerpt:
"It turns in harder, holds more mid corner speed and has better traction under hard acceleration. It can still be provoked into gentle tail slides but it all happens at much higher speeds than the regular set-up.

The improved suspension settings also play a much greater role as it reaches the limit of adhesion too. There is less body roll and pitch, which helps give it a more neutral handling balance, and the better bump absorption means it doesn't lose traction as easily on rough surfaces or mid-corner irregularities."

Source: http://www.ft86club.com/forums/showp...68&postcount=1

[Gforce]

Originally Posted by Purist

Hi,

Firstly, thanks so much for offering what amounts to free consulting on suspension. It's really appreciated!

I feel that my 100% stock car is understeering on certain corners at our hillclimb track. The two corners are positioned such that I need to accelerate though them (one just after the start and one at the top of a hill, so I'm not carrying sufficient speed to warrant the hard braking which loosens the rear and helps the car to rotate). The tyres also show wear all the way to the outside shoulder, but nearly 0.5" of unused tread on the inside. The tyres are A050s.

I'm happy with the damping and rebound, I feel like it needs a couple of degrees of camber to help with front end grip on these slower corners. I'd be interested to hear your ideas.

Thanks again

Are you sure it's not the Torsen diff developing push? Are you allowed by your Rules to add front negative camber? For your requirements the front axle would benefit from more static front camber. If the surface is loose (paved or unpaved course?) then especially at low speeds with some significant steering lock the Torsen will behave as if it is a pure locker and simply drive the front tires sideways. Even on dry pavement this will occur with significant throttle. The braking you refer to more likely releases the Torsen than allows rotation as you describe. To drift this low powered car you would lift off sharply just as you turn in sharply and then jam the throttle to the floor. I notice other posters think this induces the drift because of the suspension but I think that's how the Torsen operates. Indeed, I think the Torsen Toyota asked Subaru to use has a high bias ratio for this reason.