New Öhlins, should I also upgrade Sways?

[Robert986]

On my 986s I run R-comp tires and there is a considerable body roll on track. The shocks are Bilstein B8 but I think the springs are a bit too high and soft.

So, this winter I´ll be putting on Öhlins R&T coilovers and adjustable toelinks, I already got the front GT3 LCA:s and solid caster adjusters but will now change out the inner rubber on the LCA:s for solid versions. I will do the installation job myself but will let a qualified race-shop do a corner balance and setup, no reason to use good components if they aren´t setup in the best way I think..

So, the question: While I´m at it, should I also upgrade swaybars to adjustable versions so the race-shop can tweak this? I now have the OEM 986s versions. I´m sure the car will get a lot more stable with the Öhlins but will I still benefit from the possibility to tweak in stiffer sways?

I have searched the forum and found that GT3-bars in the front and Tarett in the rear might be a good option, anyone knows?

[SCCA_AX]

I think the best answer is "it depends." Suspension setup is a bit of a dark art as there's a LOT of situational and driver preference involved. Some people like a lot of swaybar on one (or both) ends, but it's more typical to have the springs do most of the work and think of swaybars as "seasoning" or fine tuning.

The big benefit to adjustable swaybars is a no-fuss easy adjustment at the track. Swapping springs or changing alignment based on conditions is typically not practical. Moving two endlinks a hole or two though is comparatively simple.

Do you have the desire, and the know-how, to constantly tweak the car based on track / surface / tire / weather conditions? If so, adjustable bar(s) may be a worthwhile investment. If you just want to drive the car as-is, then probably not.

The Ohlins setup - and especially the camber you're going to add - is going to dramatically change the car. If it were me, I'd drive the car with just those changes, and see if I'd like a change in balance after. You can change both swaybars without disturbing the alignment or corner balance, so one or both is an easy add after.

My $0.02, which is free, and therefore worthless.

[Robert986]

Originally Posted by SCCA_AX

I think the best answer is "it depends." Suspension setup is a bit of a dark art as there's a LOT of situational and driver preference involved. Some people like a lot of swaybar on one (or both) ends, but it's more typical to have the springs do most of the work and think of swaybars as "seasoning" or fine tuning.

The big benefit to adjustable swaybars is a no-fuss easy adjustment at the track. Swapping springs or changing alignment based on conditions is typically not practical. Moving two endlinks a hole or two though is comparatively simple.

Do you have the desire, and the know-how, to constantly tweak the car based on track / surface / tire / weather conditions? If so, adjustable bar(s) may be a worthwhile investment. If you just want to drive the car as-is, then probably not.

The Ohlins setup - and especially the camber you're going to add - is going to dramatically change the car. If it were me, I'd drive the car with just those changes, and see if I'd like a change in balance after. You can change both swaybars without disturbing the alignment or corner balance, so one or both is an easy add after.

My $0.02, which is free, and therefore worthless.

Thanks a lot!

"Do you have the desire, and the know-how, to constantly tweak the car "
-Must say no to this one..

So to enable corner balance I need at least adjustable droplinks I guess, but then I think I start with the OEM sway bars and let the Öhlins do the heavy lifting :-)

[SCCA_AX]

This is more nit-picky than anything else, but you can definitely corner balance a car without adjustable drop links. You (maybe) can't have a corner balanced car with no preload in the swaybars though. That's more being pedantic than anything else.

Corner balancing is like fixing a wobbly chair. Raise the low corner. Since a car is on moving suspension, and it's not perfectly symmetrical, you need scales and you get the cross weights to add up, but it's pretty much the same thing conceptually. It makes the car handle as equally as possible in LH turns as it does RH turns.

It's nice to have done, but it's not magic. It's really only noticeable if you happen to set it up initially really wrong, or you are a very observant driver.

The stiffer the springs, the easier it is to screw up the corner balance.

[Robert986]

A follow up question..

With adjustable sway bars you can tune in under-/over steering, since the Öhlins got easily adjustable damping, would it be possible to do a similar tune with this? Eg making them stiffer in the rear to reduce understeer just like adjusting swaybars.. What´s the therory on this?

[SCCA_AX]

Well, kinda, but no? Every component has a very generalized "more oversteer" and "more understeer" setting, but how and when they act is important to understand.

- Springs control how much force it takes to compress the suspension (bump, lateral load)
- Swaybars are springs, but they only work with lateral suspension deflection differential (lean, one wheel bump)
- Shocks control the rate of movement of a suspension

Examples of how to think about it:

Heading down a straight and getting on the brakes, all the load on the car is transferring to the front. The springs handle how far the nose dips, the shocks handle how long it takes for the nose to dip, and the swaybars are doing nothing.

If you're on a flat skidpad, going constant speed, the car is set and the suspension isn't moving, so the shocks have zero input on the balance of the car. That's spring, bar, and alignment. A sweeper on a track is not far off from a skidpad.

Shocks have a large input on the balance of the car when the suspension is moving - bumps, obviously, but also turn-in and corner exit. Something like a chicane where the car is in left to right to left transition for a long time is where shock tuning is super important to the balance of the car.

Sounds daunting, and if you have tons of adjustments on your car, it is very difficult to recognize which is the right one to change and when. Fortunately, with an off-the-shelf engineered package like the Ohlins, it's pretty hard to end up too screwed up. Just set all 4 shocks in the middle and focus on the driving.

[Robert986]

Originally Posted by SCCA_AX

Well, kinda, but no? Every component has a very generalized "more oversteer" and "more understeer" setting, but how and when they act is important to understand.

- Springs control how much force it takes to compress the suspension (bump, lateral load)
- Swaybars are springs, but they only work with lateral suspension deflection differential (lean, one wheel bump)
- Shocks control the rate of movement of a suspension

Examples of how to think about it:

Heading down a straight and getting on the brakes, all the load on the car is transferring to the front. The springs handle how far the nose dips, the shocks handle how long it takes for the nose to dip, and the swaybars are doing nothing.

If you're on a flat skidpad, going constant speed, the car is set and the suspension isn't moving, so the shocks have zero input on the balance of the car. That's spring, bar, and alignment. A sweeper on a track is not far off from a skidpad.

Shocks have a large input on the balance of the car when the suspension is moving - bumps, obviously, but also turn-in and corner exit. Something like a chicane where the car is in left to right to left transition for a long time is where shock tuning is super important to the balance of the car.

Sounds daunting, and if you have tons of adjustments on your car, it is very difficult to recognize which is the right one to change and when. Fortunately, with an off-the-shelf engineered package like the Ohlins, it's pretty hard to end up too screwed up. Just set all 4 shocks in the middle and focus on the driving.

Great, thanks a lot again for you insights, great explanations, this is really interresting but I guess I´d need ny own test-track and a lot of time to really learn. Fortunately the shop I´m using for setup are top notch so I won´t tweak it myself :-)

[DarrenD]

I just installed Eibach anti-roll bars on my '99. I run Hankook RS-4's at the track and stock dampers and springs. I have about 20 years of racing/tracking/autoX experience. Just the addition of the anti-roll bars made the car handle fantastic. It didn't hurt the ride, it significantly reduced roll, and it turned the car into a precision instrument. I did a back-to-back at our local track and while the car was fantastic before(for a stock car), it was just so much better after. My ability to place the car EXACTLY where I wanted to with no understeer was incredible. I am currently waiting on a set of Koni Special Actives. They are by no means a track damper like an Ohlins but my car is mostly a top down cruiser and my wife loves it so I couldn't go too track focused. Truly I don't care. Having had many dedicated track cars, I've been there and done that. The Boxster handles beautifully out of the box(no pun intended) and rides great. Adding the Anti-roll bars was the icing on the cake. At our local PCA events at Mosport, I routinely out brake and out corner many, much faster cars. The Boxster is a fabulous track weapon made even better with some stiff sway bars.

[pilot4fn]

This was fantastic info, thank you. I'm planning on similar improvement as I do track the car also few times a summer.
Were there some optional Eibach arb specs that you installed or do they carry only one spec for the front end and another to the back end?

Originally Posted by DarrenD

I just installed Eibach anti-roll bars on my '99. I run Hankook RS-4's at the track and stock dampers and springs. I have about 20 years of racing/tracking/autoX experience. Just the addition of the anti-roll bars made the car handle fantastic. It didn't hurt the ride, it significantly reduced roll, and it turned the car into a precision instrument. I did a back-to-back at our local track and while the car was fantastic before(for a stock car), it was just so much better after. My ability to place the car EXACTLY where I wanted to with no understeer was incredible. Adding the Anti-roll bars was the icing on the cake.

[ike84]

Sway bar upgrades have been extensively covered in the past on this forum. Eibach, gt3, stock front with rear removed, and the interactions of these with different sized tires, ride height etc. Before you go and drop the cash, I would first encourage examine your driving style and ask what you want to accomplish. Don't just get a gt3 or eibach front bar and throw it on there because you can. Match the setup to how you drive the car, or rather, how the car drives with you behind the wheel.

For example, if understeer is your issue, that can be fixed easily with 225 front tires. Also, disconnecting the rear sway bar will do the same. If your steering is good but you want to reduce roll, go bigger on the front but be mindful that it will introduce understeer, potentially necessitating other changes.

Just my 2c



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[joliver3]

Originally Posted by ike84

For example, if understeer is your issue, that can be fixed easily with 225 front tires. Also, disconnecting the rear sway bar will do the same.

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Disconnecting the rear sway bar will increase understeer, not reduce it.

[ike84]

Originally Posted by joliver3

Disconnecting the rear sway bar will increase understeer, not reduce it.

Ahh, you are correct. I meant to stay that disconnecting the rear will reduce oversteer. Sorry about that.

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[DarrenD]

Eibach only has one spec BUT the rear is adjustable with 3 different positions. I have only run the centre hole at this point but come springtime I plan on trying each position during the same track day to feel the differences. I prefer a car that is neutral with a bias towards slight oversteer. Based on my initial impressions with the bar at the centre hole, the car was very neutral and easily steered with the throttle. Want to tuck in? back off the gas a hair. Want a touch of oversteer? Gas it hard. But it's so easy to control and place the car. The sway bars made what I already considered magical steering just that much better.
It should also be noted I run 1.5 degrees of negative camber all the way around with 1/32" toe out in the front and 1/32" toe in the rear. I plan to run 2 degrees negative in the front this season based on my tire wear.
I can't wait to try the car with the Koni special active's and slightly stiffer "S" springs. I was struggling at Mosport to get the car to settle at initial turn-in, it just didn't want to take a "set". I'm hoping the new setup will help with that.

Originally Posted by pilot4fn

This was fantastic info, thank you. I'm planning on similar improvement as I do track the car also few times a summer.
Were there some optional Eibach arb specs that you installed or do they carry only one spec for the front end and another to the back end?

[pilot4fn]

Fantastic, thank you Darren. I'll try to follow the same as you have done and test it on the track when the snow disappears.

Originally Posted by DarrenD

Eibach only has one spec BUT the rear is adjustable with 3 different positions. I have only run the centre hole at this point but come springtime I plan on trying each position during the same track day to feel the differences. I prefer a car that is neutral with a bias towards slight oversteer. Based on my initial impressions with the bar at the centre hole, the car was very neutral and easily steered with the throttle. Want to tuck in? back off the gas a hair. Want a touch of oversteer? Gas it hard. But it's so easy to control and place the car. The sway bars made what I already considered magical steering just that much better.
It should also be noted I run 1.5 degrees of negative camber all the way around with 1/32" toe out in the front and 1/32" toe in the rear. I plan to run 2 degrees negative in the front this season based on my tire wear.
I can't wait to try the car with the Koni special active's and slightly stiffer "S" springs. I was struggling at Mosport to get the car to settle at initial turn-in, it just didn't want to take a "set". I'm hoping the new setup will help with that.

[steved0x]

Eibach's are pretty stiff, about twice as stiff as the regular boxster swaybars:

Drilling an extra hole in a sway bar end to give a softer setting

The front is comparable to the gt3 front bar in full stiff, and all 3 holes on the rear bar are stiffer than the tarret bar in the stiffest position. In addition, running the softest hole on the eibach with aftermarket drop links may cause contact between the axle and the drop link. I carved a little chunk out of my aluminum drop link bodies. But I may also have had something else wrong as well.

I think that set would help with the stock suspension but might be more than necessary if using the Ohlin's.

I'm running the Ohlin's on my Cayman with tarret bars and it is fantastic, and I also ran the tarret bars on my 986 with sport suspension with Koni FSD/special active and it was really good.

Can't go wrong with the Ohlin's, and if you set the car up with them, and later go with adjustable bars, it shouldn't affect your alignment or corner balance.

[bcrdukes]

@steved0x - Did you run both front and rear Tarret bars on the 986? I picked up a used set from a few Rennlisters. Looking to get a baseline for HPDE this year with local PCA group.

[Van914]

Bcrdukes,
I run the Tarrett bars front and rear with their drop links. I run front bar full soft and the rear in the 2nd hole from fullnsoft.

[j.fro]

For me, one of the biggest benefits of adjustable sways is that they give you quick tuning as the tires age and lose grip.

[steved0x]

Originally Posted by bcrdukes

@steved0x - Did you run both front and rear Tarret bars on the 986? I picked up a used set from a few Rennlisters. Looking to get a baseline for HPDE this year with local PCA group.

On my 986 I ran the following combos with the tarret bars:

M030 sport springs plus Koni FSD
PSS9

Both felt really good.

I ran front bar middle hole, back bar 2nd softest hole. Ended up on both bars 2nd hole from softest.

On my Cayman with Ohlin's, I have the tarret rear bar 2nd hole from softest, and TPC front bar (I believe equivalent to the thicker tarret front bar) also 2nd hole from softest. I think I run the Ohlin's at the softest end of the "track" range, so 7 clicks from full hard?