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Yes, I have experimented with a softer swaybar settings and less compression/rebound on the Ohlins, but when using Hoosier race tires, the car does want to roll due to the sticky tires. Hoosier even recommends, -3.0 camber, stiffer swaybars settings, stiffer springs, to keep the tires flat on the surface of the track. So, I am drifting towards those settings, but still using my car daily. Changing the swaybars to a stiffer f & r setting definately changes the roll center. Its like changing the spring rate a little stiffer, but it only works a smooth tracks. Bumpy tracks require softer springs and swaybar settings. I really don't want to go that direction, so I will bandaid the spring rate on bumpy tracks and back country roads. I have found that using my OEM wheels and Michelins PS4's with spacers to the fender lips give a good ride even in those conditions. The weight of the wheels/tires/spacers and the fulcrum effects of the spacers/weight on the springs allow for a smoother ride.
 

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Wouldn't adjustable GT3 sway bars help adjusting sway bar strength ?
 

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Some tires require more camber due to their softer spring rate and tire side wall construction, ie, Hoosier A7s. Bridgestones RE71R's have a more robust sidewall construction so they certainly can be used with softer adjustable roll bar, letting the tires sidewall work more in the turns to keep the tire tread in contact with the track surface. Hoosiers with softer sidewall and overall makeup require less body roll and higher tire pressure to maintain a good contact patch. The Michelin's PS4s are in between the Hoosiers and RE71Rs as sidewall construction and overall construction makeup. The Michelins are not a race tire, their breakaway on the slip angle is much more peaked, while both the Hoosiers and RE71R's give the driver a rounded slip angle curve to work with before a snap oversteer occurs.
 
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Discussion Starter #125
Wouldn't adjustable GT3 sway bars help adjusting sway bar strength ?
Yes, GT3 sway bars do allow you to go a little stiffer as well as balance front to rear. I have a GT3 front swaybar and a Tarett GT3 style rear bar.

This is why we use SPL LCAs; roll center adjustment as well as anti-squat and anti-dive adjustment.
Those certainly look nice and looks like there's a good amount of adjustability in the ball joint. Knowing what I know now I may have gone that route.

I don't think I ever mentioned how my experience with speaking to SPL ended. I spent about a month of back and forth with them and never ended up with a working product for my car. I am not sure how much longer it would have taken to get there. Overall they were friendly and tried to help but it took too long and too many revisions. I ended buying Tarett links and they work fine out of the box with the high misalignment spacers. If SPL sold the drop links as two separate kits (F/R) and packaged the front with shorter center sections and high misalignment spacers they would probably work just fine. I am using their links on the rear still, and now have a second brand new set sitting in my garage... they said they couldn't help me get a refund even though this set is brand new and sealed still. Sucks, but I get it.
 

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We have the LCAs in stock if you ever need them!

We've been working with their engineering department on endlinks. There's upper management resistance to multiple front endlinks for our cars. They make custom stuff but they really just need to add one more part number..

We use the SPLs on 987s with Tarett adjustable sways front and rear no problem. In fact that's what I have on my car. However, there are swaybars that the front links are too long for.

Yes, GT3 sway bars do allow you to go a little stiffer as well as balance front to rear. I have a GT3 front swaybar and a Tarett GT3 style rear bar.



Those certainly look nice and looks like there's a good amount of adjustability in the ball joint. Knowing what I know now I may have gone that route.

I don't think I ever mentioned how my experience with speaking to SPL ended. I spent about a month of back and forth with them and never ended up with a working product for my car. I am not sure how much longer it would have taken to get there. Overall they were friendly and tried to help but it took too long and too many revisions. I ended buying Tarett links and they work fine out of the box with the high misalignment spacers. If SPL sold the drop links as two separate kits (F/R) and packaged the front with shorter center sections and high misalignment spacers they would probably work just fine. I am using their links on the rear still, and now have a second brand new set sitting in my garage... they said they couldn't help me get a refund even though this set is brand new and sealed still. Sucks, but I get it.
 

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Discussion Starter #127 (Edited)
We have the LCAs in stock if you ever need them!

We've been working their engineering department on endlinks. There's upper management resistance to multiple front endlinks for our cars. They make custom stuff but they really just need to add one more part number..

We use the SPLs on 987s with Tarett adjustable sways front and rear no problem. In fact that's what I have on my car. However, there are swaybars that the front links are too long for.
Haha I will definitely keep it in mind.

Mind if I ask what your full suspension setup and specs are? Ride height and rake, too?
 

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Our custom Ohlins Track Package with 400/500 springs. SPL LCAs front and rear. SPL bump steer correcting TREs. SPL Toe links. Tarett top mounts. Tarett GT sway bars with SPL drop links.
-2.5 camber and zero toe.
Ride height is 25"/25.75"
I have a 550/650 spring and valving package going on after testing this weekend.

Haha I will definitely keep it in mind.

Mind if I ask what your full suspension setup and specs are? Ride height and rake, too?
 

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Discussion Starter #129
Our custom Ohlins Track Package with 400/500 springs. SPL LCAs front and rear. SPL bump steer correcting TREs. SPL Toe links. Tarett top mounts. Tarett GT sway bars with SPL drop links.
-2.5 camber and zero toe.
Ride height is 25"/25.75"
I have a 550/650 spring and valving package going on after testing this weekend.
You'll have to let us know how that stiffer springrate feels. I may send my Ohlins off to you to revalve when I've run out of personal improvements in the short term haha.

Where are you measuring ride height at?
 

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They work great. I have been running our light springs for some testing to see if we want to continue to offer the light spring package.

We offer springs and valving for:
458/572
516/630
572/687

 

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Discussion Starter #132 (Edited)
Today I moved my ride height back up quite substantially. I was trying to decide where to put it, and in the end, I figured I'd just move it back up to what Ohlins specified in their install guide. I opened that up and realized that they must have swapped the measurement for the ride height between the 986 and 987 in their instructions. They specify a gap (between the preload lockring/height adjuster ring) of 59mm in the front and 105mm in the back. That cannot possibly be right for their description of "lowered approximately 20mm" because my car was a lot lower than that, and that measurement was pretty close to what I already had. Their recommendations for the 986 are 80mm in the front and 130mm rear which does actually correspond with about a 20mm drop in the 987. That's about what I have mine set at right now.

See here for the manual I am referencing: https://www.ohlins.com/app/uploads/world/2017/10/MI_POSMR80-1.pdf

I'll also attach the pages I am talking about. This mixup does make me wonder about their specified preload, now. If the heights were swapped then possibly the recommendation for 15mm of preload over 2mm of preload is also true? Josh, what do you think about all of this?

Here's what my LCAs look like at rest now. My phone told me I was holding it at a level 0* so it should fairly closely represent their actual angle. I spoke to Mike at RSS and he said they don't recommend changing from the 2 spacers on top 2 spacers on bottom of the ball joint which is how I have it now. I guess it stresses the pin too much. But then, I wonder how they get away with saying the roll center height on their LCA is adjustable... directly from their website "Adjustable Suspension Geometry: Adjust dynamic camber values and roll center heights with our unique zinc plated steel bushings." 361 RSS Front Lower Control Arms (987, 997/991 C2, C4, Turbo, 981/982/718)

Am I missing how you would otherwise adjust the roll center? It seems like false advertising.




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So my rear height adjuster and sleeve clamp are approximately 15mm up the barrel than standard. Part of this is due to corner balance and my wishes to get more rear traction, like the 911's. I still have rake, but not as much as you most likely. This just provides more forward bite especially now with the Wavetrac LSD. This setup also puts the adjustment knob close to the half shaft billows, I still have space for my thumb twisting the knob.
 

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Discussion Starter #134
Headed out for another day at Thunderhill East tomorrow! Got my ride height set at 350mm front 360mm rear to get those LCAs pretty close to level with the ground. Alignment guy who has been racing for a long time approves. With this new higher ride-height I need more shims for my front LCAs as I could only get -2.6*F camber, I have also got -2.3*R. It could be a little bit understeery with this setup and I may be riding the outside of the NT-01's more. Just going to have to watch the tire temps and see how it feels. I can adjust the swaybars for now if it's understeering too much.
 

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So, how did it go with a higher ride height with the center of gravity a little higher? More weight transfer across the car relying on your swaybars a little more to keep the horizon level? Just wondering why there is such a big deal about the angle of the LCA's? What I found to be effective is increase the rebound rate to 3 f and 4 r. This makes the shocks work more, but it adds to the springs in controlling the compression as well as the rebound, so a flatter car, especially in tight 180 degrees corners. I'm running -2.9f and -2.5r, past weekend with RE71R's seemed to grip nicely. This setup works only on a relatively flat track. On a bumpy track, I would allow the shocks to work more with lower settings, even so, I have yet to bottom out with the standard Ohlin spring rate and my lowered car.
 

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Discussion Starter #136
The sessions I did get went well! Unfortunately someone inadvertently started a grass fire so I really only got a half day. It was HOT out, too.

I definitely need that camber up front. My tire temps were perfectly even across the tire last time. This time they were about 20* hotter on the outside. To counteract the lack of front camber I had to move the rear sway up two holes, too. Definitely missing a little grip.

I definitely will start playing more with the damper settings next time. I have still been trying to learn the car and I'm starting to put down some good laptimes now.

The idea behind raising the ride height is to get roll center higher. As I understand it, when your roll center is below ground level it start to affect your effective spring rates. You need stiffer springs to counteract this (there is a lot more to it, and some good articles online). Your roll center is a measure of a few angles but an easy way to tell if it's underground is if your LCAs are inverted at ride height. Also, in general, without some more major modifications (mount points for example) substantially lowering MacPherson suspension from it's optimal range will affect handling negatively. It's a balancing act. Check out what kind of setups the spec Boxters/Caymans have. They don't go very low.

I'd say overall the car behaved better today and felt flatter in the corners.
 

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I get what you are talking about, but from my readings, as long as the car is not bottoming out, the spring rate is enough to keep the shocks in their working zone. As far as the inverted LCA's, yes I can see that mine are not level, however the spring rate is enough to keep the suspension from changing camber or toe a lot. The Tarett Cup LCA's basically keep the alignment consistent due to the solid Red thrust bearing, so nothing moves around. Also because of the inverted LCA's. I did have the Elephant toe links adjusted (bumpsteer) to that same angle as the LCA's. Again, keeping a parallelogram between the LCA's and the rear toe links. In front I had Cantrell measure the steering link angle at rest and adjust the via the bumpsteer adjustment on the front link to level.

So, I am interested in how you achieve -2.9 or so camber. You certainly could use camber plates to help. I had Cantrell slot the adjustment holes to allow for -4 degree more camber. They really did not want to do this, but they also agreed that camber plates do rattle after a couple of years, The end result is with -1.7 degrees from the stock front camber adjuster, and -1.2 from the LCA shims, I arrive at -2.9 camber and 8.2 caster. I tried to get them to reduce the caster to 7.9 but it maxed out at 8.2 with the drop in ride height.

Lastly, my rear end is not too far from the track in the drivers seat, so I can sense the suspension/tires sidewalls and traction patch a little better than with a taller ride height. This seems to be exaggerated with the Wavetrac pulling traction from the unloaded side to the weighted side, ending up with better forward thrust out of the corners and virtually no toe steer. So, I can hammer the throttle just before the apex, after trailbraking and the rear tires just bite. This does have some understeering effects so I do take the 180 degree corners with a wider arc on the exit. The tires do not seem to be chattering or anything, just a slightly larger steering angle is needed to point the front in.
 
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Discussion Starter #138
So, I am interested in how you achieve -2.9 or so camber. You certainly could use camber plates to help. I had Cantrell slot the adjustment holes to allow for -4 degree more camber. They really did not want to do this, but they also agreed that camber plates do rattle after a couple of years, The end result is with -1.7 degrees from the stock front camber adjuster, and -1.2 from the LCA shims, I arrive at -2.9 camber and 8.2 caster. I tried to get them to reduce the caster to 7.9 but it maxed out at 8.2 with the drop in ride height.
Sometime this weekend I am going to get under the car and see if I have enough threads left to put some more shims in. If I do, I'll go that route. If not, I may take my dremel to the adjustment holes like you did.

This is all a learning process for me so I am going by my reading, the professionals I have to speak to, and the feel/laptimes I'm coming out with. So far I am happy with it but of course I can keep adjusting to my heart's content if I decide to drop it again. :)
 

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I didn't know it was common to slot the adjustment holes. I was told with my 1st Boxster S in 2000 that you can't or shouldn't do it. Guess I wasn't nuts to do it. To me at the time it was a free easy way to get adjustment without buying a bunch of expensive things.
It's interesting to read the things you all are doing & trying. Thanks for the informative posts. I'm sure others are gaining from them also.
 
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Discussion Starter #140
I didn't know it was common to slot the adjustment holes. I was told with my 1st Boxster S in 2000 that you can't or shouldn't do it. Guess I wasn't nuts to do it. To me at the time it was a free easy way to get adjustment without buying a bunch of expensive things.
It's interesting to read the things you all are doing & trying. Thanks for the informative posts. I'm sure others are gaining from them also.
It's probably not the best practice but it does work. Since I already have adjustable LCAs, I am hoping I can just fit some more shims though!

I'm glad you're enjoying the thread, hopefully, it does help someone out. I certainly have learned a lot through all of this, and I'm barely scratching the surface. Having a good time doing it though.

Unrelated but I'll dump a little more info I just remembered. I did a bump steer measurement front and rear and replicated the results in the below thread I am linking. I've also got about the same ride height F/R as him, and found the least variation in toe change was with the spacers all on the bottom, meaning putting the link as close to the mount point as possible. Seems like this thread didn't get much attention but it has some great info for people with similar setups.

 
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