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I feel like VR is talking about the goal for primary inputs and winders is talking about what's needed for corrections and nobody is wrong but maybe because you are not talking about the same thing?
You are exactly right. I was specifically addressing what Francois said. Which I made clear ...
In an ideal world, pick your initial brake marker, and don't stand on the pedal. Really focus on a less dramatic weight transfer, getting the car to squat on all fours under braking rather than slamming down the nose. And also really focus on purposely using ALL of the flat apex rumble strip. Every single inch. Most folks THINK they are using it, but in reality are barely touching it. As you're going down the downhill brake zone, focus eyes on that apex rumble strip & begin fading off the brake pedal. There may be a very brief moment where the back of the car feels slightly unsettled, but this is actually necessary rotation...and will go away instantly as you approach the apex when you hit the on-camber. Transition to positive throttle and use ALL the apex, and move your eyes ALL THE WAY DOWN to the far end of the track out curbing. If you use ALL of the apex, you can begin unwinding the wheel slowly and EARLY...and by the time you get to track out, you'll be wheels straight and on full throttle. If you don't use all the apex, you'll notice a good degree of steering angle at track out (which slows your acceleration all the way to the Bus Stop, and you may not be able to use full throttle yet. Alternately, if you don't fade off the brakes in time...or if you fade off the too soon...the chassis won't be ready to accept full throttle yet. All of this will affect your MPH into the Bus Stop.
Think of your inputs this way: slow is smooth and smooth is fast . I learned this truism in my first career but it sure as heck also applies to performance driving on track!
Well this seems like a very general statement and not a specific statement for a specific person in a specific situation....but hey, VR is ALWAYS right and I am ALWAYS wrong.....
VR, hoping you can provide some advice and input on setting up a new 3 way suspension based on feel and car behavior (without the use of shock sensors and other advanced telemetry).
Do you have a specific order you prefer to do the setup? IE REB first, followed by LSC then HSC? Or some other order? What are you you specifically looking (or feeling) for when adjusting each setting?
I've recently installed AST 3-way dampers with 800lb springs f/r. Car is a 987.1 Cayman S. Other than the AST dampers, the rest of the suspension is the Tarett SPC package.
I started off with the manual's recommended starting set points (generic and not specific for 987) of REB 6/12, LSC 3/15, HSC 5/12 (with 1 being the least resistance / softest setting). I've made some adjustments over the past few weekends, playing with the whole ranges of each setting (one setting at a time) to get a feel for what the ranges of each setting feel like. My biggest issue has been that the car always seems sensitive to bumps in the track, especially mid corner. For example, Mosport entry into turn 2 at the first apex. There is a bump in the track right at the apex; other cars I've been in, the suspension soaks it up with without upsetting the chassis. My car kind of bounces right off it and doesn't want to settle down therefore I cannot get on the power early. The settings I have found to work best (or feel the best anyways) are REB 3/12, LSC 12/15 and HSC 6/12 and that's where it is now.
The mid track bump issued seemed like HSC to me, so I lowered the HSC setting all the way to 1/12 which should allow the bypass to open with the least amount of force on the high speed circuit. But the sensitivity to bumps is still there it seems.
Anyways, would love to hear your feedback on experience helping people get 2 and 3 way damper systems 'close'. I know there is no such thing as perfection, and even 90% requires telemetry. But hoping to get into the 80th percentile with the seat of my pants and palms of my hands. Cheers
VR, hoping you can provide some advice and input on setting up a new 3 way suspension based on feel and car behavior (without the use of shock sensors and other advanced telemetry).
Do you have a specific order you prefer to do the setup? IE REB first, followed by LSC then HSC? Or some other order? What are you you specifically looking (or feeling) for when adjusting each setting?
I've recently installed AST 3-way dampers with 800lb springs f/r. Car is a 987.1 Cayman S. Other than the AST dampers, the rest of the suspension is the Tarett SPC package.
I started off with the manual's recommended starting set points (generic and not specific for 987) of REB 6/12, LSC 3/15, HSC 5/12 (with 1 being the least resistance / softest setting). I've made some adjustments over the past few weekends, playing with the whole ranges of each setting (one setting at a time) to get a feel for what the ranges of each setting feel like. My biggest issue has been that the car always seems sensitive to bumps in the track, especially mid corner. For example, Mosport entry into turn 2 at the first apex. There is a bump in the track right at the apex; other cars I've been in, the suspension soaks it up with without upsetting the chassis. My car kind of bounces right off it and doesn't want to settle down therefore I cannot get on the power early. The settings I have found to work best (or feel the best anyways) are REB 3/12, LSC 12/15 and HSC 6/12 and that's where it is now.
The mid track bump issued seemed like HSC to me, so I lowered the HSC setting all the way to 1/12 which should allow the bypass to open with the least amount of force on the high speed circuit. But the sensitivity to bumps is still there it seems.
Anyways, would love to hear your feedback on experience helping people get 2 and 3 way damper systems 'close'. I know there is no such thing as perfection, and even 90% requires telemetry. But hoping to get into the 80th percentile with the seat of my pants and palms of my hands. Cheers
Congratulations on utilizing the great Cayman platform! Yes, 3 ways up the complication factor exponentially...literally. .One thing you didn't mention was canister pressures in the AST dampers. This (to overly simplify) is additive to effective spring rates. So it's tough to determine for certain the answer to your question. With a lot of canister pressure & 800 lb springs, it's very possible that your car is simply over-sprung, which might cause the behavior you mentioned. You also don't mention sway bar settings. But let's forget that for a minute. Some of the tricky things about Mosport set up are the notable elevation changes, pavement irregularities, pavement changes, and curbing. With 3 ways, HSC and LSC are not necessarily related to vehicle speed, but rather the speed the dampers need to compress, as well as how far they compress. HSC primarily deals with places where the dampers are forced to compress fast and pretty far. LSC primarily deals with places they are forces to compress relatively gently and not as far. So for T2, with all its complications (and elevation), it's good your HSC is moderate. I'd first try to also lower LSC, and see how the car behaves there. Then, if that helps (which I suspect it will), I'd subsequently add some REB due to all the elevation changes at Mosport, and see what you think after that. I have a whole notebook of "if X then Y" suspension notes I employ when I am helping clients with set up, as well as generalized notes for specific tracks...but I have sort of over simplified here to keep it brief
It's probably in this thread, but buy Shocks for Drivers https://speedsecrets.com/ebooks/ It's the best $2.99 you'll spend today (and probably tomorrow).
Canister pressure is often misunderstood. It's like spring rate, but not the same. It's the pressure created by the volume taken up by the shock shaft. Canister pressure is thought of differently by lots of different folks. AST/Moton people seem to like to run a lot. Penske runs as little as needed to keep from having cavitation in the shock. Ohlins (and Penske) at the highest levels ditched canisters and made through rod shocks. It gets pretty in depth!
A common misperception with 3-way dampers and an important thing to keep in mind that hasn't been mentioned yet is that the high-speed and low-speed compression settings are completely independent, which they are not. The low-speed (helpful to think in terms of shaft speed vs. displacement force) adjuster works in conjunction with the high-speed adjuster to delay the high-speed circuit and there is "cross-talk" between both adjustments especially as you get at or near the end of each adjustment range. If you make big adjustments on one end, you will need to make adjustments to the other to keep the overall "damper curve" intact. The higher end dampers are more effective at reducing this cross talk effect.
As VR suggested, the first adjustment you should probably make is returning the low-speed adjuster back towards the center of the range and you will likely then see a greater sensitivity to your high-speed adjustment. If you feel like you have a "stability" problem after the disturbance/displacement event (ie. the bump you are hitting), that would likely be improved by adding more rebound incrementally given that you are on the "soft" end of the rebound adjuster currently. When a car is over damped in rebound it can pack down in a series of bumps and a driver might mistake this as "too stiff" and mistakenly think it's too much compression damping, but I don't think that's the case here given your relatively soft rebound setting. Hire a pro coach like the ones on this board and have them help you sort the setup out.
I also have some very good Penske technical documents that you may find helpful. PM me and I'll e-mail them to you.
Originally Posted by cstyles
VR, hoping you can provide some advice and input on setting up a new 3 way suspension based on feel and car behavior (without the use of shock sensors and other advanced telemetry).
Do you have a specific order you prefer to do the setup? IE REB first, followed by LSC then HSC? Or some other order? What are you you specifically looking (or feeling) for when adjusting each setting?
I've recently installed AST 3-way dampers with 800lb springs f/r. Car is a 987.1 Cayman S. Other than the AST dampers, the rest of the suspension is the Tarett SPC package.
I started off with the manual's recommended starting set points (generic and not specific for 987) of REB 6/12, LSC 3/15, HSC 5/12 (with 1 being the least resistance / softest setting). I've made some adjustments over the past few weekends, playing with the whole ranges of each setting (one setting at a time) to get a feel for what the ranges of each setting feel like. My biggest issue has been that the car always seems sensitive to bumps in the track, especially mid corner. For example, Mosport entry into turn 2 at the first apex. There is a bump in the track right at the apex; other cars I've been in, the suspension soaks it up with without upsetting the chassis. My car kind of bounces right off it and doesn't want to settle down therefore I cannot get on the power early. The settings I have found to work best (or feel the best anyways) are REB 3/12, LSC 12/15 and HSC 6/12 and that's where it is now.
The mid track bump issued seemed like HSC to me, so I lowered the HSC setting all the way to 1/12 which should allow the bypass to open with the least amount of force on the high speed circuit. But the sensitivity to bumps is still there it seems.
Anyways, would love to hear your feedback on experience helping people get 2 and 3 way damper systems 'close'. I know there is no such thing as perfection, and even 90% requires telemetry. But hoping to get into the 80th percentile with the seat of my pants and palms of my hands. Cheers
It's probably in this thread, but buy Shocks for Drivers https://speedsecrets.com/ebooks/ It's the best $2.99 you'll spend today (and probably tomorrow).
Canister pressure is often misunderstood. It's like spring rate, but not the same. It's the pressure created by the volume taken up by the shock shaft. Canister pressure is thought of differently by lots of different folks. AST/Moton people seem to like to run a lot. Penske runs as little as needed to keep from having cavitation in the shock. Ohlins (and Penske) at the highest levels ditched canisters and made through rod shocks. It gets pretty in depth!
Just to follow up on this, I read the e-book and it really got me thinking about the system in a different way that was easier to make sense of. I made some adjustments yesterday at the track, starting with 75% stiffness on rebound and low speed compressor, and 20% stiffness on high speed. What should be a nice digressive curve with good handling and able to soak up the larger bumps. Immediately the car felt so much better, and I set some new personal bests @ Mosport (1:31.3 best lap, 1:30.5 best rolling lap, 1:26.6 best theoretical lap).
Just to follow up on this, I read the e-book and it really got me thinking about the system in a different way that was easier to make sense of. I made some adjustments yesterday at the track, starting with 75% stiffness on rebound and low speed compressor, and 20% stiffness on high speed. What should be a nice digressive curve with good handling and able to soak up the larger bumps. Immediately the car felt so much better, and I set some new personal bests @ Mosport (1:31.3 best lap, 1:30.5 best rolling lap, 1:26.6 best theoretical lap).
Thx again for the link to the e-book.
Awesome! Once you understand shocks a bit, they get really fun to play with and run some experiments on your car. The diagrams that Cogito posted above are great too!
06-06-2019, 09:27 AM
