Originally Posted by wannafbody
(Post 658265)
Don't you use swaybars and springrate to tune for roll? Springs function to support the vehicle. Shocks function to control the spring.
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YES, I see we are finally agreeing , Y8S and philMD have nailed it with regards to using the dampers to fine tune and control the rest of the suspension, dampers are not a band aid to a badly tuned suspension system.
Bernie S has been trying to say that all along , but I think he was way ahead of the curve and the posts have started to catch up to him. |
I think Bernie and Phil are in agreement somewhat. I've never seen a shock dyno with 0 compression. NA HD's have 50#, IIRC R Pack is about 100# and LG Billie racing coilovers for the Vette have about 100# compression.
Does the weight of the wheel/tire play a role in determining the amount of compression and rebound needed or is it simply a function of the springrate? |
Originally Posted by PhilMD
(Post 658376)
You should be using springs for your chosen ride frequency and look to have a higher frequency at the rear than the front. This allows the car to move as one over bumps and undulations to prevent the car from pitching (the front will hit the bump before the rear, so the rear needs to 'catch-up').
Sways are used for roll moment distribution. You should also match the sway rate with the spring rate if you want to have correct damping in roll. Slapping on a stiff sway will make you underdamped in roll. You'll get quicker response, a pointy car, but you'll also get overshoot of steady state and nasty contact patch loadings. Once you've done the spring/sway stuff, you can then go on to design damper rates. P I've been using this to determine FRC: http://www.fatcatmotorsports.com/FRC...MSDS_1_6NA.htm How much of a higher rear frequency should we be looking for, and how should ride frequency be chosen in general? (I can only assume by tire compound) Great thread guys, I am just trying to absorb as much info as I can. |
Originally Posted by wannafbody
(Post 658547)
Does the weight of the wheel/tire play a role in determining the amount of compression and rebound needed or is it simply a function of the springrate?
In a Miata, the tub is flexing quite a bit, even with a roll bar. How this other level of damping might apply would be in a national level CSP car which will sustain about 1.6g on a good concrete surface with 275 A6's. Thos care are stripped of all OEM bracing and run upwards of 900lb front springs and no rear sway bar. In that extreme case, the torsional stiffness or resonant frequency of the tub is exceptionally low (bad). It's winding up and unloading. The roll couple bias is obviously affected and one of the main reason they need such massive springs to keep the cars neutral. While no shock designer adds that into the mix while selecting valving, the racer will continue to tune the car and request this or that valving. Unknowingly compensating for the fact that the actual tub of the car twisting is probably some crazy 15% of the otherwise undamped wheel rate at 1.6g. |
I think we are all coming to terms here.
I have been trying to point out since the beginning that we are trying to understand proper damping before we worry about manipulation. When you start to tune the suspension using the shocks for purposes other than dampers, that is manipulation. This is where you apply compression damping, excessive rebound damping and all sorts of other stuff to "dial" in your car. |
Originally Posted by Bernie S.
(Post 658586)
I think we are all coming to terms here.
I have been trying to point out since the beginning that we are trying to understand proper damping before we worry about manipulation. When you start to tune the suspension using the shocks for purposes other than dampers, that is manipulation. This is where you apply compression damping, excessive rebound damping and all sorts of other stuff to "dial" in your car. |
I gotta say this thread is why I love MT. Vendors at Mnet rarely have such reasonable and informed discussions without it devolving into bashing each other, trying to undermine another's thought process, knowledge and products.
While MT.net is known to be hard on newbs, intolerant of dorifto jdm yo boyz and coarse in general, here are two great resources playing nice in the same sandbox. Are we the only forum using Multi-Cat litter? |
So outside of miata world here.....
Let's say I run an ST integra with koni yellows and 400f , 450r gc's and the car comes completely unsettled going over the slightest bit of road change. With only have the adjustabilty of compression tuning, what do I do? Turn the comp. down or get different springrates or what? Guess I'm looking for more of a quick fix I could do between autox runs. |
The quick fix would be trying to dial out the compression before replacing springs.
Originally Posted by flier129
(Post 658669)
So outside of miata world here.....
Let's say I run an ST integra with koni yellows and 400f , 450r gc's and the car comes completely unsettled going over the slightest bit of road change. With only have the adjustabilty of compression tuning, what do I do? Turn the comp. down or get different springrates or what? Guess I'm looking for more of a quick fix I could do between autox runs. |
Originally Posted by flier129
(Post 658669)
So outside of miata world here.....
Let's say I run an ST integra with koni yellows and 400f , 450r gc's and the car comes completely unsettled going over the slightest bit of road change. With only have the adjustabilty of compression tuning, what do I do? Turn the comp. down or get different springrates or what? Guess I'm looking for more of a quick fix I could do between autox runs. I think there is a mistake here, Koni yellows only adjust rebound unless you have the DA's which have a seperate compression adjustment. I have Koni montubes on the rear of my TA. At the softesst setting they are like butter. The rear of the car just glides but that comes at a price-understeer and a floaty feeling at 65mph. I recently adjusted them up 1 click which is +20% on the rebound. The understeer and floaty feeling is gone but the seams in the road are more pronounced. The ride is firmer. |
Yeah your right, my mistake, rebound only.
So could I raise the hide height a tad and up the rebound? So then the energy would be released less violently? |
Originally Posted by greeenteeee
(Post 658550)
Is the ride frequency the same as bounce frequency?
I've been using this to determine FRC: http://www.fatcatmotorsports.com/FRC...MSDS_1_6NA.htm How much of a higher rear frequency should we be looking for, and how should ride frequency be chosen in general? (I can only assume by tire compound) Great thread guys, I am just trying to absorb as much info as I can. I know that a lot use the FRC calculation, but it doesn't tell the whole story. It would be fine if we all drove around at steady state, but that's seldom the case. Because you have one damper per corner, you need to ensure that both ride springs and sways are matched properly if you want proper damping in ride (one spring) and roll (two springs). P |
Originally Posted by flier129
(Post 658669)
So outside of miata world here.....
Let's say I run an ST integra with koni yellows and 400f , 450r gc's and the car comes completely unsettled going over the slightest bit of road change. With only have the adjustabilty of compression tuning, what do I do? Turn the comp. down or get different springrates or what? Guess I'm looking for more of a quick fix I could do between autox runs. Phil |
Oh, good thread! Here's a simple question:
For a dual purpose car, can a shock be revalved such that it has maximum performance (autocross) and maximum comfort (street)? This assumes a given spring rate. If not, what specific compromises must be made? I understand, of course, that many other aspects of a race car will sacrifice ride quality on the street (bushings, springs, anti-roll bars, seat, etc). Edit: To be clear, I'm asking regarding the *shock valving* alone, on a car that has a high spring rate. |
Originally Posted by JustinHoMi
(Post 659855)
Oh, good thread! Here's a simple question:
For a dual purpose car, can a shock be revalved such that it has maximum performance (autocross) and maximum comfort (street)? This assumes a given spring rate. If not, what specific compromises must be made? I understand, of course, that many other aspects of a race car will sacrifice ride quality on the street (bushings, springs, anti-roll bars, seat, etc). |
Originally Posted by JustinHoMi
(Post 659855)
For a dual purpose car, can a shock be revalved such that it has maximum performance (autocross) and maximum comfort (street)? This assumes a given spring rate.
Originally Posted by JustinHoMi
(Post 659855)
If not, what specific compromises must be made?
Originally Posted by JustinHoMi
(Post 659855)
I understand, of course, that many other aspects of a race car will sacrifice ride quality on the street (bushings, springs, anti-roll bars, seat, etc).
You have to decide if you need to win...or just have fun. IMHO, if you really want to compete to win it is best to get a car purposely designed for AutoX and a separate DD. The DD doesn't have to be boring. I know a few guys who have a pair of Miatas...one set up for the track, another for a DD. |
You don't understand the question. I'm talking about performance pertaining to the shock valving alone. And I'm looking for specifics regarding the compromises that might have to be made to the shock valving.
FYI my car (with high spring rates) and Koni RACE shocks is great on the street. I have few complaints. As far as my class goes (Street Touring Sport), you can definitely have a winning car that is also a joy to drive on the street. But that's not exactly what I'm asking. |
Originally Posted by JustinHoMi
(Post 660018)
You don't understand the question. I'm talking about performance pertaining to the shock valving alone. And I'm looking for specifics regarding the compromises that might have to be made to the shock valving.
FYI my car (with high spring rates) and Koni RACE shocks is great on the street. I have few complaints. As far as my class goes (Street Touring Sport), you can definitely have a winning car that is also a joy to drive on the street. But that's not exactly what I'm asking. |
Yep, but like I said... I'm not talking about stock spring rates. :)
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