Disaster

iTrader: (1)

You sound happy with what you've got. Was the question rhetorical?

JustinHoMi

Of course it's not rhetorical. I don't have the knowledge or experience needed to answer the question. And Bernie may be the only one here that does. Let's just wait for him to chime in.

Nagase

iTrader: (6)

Yes, everything on a car is a tradeoff. There's nothing I can think of where you can get the best comfort and the best performance.

The specifics can be left up to someone else, that's not my point here.

It's always a trade. Springs, shocks, seats, wheels, tires, belts, interior, anything you name is a compromise. This is important to get in your mind.

Bernie S.

I left this question alone because I felt the others had answered it.

Just like they have said, everything is going to be a compromise. Do you want more performance for when you push the limits on the street, along with the track, or do you want more comfort?

I think in your case you may be asking what would you have to give up on the street to gain a little more performance on the track using your stiffer springs?

Is this correct?

Bernie S.

Also, don't discount the other people making contributions to this thread. We all have great experiences that we ALL can learn from.

JustinHoMi

Bernie -- I'm asking for technical specifics regarding high and low speed compression/rebound.

If someone brought you a set of shocks, and said "I want these revalved for pure track performance" what would you do different than if someone said "I want these revalved for performance and street use". Where, specifically (in the valving), do the tradeoffs need to be made, and why?


As it pertains to this question, I'm referring to track performance, and street comfort. Street "performance" does not matter.

Yes, as it pertains to shock valving... not ride height, spring rates, etc, etc.


Most of the contributions in this thread have been very interesting to read, whether right or wrong. I was just getting a little flustered that none of the responses had anything to do with the question that I was trying to ask. But I may not have been clear in my original question.

Disaster

iTrader: (1)

I don't think you are going to get a "pure" answer, or like the answer you are going to get, ie., continue to be flustered.

The difference in the car's setup for example is a huge factor. Are you running stock HP, or F.I.? Are you a running bigger sways? Are you interested in AutoX performance or track? What camber are you running? Is it a flat track or bumpy one? Have you stiffened the cars chassis? Have you effected the weight balance with any mods? Do you like a little understeer...or oversteer? What tires and wheels are you running? What type of shocks...mono or twin? Have they been dynoed? How much unsprung weight are you carrying?

The basic answer is first figure out the spring rate you need or can live with than put on just enough dampening for that spring rate. The high speed and low speed settings are one of those things that are tweaked based on the car's individual characteristics.

When talking about high speed vs. low speed shock experts will talk about the degressive, linear and progressive behavior and analyze the shock at different frequencies (dyno.)

You will either need to be more specific about your particular setup, or more specific about your particular questions, because there isn't a "best compromise" or solution. Tuning is a huge part of shock design...and tuning means tuning for your car and you as a driver.

Here is some interesting reading for you.

http://www.optimumg.com/OptimumGWebS...Tech_Tip_1.pdf

http://www.optimumg.com/OptimumGWebS...Tech_Tip_2.pdf

http://www.optimumg.com/OptimumGWebS...Tech_Tip_3.pdf

http://www.optimumg.com/OptimumGWebS...Tech_Tip_4.pdf

http://www.optimumg.com/OptimumGWebS...Tech_Tip_5.pdf

wannafbody

iTrader: (1)

The optimum info is cool but way over my head and I suspect others as well. The key is to find someone who knows the answers and can valve the shocks for your particular needs. Luckily this board has two people (Bernie and Emilio) who can provide the solution to anyone's Miata needs.

In the case of Bernie, I asked if he could meet a couple different criteria and he indicated it wouldn't be an issue. I'm sure they are gonna be good.

I like the fact that Bernie, Emilio and FM have posted graphs and are open and willing to discuss their products.

IMO if you're driving your car on the street then double or triple adjustable shocks are way more than you need. Those type of adjustments are only needed by those who already have their car operating at it's peak potential and are trying to get a few 10th's faster.

I've read of guys tweaking shocks and revalving several times and only gaining a couple tenths compared to an off the shelf shock. In fact Grassroots Motorsport did a test of FCM adjustable coilover shocks vs Bilstein PSS9 and found on average the FCM was better by 2 or 3/10 on an AX course but the kicker is that the PSS9 have less than optimal springrates which made the Miata difficult to drive.

Disaster

iTrader: (1)

My subtle way of saying it's complicated. The answer isn't going to be A is best.

I was trying to say that too, but you were way less wordy and to the point than me. I had a little case of keyboard diarrhea. :-)

One thing the Miata community is lucky to have is guys like them...who know their products and have the patience to work with customers and answer questions.

...and if you don't know what you are doing there is lots of room to mess things up. There is some use for adjustability, especially with guys who swap springs, but for most of the rest of us, a properly matched spring/shock system will be all we need.

Don't get me started on the unscientific nature of that test, but it did show how well some of these very reasonably priced products can perform.

Bernie S.

The typical difference between a set of "street valved" shocks and full race shocks would be the amount of low speed rebound.

This can be changed several ways using the bleed along with the sealing shim on the face of the piston. A shock with less low speed damping is generally more compliant over rough surfaces and more comfortable for a DD, but you also get more roll out of the car.

VERY IMPORTANT!
A lot of people mistake an adjustable shock as a universal shock. They think that if they are running less spring, they just open the adjustment up more. This is not the proper way of tuning a shock. The adjustment controls the bleed in the shock, and in turn controls the low speed damping, but you are not adjusting the actual valving.

We discussed last week a little about how a shock can have a small bleed and still dyno the same as one with a large bleed. This can be done with the right combination of shims on the piston along with the bleed. They will not feel the same on the road/track, and this is why it is very important to have the right valving and only use the adjuster to fine tune.

An adjustable shock is not meant for multiple spring applications, or different setups. It is meant to tune ONLY. If it were this simple, we would simply keep the shims on the piston and just drill the bleed to where the shock dynoed right.

Disaster

iTrader: (1)

This is a very good point indeed. That is why one should always decide what spring rates they want to run first, then pick/tune a shock to match. I read too many stories of people who buy adjustable shocks and then crank them to the "hard" setting for "better performance." Those people would have been MUCH better served with stiffer springs and properly tuned shocks...though, I think some people equate harshness with a "sporty" ride.

richyvrlimited

iTrader: (1)

With that in mind, has anyone dyno'd a KONI yellow to find the optimum spring strength for the shock?

I know it's a of an *** backwards way of looking at it, but I've read many times on here and other MX5/miata sites that the KONI yellow is brilliant with any spring from OEM to 500ft/lbs. That can't be right surely?

Thucydides

I agree this is the right way to design an adjustable shock, but when I look at most Miata adjustable shock dyno charts, and see an order of magnitude or more range of adjust-ability, I think the manufactures are trying to market a shock that is meant for multiple spring applications; or at least they're trying to convince the customer of that.

The right way is how you've describe it; build the valving around a single set of spring rates and fine tune from there. But in the economical sports car world, like ours, this level of effort is almost unheard of. When most of us order a set of adjustable shocks the valving's the same for all spring rates, and the adjuster's job is to make up for the differences. Not the right way to do it, but that's (mostly) how it's done.

Perhaps your explanation will help raise the bar on how adjustable shocks are set up for our Miatas, in that we'll begin having our shocks custom built for our spring rates, but the bleed control is going to have to become a lot finer and more precise if it's to remain truly useful for tuning.

Thucydides

Not to pick on anyone's shock, but here's an example.

If you were to pick a given damping curve as optimum for the springs you have on your car, what is the likelihood that adjustments more than one or at most two lines away will be of any value for tuning on the race track. I would think having the lines closer together around a closer to optimum middle adjustment would be the better solution. Yes?

wannafbody

iTrader: (1)

Well, there is a difference between a good all purpose OTC shock(Koni, Tokico) vs a custom spec shock and what is acceptable handling wise for a street application might not cut it for a pure race or AX application. Both SD and Xidas have been praised for having good street manners though.

wannafbody

iTrader: (1)

I think adjustability is best used to increase or decrease bite at one end of a car.

Thucydides

Among other things, but those are awfully big bites, and it's quite easy to chew off more than you really want to.

I'm thinking smaller nibbles around valving built for your spring rate is the way to go with a dedicated race shock.

Bernie S.

You are correct. A properly tuned shock would be to have the lines evenly spaced with a finer adjustment.

In order to do this, the initial valving would have to have the bleed of the adjuster figured in.

Penske, Ohlins, and a few others that custom build your shock when you order it do a little better job in that they valve the shock first. Then you adjust for tuning. Even though these setups are better, they still have too wide and course of an adjustment.

When I make an adjustment on the shocks at the track, it is never more than the first 5 "clicks" off of 0. Any more than that, you need to revalve the shock.

A little trick is to machine more detents into the adjuster so that the adjustment is finer.

Bernie S.

I don't think that a dedicated race shock is the only one that needs proper damping curves.

hustler

iTrader: (6)

I don't know if this post belongs here, but my car was sweet this weekend. I tightened the sway bar up and ended-up taking 1-click out of the rear rebound...it turned-in at highspeed, it turned at low speed, I could throttle steer, I could increase steering angle in steady-state throttle and oversteer, I could drive through the bumps, no more body roll...it was sweet. There is no substitute for a properly valved shock.