Koni Sport dampers and Evolution driving school..

[modernbeat]

One of the issues with doing it by-the-numbers is that it requires you to build a very accurate model, and most people build hugely simplified models. The simplified models are a good way to see the -difference- between two setups, but not the absolute results. If you have a good real-world baseline, and can calculate the difference, then it's useful.

Otherwise, it's just plain easier to rent a track and test multiple configurations than building the super accurate model.

Coming from someone that worked in aerodynamics and hydrodynamics at the beginning of his profession career preparing racing sailboats, where EVERYTHING was modeled. Real world testing trumped the models every time.

 

[Sam Strano]

I just caution you to maybe not think so hard about things.

To answer kcbrown's question about how I figure out what to do. Yes, experience, but I had to gather that too. And I'm a bit lucky in that I can get gather a lot more than most folks can because I drive so many cars every year, of all different types and setup.

There is substitute for it. I know that I've talked to Ford engineers, some of whom are VERY highly involved with the Mustang and they could not for understand how I could get on to turn (not even a Shelby) without a bigger rear bar and a smaller front. Then you get newer S197's that show up with big rear bars (shocking) and a completely bound up front bar. That makes little sense to anyone as far as I can tell, so I'm not going to just ride their baseline for everything, depends how well the baseline works, and we get that by testing, and test driving. And the first rule of that is that the driving HAS to be consistent (and hopefully fast). Top licensing for Ford is based on how consistent you can run, not necessarily how fast the car is run and cars do things differently depending how hard they are being pushed.

Case in point, a car on a PHB not being driven that hard is a lot more obedient than one being flogged. Same car, same parts.... but working under different condition. Well if person A tends to overdrive slow corners chances are the car will push. What I see, a LOT, is that people then want to change the car to make it not push.... even if it's driven induced, which then makes it looser elsewhere. Well in the end it's their car and they can do what they want, but when it comes to setup, the driver (and the driving) does in fact matter.

No, I'm not an engineer. I've got nothing against them either. ALL my best friends are very technically minded people. I am too, I'm just more of a hands on first kind of guy. There is value in thinking about this stuff. I just do it a little in reverse and at times have sat back and really thought hard about why something happened the way it did. But it's rare that I miss the boat doing things the way I do them.

Experience is gathered many ways, including talking to others you can trust... and critically, who can explain to you what happens. It doesn't have to be done via a text book.

Glad to be back.

 

[kcbrown]

I just caution you to maybe not think so hard about things.

Well, for myself, thinking hard just comes naturally to me. It's in my nature: I'm driven to understand not just how things work, but why. It's at the core of my being. Can't be helped.

To answer kcbrown's question about how I figure out what to do. Yes, experience, but I had to gather that too. And I'm a bit lucky in that I can get gather a lot more than most folks can because I drive so many cars every year, of all different types and setup.

There is substitute for it. I know that I've talked to Ford engineers, some of whom are VERY highly involved with the Mustang and they could not for understand how I could get on to turn (not even a Shelby) without a bigger rear bar and a smaller front. Then you get newer S197's that show up with big rear bars (shocking) and a completely bound up front bar. That makes little sense to anyone as far as I can tell, so I'm not going to just ride their baseline for everything, depends how well the baseline works, and we get that by testing, and test driving. And the first rule of that is that the driving HAS to be consistent (and hopefully fast). Top licensing for Ford is based on how consistent you can run, not necessarily how fast the car is run and cars do things differently depending how hard they are being pushed.

Yep. One of the biggest reasons I started with the stock suspension and didn't change a thing save for wheels and tires is that I wanted to get a feel for how the car behaves by default. I figured that you can't really fix something if you don't know what's broken first.

I've had no problem getting the car in stock form to turn in (it does so a bit easier with the Konis and camber plates, though). I'm frankly not at all unhappy with the performance of the stock suspension. My main complaint was the ride harshness, which the Konis fix nicely, and the tendency to eat the outside edges of the front tires (but, in my case, that happens relatively slowly because, firstly, I'm running 280 treadwear tires and, secondly, I don't push the car as hard as some except at autocross-format events like the Evolution driving school), which camber plates fix.

It's entirely possible, and indeed more likely than not at this point, that I won't want to change anything else from this point forward. We'll see. It'll depend on whether or not I run into what I regard as a major shortcoming in the suspension sometime in the future. Based on what I felt from the car at the Evolution driving school, it may be quite a while before that happens.


One thing that is a bit different about me is that unlike a lot of the people here, having the suspension move around under me doesn't bother me. It's what the suspension is for. It's supposed to move around so as to keep the tires planted firmly under lots of different conditions. Similarly, the nose dive under braking hasn't bothered me either, probably because when I'm braking, all my attention is on my turn in point, the apex, and/or the track-out point, and I tend not to notice what I'm not focused on.

Case in point, a car on a PHB not being driven that hard is a lot more obedient than one being flogged. Same car, same parts.... but working under different condition. Well if person A tends to overdrive slow corners chances are the car will push.

What if they trail brake into the corner?

I've found with mine that if I overdrive into a corner, lifting the throttle will neutralize the push nicely (more so now than before) and brushing the brakes will easily do that and may even make the rear come out some.

What's different about a Watts link in this respect?

What I see, a LOT, is that people then want to change the car to make it not push.... even if it's driven induced, which then makes it looser elsewhere. Well in the end it's their car and they can do what they want, but when it comes to setup, the driver (and the driving) does in fact matter.

Not only does it matter, I'd argue that it matters more than anything else!

The setup just determines how the car behaves for the driver with his driving style. The driver determines what the car actually does within its behavioral limits.

I've mentioned it before elsewhere in this forum, but I'll say it again here. I like the fact that the suspension covers everything from understeer, through neutrality, through oversteer, and that you can control which of those regimes you're in through your inputs. Seems to me that a car that is controllable in that way is highly flexible, one that you can make dance around the corners. There's something special about that.

No, I'm not an engineer. I've got nothing against them either. ALL my best friends are very technically minded people. I am too, I'm just more of a hands on first kind of guy. There is value in thinking about this stuff. I just do it a little in reverse and at times have sat back and really thought hard about why something happened the way it did. But it's rare that I miss the boat doing things the way I do them.

Lots of experience helps for that. Not only does it inform you of what works and what doesn't, it also informs you of where to start looking when you identify a problem.

You'll never see me arguing that experience doesn't matter. It matters a lot. And, in fact, experience is the ultimate litmus test of any theoretical model. The scientific method has experience, in the form of experimentation, baked into its foundation, as you use experimentation to verify or disprove the predictions made by the model.

But, especially for those of us who don't have the kind of experience you have, having a model helps as well. It helps us to make sense of what we're experiencing, if nothing else.

Experience is gathered many ways, including talking to others you can trust... and critically, who can explain to you what happens. It doesn't have to be done via a text book.

This is very true. Not only that, but that kind of discussion can reveal what your model hasn't been accounting for. It can help you refine your model, make it closer to real-life than it would be otherwise. It's one of the major benefits of a forum like this.

The value of a forum like this is not to be underestimated.

 

[Norm Peterson]

I've found with mine that if I overdrive into a corner, lifting the throttle will neutralize the push nicely (more so now than before) and brushing the brakes will easily do that and may even make the rear come out some.

What's different about a Watts link in this respect?

Symmetrical behavior. Think in terms of both roll steer and geometric roll center height, left turns vs rights. And left side vs right side forward bite on corner exit and what that might imply when they're unequal.


Norm.

 

[kcbrown]

Symmetrical behavior. Think in terms of both roll steer and geometric roll center height, left turns vs rights. And left side vs right side forward bite on corner exit and what that might imply when they're unequal.

I noticed that our Panhard bars are not horizontal at ride height. Would it help if they were? I would think so...


In any case, does the Panhard bar induce additional push compared with a Watts link? I wouldn't think so in the general case, but could see it differing in terms of the amount of push depending on whether one is entering a left-hand corner versus a right-hand corner...

Also, just how much of a difference (left turn versus right term) are we talking about with respect to the behavior? Is this something the average driver is going to really notice, or is it something only a seasoned driver with a finely tuned posterior would notice?

 

[csamsh]

I noticed that our Panhard bars are not horizontal at ride height. Would it help if they were? I would think so...


In any case, does the Panhard bar induce additional push compared with a Watts link? I wouldn't think so in the general case, but could see it differing in terms of the amount of push depending on whether one is entering a left-hand corner versus a right-hand corner...

Also, just how much of a difference (left turn versus right term) are we talking about with respect to the behavior? Is this something the average driver is going to really notice, or is it something only a seasoned driver with a finely tuned posterior would notice?

If you're not incredibly in tune with what your car does, you won't notice. Will you notice at all on track? Not sure. I noticed in autocross- especially in slaloms.

 

[kcbrown]

If you're not incredibly in tune with what your car does, you won't notice. Will you notice at all on track? Not sure. I noticed in autocross- especially in slaloms.

I didn't notice in the slaloms, and I was modulating the throttle in them and everything, so it must be really minor in comparison with other things, or my posterior needs a lot of fine tuning, or something.

 

[Norm Peterson]

I noticed that our Panhard bars are not horizontal at ride height.

I'll bet that they get pretty close to horizontal with the car approaching its max rated passenger load . . . and perhaps having the loaded condition result in the least amount of lateral axle shifting as the suspension moves while you're driving is the better consumer-oriented decision.

Would it help if they were? I would think so...

With a few caveats if/when your driving is good enough to really appreciate it and you have no reason to intentionally favor turns in one direction over turns in the other. Think MT's "figure-8" vs a 1/3 mile paved oval. Being picky, road courses fall variously somewhere in between but probably closer to the figure-8.


Norm

 

[Pentalab]

I noticed that our Panhard bars are not horizontal at ride height. Would it help if they were? I would think so...


In any case, does the Panhard bar induce additional push compared with a Watts link? I wouldn't think so in the general case, but could see it differing in terms of the amount of push depending on whether one is entering a left-hand corner versus a right-hand corner...

Also, just how much of a difference (left turn versus right term) are we talking about with respect to the behavior? Is this something the average driver is going to really notice, or is it something only a seasoned driver with a finely tuned posterior would notice?

Steeda makes an adjustable length PHB, that also has adjustable mounts at both ends. It appears that you could get their PHB level. On lowered cars, the PHB is at a shallower angle..but still not level.

 

[Norm Peterson]

I hope that anybody who goes to the trouble of levelling their car's PHB takes driver weight into account in some fashion.


Norm

 

[claudermilk]

From my understanding of what I've read in conjunction with what I've felt driving is stability. A mid-corner bump give the back end a nice wiggle which then causes it to step out a bit (more the faster you're going). It just gives an unsettled feel to the car mid-corner. I have a nice corner by the house that the pavement isn't the best & can predictably cause this behavior. When the car was new to me, it bugged me a bit; now I will induce it to get giggles from the little ones in the back seat. I'm a bad dad...

With a Watts link--again from my understanding reading what it's supposed to accomplish--this behavior is neutralized and allows the rear end to stay stable.

 

[Mineral_'01]

In regards to the above scenario I think no matter what, a watts link could not keep the axle perfectly stabilized when dealing with a single wheel bump. Although it would make a major improvement. I think this is where an IRS rear axle really shines.

 

[sheizasosay]

In regards to the above scenario I think no matter what, a watts link could not keep the axle perfectly stabilized when dealing with a single wheel bump. Although it would make a major improvement. I think this is where an IRS rear axle really shines.

I'm not sure that "live axle" and "single wheel bump" even belong in a sentence together.

Watts will never do the job of IRS.

 

[Sam Strano]

Well, for myself, thinking hard just comes naturally to me. It's in my nature: I'm driven to understand not just how things work, but why. It's at the core of my being. Can't be helped.


Yep. One of the biggest reasons I started with the stock suspension and didn't change a thing save for wheels and tires is that I wanted to get a feel for how the car behaves by default. I figured that you can't really fix something if you don't know what's broken first.

I've had no problem getting the car in stock form to turn in (it does so a bit easier with the Konis and camber plates, though). I'm frankly not at all unhappy with the performance of the stock suspension. My main complaint was the ride harshness, which the Konis fix nicely, and the tendency to eat the outside edges of the front tires (but, in my case, that happens relatively slowly because, firstly, I'm running 280 treadwear tires and, secondly, I don't push the car as hard as some except at autocross-format events like the Evolution driving school), which camber plates fix.

It's entirely possible, and indeed more likely than not at this point, that I won't want to change anything else from this point forward. We'll see. It'll depend on whether or not I run into what I regard as a major shortcoming in the suspension sometime in the future. Based on what I felt from the car at the Evolution driving school, it may be quite a while before that happens.


One thing that is a bit different about me is that unlike a lot of the people here, having the suspension move around under me doesn't bother me. It's what the suspension is for. It's supposed to move around so as to keep the tires planted firmly under lots of different conditions. Similarly, the nose dive under braking hasn't bothered me either, probably because when I'm braking, all my attention is on my turn in point, the apex, and/or the track-out point, and I tend not to notice what I'm not focused on.


What if they trail brake into the corner?

I've found with mine that if I overdrive into a corner, lifting the throttle will neutralize the push nicely (more so now than before) and brushing the brakes will easily do that and may even make the rear come out some.

What's different about a Watts link in this respect?


Not only does it matter, I'd argue that it matters more than anything else!

The setup just determines how the car behaves for the driver with his driving style. The driver determines what the car actually does within its behavioral limits.

I've mentioned it before elsewhere in this forum, but I'll say it again here. I like the fact that the suspension covers everything from understeer, through neutrality, through oversteer, and that you can control which of those regimes you're in through your inputs. Seems to me that a car that is controllable in that way is highly flexible, one that you can make dance around the corners. There's something special about that.


Lots of experience helps for that. Not only does it inform you of what works and what doesn't, it also informs you of where to start looking when you identify a problem.

You'll never see me arguing that experience doesn't matter. It matters a lot. And, in fact, experience is the ultimate litmus test of any theoretical model. The scientific method has experience, in the form of experimentation, baked into its foundation, as you use experimentation to verify or disprove the predictions made by the model.

But, especially for those of us who don't have the kind of experience you have, having a model helps as well. It helps us to make sense of what we're experiencing, if nothing else.


This is very true. Not only that, but that kind of discussion can reveal what your model hasn't been accounting for. It can help you refine your model, make it closer to real-life than it would be otherwise. It's one of the major benefits of a forum like this.

The value of a forum like this is not to be underestimated.

That's a lot, I'm not sure I can cover all that but I'll try.

Our brains are basically computers with lots of RAM. But the more crap that is in there that might not really help, the slower the computer runs. Instead of worrying about a hundred things and seeking to understand it all, why not worry about what's happening and then seeking to understand *that* thing you want to deal with first. And here's why. Things are integrated, change begets change. A driving style change will alter the way the car acts. An air pressure change might well help a car rotate or maybe settle down, but it won't just do it in on phase of a corner. Change your RC height and you might well need to play with roll stiffness front or rear, or both. On and on it goes.

At least when you are driving, you need to just focus on driving and what the car is telling you. Maybe that's off topic a little, but to me it's part of the game as driving errors lead to setup changes that are ill advised.

You say you had no trouble with the car turning in with the stock stuff... but it's better with plates and Koni's. Ok I'd agree with both to point, but I'd not say stock is adequate or even ok for performance driving. And then we get into semantics. How about when you trail brake? Depends on *how* you trail brake. Many folks seem to think it's something different from what I do. Trail braking to me isn't dragging brake into a corner, period, but also how and when I release the brakes. It's trailing OFF the brakes. Not everyone defines it as such. Even if you run brake into a corner, if you pop off vs. roll off will change things greatly. This are things that numbers can't quantify, but matter in terms of how the car is behaving.

If you overdrive, of course getting off the gas will help mitigate push. But the last thing I'd recommend is hitting the brakes in that situation unless you are so far beyond the limit it's not funny. You are already asking more from the front tires than they have to give. Adding brake to turning doesn't do them any favors. At some point the total load will come down to a level where the car will turn, but it's certainly not efficient to do it that (or easy on tires). And more to the point if you are going to miss an entry, better to miss a little slow than a little fast.

As for the PHB being level vs. not. Would it help being level? Not really, because it never stays level when you drive. Also consider when you see it the car is sans driver. Get in and it levels out a bit anyway, but the geometry of the PHB is still the same. Fixed on one end to the axle, other end moving with the body. Even if you don't drop the RC a long way with a Watts it's more stable and predictable. Of course that can, on it's own, cause some folks a "push" issue if they loose the swing from the ass end.

Again let me point out I'm not telling you to NOT think about things like you want too. Just don't put so much damned stock into them because it will bog you down. And remember while I don't personally know you, I did get a debrief about how things went in general, including the conversation about how you can't talk while driving and it messes you up, etc.... but then you nailed a slalom while... telling Shelly that. Keep the brain clear. Apply your lessons well and you might find you don't need to think so hard about how things are happening with the car.

And experience can be shared too. Maybe I won't explain something in as much technical detail as you crave, but folks with experience can help. But like anything else, there are varying opinions.

 

[Sam Strano]

I'm not sure that "live axle" and "single wheel bump" even belong in a sentence together.

Watts will never do the job of IRS.

You might be surprised how a properly setup, non binding Watts link does deal with such things. Better than many IRS's that aren't the best for sure.

If I have a solid axle car again (currently I have one in my old A-Sedan car) it will have a Watts unless it is precluded from the rules in the class I compete. I'm sorting out other issues with the '84 now, it will eventually have a Fays2 on it I'm sure.

 

[Sam Strano]

In any case, does the Panhard bar induce additional push compared with a Watts link? I wouldn't think so in the general case, but could see it differing in terms of the amount of push depending on whether one is entering a left-hand corner versus a right-hand corner...

Also, just how much of a difference (left turn versus right term) are we talking about with respect to the behavior? Is this something the average driver is going to really notice, or is it something only a seasoned driver with a finely tuned posterior would notice?

Sure. Left corners result in the right rear being pulled down, rights it gets shoved up some. Watts even help with inside wheelspin for the same reason. They help.

Even not so hot ones, IMHO, help as long as they don't bind. I just prefer them with RC height adjustable that's got a big range from stock PHB height to a lot lower, not just kind of something in the middle.

 

[sheizasosay]

You might be surprised how a properly setup, non binding Watts link does deal with such things. Better than many IRS's that aren't the best for sure.

If I have a solid axle car again (currently I have one in my old A-Sedan car) it will have a Watts unless it is precluded from the rules in the class I compete. I'm sorting out other issues with the '84 now, it will eventually have a Fays2 on it I'm sure.

The rear of my car is actually pretty decent, with respect to an S197, IMO. I have a watts link. It used to be a Techo and then I had 908SSP modify it to put the center bolt in doulbe shear after I wallowed it out my first track day. But I have no idea if it binds. How do you know if it is binding? The binding that comes to my mind would be from not having heim joints on the arms. And in that case, it seems that either the center bolt would want to go or the bolts holding the diff cover on the pumpkin would want to pop. At least that's the bind I am thinking about. Don't know if that is right or not.

I have no complaints about the rear of my car. Only the front. Need more front spring rate. More than the 240 in/lbs springs I got now for sure. But as good as the rear of my car is, bumps and curves are NOT a good combo for my car.

Edit- not talking about little bumps either. The bumps I'm respectful to are on the street. I only drive one track and bumps are of no concern there.

 

[kcbrown]

Got the other two dyno plots and, even better, got the raw data! You can get the software to open and manipulate the raw files (which have a .mcr suffix) here, but I have extracted the data into force versus velocity points stuffed into CSV files, one per setting per damper, and have also consolidated all of those into a single CSV file (alldata.csv), which has a damper ID and pass number (zero represents full soft, and each subsequent pass represents a 1/4 turn of the adjustment knob towards full stiff) for each entry. I stuffed the data into a SQL database so I could manipulate it more easily (I'm a nerd that way).

Here's the second front plot: View attachment F2 Dyno Range.pdf

And the second rear plot: View attachment R2 Dyno Range.pdf


And here's the zip with all the data: View attachment Shock-Data.zip


Be interesting to see what you guys determine from the raw data...

 

[Norm Peterson]

"Invalid Attachment specified"


Norm

 

[frank s]

Ain't it the truth...