Koni Sport dampers and Evolution driving school..

[Norm Peterson]

I imagine Shock Shop is looking at curves like this one (RCVD), and trying like hell to avoid operating much to the right of where optimum z for road handling lies. These curves are really for illustration and likely differ depending on the specific make/model car and all the other things on their form.

FWIW, I know I've felt a difference in front cornering grip depending on the damper settings - a less "slide-y" feel going through a turn sequence that I'm extremely familiar with. I wasn't even expecting it when I first noticed, more like "hey, it's definitely sliding more at this softer setting". IIRC, about half a turn of Koni yellow adjustment (all four) was involved, with the "soft" settings not being full soft at either end of the car.


Norm

 

[kcbrown]

No. I read their philosophy on shock tuning and how they very much aimed at critical damping. I continued to read what they were proclaiming and couldn't help but think of KC and how he was aggressively seeking critical damping. I saw the links for the spreadsheet and excel and didn't click on them myself. I see now that it is a form that you fill out that you give to the shop so they can valve the damper you purchase for critical damping with the software they have. Apologies for not being more thorough.

I still think, based off their philosophy, that this shop has KC's name all over it. It's an opinion anyway.

I've been to that site before and thought it was interesting. It might actually be rather fascinating to have them valve a set of Konis and see the resulting dyno plots, just to get some insight into their views on the subject, particularly as regards compression damping.

The Konis I have on the car now are working very nicely on the street. They've actually smoothed out somewhat since I initially got them, and so I might have to have them put back onto the dyno to see if anything's changed significantly. But Sam has experience with these, so he might be able to tell me what the changes to the curves are and if there's any need to change the settings in response. I can't tell any difference in terms of how it goes around corners or takes a set, but I don't know if that's me or the car.


Much of this really comes down to a simple question: how do you know whether or not the fact you're not detecting any differences is the result of those differences not existing versus some inability on your part to detect such things? I'm new enough at this that I can't presume any real ability on my part to tell the difference in terms of handling between two different configurations (the fact that I couldn't tell much of a difference between the stock dampers and these plus camber plates in terms of handling, save for the fact that the current configuration seems to be more neutral in corners as evidenced by the fact that I was able to get the rear to come out enough to demand countersteering just by lifting the throttle enough, is some indication that I don't yet have such ability). How do you know if you're skilled enough to tell the difference? And if you're not yet skilled enough to tell the difference, how will you know when you get to the point that you are skilled enough? It's not like you have some instrument to tell you that there is a real and consistent difference in cornering capability, particularly if your driving isn't terribly consistent. My lap time differences on the real track are measured in seconds when I bother to have them measured at all (and part of that may be the result of things like encountering traffic), but it sounds like most of the changes that people make result in tenths of a second difference per lap. I frankly haven't a clue how you tell whether or not a change makes for any improvement when the lap time difference is that small.

That's why my initial focus was on setting the car up properly "by the numbers", because that would be a way to get me something reasonably good that I can continue to learn with. If I ever get good enough that my lap times vary by hundredths of a second, then and only then could I reasonably consider myself good enough to tell the difference by lap time whether or not a change I made was detrimental or beneficial, as it would only then be that a lap time difference in the tenths of a second range would be reliably detectable. And that still doesn't address the question of whether or not you'd be able to tell the difference by feel. I suppose if, when your driving is that consistent, you can tell the difference in lap time but not in feel, you'll know that your ability to feel differences isn't up to snuff yet.


It's entirely possible that I'll never get to the point where I can feel the difference from changes made to the car. I say this because I'm also a private pilot, and despite having nearly 1000 hours of flight time, I still can't tell by the seat of my pants whether the airplane is in coordinated flight or not. I have to look at the instruments for that. Most pilots are able to feel such things. I cannot. But I know from experience that I can feel some things in the car, such as the wiggle in the rear end during braking into turn 2 at Laguna Seca when the track is damp that tells me that any more braking pressure and the car will come around on me. So I know from experience that there's some hope for me yet.

 

[Whiskey11]

Much of this really comes down to a simple question: how do you know whether or not the fact you're not detecting any differences is the result of those differences not existing versus some inability on your part to detect such things? I'm new enough at this that I can't presume any real ability on my part to tell the difference in terms of handling between two different configurations (the fact that I couldn't tell much of a difference between the stock dampers and these plus camber plates in terms of handling, save for the fact that the current configuration seems to be more neutral in corners as evidenced by the fact that I was able to get the rear to come out enough to demand countersteering just by lifting the throttle enough, is some indication that I don't yet have such ability). How do you know if you're skilled enough to tell the difference? And if you're not yet skilled enough to tell the difference, how will you know when you get to the point that you are skilled enough? It's not like you have some instrument to tell you that there is a real and consistent difference in cornering capability, particularly if your driving isn't terribly consistent. My lap time differences on the real track are measured in seconds when I bother to have them measured at all (and part of that may be the result of things like encountering traffic), but it sounds like most of the changes that people make result in tenths of a second difference per lap. I frankly haven't a clue how you tell whether or not a change makes for any improvement when the lap time difference is that small.

That's why my initial focus was on setting the car up properly "by the numbers", because that would be a way to get me something reasonably good that I can continue to learn with. If I ever get good enough that my lap times vary by hundredths of a second, then and only then could I reasonably consider myself good enough to tell the difference by lap time whether or not a change I made was detrimental or beneficial, as it would only then be that a lap time difference in the tenths of a second range would be reliably detectable. And that still doesn't address the question of whether or not you'd be able to tell the difference by feel. I suppose if, when your driving is that consistent, you can tell the difference in lap time but not in feel, you'll know that your ability to feel differences isn't up to snuff yet.


It's entirely possible that I'll never get to the point where I can feel the difference from changes made to the car. I say this because I'm also a private pilot, and despite having nearly 1000 hours of flight time, I still can't tell by the seat of my pants whether the airplane is in coordinated flight or not. I have to look at the instruments for that. Most pilots are able to feel such things. I cannot. But I know from experience that I can feel some things in the car, such as the wiggle in the rear end during braking into turn 2 at Laguna Seca when the track is damp that tells me that any more braking pressure and the car will come around on me. So I know from experience that there's some hope for me yet.

I'm going to steal Jason Rhoade's analogy, but tuning a car is a lot like hitting a bump in your car. You get your big initial displacement, it rebounds to just shy of the same value in the other direction, then just shy in the compression side, etc. Experience is like a adding a stiffer damper to the front suspension and the "zero" line is your ideal car handling. Experience reduces the number of oscillations before reaching that ideal point.

What he's getting at is you will set your bar wherever you start at and you'll make changes that are too big in one direction, make changes that are too big in the other and you'll keep stepping those changes back and forth, but less extreme, until you find the right handling for you.

Learning to know what the car is doing requires you to go through a similar cycle. Most drivers will oscillate back and forth between under and over driving the car as changes are made to find where the new limit is at. The only way to really know when a change has been made is to go through those oscillations with the car and find those new limits. This is why I'm a strong advocate of autocross. It is safe and cheap and allows you to really push the car to figure out what it is doing. It is very easy to drive around a road course at 6/10ths-7/10ths and never know what is going on with the car. If you never push the limits and exceed them (which can be dangerous on a road course) you'll never truly know what the car is doing and what it's ultimate performance is and you wont know if the changes you've made are positive changes or negative changes.

Autocross also teaches you in a very intense manner. There is a lot to be gained in 3-6 runs of driving experience because the potential damage to the vehicle is so much lower which allows you to be more willing to approach the limits.

 

[kcbrown]

I'm going to steal Jason Rhoade's analogy, but tuning a car is a lot like hitting a bump in your car. You get your big initial displacement, it rebounds to just shy of the same value in the other direction, then just shy in the compression side, etc. Experience is like a adding a stiffer damper to the front suspension and the "zero" line is your ideal car handling. Experience reduces the number of oscillations before reaching that ideal point.

What he's getting at is you will set your bar wherever you start at and you'll make changes that are too big in one direction, make changes that are too big in the other and you'll keep stepping those changes back and forth, but less extreme, until you find the right handling for you.

Learning to know what the car is doing requires you to go through a similar cycle. Most drivers will oscillate back and forth between under and over driving the car as changes are made to find where the new limit is at. The only way to really know when a change has been made is to go through those oscillations with the car and find those new limits.

Well, let's take the autocross setting. You may be able to feel a change in the car's behavior, but how do you know whether or not it's a beneficial change? You generally only get 3-6 runs at a given autocross course, and while changes to the car may make a few tenths of a second difference in lap time on the road course, wouldn't that translate to a few hundredths of a second on the autocross course? I don't know about you, but my memory isn't good enough to let me learn an autocross course simply by walking it, or by driving it once. I have to drive it at least 4 times just to learn the course. My experience with the Evolution Driving School is that my variation once I've learned the course is on the order of tenths of a second per run after I've figured out the course. Prior to that, the variation (generally improvement) is on the order of over a second per run. And that's with something like 12 days of track driving and a previous 2 days worth of Evolution Driving School under my belt.

How can you possibly tell the difference in terms of how the car is behaving at an autocross event when you're up against all that?

This is why I'm a strong advocate of autocross. It is safe and cheap and allows you to really push the car to figure out what it is doing. It is very easy to drive around a road course at 6/10ths-7/10ths and never know what is going on with the car. If you never push the limits and exceed them (which can be dangerous on a road course) you'll never truly know what the car is doing and what it's ultimate performance is and you wont know if the changes you've made are positive changes or negative changes.

I completely agree. I loved the autocross format of the Evolution Driving School for that very reason.

Autocross also teaches you in a very intense manner. There is a lot to be gained in 3-6 runs of driving experience because the potential damage to the vehicle is so much lower which allows you to be more willing to approach the limits.

That's true about the limits, but my experience is that getting only 3-6 runs doesn't teach me very much, sadly. But I suspect that may be because in the past, I was concentrating on doing well at driving the course, rather than learning how the car was behaving. It might go much better if I just concentrate on the latter, and forget about how well I'm driving the course itself.

One of the things I'm going to do is take advantage of Hooked On Driving's "car control clinic". They set up a figure 8 in a nice open area of the paddock and let people drive it to their heart's content. I expect there's much to be learned about how the car feels from that.


All of this seems quite overwhelming. My experience to date has not been confidence inspiring in this regard. Usually experience tends to make clear what one needs to do in order to really improve, but that's not true here (at least with respect to things like consistency and feeling the car's behavior), and I can't figure out why that is.

 

[Whiskey11]

Well, let's take the autocross setting. You may be able to feel a change in the car's behavior, but how do you know whether or not it's a beneficial change? You generally only get 3-6 runs at a given autocross course, and while changes to the car may make a few tenths of a second difference in lap time on the road course, wouldn't that translate to a few hundredths of a second on the autocross course? I don't know about you, but my memory isn't good enough to let me learn an autocross course simply by walking it, or by driving it once. I have to drive it at least 4 times just to learn the course. My experience with the Evolution Driving School is that my variation once I've learned the course is on the order of tenths of a second per run after I've figured out the course. Prior to that, the variation (generally improvement) is on the order of over a second per run. And that's with something like 12 days of track driving and a previous 2 days worth of Evolution Driving School under my belt.

How can you possibly tell the difference in terms of how the car is behaving at an autocross event when you're up against all that?


I completely agree. I loved the autocross format of the Evolution Driving School for that very reason.


That's true about the limits, but my experience is that getting only 3-6 runs doesn't teach me very much, sadly. But I suspect that may be because in the past, I was concentrating on doing well at driving the course, rather than learning how the car was behaving. It might go much better if I just concentrate on the latter, and forget about how well I'm driving the course itself.

One of the things I'm going to do is take advantage of Hooked On Driving's "car control clinic". They set up a figure 8 in a nice open area of the paddock and let people drive it to their heart's content. I expect there's much to be learned about how the car feels from that.


All of this seems quite overwhelming. My experience to date has not been confidence inspiring in this regard. Usually experience tends to make clear what one needs to do in order to really improve, but that's not true here (at least with respect to things like consistency and feeling the car's behavior), and I can't figure out why that is.

I spent the better part of a year learning car control and course reading in a STOCK 2009 Mustang GT. It wasn't until my second year that I started tweaking things with the suspension first by adding D-Specs, then later Steeda Sport Springs, Steeda HD Mounts, Watts link and Strano bars on Z1 Sport Star Specs. More seat time revealed that I didn't like the body roll and the tied together compression/rebound damping adjustment on the shocks/struts.

You wont learn everything in one event. It takes people dozens of events to really get the hang of autocross and car control. If you can't reliably find the limits of the car and recover from it, you aren't close to being ready to start tweaking things IMO.

 

[kcbrown]

I spent the better part of a year learning car control and course reading in a STOCK 2009 Mustang GT. It wasn't until my second year that I started tweaking things with the suspension first by adding D-Specs, then later Steeda Sport Springs, Steeda HD Mounts, Watts link and Strano bars on Z1 Sport Star Specs. More seat time revealed that I didn't like the body roll and the tied together compression/rebound damping adjustment on the shocks/struts.

You wont learn everything in one event. It takes people dozens of events to really get the hang of autocross and car control. If you can't reliably find the limits of the car and recover from it, you aren't close to being ready to start tweaking things IMO.

That seems dead on. And it's why I'm comfortable with where my car is right now and the approach I'm taking, which is to accumulate seat time in what is at least a competent car, one which has enough capability to be instructive but which is also forgiving enough to keep me from killing myself as long as I exercise a reasonable amount of caution.

I'm just entering my second year of high performance driving, so it'll be interesting to see what I learn along the way and where I find myself at the end of the year.

It's been interesting reading not just this forum, but the M3 forums as well, and the discussions that have ensued there about damper selection and such. Many there believe the stock M3 to be a very capable car on the track as long as the suspension components are relatively new. And seeing how the Mustang GT is capable of keeping up with an M3 on the track when driven by the same professional driver, I suspect the same can be said of the Mustang as well, especially if the one thing it seems to lack, rebound damping control, is addressed, as I believe it is now.

Since my main mission is to have fun while learning a thing or two along the way, it could easily be that I'll keep the car the way it is for much longer than most here would, because this car is most certainly fun to drive, and I'll be happy with it as long as that remains the case. I guess I'll know that it's time to make a change to the car when I get to the point where I'm wishing the car could do more than it currently can.

 

[csamsh]

On the M3 vs. Mustang thing- yeah...they'll run about the same times, BUT, with what driver? Randy Pobst? Yes he can do it, and in that video that everyone always links to, the Mustang takes a lot more work to get it done. The point is...the tires, power and weight on each car are reasonably similar from the factory, so the frictional & accelerative properties are probably close. However, the M3 is much more [insert automotive journalism cliche of your choice] than the Mustang.

My point is, I'm not Randy Pobst.

Drive an E92 and you'll see what I mean

 

[sailorrhett]

Didn't think this would be post one but.... The m3 is a german surgical instrument of speed that is easy to drive fast. The s197 is a blunt force hammer. Can the right guy go as fast, yeah, but he would have an easier go in the m. And I had both. Now cost and maintance wise give be the stang.

 

[csamsh]

Didn't think this would be post one but.... The m3 is a german surgical instrument of speed that is easy to drive fast. The s197 is a blunt force hammer. Can the right guy go as fast, yeah, but he would have an easier go in the m. And I had both. Now cost and maintance wise give be the stang.

Somebody took [insert automotive journalism cliche of your choice] to heart.

 

[Norm Peterson]

while changes to the car may make a few tenths of a second difference in lap time on the road course, wouldn't that translate to a few hundredths of a second on the autocross course?

I doubt that any correlation can be defined solely in terms of lap times. Percentagewise, at autocross you're almost constantly turning one way or the other, but it's far less common for turns on a road course to be that closely spaced even in terms of time. There are a few road course turn sequences that feel like they need to be driven like an autocross, but sections like that have been the exception at least on the tracks I've run at and don't involve more than two or maybe three turns in quick succession.

An autocross is far more transient-intensive, where other things (momentary corner weights while the car is in the process of rolling, which the amount of damping does influence) are probably more important than how close you are to an optimum road handling amount of damping. Autocross is probably more forgiving of running excessive amounts of %critical damping - most courses at least try to avoid the worst bumps, which at ~35 - 45 mph don't involve the same risk as hitting a rough curb at 100+.


Norm

 

[sailorrhett]

Ha! I was having a lyrical moment. I usually just lurk around trying to decide how to best correct some of the understeer in this car.

 

[csamsh]

I doubt that any correlation can be defined solely in terms of lap times. Percentagewise, at autocross you're almost constantly turning one way or the other, but it's far less common for turns on a road course to be that closely spaced even in terms of time. There are a few road course turn sequences that feel like they need to be driven like an autocross, but sections like that have been the exception at least on the tracks I've run at and don't involve more than two or maybe three turns in quick succession.

An autocross is far more transient-intensive, where other things (momentary corner weights while the car is in the process of rolling, which the amount of damping does influence) are probably more important than how close you are to an optimum road handling amount of damping. Autocross is probably more forgiving of running excessive amounts of %critical damping - most courses at least try to avoid the worst bumps, which at ~35 - 45 mph don't involve the same risk as hitting a rough curb at 100+.


Norm

Agreed. And...the funny thing about the tight, quick parts of a road course is...wait for it...the autocrossers are fast there!

See: Rattlesnake, T2/3 at Hallett, for you TX/OK types

 

[kcbrown]

On the M3 vs. Mustang thing- yeah...they'll run about the same times, BUT, with what driver? Randy Pobst? Yes he can do it, and in that video that everyone always links to, the Mustang takes a lot more work to get it done.

That's probably true. Would a top-notch driver like Randy Pobst notice that? I would have expected him to comment to that effect if the Mustang were that difficult to drive fast in comparison with the M3. He does complain about the lack of damper control and the brake dive, but those seem to be his only complaints. Strangely, he seemed to think the M3 had more understeer than the Mustang, and also seemed to think the Mustang was better under braking despite the brake dive.


But if we assume for the moment that the Mustang is indeed difficult to drive fast in stock form, that raises a question: in what ways is it difficult? Which is to say, what driving characteristics does it have that would prevent an average person from driving it as fast on the track as that same average person could drive the M3?

 

[claudermilk]

The lack of damping control causes a lot of weight transfer. That is what bugged me about the stock suspension eventually.

I can only echo what Whiskey has been saying above. For my part, I spent a year-and-a-half running my '95 Probe GT in GS (quite successfully locally in SD region, to toot my horn) before touching the suspension. Then I spent another 6 months running in STX when it was first introduced--then life and mileage on the car got in the way. I returned to autocross with the Mustang, and again spent a year running it stock before touching a bolt. This time I had a lot more focus on what I was looking for in terms of what to "fix." The first event after installing the Konis and springs, I deliberately did that oscillation Whiskey alluded to; I ran full soft on the first run, then cranked them to full stiff the next one. That gave me a seat-of-the-pants reference for the limits of what the damping could do. Then I started dialing things in. I'm still fiddling, but I feel like I am at least making semi-educated guesses as to what to do.

 

[csamsh]

Which is to say, what driving characteristics does it have that would prevent an average person from driving it as fast on the track as that same average person could drive the M3?

-Bad Dapmers
-Noodle Springs
-Ride height

Fix those three and everything gets easier, roll centers be damned.

 

[Lucky_13]

And, uh, lack of steering feel. Much easier to drive a car fast when it gives you more confidence through the tiller.

 

[sailorrhett]

And, uh, lack of steering feel. Much easier to drive a car fast when it gives you more confidence through the tiller.

Yes

 

[kcbrown]

-Bad Dapmers
-Noodle Springs
-Ride height

No argument on dampers.

But "noodle springs"? The spring rates on the E92 are 160 lb/in up front and 550 in the rear, but the motion ratios are 0.96 up front and 0.58 in the rear, so the wheel rate up front (from the springs) is 147 lb/in up front and 185 lb/in in the rear. That's according to this thread at m3post.com.

That's somewhat different from the stock Brembo GT (131 lb/in at 0.96 motion ratio gets you about 121 lb/in wheel rate), but pretty close to that of the Boss 302 (148 lb/in in the front gets you 136 lb/in wheel rate). Either way, I suspect when you say "noodle springs", you mean usage of springs with rates of around 450 to 550 lb/in up front, and 250 lb/in in the rear, i.e. the typical coilover setup.


As for ride height, which you want to lower to get a lower CG, I can't find any data whatsoever on the stock E92's CG, so I can't say how much of a difference there is on that front.


I guess I'd have to drive an E92 around an autocross course and compare that against my Mustang to really know if the E92 is that much easier to drive fast. No way I'm going to get that kind of opportunity on the track, and in any case, I don't push my car quite that hard on the track.


Oh, and I completely agree on steering wheel feel. And that raises a question: does the Ford Racing steering rack (M-3200-EPAS) take care of that problem?

 

[csamsh]

Well, to be fair the m3 also has pretty soft fronts.

No, the steering rack doesn't do anything. The fact that we have EPAS and not electro hydraulic steering is the main culprit in the lack of feel dept. I'm perfectly happy to trade steering feel for having to mess with an additional hydraulic system though. It's also nice to ditch the #1 fire starter that is power steering fluid.

 

[sailorrhett]

So the only reason to swap the EPAS seems to be if you get the steering shake. Guess I will stay away from the front control arms and bushings. I miss the feel, but it isn't something that I can overcome.