From Koni to bilstein. I've seen the light. Thanks vorshlag!

[white86hatch]

Terry, you specifically mention that the Bilstein front struts in your Street Pro kit are 1.5" shorter than stock. Are the rear shocks shorter as well?

They were shorter than the koni yellows they replaced on my car. So I'm guessing the koni shocks were stock length.

 

[kcbrown]

A few folks (like kcbrown and others) really like the adjustable Konis, and asked some really good questions. I wasn't ignoring them - just buried with work and haven't been on the forums almost at all.

No worries.

I like them quite a lot more than the stock dampers. For the stock (Brembo) springs, they seem to work well. There are quite a few people who seem to like them, including on forums like bossmustangsonline.com.

I certainly get that coilovers are ultimately the way to go on these cars. It's just that my use won't tolerate lowering, so I have to use a solution that can maintain the stock ride height. And since the roll geometry is worse when you lower the car than when you keep it stock, the spring rates will (I expect) necessarily be different up front (probably lower) when you keep the stock ride height than when you lower the car. Yes, brake dive isn't going to be helped as much, but that's not necessarily a bad thing. What matters (I'd think) is whether or not your suspension geometry is near-optimal under heavy braking and (particularly for the outside tires) under cornering.

For your case, you're looking to lower the CG as much as possible while still keeping the suspension functional, so I get that you'd want to lower the car and, since you don't really care about how much spring rate you have up front (as long as it works for maximizing grip and responsiveness), you're willing to put 800 lb/in springs up front and call it good (after testing, of course!). No matter how good the dampers are, 800 lb/in up front is simply not going to work for me.

Some of the numbers don't work, because there are no lowering springs that are in the spring rates range that were mentioned (all of the many we have tested are 0-60% stiffer than stock, when measured by someone who knows how to use a spring rating machine). Don't confuse coilover spring rates with lowering springs, which are ALL soft in comparison. We add 300-700% to the front spring rates with coilovers on the S197. Because these fat cars NEED it to resist dive and roll with proper tires.

(bolded emphasis mine).

That is the key. You guys are going for maximum grip, because you're trying to win competitions. That means you're putting the fattest, grippiest rubber under the car you can lay your hands on. I'm going for maximum enjoyment, because I'll never actually win competitions (you think you're a "hack driver"?? Hah! You ain't seen nothin'!) and, for myself, find that competition actually takes the fun out of it, and converts it into a serious activity.

Take the available grip past the "good behavior" design limits of the suspension and of course it's going to behave badly!

The car above has 800#/in springs and Whiteline bars on full stiff, and still has significant roll

With the roll moment arm lengthening by twice the amount you drop the car, of course you're having to use such high spring rates in order to control the roll. You'd probably get significantly less roll if you raised the ride height back to stock levels, but your CG height would probably make the end result perform worse in the end. It's all a tradeoff.

Also of note is that the above roll is probably with, what, 1.4G to 1.5G worth of lateral force? The more grip budget you have, the more roll you're going to get when you're at the limits of that budget, all else being equal.

Without the spring rates a coilover can provide, there's only so much you can hope for with lowering springs, but its a big cost savings to stick with this system vs a proper coilover. The OEM rates of 100-150#/in are so soft that the cars flop around and roll and dive like crazy, on the stock tires.

Compared with cars like the one in the picture above, I have no doubt at all. With the exception of Corvettes and other such cars, are there any cars for which you won't be able to say exactly the same thing?

I've started to notice the roll in my car, too, so it's definitely there. But I haven't (yet) found it to be a hindrance. I'm going to drive another few track events before making changes, to see if things like that appear to be consistent to me.

One last thing: clearly, body roll is regarded as a bad thing around here. Why is that? Doesn't body roll mean that the inside tire is getting more grip? Isn't that a good thing as long as the outside tire's grip isn't compromised by, e.g. the camber curve?

Indeed, by lowering the car, aren't you making the camber situation at the outside tire worse?? Certainly, you're positioning the LCA so that it's that much closer to the point beyond which the camber starts getting worse, thus necessitating that much more in the way of wheel rate just to keep the outside front suspension geometry under control, yes?


Finally, if you think the (Brembo-equipped -- the non-Brembo car is a boat in comparison to nearly anything) Mustang's body motion on stock tires is all over the place, you haven't driven a Nissan 300ZX Twin Turbo on an autocross course. That has motion that (most importantly) is slow enough to settle that you have to move the controls a noticeable amount of time before the turn you're attempting if you want to get real precision out of it. The Mustang in stock form is way ahead of that. It just ain't as bad as you make it out to be (I do realize, though, that some of this stuff is a matter of what you're used to, what your experience level is, etc.).

When you up the mechanical grip things go nuts, and this is why people bottom out stock length shocks with lowering springs in autocrosses and on a road course. Never mind when they hit a bump on the street, that can make for a "total loss of bump travel" as well.

Exactly! My view on this is: if you're going to lower the car at all, then go with coilovers and be done with it. You have to make so many changes in order to keep things properly under control anyway that coilovers are really the only way to do it right.

Or you could avoid lowering the car. It might be possible to get springs that would maintain the stock ride height and give you more spring rate. I'm not sure what would be involved in that. I believe there are some places that will custom make springs for you, but I don't know what kind of prices they charge. See, e.g., http://www.coilsprings.com/sports_cars.aspx.

My suspicion is that by the time you get to the point that you're talking about getting custom springs made, you're already in the price territory occupied by low to midrange coilovers, and it's then just a question of getting a set of coilovers that will cover the ride height range you're looking for. The only coilover set I've been able to find that (at least is claimed) will allow me to retain the stock ride height are the JRi coilovers sold by Maximum Motorsports, and I only got that information by talking with them directly. Those are expensive, at around $4k.

If the Bilstein coilover setup you're working on will cover the stock ride height, then I'm going to be interested, but probably not for a while. There are other changes to the car that I expect I'll want to make first (e.g., a Watts Link, seeing how I've noticed a left versus right difference in understeer/oversteer), and I'm not going to make more than one change at a time, since otherwise I won't know what change caused what.

We are packaging the best length Bilstein monotubes we could find with lowering springs that lower these 4x4 OEM ride heights (that was my 2011 Brembo GT when it was bone stock, above) by about 1-1.5 inches, but since we found the shorter front strut you aren't losing the normal 1-1.5" of bump travel that would be lost with stock length struts. Konis, Tokicos, KYBs, "Ford Racing" struts, and virtuatlly anything else made to use the OEM style springs are the same OEM length and DO lose significant bump travel when used with lowering springs.

This is why many people complain of poor ride with Konis (or whatever OEM length twin tubes) with lowering springs - they are slamming into the bump stops constantly. This can and will damage the struts and shocks over time.

But if you're not hitting the bump stops with the Bilsteins, won't your tires be contacting the fenders or some other part of the car? If not, then it sounds like the OEM spec dampers were improperly specified for the car from the beginning, because it means that there is more potential compression travel available that they're intentionally not making use of.

This is what it usually takes - first hand experience with the WORST options and the BETTER options to understand all this. You can read a million reviews and not get the experience of feeling the difference.

And therein lies the real problem. How can you possibly find out how a different setup feels without driving it? How are you going to ever be able to drive a different setup without committing the funds to it? It's not like someone with the setup you're considering is going to let you take their car onto the track, most especially if you haven't got any experience driving the setup and thus don't know what to expect from it. And how a car behaves on the track isn't the same as how it behaves in the autocross.

And finally, the type of setup that I'd be interested in is something that nobody has on their car. Nobody has stock ride height coilovers with spring rates anywhere in the ballpark of what I would consider to be livable on the street. And that's before we get into the fact that higher spring rates on the street are going to pound the wheels harder. Wheels are supposedly a "wear item" in the sport, but when it's the street that bends them, then one has to be concerned about making any changes that would cause the wheels to see higher transient forces on them.

I'm willing to bet that a significant portion of the Koni users here that have 12+ months and/or significant miles on their shocks with lowering springs, if they took the dampers off their car they'd find at least one shock that was blown - one with no Nitrogen charge left. Take em off, compress the shafts, and see if they come back to full extension.

Wouldn't surprise me. My bet is that the Konis are designed, first and foremost, for stock springs, stock ride height, and stock suspension travel.

But if you appreciate the work we've done, buy them for us for a tiny bit more. If you appreciate convenience of having the right Bilstein B6 dampers coupled with springs we have tested first hand and Vorshlag camber plates, all pre-assembled and packaged together, then buy them from us.

I can't agree with the above more. The support is worth it, even if it doesn't always result in any real resolution of the issue.

 

[Vorshlag-Fair]

Whoa, who, whoa.... KCBrown.... you are massively over-thinking a lot of this stuff!!! By chance, are you an engineer? Please take all of this knowing that I respect your thinking, but feel that its all overblown and off base. You talk about roll couples and roll centers and geometries... camber curves, and ruining the car by lowering it. I got about halfway through your post and my eyes crossed... your logic and debates hurt my brain and I actually understand this stuff, have an engineering degree, and design suspensions for a living.

Please stop writing so much and relax a little. Honestly, some of the stuff you write is way off base, and you are confusing people with a lot of technical jargon that is mostly meaningless in these situations (not Formula 1) or that are blown way out of proportion. This over-thinking, propagated via the internet forums, is how so many people get confused into buying bad parts, or learning things that are the opposite of fact. This is how shops sell lots of "bump steer correction" kits, tubular control arms and K-members, subframe reinforcements, bolt-on braces and other useless doo-dads. Over-analyzing problems that don't exist or that are so inconsequential that they can be ignored. Magic shock frequencies, roll couples, migrating roll centers... those are all well and good on an F1 car, but we're talking about two steps up from a horse and buggy with this chassis.

The number of formulas, graphs, charts and confusing terms in my reply will be zero. Why? Because none of that "calculating" really matters on these cars because they are SO compromised in so many ways.

KCBrown here is one of the VERY few people on this or any enthusiast automotive forum who would continue to run OEM springs, stock ride heights, and skinny tires on purpose. I suspect he is 1 in 500 that does it for anything other than budget reasons, if I were a betting man.

I need to make a video of what driving a STOCK late model S197 Mustang HARD on track looks like. It is TURRIBLE. It will give most people motion sickness, and it is EXTREMELY unpleasant to drive like that for very long stints on track. In my position as owner at Vorshlag and an instructor for many autocross schools and HPDE groups, I get to drive hundreds of Mustangs - and more stock ones than I want to. The S197 chassis is not "God's Chariot" in stock form. It's not a good handling car - it is a big, heavy, tall, soft marshmallow PIG of a car.

Luckily it has one main saving grace: it came with a big honkin 5.0L V8 (unless you chose poorly) and pretty decent brakes (Bembos). That's why I bought our 2011 - when the Coyote came in it, now it was worth using. The platform itself has a very rigid chassis and decent enough "bones" to work with, too.

Quick and Rude Mustang Facts: the GT500 is worse in almost every way. The Boss302 is not special or magic, its just a bunch of stickers and a few dood-dads slapped onto a 5.0L Brembo car that a real track driver will toss in the trash (Tokico shocks?!). The V6 is not worth buying unless you are a middle aged secretary and the automatic should be banned. hehehe...

The S197 V8 cars are not alone in this predicament of being "terrible handling cars in stock form". And I don't care what magazine journalists have to say about this car - they only get to drive OEM unmodified rubbish cars, anyway. There are other, heavy-ish modern cars with decent power that come with crap suspension from the factory. The top of the line EVO X MR (above) was a JOKE in stock form. 3610 pounds (very similar to the 2011-14 V8 Mustangs) and yet it had soft springs and tall ride heights with skinny stock wheels (17x8") and tires. It felt like it was going to flip over and I would have sworn we were dragging the door handles in that first autocross event where we ran it with stock springs/shocks (above).

And just like with the S197, we made it handle better with improvements to spring rates, shocks, bars, bushings and lowering the ride heights. But unlike our "over the top" TT3 Mustang, we kept this one street friendly with moderate spring rates (450#/in) and no aero mods. Like our S197 formula, this car got the same basic upgrades: 18x10.5" wheels, 275mm tires, more spring rate, lowered by 1.5 inches, good monotube adjustable coilover dampers (AST), and camber plates up front. To help control roll it also got adjustable swaybars, and of course a few power mods. It was a LOT more fun to drive and it won a lot of races and even set some NASA track records in TTA. There are dozens of useless doo-dads and "fixes", available as parts from the aftermarket, it did NOT get, too.

The stock S197 is similar in almost every way. Too tall, too soft (springs and bars), skinny wheels (18x8" or 19x9") and tires. It has big sloppy bushings and soft rubber strut top mounts that allow all SORTS of camber loss under loading, toe change under braking, and makes for a big wonky mess when pushed hard. All of the formulas in a suspension engineering book get thrown out the window when the wheel is moving laterally 1/2" due to hydraulic bushings! Add more mechanical grip (tires) while keeping all of this stuff stock and it can get downright ugly. It might work for somebody going really slowly, but not real enthusiasts, track junkies or autocrossers - unless they like painfully sloppy cars that eat tires at an alarming rate (ie: Stock class SCCA competitors).

Look, you are NOT "ruining" these cars by lowering them, if you do it the right way. Lowering the CG is one of many ways we make this chassis corner harder (look it up) and LESS of a floppy, sloppy parade float for track or autocross use. Sure, there are considerations that must be looked at when you lower the S197, and you CAN "over-lower" this and any car. When the ride height is lowered more than 1/2" from stock you should:

1. Add rear LCA relocation brackets to improve the anti-squat
2. Go to an adjustable panhard bar or watts link to center the axle (it shifts laterally in one direction at ride height when lowered)
3. Increase spring rate and/or shorten the damper lengths to prevent loss of bump travel
4. Check bump travel and trim bump stops accordingly

That's not rocket science, and its not as complicated, detrimental or dangerous as some interweb posts would have us believe. Again, I think someone along the line spooked kcbrown about lowering cars, or he read some over-blown article explaining the evils of lowering. Its just not that terrible of a thing, and the factory suspension geometries just aren't that good to begin with on this car.

In the 1960s and 70s, lowering a car could put it into some wacked out camber curve that GAINED positive camber as suspension went through its motions. But those cars were beyond terrible even in stock form - some of those old muscle cars have NEGATIVE caster, went into positive camber under cornering (above), and virtually all of them had weird problems and terrible static and dynamic geometries. And even the 19880-90s Mustangs were fairly terrible, but they could be made better than stock with the right aftermarket parts.

Even the S550 is soft and sloppy in stock form! But we can make those better, too

The S197 is a lot better car than any previous generation Mustang, in every way except weight. To compensate for the added mass we use THE BIGGEST TIRES MONEY CAN BUY and every increase in width helps. There is NO downside to bigger tires on these cars, except if you spec the wheels wrong and run out of room (rubbing).

But to say that "brake dive isn't necessarily bad" is patently absurd. Look at this stock 2006 GT under braking at an autocross and tell me "that looks fine."...

That's Jon's Mustang (above) when it was still bone stock, with the OEM springs and shocks. It was TURRIBLE. Turrible, turrible, turrible! The massive brake dive transfers too much weight to the already over-loaded front tires (due to a heavy front weight bias), and reduces braking potential dramatically.

Now here is the same car and driver HARD on the brakes on track, after a spring upgrade (550F/250R), new shortened housing dampers (MCS TT2), adjustable camber plates, wider wheels (18x11") and wider tires (295 Rivals). Its over 2" lower than stock, and has the fixes above we say help (LCAs + brackets, adj panhard bar), but nothing else it doesn't need. It still rides well, is still daily driven, but it is MUCH faster in autocross and track events and a LOT more fun to drive. It also wears tires dramatically better, doesn't have 5 degrees of tilt cornering and 12 degrees of brake dive when stopping. Everyone who rides in this car at an event wants to buy the shocks it has. Every. Single. One.

So anyway, that's my response to the "over-analzing" and "stock is safe" arguments of others. No offense is meant, just want people to keep things in perspective and not be AFRAID of lowering or modifying their cars, with the help of real suspension experts that understand "what matters and what doesn't". We work on a LOT of these cars and have made hundreds handle better without getting into the extremes we do on our TT3 car. The above two Mustangs have our suspension upgrades, handle better, and lap times went down as smiles got wider. None of them worried "Are my camber curves ruined?!", they just trusted the source and had fun. Isn't that what this is all about?

Cheers,

 

[sailorrhett]

I am just here to steal the chart for an engineering review later. Thanks!

 

[claudermilk]

Goody, Terry's gotten wound up. Dis gon' be gud!

This is how I feel with some of the very techincal discusions that get going around here. Not to bash them--and I try to follow as much as possible to learn something--but they often turn into the Charlie Brown parents' speech.

Compare that with my last outing. This is full braking from ~120 to ~30. It's harder to see because of the head-on angle, but the amount of brake dive is visible--not much. There was no tail-wagging this time where the car was starting to wiggle on OEM suspension in the same place the year before.

Look, you are NOT "ruining" these cars by lowering them, if you do it the right way. Lowering the CG is one of many ways we make this chassis corner harder (look it up) and LESS of a floppy, sloppy parade float for track or autocross use. Sure, there are considerations that must be looked at when you lower the S197, and you CAN "over-lower" this and any car. When the ride height is lowered more than 1/2" from stock you should:

1. Add rear LCA relocation brackets to improve the anti-squat
2. Go to an adjustable panhard bar or watts link to center the axle (it shifts laterally in one direction at ride height when lowered)
3. Increase spring rate and/or shorten the damper lengths to prevent loss of bump travel
4. Check bump travel and trim bump stops accordingly

Check. Check. Check. Check.

That's not rocket science, and its not as complicated, detrimental or dangerous as some interweb posts would have us believe. Again, I think someone along the line spooked kcbrown about lowering cars, or he read some over-blown article explaining the evils of lowering. Its just not that terrible of a thing, and the factory suspension geometries just aren't that good to begin with on this car.

<snip>

So anyway, that's my response to the "over-analzing" and "stock is safe" arguments of others. No offense is meant, just want people to keep things in perspective and not be AFRAID of lowering or modifying their cars, with the help of real suspension experts that understand "what matters and what doesn't". We work on a LOT of these cars and have made hundreds handle better without getting into the extremes we do on our TT3 car. The above two Mustangs have our suspension upgrades, handle better, and lap times went down as smiles got wider. None of them worried "Are my camber curves ruined?!", they just trusted the source and had fun. Isn't that what this is all about?

Cheers,

The camber looks fine to me after lowering. The car now handles better in almost EVERY way. This is on "craptasic" Konis, OEM-style springs (considered still soft around here @ 200 lb/in), Steeda adj Panhard, BMR LCA & relo brackets. A very mild setup for around here. Yet, I've shaved SECONDS off lap times around the course, the car feels much more confident, and likely has more time in it as it sits now.

I said "almost every" way and that applies to DD. On the street, the bumps are harsher and there are some surfaces the car doesn't like (though the worst section even OEM didn't like). It's a trade-off made for a firmer suspension to get better handling. If I wanted a Cadillac ride, I would have bought a Cadillac.

 

[kcbrown]

Whoa, who, whoa.... KCBrown.... you are massively over-thinking a lot of this stuff!!! By chance, are you an engineer? Please take all of this knowing that I respect your thinking, but feel that its all overblown and off base.

I have an engineering mindset, at least. I do software, but did my first couple of years of college in the electrical engineering program. I switched to computer science because I found I was spending most of my free time messing around with computers, and realized that it was my calling. Best decision I ever made, but I never lost the mindset that goes with engineering...

You talk about roll couples and roll centers and geometries... camber curves, and ruining the car by lowering it. I got about halfway through your post and my eyes crossed... your logic and debates hurt my brain and I actually understand this stuff, have an engineering degree, and design suspensions for a living.

Then either I'm not explaining what I'm saying properly, or I'm actually getting something wrong. If I'm actually getting something wrong, I'd like to know what.

Please stop writing so much and relax a little. Honestly, some of the stuff you write is way off base, and you are confusing people with a lot of technical jargon that is mostly meaningless in these situations (not Formula 1) or that are blown way out of proportion.

And that is not my intention at all. If I'm getting something wrong, this is the perfect place and time to correct it. So please tell me what I'm getting wrong and why, because getting anything wrong does nobody any good, including me!

This is the most awesome graph! Had me laughing out loud.

KCBrown here is one of the VERY few people on this or any enthusiast automotive forum who would continue to run OEM springs, stock ride heights, and skinny tires on purpose. I suspect he is 1 in 500 that does it for anything other than budget reasons, if I were a betting man.

I am certainly "unique". Part of that is that I know my limitations. I know I'm not going to win anything, because I know I'm just not that good. So if I can choose between relaxing, having fun, and learning to drive as well as I can, versus trying and failing to win, I'll choose the former.

I don't expect most people are like that...

I need to make a video of what driving a STOCK late model S197 Mustang HARD on track looks like. It is TURRIBLE. It will give most people motion sickness, and it is EXTREMELY unpleasant to drive like that for very long stints on track.

I'd very much love to see that video.

I suspect that part of the reason I don't see/feel the kind of motion that you're talking about is that my control inputs are smooth to a fault. For instance, when braking, my braking pressure increases linearly from zero to somewhere between 80 and 90 percent (I always hold braking in reserve because if I screw up, I'll need something to work with to save the car and myself) over a period of somewhere around a second. That is an eternity compared with how most people brake. My control inputs around corners is similarly smooth where the track allows, which is most corners.

In my position as owner at Vorshlag and an instructor for many autocross schools and HPDE groups, I get to drive hundreds of Mustangs - and more stock ones than I want to. The S197 chassis is not "God's Chariot" in stock form. It's not a good handling car - it is a big, heavy, tall, soft marshmallow PIG of a car.

Then perhaps my driving style simply doesn't reveal that.

The stock S197 is similar in almost every way. Too tall, too soft (springs and bars), skinny wheels (18x8" or 19x9") and tires. It has big sloppy bushings and soft rubber strut top mounts that allow all SORTS of camber loss under loading, toe change under braking, and makes for a big wonky mess when pushed hard. All of the formulas in a suspension engineering book get thrown out the window when the wheel is moving laterally 1/2" due to hydraulic bushings! Add more mechanical grip (tires) while keeping all of this stuff stock and it can get downright ugly.

(bolded emphasis mine)

That's exactly why I agree with you. If you increase the mechanical grip, you have to change the suspension accordingly. It'll overwhelm the springs, bars, dampers, etc. otherwise, and put the suspension into unhappy places.

It might work for somebody going really slowly,

Which could easily be me. My "best" at Laguna Seca so far is about 1:54. I rarely measure my lap time because I know myself, and know that if I do, I'll start chasing lap times and eventually stuff the car into a wall in the process. And I'm just not sufficiently consistent for it to be a meaningful gauge of how well I'm driving anyway.

Look, you are NOT "ruining" these cars by lowering them, if you do it the right way.

Nor am I saying that you are. Which is to say, I agree with you on that.

My comment with respect to lowering these cars is with respect to the comments about how much spring rate you need up front (800 lb/in!) to control the roll. My comment is not about lowering cars in general, it's only about these cars, and only because lowering the car drops the front roll center 3x faster than the CG drops.

But, let's say that I'm wrong about that. If that isn't why you need so much spring rate up front, then what is? Why do you need 3 times the amount of rate up front than you do in the rear just to keep the roll in check?

Lowering the CG is one of many ways we make this chassis corner harder (look it up) and LESS of a floppy, sloppy parade float for track or autocross use. Sure, there are considerations that must be looked at when you lower the S197, and you CAN "over-lower" this and any car. When the ride height is lowered more than 1/2" from stock you should:

1. Add rear LCA relocation brackets to improve the anti-squat
2. Go to an adjustable panhard bar or watts link to center the axle (it shifts laterally in one direction at ride height when lowered)
3. Increase spring rate and/or shorten the damper lengths to prevent loss of bump travel
4. Check bump travel and trim bump stops accordingly

Yep. But in order to control the roll up front, you have to add a bunch of extra spring rate that you otherwise wouldn't need just to get the same amount of roll as you had before.

It has other benefits, though, as you note (reducing brake dive).

The S197 is a lot better car than any previous generation Mustang, in every way except weight. To compensate for the added mass we use THE BIGGEST TIRES MONEY CAN BUY and every increase in width helps. There is NO downside to bigger tires on these cars, except if you spec the wheels wrong and run out of room (rubbing).

Or if you increase the mechanical grip enough and fail to compensate for it.

It's a system, right? With everything having to work together to achieve something better than what you had before.

But to say that "brake dive isn't necessarily bad" is patently absurd. Look at this stock 2006 GT under braking at an autocross and tell me "that looks fine."...

That's Jon's Mustang (above) when it was still bone stock, with the OEM springs and shocks. It was TURRIBLE. Turrible, turrible, turrible! The massive brake dive transfers too much weight to the already over-loaded front tires (due to a heavy front weight bias), and reduces braking potential dramatically.

Does the brake dive cause additional weight transfer, or is it the result of weight transfer? If the former, then yeah, that's bad. If the latter, then, well, that just means the dive itself is just symptomatic of something else that needs to be addressed.

So anyway, that's my response to the "over-analzing" and "stock is safe" arguments of others. No offense is meant, just want people to keep things in perspective and not be AFRAID of lowering or modifying their cars, with the help of real suspension experts that understand "what matters and what doesn't".

And I should emphasize that I am not against lowering cars in general! Not at all. What I am saying is that if you're going to lower your car, do it right. And yes, the help of suspension experts (such as yourself) will ensure that the end result is that it is done right.

We work on a LOT of these cars and have made hundreds handle better without getting into the extremes we do on our TT3 car. The above two Mustangs have our suspension upgrades, handle better, and lap times went down as smiles got wider. None of them worried "Are my camber curves ruined?!", they just trusted the source and had fun. Isn't that what this is all about?

It is, indeed.

I'm unique. My requirements are unique. I've stated that more than once. Nobody else needs to keep their ride height stock Because Streetcar. I do because I can't drive into my driveway otherwise.

That comment I made about wheels in my previous message wasn't an idle one, either. Terry, you know exactly what I'm talking about there because I discussed it with you on the phone. It's one of the big reasons that I'm very hesitant to increase my spring rates.

 

[Vorshlag-Fair]

kcbrowns 86 part quote just proved my point....

 

[SoundGuyDave]

Nobody else needs to keep their ride height stock Because Streetcar. I do because I can't drive into my driveway otherwise.

Here you go:

Now that the problem is solved, would you like your coil-overs single, dual, or triple adjustable?



Just having fun, but honestly, you ARE overthinking things... Like the brake dive issue. Whether load transfer is a cause or effect is immaterial. The fact that it happens IS material, and the solution is to reduce the load transfer. That means either not braking as hard (BOO!!), or increasing the resistance to that dive, which means higher wheel rates up front. Since this is a pure longitudinal force, with no roll contribution, swaybars are out of the equation, and the only (reasonable) way to get more wheel rate becomes.... higher spring rate! QED. If transfer causes the dive, then problem solved. If dive causes the transfer, also problem solved.

 

[Norm Peterson]

Whoa, who, whoa.... KCBrown.... you are massively over-thinking a lot of this stuff!!! By chance, are you an engineer? Please take all of this knowing that I respect your thinking, but feel that its all overblown and off base. You talk about roll couples and roll centers and geometries... camber curves, and ruining the car by lowering it. I got about halfway through your post and my eyes crossed... your logic and debates hurt my brain and I actually understand this stuff, have an engineering degree, and design suspensions for a living.

So anyway, that's my response to the "over-analzing" and "stock is safe" arguments of others. No offense is meant, just want people to keep things in perspective and not be AFRAID of lowering or modifying their cars, with the help of real suspension experts that understand "what matters and what doesn't". We work on a LOT of these cars and have made hundreds handle better without getting into the extremes we do on our TT3 car. The above two Mustangs have our suspension upgrades, handle better, and lap times went down as smiles got wider. None of them worried "Are my camber curves ruined?!", they just trusted the source and had fun. Isn't that what this is all about?

Terry, I'm pretty sure you were hinting about me. So I'll just say that some people just have to understand things more completely and on their own terms rather than just taking somebody's word for it. That's not to say that experience-based suggestions aren't appreciated, only that in and of themselves it is not possible to see the thought process behind them.

While I can't speak for KC, I can say that of the few times I've been dissatisfied with a modification - spread out over 45+ years - most of those cases have resulted from me not doing enough of my own due diligence and, well, taking somebody else's word at face value.


Re: lowering . . . I have a little personal experience to fall back on here and I can certainly agree with the problems associated with most of the common "lowering springs". Case in point involves a Mazda 626, which tries to corner on the door handles to begin with. Adding ~60% stiffer springs and it still cornered on the door handles - and made shorter tires rub in easy street cornering where it hadn't rubbed the taller OE-size tires at autocross. I didn't much care where it was classed anyway, so I ended up fabricating spacers to regain some ride height (and more importantly corrected the LCA inclinations and geo roll center heights). Rolled less and never rubbed again with either set of tires. I'd really rather not have to do a DIY mod right on top of a mod that I just paid for . . . but I will if I have to and can actually accomplish the fabrication.

The S197's lowering situation seems to be that lowering without "enough" spring rate WILL result in bottoming and is apt to result in damage to off-the-shelf Koni yellows. Something that those of us with those dampers do need to keep in mind, given that none of the "big springs" have enough rate for the amount lowered.


It's not that I'm afraid to mod, or even to lower. Hell, I've got a set of your 18x11's. But I guess I've got a more stringent definition of "doing it right". While I already know I'd benefit from stiffer springs from the nose dive under braking perspective, as an engineer for most of my career it just rubs me the wrong way to install stiffer springs without getting the full benefit of the increased rate. Feels like I'd be taking three steps forward and one step back, or in other words not being very efficient about what I'd really be trying to do. For now, and probably for as long as I continue to run on 200&up treadwear street tires as opposed to R-comps, an inch or so of CG height just isn't going to matter (and FWIW I don't like the way the gap to the sheetmetal gets wider down at the lower edges of the body as the body is lowered anyway . . . everybody else just looks at the gap around the top quadrant and hey, I'm just different).


I realize that you can't look at the S197's suspension solely in geometric terms like you can with an all rod-ended race car suspension (even there it still comes with an assumption or two). The Mustang's so-called "pivot points" just move around too much. But that doesn't totally disqualify the idea of trying to understand the geometric behavior on the one hand and having at least a little feel for the compliance effects on the other. But maybe it's not "precise answers" that you're really after (and won't get, anyway) but trends.


I too would like to see some videos of a stock or mostly stock S197 on stock springs being driven hard. Make that "driven hard, smoothly".


Norm

 

[CobraRed]

 

[ddd4114]

KC, I've noticed that you've mentioned the front roll center dropping three times more than dropping the CG in several threads recently, and I suspect you got that from my thread a year ago. While I don't think that's wrong, I just posted an update that I think might shed some light on the issue (see post #58): http://www.s197forum.com/forum/showthread.php?t=113508&page=3

For what it's worth, I support KC's independent thinking whether it's right or wrong. Everybody learns differently, and my personality is definitely the over-analyzing skeptical type like his, so I can relate. However, I do understand that this has its limitations just as blindly following the norm does. I also think it's good to spark some good discussion and creative thinking from differing views like this as long as we all can be mature about it. After all, this is part of the reason for why message boards like this exist.

 

[kcbrown]

Here you go:

Now that the problem is solved, would you like your coil-overs single, dual, or triple adjustable?

I'll take triple, please.

Just having fun, but honestly, you ARE overthinking things... Like the brake dive issue. Whether load transfer is a cause or effect is immaterial. The fact that it happens IS material, and the solution is to reduce the load transfer.

Yes, reducing the load transfer would be the answer that takes care of both things. But if the solution is to reduce the brake dive, then, well, that might not reduce the load transfer.

For instance, what if you could (like you can with the rear suspension) change the front geometry to add an anti-dive component to it? Would you? That might take care of the dive for sure, but it wouldn't reduce the load transfer.

Finally, how can merely increasing the spring rate reduce the load transfer itself? All it's doing is changing the amount of movement you get up front when the load transfer happens. So what have you really accomplished by increasing the front spring rate that way?


It's lowering the CG (which means lowering the car) that reduces the load transfer, right? But in order to do that, you need to account for changes to the geometry of the suspension. You need more spring rate to deal with the reduced available compression travel, and then you need more spring rate again to deal with the increased roll moment arm.

That means either not braking as hard (BOO!!), or increasing the resistance to that dive, which means higher wheel rates up front. Since this is a pure longitudinal force, with no roll contribution, swaybars are out of the equation, and the only (reasonable) way to get more wheel rate becomes.... higher spring rate! QED. If transfer causes the dive, then problem solved. If dive causes the transfer, also problem solved.

Oh, I've no doubt of that. But look at the rates! 450 lb/in (nearly 4x stock) minimum, when even 800 lb/in isn't enough to control roll to the degree that Terry apparently would like. That seems excessive, but maybe that's because these cars are so incredibly undersprung that there's nothing for it. But there is an inescapable relationship between spring stiffness and ride hardness. The hardness one experiences on the stock springs with semi-decent dampers (Koni Sports) is sufficient to make me skeptical that the car is massively undersprung with the stock ride height.

Also, a lot of the dive that's apparent from that picture is actually from the rear lifting. Will stiffening the front (without lowering the car) reduce that? I'm skeptical.

 

[kcbrown]

KC, I've noticed that you've mentioned the front roll center dropping three times more than dropping the CG in several threads recently, and I suspect you got that from my thread a year ago. While I don't think that's wrong, I just posted an update that I think might shed some light on the issue (see post #58): http://www.s197forum.com/forum/showthread.php?t=113508&page=3

Interesting.

I completely agree that lowering the car will give you advantages. It's just that roll control ain't one of them for the S197 front suspension.

Also, of note is that the changes you made involved lowering the car from the beginning. I don't know if anyone here has ever played with optimizing the handling of the car while maintaining the stock ride height, precisely because lowering the CG is almost religiously regarded as a Good And Necessary Thing To Do.

I have no doubt that a lowered and handling-optimized car will outperform a car with optimized handling but which maintains the stock ride height. And if your goal is Because Racecar, then that's fine.

But what if your goal is good-performing Streetcar? When your car has to handle street bumps (and I'm not talking about the piddly little stuff most people seem to be speaking of, I'm talking about things like 3+ inch deep ruts across the freeway), without damaging your wheels, the ability of the suspension to absorb bumps becomes very important. That is obviously compromised when you increase the spring rates, and when you're talking about increasing it by nearly a factor of six in order to get close to properly controlling roll, dive, etc., then your 19 inch wheels Will Not Survive the street, unless they're the expensive forged variety, and maybe not even then.

For what it's worth, I support KC's independent thinking whether it's right or wrong. Everybody learns differently, and my personality is definitely the over-analyzing skeptical type like his, so I can relate. However, I do understand that this has its limitations just as blindly following the norm does. I also think it's good to spark some good discussion and creative thinking from differing views like this as long as we all can be mature about it. After all, this is part of the reason for why message boards like this exist.

Yes, indeed.

I never presume I'm actually right about anything. I do try to be, and try to be aggressive about correcting those things I get wrong, but I'm the sort that has to understand how and why things work, and will be skeptical of claims that lack the explanatory justification for them, and especially skeptical of such claims when I can't even experience those claims for myself. I've been bullshitted too many times to do otherwise.

I've ridden in (not driven) a few reasonably well-prepped cars on the track. Whether they were set up "properly" I cannot say. What I can say is that they didn't feel massively better to me on the track than my own car does. Maybe that is because I simply lack the ability to feel such things. Maybe it's because I lack the necessary experience to interpret what I was feeling. Maybe it's because my driving style is such that it simply doesn't reveal the bad manners that people here insist that Mustang has when it doesn't have at least 450 lb/in springs on monotube coilovers up front. Whatever the reason, the claims that are being made here are claims that I simply cannot verify myself without making the appropriate investment and at least risk ruining the streetworthiness of my car. And, most importantly, those claims are ones that the people who are making them either cannot or will not back with verifiable explanations as to why their claims are true.

That doesn't mean their claims aren't true. Far from it. Terry's results on the track speak for themselves, as do the results of so many others. But that does me no good at all because it means I can't use their claims to determine how to integrate what they've learned into a package that meets my needs. And I'm not willing to commit the funds to something that I can't even experience for myself ahead of time.

And as I said before, it seems that nobody has the needs I have. Jokes about fixing the driveway with concrete aside, the plain fact is that where I live, driveways like mine are common, and my car is a daily driver. Those things, combined with the apparent fragility of 19 inch wheels, place some rather serious limits on the things I can do to the car.

 

[csamsh]

3 steps forward, 1 step backward is still 2 steps forward. JS.

Gotta love the theoreticians....then again I'm an experimentalist so I would think that. I've never understood the need to know before something happens. Kind of defeats the purpose of trying things in the first place. But I guess there's a difference between blowing up a full scale reactor and having a leak at a pilot plant.

I of course understand there's a monetary side to all of this.

This post brought to you by the absentminded ramblings of Mark, a scientist who will never understand why engineers are the way engineers are.

 

[kcbrown]

3 steps forward, 1 step backward is still 2 steps forward. JS.

Gotta love the theoreticians....then again I'm an experimentalist so I would think that. I've never understood the need to know before something happens. Kind of defeats the purpose of trying things in the first place. But I guess there's a difference between blowing up a full scale reactor and having a leak at a pilot plant.

I of course understand there's a monetary side to all of this.

This post brought to you by the absentminded ramblings of Mark, a scientist who will never understand why engineers are the way engineers are.

Oh, I'm all for experimentation. But as a scientist, you know that an experiment isn't useful (i.e., it doesn't tell you anything) unless you have proper controls on it, because the purpose of the experiment is to help you understand what you're studying so that you can predict it.

It's one of the reasons I've decided to try to change one thing at a time when possible. I want to see the effects of what I'm changing and, when possible, only of what I'm changing. The last thing I want is to see that there's an improvement without knowing why there's an improvement, in such a way that I can predict what happens when I change the same thing in a different way.

Unpredictability is the bane of most of us. Whether it's predictability of the machine we're driving or of the changes we're making to it, or of the things we choose to do in the world, we depend on being able to predict outcomes for our ability to make decisions. And I, for one, depend on my understanding of how things work to predict the consequences of my actions.

 

[5.0 Probie]

Here... Let me dumb this down a bit...

I haz bilstien setup. Now kar stayz flat as tyres melt ooff wheelz.

 

[Norm Peterson]

3 steps forward, 1 step backward is still 2 steps forward. JS.

Of course. It also suggests that you could do better (and should perhaps try to). Competition rulesets permitting, anyway. Which doesn't matter to me any more and never will unless track day sessions lead to time trialing.

Gotta love the theoreticians....then again I'm an experimentalist so I would think that. I've never understood the need to know before something happens. Kind of defeats the purpose of trying things in the first place. But I guess there's a difference between blowing up a full scale reactor and having a leak at a pilot plant.

I of course understand there's a monetary side to all of this.

It's like I've said to Sam Strano, the time and ability to install and test a variety of choices before settling on what ultimately proves to be best is not an approach available to everybody. And that's separate from the expense involved - there's no way I could ever justify testing a couple of sets of "regular" shocks and struts with two or three different sets of big springs . . . and then going through it all over again with coilovers and their springs, before settling on one combination out of a dozen or more. All that for a car that still sees mostly street driving miles??? As a more or less independent individual, I wouldn't be able to justify the time or the expense or the labor to run such a program, assuming I could even locate a test venue . . .

Understanding what's going on and working from there is arguably the best substitute. You do need to be able to relate that understanding to your own needs, so you do have to take the engineer's hat off and put the test driver's helmet on from time to time.

This post brought to you by the absentminded ramblings of Mark, a scientist who will never understand why engineers are the way engineers are.

KC described it at least as well as I can; it's about being able to predict results based on known inputs or known changes to those inputs. It's also about having some idea what direction to take if the results don't match expectations. Understanding on a technical level may be a weakish substitute for an extensive collection of test data, but it's still better than wildly guessing and is easily good enough to keep from being sold parts that your car at any stage in its development does not need (*cough* bumpsteer kits for a very mildly lowered DD *cough*).


Norm

 

[jmauld]

Here you go:

Now that the problem is solved, would you like your coil-overs single, dual, or triple adjustable?



Just having fun, but honestly, you ARE overthinking things... Like the brake dive issue. Whether load transfer is a cause or effect is immaterial. The fact that it happens IS material, and the solution is to reduce the load transfer. That means either not braking as hard (BOO!!), or increasing the resistance to that dive, which means higher wheel rates up front. Since this is a pure longitudinal force, with no roll contribution, swaybars are out of the equation, and the only (reasonable) way to get more wheel rate becomes.... higher spring rate! QED. If transfer causes the dive, then problem solved. If dive causes the transfer, also problem solved.

You could also remove the engine, which would result in less weight transfer.

 

[Norm Peterson]

KC, I've noticed that you've mentioned the front roll center dropping three times more than dropping the CG in several threads recently, and I suspect you got that from my thread a year ago.

It's a fairly simple geometric construction, and vertical RC migration equal to 3 times the amount lowered actually is pretty close (based on some measurements I took off my own '08 GT I get 2.7:1 or so).

I'll be interested in that linked thread's update.


Norm

 

[Rabee]

I am also among the minority who like to keep the car stock for a while.
I own 2013 Boss 302 which I DD and track all year around.
I believe the car outperforms me as a driver. Once I am able to exploit "all" the performance it offers, then I will step up to proper coilovers and other supporting mods.

Bomarito lapped Laguna seca in 1:39.50! Darn fast.
Randy Pobst lapped Laguna seca in 1:41.06! Very fast

All stock!

The point I am trying to make, those ponies are capable, focus on your driving and improve yourself as a driver rather changing the suspension first.

This is applicable to most of us, now if you talk about race drivers like Terry for example, those people need the maximum ever from this chassis, best performing suspensions and tires...etc but please make no mistake, if you modify your car like Terry's there is zero guarantee you will be as fast as him.

I completely understand the aftermarket bussiness and the modifications pathways, they promote creativity, competition, better economy and more active busy market!

Imagine if no one rushes into buying any aftermarket suspension and the car guys decide to spend all that money learning to drive fast and participating in HPDE! We will end up with armies of great brilliant drivers and piles of dust over the aftermarket off shelf products. May be not so good for economy and too extreme of a statement, but something in the middle will be good.

Once again, if you own a violin does not mean you will ever be Niccolo Paganini.

However, perfect practice makes perfect! (Quoted from Ross Bentley)