Koni sports in conjunction with Boss 302 springs?

[Vorshlag-Fair]

At Sam Stranos' suggestion I changed My Brembo Package to a a Steeda Sport / Koni Sport package. I live in Los Angeles, which has recently been confirmed by NHTSA has having the worst roads in the U.S.. The Steeda Sports were too stiff. The ride was uncomfortable even on full soft. Too many bad roads to tolerate that set up. In one year, I had already blown out a ball joint and a set of Koni yellows that I am now having rebuilt. That is how bad the roads are. If I lived in Northern California or San Diego where the roads are better, it would have been fine. However, the rear Steeda Sports still do not give you enough suspension travel. And on rough roads at high speed the car became stiff and bouncy and dangerous.

Yep, have heard similar stories from hundreds of folks. OEM length struts + lowering springs = BAD NEWS. But Konis can work well in competition use, with a lot of "but ifs". If you run a lowering spring, they will bottom out constantly. They are virtually the OEM length, afterall. Koni makes a super short version for some cars (Miatas and Civics) to address this limitation. The ride quality is also "limited", and I wouldn't use them on the street. I drove a customer's 2012 GT today with Konis and it rides terribly, in my opinion.

Even a shortened coilover can still be run too low, where it is slamming around on the bumpstops and damaging the shocks. With the proliferation of cheap Chinese coilovers we are seeing this more and more in the stance crowd. As bad or worse then the stock strut/lowering spring issues.

I switched to Boss Springs and Koni yellows and it was a match made in heaven. Much more suspension travel. Less driveway scraping. Much more compliant on the road. Not quite as stiff as I would like at the track, but the compromise is well worth it and the car is still much faster than I am. It is not the Springs holding me back.

Tall (OEM) ride heights (like the Boss302 LS above, under braking at MSR-Houston) will always have more suspension travel, ground clearance, and such. Which is great for a street only car. But the statement "It is not the Springs holding me back" is pretty subjective. I'd wager you would be significantly faster on virtually any type of race track with a lower ride height and more spring rate, along with properly sized coilover shocks and struts. We saw 4 second drop in time on a 2 minute road course with a monotube coilover shock & spring change on an OEM 2013 GT (below), same conditions / tires and bars / driver / camber plates. That is, well, a lot.

Also, we need to give Ford Engineers a little more credit. The compromises they made between performance and comfort are sensible. They have tested these cars more than everyone on this forum has collectively. There is a good reason the Boss springs are softer in the front then in the back and I am totally down with it. To give up liveablility for some incremental increase in theoretical track performance makes no sense.

Well... that's not the only reasons they chose the OEM spring rates and lengths. OEM suspension engineers (and yes, I know some) have an impossible job: make the car SAFE for EVERY possible driver, yet have good performance and a perfect ride. Oh, and they need to be able to traverse crazy weather conditions, dirt roads, steep inclines, and speed bumps. And don't spend any real money, because these are still Fords here, not 911 GT3s. Impossible goals because they are conflicting goals. Even Boss302 owners don't get the best bits, because at least 1/2 (probably a lot more) of these buyers are folks who will never track these cars, and many end up stored in garages collecting dust.

So the result ends up as a huge compromise, even on the Boss302. Sure, they managed a decent "balance" on track (with a front spring rate bias, which everyone that understands suspensions gravitates towards on this chassis) and some commendable performance (remember when the Boss302 was being compared to the E92 M3, favorably, because it was matching or beating the $70K M3s times on road courses?) but the Boss302 is still jacked up in the air like a 4X4. They are still super soft (we've tested the spring rates) and flop around like a dead fish when you push them. Look at the in-car video with the "before and after" of Konis + lowering springs vs ASTs (with softer front rates than we use by 150#/in), in the post by SoundGuyDave above. That "massive brake dive" issue is much worse with the stock ride height/spring rate/shock set-up.

I've driven lots of these S197 5.0 and Boss302 cars, on the street and on track, from the basic Boss302 to Boss302LS and even Boss302-S. The "street car" Boss isn't much better than a Brembo equipped Mustang GT, honestly, when it comes down to lap times. Sorry, it is within a second or less on a typical road course. And your goals of "not to give up liveability" may not jive with everyone that owns one of these cars.

But the 302-S race car that Ford sanctioned and built has real money remote reservoir monotube coilover shocks, significantly more spring rate and a much lower ride height than the plain jane Boss302. Because it won't ever see snow drifts, snow chains, dirt roads, and the other unusual requirements for an OEM suspension from Ford. It actually drives pretty nicely on the street, too.

If you are interested in track and only track performance, spend $2600+ on coilovers. Otherwise Boss springs and Koni yellows are a good combination.

Well I will disagree on the "track and only track" statement, respectfully. Have you ever tracked a car with real coilovers?

We have a lot of happy customers with AST, Moton and MCS coilovers who do use their cars on track but are still predominantly daily driven street cars. I'd say at least 80% of the monotube coilovers we've sold ended up on street driven cars. Why? Because you CAN get significantly more track performance with a proper coilover set-up and still have excellent ride, if you have the right guidance. The best way to understand this it to EXPERIENCE THIS FIRST HAND by riding in a car that has monotube coilover shocks... seeing is believing, and you will will be spoiled for LIFE.

Sam had has poor results with his handful of ASTs he bought for himself and a couple of customers, many years and multiple revisions ago. We had a couple of customers that had the very same problems during the same time period, but we worked a little bit and found a real solution (a completely different AST built rear shock that we made fit these cars, rather than the inverted and too long unit that AST made on the first batch), with excellent results. Eventually AST Holland finally switched all AST 4100 and then 4150 builds for the S197 to this same length and style shock, with no serious issues on this line since.

I've got one of the very first S197 4100 sets from 2009 still running on the street and track to this day (we used them for 2.5 years and they've been on a customer's car ever since) using this alternate rear shock design we picked in early 2011 (non-inverted version with proper stroke). We've moved this set to 3 different cars and 5 different drivers. We could have slammed AST publicly and gone on a smear campaign, then been fired as a dealer, but decided to work with those guys and come up with a better solution. In the end what we helped come up with works and we've had a lot of happy customers and successful sales since then.

Sam won't ever recommend or sell that brand of shock, and he will probably talk most folks out of monotubes (he is a reluctant MCS dealer), as he seems to be a die-hard OEM-style Koni guy. And he's done well in autocross events with those shocks, especially using stock length springs (F Stock), so more power to him. But does that F Stock set-up work for everyone?

What I'm saying is that if you want a adjustable and lower then stock ride heights, real spring rate choices, maximum amount of usable suspension travel at a lower ride height, more performance and a good ride quality, you need to look seriously at quality monotube coilovers. That is an option that the nay-sayers cannot drown out, no matter how loudly they proclaim the evils of this brand or that. We simply have too many happy customers on these types of shocks with real results and excellent ride quality (on dual purpose cars).

Again, the best advice I can give is to find somebody on an AST, MCS or Moton and ride in their car. Then you can see for yourself and make your own judgements... it cannot be explained away, you simply have to experience this first hand to believe it.

Cheers,

 

[kcbrown]

What I'm saying is that if you want a adjustable and lower then stock ride heights, real spring rate choices, maximum amount of usable suspension travel at a lower ride height, more performance and a good ride quality, you need to look seriously at quality monotube coilovers.

But how much lower than stock? What's the minimum drop we're talking about here? And at that drop, how much additional extension do you have before the shocks hit their extension limit? And how much suspension travel do you have?

C'mon, man, don't just give me the platitudes, give me the hard numbers.

That is an option that the nay-sayers cannot drown out, no matter how loudly they proclaim the evils of this brand or that. We simply have too many happy customers on these types of shocks with real results and excellent ride quality (on dual purpose cars).

Again, the best advice I can give is to find somebody on an AST, MCS or Moton and ride in their car. Then you can see for yourself and make your own judgements... it cannot be explained away, you simply have to experience this first hand to believe it.

I completely agree. Experience is necessary for this, because it's a ride quality question that is subjective by nature.

So: anyone in the Silicon Valley area got a setup like Terry describes that would be willing to let me ride in it?

 

[SoundGuyDave]

I can't give you numbers, but the strut probably has something on the order of a 7" or so total stroke available.

If you assume no spring preload at all, 250lb spring rates, and roughly 1000lb corner weights up front, that translates to a ride-height 4" down from full droop, leaving 3" of bump travel and 4" of rebound travel. With a coil-over setup, you can alter the spring perch location along the length of the strut, which then affects where that ride-height comes in. If you preload the spring, with say 125lbs of seat pressure, that would move the ride height up 1/2", yielding 3.5" of bump, and 3.5" of jounce travel. If you leave the spring slack, with 1/2" of free space above the spring, that will give you 2.5" of bump, and 4.5" of jounce.

This is the real beauty of a coilover. You can select the spring rate that works the best for you, then adjust the ride height to best suit the geometry, then fine-tune with bars. Completely tunable, without large parts swaps upsetting equilibrium if you wanted to make a single change without corresponding side-effects.

With stock-perch dampers, if you want to change spring rates, you will also wind up changing ride-height. If you want to change ride-height, you'll wind up also having to change spring rates.

 

[2013DIBGT]

I'm curious to hear from those who have gone with the AST or similar coilover setup and have NOT found a need to delve into playing with bumpsteer correction.

Things like changing out their OEM Ball Joints for longer units like the Steeda X11 and also a bump steer kit like the Maximum Motorsport/FRPP 302S unit. I was under the impression this would be almost a requirement based on the amount of drop you would end up with using the AST or similar coilover units.

If you haven't changed out those parts do you have any bumpsteer charts of your cars showing what it looks like using the AST's?

I don't recall ever seeing mention of needing to correct bumpsteer in any of the Vorshlag threads. Then again, maybe I just missed it.

Thanks

 

[phoenix335]

But Konis can work well in competition use, with a lot of "but ifs". If you run a lowering spring, they will bottom out constantly. They are virtually the OEM length, afterall. The ride quality is also "limited", and I wouldn't use them on the street. I drove a customer's 2012 GT today with Konis and it rides terribly, in my opinion.

I have been running Koni Sports on Steeda Ultralights for the past 10 months. They are as good as stock on the street and I've never had them bottom out. I have run them in many local autocross and a few national events on street tires and A6s without a single issue. No riding the bump stops etc. They performed well on the track as well (Caveat being that this was my first PDX weekend).

Now...if the 4150s were available when I purchased this setup I would have gone with the 4150s. Even still I am seriously thinking about making the upgrade for a number of reasons but the ability to change spring rates and ride height easily are a big part of that. In order to have a chance at a competitive 2011+ Mustang in ESP I'm thinking the ASTs would be a requirement.

 

[SoundGuyDave]

I'm curious to hear from those who have gone with the AST or similar coilover setup and have NOT found a need to delve into playing with bumpsteer correction.

Things like changing out their OEM Ball Joints for longer units like the Steeda X11 and also a bump steer kit like the Maximum Motorsport/FRPP 302S unit. I was under the impression this would be almost a requirement based on the amount of drop you would end up with using the AST or similar coilover units.

If you haven't changed out those parts do you have any bumpsteer charts of your cars showing what it looks like using the AST's?

I don't recall ever seeing mention of needing to correct bumpsteer in any of the Vorshlag threads. Then again, maybe I just missed it.

Thanks

Just so that we're all on the same page, let's define "bump-steer." Bump-steer is defined as the change in toe angle during suspension travel. That means that as the suspension cycles up and down, the toe in/out dimension changes as well (or not, if the bumpsteer is perfect). This is a result of differing arcs described by the lower control arm and the tie-rod.

Again, just to clear up the misconception, coilovers do NOT affect or change the bumpsteer curve of the car. In the sense that you're mentioning, with the "drop you would end up with," this is a function of where you SET the ride-height of the car. THAT in turn is a function of installed perch height, spring free-length and rate.

At stock ride-height, the bump-steer curve of the chassis is just about perfect. The further you drop the car, the worse the bumpsteer curve gets, and at the same time, you also blow the front roll center downwards. At some point, you will want to correct that geometry change by installing the taller ball joints, and then that DOES severely impact bump-steer. In other words, the bump-steer problems are a second- or third-order effect of altered ride-height. None of the above have anything to do with whether you have coilovers (AST, Moton, Sachs, MCS, whoever) or stock-style struts installed. You can get into the same problem with OE struts if you "hella-slam" the car by cutting coils off the stock springs.

This really is a case of form following function. If you want to drop your CG far enough to really matter, then you WILL have to correct the front roll center to have the car handle properly. When you do THAT, then you'll need to correct the bump-steer.

I don't have plotted curves, since I always set mine up on a John Bean computerized alignment machine which has a bump-steer function. I wound up with a Steeda bump-steer kit on a series of trades, and it sat on the shelf for a while unitl I had a tie-rod end failure. I initially set up the bumpsteer kit to match the OE tie-rod end stud length then threw it on the rack, and the bump-steer curve was less than 1/16" net toe change over a 4" suspension cycle, IIRC. Close enough to where I didn't bother changing it.

Last year, I did wind up installing a set of X5 ball joints, and then yes, I did have to dial in the bumpsteer, and it was a BIG change.

 

[2013DIBGT]

Just so that we're all on the same page, let's define "bump-steer." Bump-steer is defined as the change in toe angle during suspension travel. That means that as the suspension cycles up and down, the toe in/out dimension changes as well (or not, if the bumpsteer is perfect). This is a result of differing arcs described by the lower control arm and the tie-rod.

Again, just to clear up the misconception, coilovers do NOT affect or change the bumpsteer curve of the car. In the sense that you're mentioning, with the "drop you would end up with," this is a function of where you SET the ride-height of the car. THAT in turn is a function of installed perch height, spring free-length and rate.

At stock ride-height, the bump-steer curve of the chassis is just about perfect. The further you drop the car, the worse the bumpsteer curve gets, and at the same time, you also blow the front roll center downwards. At some point, you will want to correct that geometry change by installing the taller ball joints, and then that DOES severely impact bump-steer. In other words, the bump-steer problems are a second- or third-order effect of altered ride-height. None of the above have anything to do with whether you have coilovers (AST, Moton, Sachs, MCS, whoever) or stock-style struts installed. You can get into the same problem with OE struts if you "hella-slam" the car by cutting coils off the stock springs.

This really is a case of form following function. If you want to drop your CG far enough to really matter, then you WILL have to correct the front roll center to have the car handle properly. When you do THAT, then you'll need to correct the bump-steer.

I don't have plotted curves, since I always set mine up on a John Bean computerized alignment machine which has a bump-steer function. I wound up with a Steeda bump-steer kit on a series of trades, and it sat on the shelf for a while unitl I had a tie-rod end failure. I initially set up the bumpsteer kit to match the OE tie-rod end stud length then threw it on the rack, and the bump-steer curve was less than 1/16" net toe change over a 4" suspension cycle, IIRC. Close enough to where I didn't bother changing it.

Last year, I did wind up installing a set of X5 ball joints, and then yes, I did have to dial in the bumpsteer, and it was a BIG change.

Thanks for the info. What would you say your ride height was set to (F/R) as compared to stock when you had to replace the broken Tie Rod End and the newly measured Toe was only off by 1/16"?

Is it safe to assume that up until the point where you swapped out the Ball Joint you didn't feel enough of a need to mess with the bump steer on the car (ie..it wasn't steering itself over bumps or bouncing into the other lane when the front wheels would impact a sharp bump in the road)

 

[SoundGuyDave]

Thanks for the info. What would you say your ride height was set to (F/R) as compared to stock when you had to replace the broken Tie Rod End and the newly measured Toe was only off by 1/16"?

Just a small point by way of clarification: The "newly measured toe" was NOT off by 1/16", but the bump-steer was. I never pulled a bump-steer number with the OE tie-rod end, but I tried to match the bump-steer kit to the OE dimensions, so I would expect that the numbers would be similar.

I haven't altered ride height in more than two years (excepting tiny tweaks for corner-weighting), and again, no reference from stock, but I'm estimating no more than 1-1/4 to 1-1/2" drop from the stock 4x4 stance. Pix if it helps:

Above is 2010, below is 2013:

Obviously, not slammed!

Is it safe to assume that up until the point where you swapped out the Ball Joint you didn't feel enough of a need to mess with the bump steer on the car (ie..it wasn't steering itself over bumps or bouncing into the other lane when the front wheels would impact a sharp bump in the road)

Absolutely correct. I felt no need for any correction to the bump-steer curve at all, until I did a roll-center relocation via the X5 ball joints. FWIW, the decision to install the X5 kit was driven by concerns other than being too low, in fact it was an attempt to improve the camber-curve on bump to protect the tire shoulders.

 

[barbaro]

Terry,
I have never ridden in a car with an excellent set of coilovers as you describe. The ones I have ridden in and driven were harsh and slammed or suitable for track only. I understand theoretically that a dialed in set of coilovers and springs would be suitable for street use but I have not experienced it. They are rare I am afraid.

I know that for good coilovers you need to spend $$ How much are those AST's for instance? Are they true coilovers in the back? Does that make a difference? What spring rates are you recommending for street liveability. What has been holding me back is i don't want to spend $$ and then hate the ride. Right now my Boss Spring, Koni Yellows, Watts Link, Torque Arm set up works nice for me. So if it works, I hesitate to fix it. On the other hand If I could just ride in what you are describing, I could be sold. I understand the superiority of a good coilover set up.

 

[2008 V6]

Obviously, not slammed!

That is a good lookin S197

 

[Department Of Boost]

Terry,
I have never ridden in a car with an excellent set of coilovers as you describe. The ones I have ridden in and driven were harsh and slammed or suitable for track only. I understand theoretically that a dialed in set of coilovers and springs would be suitable for street use but I have not experienced it. They are rare I am afraid.

IDK what coilovers you have driven on, what their spring rates are or how they were adjusted. In my experience a good set of coilovers, twin tube or single piston, single piston being better ride fantastic when set up correctly. I’m not talking about riding around on a marshmallow, of course they are firm. But done right they can be set up to be very firm yet have no harshness too them.

I think there is a misunderstanding between the definition of firm and harsh. Most people don’t mind firm. Most people do not like harsh though. And the suspension does not need to be “stiff” to be harsh. For example, my 2012 Brembo car is harsh compared to my aggressively sprung coilover 2007. My 2012 F-150 FX4 is harsher with a stock suspension than my “race car”.

I have three cars that I get quite a bit of wheel time in and have worked on all three cars dampers. And keep in mind I am driving around SE Michigan where most of the roads reseble down town Baghdad.

One has the Roush Track Pack coilovers (rebound adjustable only). They are some sort of KW I believe. They are set up with 350 front/250 rear springs. The car rides FANTASTIC! Ford could have made these coilovers a “Track Pack” option and I don’t think you would get one customer complaint about ride quality.

Another one of the cars has KW Clunbsports. They are also set up with 350 front/250 rear springs. The car rides FANTASTIC too! I could probably make an argument that they ride a little nicer than the Roush Track Pack/KW’s, but it would be thin. The only advantage is you can knock some compression out of them and put them in “full touring” mode.

And lastly one of the cars has Eibach R2’s. They are set up with 425 front/375 rear springs. This car rides really well too. It’s aggressive, there is no doubt. But you would never guess the springs are as stiff as they are. It rides no harsher than my F-150 does. The limit of what is “streetable” is of course subjective and personal preference. IMO this is as stiff as I would want to spring a true street car though. The rear springs are a non issue, the fronts are right there on the line though. I’m not saying it can’t be lived with, or even road tripped. I just wouldn’t go quite so stiff on a true daily driver.

I have never ridden/driven on the AST’s. But from what I have seen of them some people are running some really aggressive spring rates on the street and not having issues with them. If I were to buy another set of coilovers they would be AST’s.

 

[NoTicket]

I have a question related to the harshness of the ride on coil overs. My housemate has a GTO with KW V3 installed. I find that this car rides really well. The most notable difference being that there is usually only 1 bump and 1 rebound when going over a bump, instead of multiple bumps and rebounds of decreasing magnitude like in my Mustang.

However, there is one aspect I consider very harsh. When you drive over road reflectors it feels awful. It is hard to describe. Maybe it feels similar to if someone was hitting the wheels with a bat. It actually feels similar to when I hit a pothole in my car (thankfully only happened once).

I have been told that this effect is due to spring rates and will be present regardless of shock style or brand.

My question is if that is true. I pretty much want to either go with MCS or AST coil overs, but I am not sure if I want to deal with this particular aspect of the ride if I go with 400/250 springs.

Sent from my XT907 using Tapatalk

 

[Department Of Boost]

However, there is one aspect I consider very harsh. When you drive over road reflectors it feels awful. It is hard to describe. Maybe it feels similar to if someone was hitting the wheels with a bat. It actually feels similar to when I hit a pothole in my car (thankfully only happened once).

My first guess would be what tires are on the car. Most cars running V3's are running pretty aggressive tires. And they are not very forgiving when it comes to road reflectors.

There is no reason why a V3 would be harsher over a road reflector than lets say your average sharp edge bump. The KW’s have a very good “blow off” circuit which combats harshness very well.

I have been told that this effect is due to spring rates and will be present regardless of shock style or brand.

Sure, at some point you will not be able to get a spring to be suited to daily driving. That said you can run a LOT of rate before you get to that point.

If the car is only harsh a small percentage of the time bets are on it being the damper valving/adjustment or the tires. Springs are not speed sensitive (unlike dampers and arguably tires). Springs, for the most part will be harsh or not harsh. Not randomly harsh. The physics don't work out that way.

My question is if that is true. I pretty much want to either go with MCS or AST coil overs, but I am not sure if I want to deal with this particular aspect of the ride if I go with 400/250 springs.

Spring selection could be argued till the end of time. That is because there are more than one right answer. Is it a street car that gets on the road course for some non race paced lapping a few times a year? Well you would pick springs that suited that situation. Is the car getting AutoX’d every weekend and not driven on the street much? Well there is a different selection for that application. The only way to have a perfect spring selection is to have multiple springs and swap them out for what you are doing with the car. And then you would be using different springs for open track vs. AutoX. Wander through the pits at a race weekend sometime, you will see bins full of springs. People don’t bring them because they have the extra room. They need the options to get dialed in.

If you pick one set of springs that you want to work with everything realize that they will always be a compromise, always. Best bet is to figure out what you will be doing with the car the most and spring it for that. I personally like the 350/250 combo for street cars that see the track a few times a year.

 

[Mustang259]

Enjoying this thread, I tend to agree with GMITCH, there will always be a compromise when selecting suspension upgrades.
Ford selected the stock set up for all around use and the compromise is nose dive, etc., but it will work in all road conditions. They also always consider cost which is another compromise.

If you can afford it I would go with coil overs.

 

[csamsh]

Is the car getting AutoX’d every weekend and not driven on the street much?

This is my scenario. I do still street drive the car though, and I will drive it to events several hours away. The 550/250 springs I have would be tolerable for street driving if not comfortable. I think the car could use a little more spring for autox, but what I've got is a great compromise. When I autox'ed in New orleans, there was another AST'ed 5.0 there, and he ran the 450/175 setup with street tires and seemed completely ok with it.

The good news- springs are VERY easy to swap. You could probably do it in half an hour.

 

[Vorshlag-Fair]

I'm curious to hear from those who have gone with the AST or similar coilover setup and have NOT found a need to delve into playing with bumpsteer correction.

...

I don't recall ever seeing mention of needing to correct bumpsteer in any of the Vorshlag threads. Then again, maybe I just missed it.

We haven't done any of the ball joint/bump steer corrections on our car. Theoretically we probably should, as it likely has a tick of bumpsteer (when I slap a curb on track it has a small amount of toe change), but it isn't something bad enough that I feel it needs to be addressed with a bunch of funky aftermarket doo-dads. Honestly, a lot of this stuff is simply blown wildly out of proportion on the internet forums. I've seen people go completely overboard and do bump steer correction kits on nearly stock ride height cars, before even addressing big matters like added front negative camber or moving to real dampers.

That happens a lot in the Mustang world - some weird group think that makes people buy the wrong parts or the worst options for common issues. I cannot explain it, other than there are just too many cheap shiny parts that people love to buy. I've seen folks dump $20K into an HPDE/track car and it has junk shocks, soft/goofy bushings, weird ride heights, funky geometry problems, and awful wheel and tire upgrades. Can't explain it...



We've lowered our TT3 car about 2.5", which some internet experts will say is "instant death!". I don't get into these internet flame wars because if I don't agree with the "group think" I end up arguing with the resident SPEs, and if you don't have 10,000+ posts on a forum you aren't an expert. Its all good. All I know is that after lowering our red car a LOT it is still winning a lot of races and setting a lot of track records, I'm very happy with the handling on the car on track and in autocross conditions.

Of course there are always geometry changes when you lower any car, and McPherson strut cars have some of the biggest changes... but again, I feel that the lower Center of Gravity helps more than the changes "hurt", to a degree. And lowering these cars alters rear geometry more than the front, from my experience.

The major geometry issues when lowering an S197 happen at the rear, with relation to Lower Control Arm changes. We've addressed these with LCA relocation brackets, and it was noticeable. Another common upgrade that is needed when lowering a car substantially is a re-centered axle housing; the OEM fixed length panhard bar will kick the axle off to one side when lowered, so an adjustable panhard bar or watts link is needed when lowering any car.

Due to some extremely backward rule sets in SCCA we didn't address the rear geometry changes until 2012, because these $100 bolt on brackets are verboten in SCCA's STX and ESP classes, where we dabbled for two and a half seasons. Most bolt-on Watts Link kits are also illegal and will be until 2015. Don't ask me why - after hearing some of their arguments, I've deduced that most SCCA rulesmakers don't understand the basic aspects of suspension geometry or the abundant aftermarket solutions, so they just make virtually everything illegal. NASA, however, takes the opposite approach and they have much more open rulesets that allow these common, aftermarket solutions. After we switched to building around NASA rules we fixed what we felt needed to be fixed and the car handles great.

So that's my take on bumpsteer in an S197: it isn't that big of a deal, and there are much bigger issues to tackle. Someone else asked for my preferred street/track spring rates with coilovers? I really like 450 #/in front and 175 #/in rear, with aggressive/wider street compound tires, without moving the springs to the rear shocks (as in: not "true" coilover rears). That makes for a nice street ride but is still much firmer than OEM rates (around 100#/in front) and has a larger front spring rate bias, which seems to work well for me and my customers.

With R compounds it ends up with a tad too much dive/roll, so I go up from there depending on the tires and end use. Autocross cars might get a slightly different rear spring, to help the car rotate. There are a LOT of variables that go into spring rate selection, and after we test a particular set-up we still like to have extra springs on hand to tweak these when running against a clock. Nothing replaces real testing, and we always test with spring rates when we can. Changing springs is easy and little else makes as a dramatic of a change to set-up as this.

As for going to a coilover rear spring, this moves the suspension load path to the upper shock mounts, which they weren't designed for. I keep the springs in the stock (more inboard) location and use a ride height adjuster on each spring. Yes, many people do this without noticeable bad affects but I've seen things break on other cars, so I avoid it unless it is a caged car with tubes that tie into the upper shock mount. Going to the coilover might have some advantages in roll vs bump spring rates, but again, without beefing up the upper shock mount I'm not willing to risk it.

That's just my two cents... remember: everything is always a compromise, and there's more than one way to skin a cat. There is no single "right answer" for every set-up.

Cheers,

 

[Mustang259]

Terry
First let me say, I appreciate your input and knowledge.

Second, and this is slightly off topic of this thread but seems a good place to ask, When you consider lowering your car, do you also change out the stock 2 piece drive shaft for single piece Aluminum Drive shaft? And if so, do you make any attempt to adjust pinion angle etc., for handling reasons?

Basically I am asking if a single piece driveshaft is better than the stock 2 piece, for handling purposes?

 

[Sky Render]

No, there are no handling advantages to be had from a lighter driveshaft, other than overall reduced weight and reduced rotating mass (better throttle response).

The money you spend on a driveshaft would be better spent elsewhere on the suspension.

 

[NoTicket]

Hey Terry,

Did you guys also replace the UCA? I have read a lot of people saying it's necessary to do so. I just want to install the coils + LCA relocation brackets if possible. I don't really want to go to any different control arms at this point and I was planning on dropping the car the 2"+ required to run the MCS or ASTs.

 

[Vorshlag-Fair]

Terry
First let me say, I appreciate your input and knowledge.

Second, and this is slightly off topic of this thread but seems a good place to ask, When you consider lowering your car, do you also change out the stock 2 piece drive shaft for single piece Aluminum Drive shaft? And if so, do you make any attempt to adjust pinion angle etc., for handling reasons?

Basically I am asking if a single piece driveshaft is better than the stock 2 piece, for handling purposes?

See below...

No, there are no handling advantages to be had from a lighter driveshaft, other than overall reduced weight and reduced rotating mass (better throttle response).

The money you spend on a driveshaft would be better spent elsewhere on the suspension.

Agreed, 100%. We still have the 2-piece OEM driveshaft on our car... because this is an expensive way to lose a very small amount of mass.

As much as I'd like to do this it just isn't worth the $$ for the minimal changes we could see, in my opinion. The the OEM 2-piece driveshaft is super smooth and plenty strong. Going to a 1-piece would save ~10 or so pounds but lighten the wallet by nearly $800. Again, very expensive weight loss.

Seems to be a popular internet forum mod, though, and we have installed a number of them when customers brought them to us. Of course the Boss 302-S comes with a 1-piece driveshaft (above), but at that price level ($80K turn-key race car) it probably should. For an all-out race car build, yes, get a 1-piece driveshaft. For a street car? You won't notice the difference.

Did you guys also replace the UCA? I have read a lot of people saying it's necessary to do so. I just want to install the coils + LCA relocation brackets if possible. I don't really want to go to any different control arms at this point and I was planning on dropping the car the 2"+ required to run the MCS or ASTs.

I agree with your hunch - isn't really necessary. The rear Upper Control Arm is one of the things we fought with the most on this S197, and one of the last things I suggest to people to change, for several reasons. A much better mod is to replace the rear LCAs (with adjustable lengths and elastomer bushings, for a streetable car, and spherical ends for a race-only car) and the LCA relocation brackets. This change gives you the improved rear geometry (brackets) and adjustable pinion angle (adj length arms) to correct issues after lowering.

A better upper control arm?? Mmmmm, I don't have a good answer for that yet. We tried a number of options and almost all of them made a helluva lot of noise. Each one we tried kept getting loose and would clank and bang around like mad. We even modified some other people's stuff, trying to make it fit better, with no long term positive benefit. A lot of wasted effort and frustrated street driving chasing aftermarket UCA noises.



Eventually we bought the $700 Multimatic Spherical Upper Control Arm and Mount that was developed for the Boss 302-S race car. This is an expensive part but it is VERY well made, and it hasn't made a peep or loosened up in many months of use. Exceptional quality but a very high cost, and it has a spherical mount, so that will have a finite lifespan. Strangely enough they don't have any adjustment in length, so you still need adjustable length LCAs to correct the pinion angle, but I'm OK with that.

Whiteline has recently redesigned their UCA kit for the S197, and our first sample just arrived to us today. I shot some pictures a few minutes ago out on the fabrication bench, but our photographer will get some proper studio pics tomorrow and we will update the order page for the new KTA141-A (rev A). These pictures above and below show the beefed up arm, which has thicker steel and added gussets. We'll put one of these in a Vorshlag tester's car soon and see how it works. I am confident that the thicker steel and added gussets will improve this design.

What I don't want is anything that comes loose and rattles, which everything we have tried so far has (except the 302-S piece). It is a very loud clang once it gets loose, and it happens over every bump. Maddening. To tighten it properly you have to pull the back seat out, to get to the chassis mount. Total PITA. Again, unless it is an all-out track car I'd keep the stock UCA and adjust pinion in some aftermarket LCAs that have the right features. An aftermarket UCA is waaaay down the list.

Cheers,