Suspension..Street?Track?Both?

[G_Shock"00"]

Hello all. I am new here and have had great success in gathering information in the CARB forum for the FFS Coolside in California. But we are here for a different topic. I will be installing new sway bars, springs and shocks by the new year. Will you share your findings of what works and what doesn't. Thanks again for the info.

I plan on using my ride for fun drives up to a 600 hundred miles round trip and track days or auto x as often as I can.

[amgkid]

I'd recommend talking to Shaikh at www.fatcatmotorsports.com. He really knows his stuff about suspensions. Also, you would get a wider response at the miata.net forums.

[mike whitehouse]

I have not set up a Miata suspension so I am not sure I can help directly with that question. One thing you should recognize is that you have asked a very subjective question with many correct answers. Everyone has a different level of tolerance for a car’s ride. Everyone has a different driving style and this influences how the setup a car.

A question you are going to need to answer is, what do I want the car to do BEST? A good autocross car for example may be very stiffly suspended and border on unstable. A good cruising car is usually very stable and more softly suspended.

These forums have lots of discussions on setting up cars in general or specifically a Miata for different things.

specifically Miata talk:
http://www.miata.net/index.html

for Mazdas in general but has a Miata section:
http://www.msprotege.com/forum/

for SCCA motorsports and has deticated sections on suspension setup and one for autocrossing:
http://sccaforums.com/Default.aspx

Another resource could be GRM magazine’s series of articles by Andy Hollis on setting up a Miata for STS2 autocrossing. If you don't know him, he is a very technical person, past National Solo II champion and the 2006 ProSolo national Champion in STS2. The good thing about Andy's articles is that he tries to leave the reader with a basic understanding of how to test your changes. He is a very interesting and generally helpful person. Oh, he is also one of the Evolution Autocross Driving School's instructors.

Hopefully one of these can help.

[Tom @ Fast Forward]

FWIW, I have the JIC FLT-A2 12/10 (670/550) on my 99 with the RB front and rear sway bars. I don't find them excessively harsh on the street and they keep the 225/50-15 RA-1s planted on the track. I like the independent adjustability of ride height (let me keep the 10AE stock) and pre-load on the springs as well as shock rebound.

I have been told that the 12/10 is too stiff but U like them.

[Kyp J]

I'd recommend talking to Shaikh at www.fatcatmotorsports.com (http://www.fatcatmotorsports.com). He really knows his stuff about suspensions. Also, you would get a wider response at the miata.net forums.

In case you haven't been on the Miata.net often, be ready for observing a war from the sidelines if you ask a question involving opinions.

That said, I will be interested in learning what may be a good compromise in this area since I need to put a little money (that is a joke) in my suspension and don't know a lot about it. I have read a lot of opinions and still don't know what I should do. I will check out the mentioned links and try to learn.

[socal pat]

There are tons of good choices out there so I'll give you one NOT to use. I have the old style FM springs with AGX shocks and am about to pull the springs off. Over the last 3-4 years, 3 sets of tires, and 2 different wheels, I have always gotten cupping from this setup. I'm about to buy some new tires again and don't want to ruin them also. There is something about the relationship between these components that cause this problem. This along with the fact that I was never happy with the overall feel of them. Once you get the rebound set right then you have the compression too stiff, and once the compression is right you have a floaty rebound. It just isn't a very elegant setup. In the interest of economy I'm ditching the FM springs and putting on a set of $28 E-bay adjustable coilovers. They'll be going on this weekend so I'll get back and let you know how they feel.

[lovemx5]

I have a set of Bilstein PSS on my 02. The PSS are very good for the street and are pretty good for autocross but are a bit soft for the track.

I just installed (this week) a set of Tein Flex and RB sway bars on my 92. What a difference. The ride is way better than expected, firm but not harsh. I won't be able to autocross or track the car until next spring but I expect an improvement. Time will tell (pun intended).

Now I just need a supercharger for my <cough>1.6</cough> and I'll be all set.

[Dr Evol]

I second the recommendation to call Shaikh at www.fatcatmotorsports.com (http://www.fatcatmotorsports.com/). He really knows his stuff about suspensions. I ran a set of his prototype shocks for the last half of this year's autocross season and loved them. I can't wait for next year to try out the next version of his shocks. :lol:

[Shaikh@FatCatMotorsports]

Hello, gentlemen!

Chip ('Dr Evol' ;) ) mentioned this thread so I figured I'd register and jump in. Tom, if my name needs editing let me know. I have high respect for what you've done - in some moments on the street or at autocrosses I wish I had the torque of a supercharger...

Thanks for the kind words, Chip. It has been fun and informative working with you. I love hearing you chase (and beat!) 'Vettes! What you'll be running from me next year will be in another league compared to the prototypes.

Socal pat's observations about the FM spring/AGX combo are dead-on. The AGX uses a single knob to control bleed in both directions. There's a pipe connecting the top and bottom half of the damper that fluid passes through and the needle is right in that flow. Setting 1, valve is open, setting 4 (NB) or 8 (NA) is nearly closed. A useful idea except that the proportion of rebound:bump damping is off and the car ends up feeling harsh and unsophisticated. The ratio on the Illumina is much better calibrated and I greatly prefer it to the AGX for a twin-tube. It still has short-comings, though.

The work I'm doing with dampers (specifically Bilsteins from the NA, NB, or any car that uses them) is sophisticated and subtle. I'm fortunate to have built contacts at top-level universities and with top-level racers. I'm benefitting from years of previous discoveries while adding my years of testing and modeling specific to the Miata. Because of my physics training, I like to be systematic when I dive into a project, but the shadetree mechanic in me needs to just do it. I think about how to make a car handle better pretty much constantly and every ride is a test drive for me. Fortunately, I LOVE it so I never feel like I need to escape from 'work!' ;) But I do have to step away from Miataforum sometimes!

My goal is to bring suspension technology and developments at the highest levels of racing to the enthusiast. Not 'open-source', but not stratospheric either. Kind of like what FFS is about, I'd say. More power and a better suspension are very complimentary. Perhaps some joint development may occur between FFS and FCM? I'd certain love to see such a car given the thumbs-up by a big magazine! Certain other companies, while very good, get a bit too much attention and there are new players in the game :D

G_shock, since you're in San Jose, we ought to hook up for a test drive. I'm ready to be jealous of your S/C when you have that installed!

Shaikh

[99mx5]

Welcome to the FFS forums Shaikh! Gotta love it when there are lots of options to choose from and input/feedback from trial and error and testing. I, too am interested in suspension options, mainly shocks and springs. How much of an improvement can be had over the 99 sport suspension with RB sways? I was thinking of RB springs to go with the factory Bilstein shocks. Has anyone else tried this combination?

[Shaikh@FatCatMotorsports]

Thank you!

In all honesty, while the 99 Sport Bilsteins (HARD S pkg) are better suited to the springs than the R-pkg Bilsteins were, there is a lot that can be improved upon, without lowering the car or upping the spring rate. If you're already blown, then putting a big bar on the rear is not going to help you maintain traction. I have run w/o a rear bar for >3 years now (1 year since adding boost) and I won't go back. Also saves weight and not having to buy extra hardware for the rear.

Shaikh

[Tom @ Fast Forward]

Shaikh,,

Welcome to the FFS forums. You are welcome to post here anytime. There is even a special forum below where you are welcome to post ads or specials. If I can ever find time to make the rotating banner work, I would even add your banner.

My turn for a question. What do you feel is a max spring for the track for a Miata? IOW, am I losing performance with 670/550? Too stiff?

[Dr Evol]

Shaikh has a very interesting suspension design worksheet on his web site. You can use this to help figure out your suspension.

Check it out: http://www.fatcatmotorsports.com/FCM_MSDS_v7_1.xls

[99mx5]

Your right about the rear bar. I had the RB rear sway (at the time I recommended it to Tom). I added the rear sway at the time I installed the SC and I thought the extra power was making the car tail-happy. It turns out when I reinstalled the HARD-S rear bar, the car slid less. Tom is able to keep his rear bar because he now has the rest of the suspension to complement it.

Ive thought of reinstalling the rear sway and setting the front swaybar to the hard setting to compensate for the rear. Is this a good idea?

Did you remove your rear bar altogether? Ive heard of people running w/o the rear swaybar.

I had both swaybars in the video of my car. Tim (a professional driver) commented that the may car handled better because of the swaybars. It led me to believe that in the hands of a good driver (not me ;) ), the rear bar actually improved handling.

[chuckerants]

Socal Pat and I have almost identical cars (suspensionwise)- 99 with old FM springs and KYB AGX shocks. Hell, we even have the same colors 99s.

With that said, I've had the FM spring/KYB combo for around 1 1/2 years and 10,000 miles on a new set of Azenis and I have had zero problems with the tires cupping. I've also had "Lanny's Alignment" for around 2 years.

The FM springs/KYB are a great improvement over the OEM (worn out) shocks and OEM springs. However, they seem to lower the car too much. Also, If I had to do things over again, I'd buy a set of real coil-overs right from the beginning.

Now that my car is around 200~210HP, I'm starting to think about the susension again. Maybe Tein SS this time around?

[Shaikh@FatCatMotorsports]

Shaikh,,

Welcome to the FFS forums. You are welcome to post here anytime. There is even a special forum below where you are welcome to post ads or specials. If I can ever find time to make the rotating banner work, I would even add your banner.

My turn for a question. What do you feel is a max spring for the track for a Miata? IOW, am I losing performance with 670/550? Too stiff?

Tom,

What can I say?? Thanks!

Your question is a tough one to answer because there are a lot of variables. According to my spreadsheet (which I trust about 80% but need to perform actual bounce experiments on a car with de-gassed shock to really nail the wheel rates/bounce frequencies) your combination is at about 2.3Hz front and rear. The JICs are a well-matched setup and are well-regarded for a reason. I think the car must be very stable and predictable at the track. You want that for high speed manuevers.

You may be losing some ultimate grip with such stiff springs.. in fact, I'd almost say for certain you are, but sometimes the trade-off in predictability is worth it. My personal preference (and the advice I've heard from tuners with more experience) is to softer the rear to get the traction you want and stiffen the front to get the turn-in you desire. I would definitely say that using the smallest rear bar possible will aid both traction and predictability. I've found that to be the case years ago.

Nearly everything comes down to what makes you fast. If I got my hands on your car and put my 'works' suspension on it, I almost guarantee you'd turn lower lap times but you may need to get comfortable with the way it behaves, which would be softer, smoother, and more subtle. Having gone from a stiffly-sprung autox setup (from 375/250 to 550/350 and as high as 700/300) I'm of the belief that rates in the middle of that range will provide reduced movement of the sprung mass without diminishing road holding. A stock Miata can often be hustled around a track surprisingly quickly.

If you can locate a complete set of Bilsteins for your NB and send them to me I can tune them for your needs. That way you can see which setup works best for you. Of course, I'd love to come out and try your car at the track as well ;)

Shaikh

[Shaikh@FatCatMotorsports]

Your right about the rear bar. I had the RB rear sway (at the time I recommended it to Tom). I added the rear sway at the time I installed the SC and I thought the extra power was making the car tail-happy. It turns out when I reinstalled the HARD-S rear bar, the car slid less. Tom is able to keep his rear bar because he now has the rest of the suspension to complement it.

Ive thought of reinstalling the rear sway and setting the front swaybar to the hard setting to compensate for the rear. Is this a good idea?

Did you remove your rear bar altogether? Ive heard of people running w/o the rear swaybar.

I had both swaybars in the video of my car. Tim (a professional driver) commented that the may car handled better because of the swaybars. It led me to believe that in the hands of a good driver (not me ;) ), the rear bar actually improved handling.

Glad you see where my recommendation comes from. Now, a car that is slightly tail-happy will be a faster autocrosser and that is often why people in STS or STS2 class use big rear bars. They also don't have the power that a boosted Miata does so they need something to rotate the car.

Yes, I've been running no rear bar on my '91 FM2 car since oh... 2003? The improvement in predictability and power slides is terrific!

Keep in mind, handling (what I think of as how fast a car 'feels') and lap times (how fast a car really is) are not the same thing. I don't know which Tim you refer to but I'm sure he's capable. The thing is, people can only perceive speed through what their body tells them. If you feel bumps you think you're going fast. Many of us have been in cars that are so smooth you can't tell how fast you're going until the po-po come up behind you! or you look at the speedo and think 'I better slow down.' The stop watch doesn't lie, and what makes one driver faster is not going to be true for everyone else.

If you tell me your full setup (springs/sways, alignment settings) I can make some recommendations on how to keep the same balance but improve exit traction under power.

Shaikh

[99mx5]

My 99 sport pkg is HARD-S with RB front tubular swaybar on the soft setting and factory sport pkg rear swaybar. Wheels are factory 15" with 205 Falken Azenis. I use 13x9 wheels with 205/50-13 Kumho V710 tires. Tim is the driver that piloted our cars at Bondurant.

I posted a video of one of my auto-x runs in this thread (apologies to Chip ;)).

http://www.fastforwardsuperchargers.com/forum/showthread.php?t=249

Edit: My alignment is Lanny-based. I followed the rule of no more than .5 difference in camber between front and rear. Its set to: -0.9 front and -1.4 rear and 1/32" toe in each wheel

[Tom @ Fast Forward]

Tom,

What can I say?? Thanks!

Your question is a tough one to answer because there are a lot of variables. According to my spreadsheet (which I trust about 80% but need to perform actual bounce experiments on a car with de-gassed shock to really nail the wheel rates/bounce frequencies) your combination is at about 2.3Hz front and rear. The JICs are a well-matched setup and are well-regarded for a reason. I think the car must be very stable and predictable at the track. You want that for high speed manuevers.

You may be losing some ultimate grip with such stiff springs.. in fact, I'd almost say for certain you are, but sometimes the trade-off in predictability is worth it. My personal preference (and the advice I've heard from tuners with more experience) is to softer the rear to get the traction you want and stiffen the front to get the turn-in you desire. I would definitely say that using the smallest rear bar possible will aid both traction and predictability. I've found that to be the case years ago.

Nearly everything comes down to what makes you fast. If I got my hands on your car and put my 'works' suspension on it, I almost guarantee you'd turn lower lap times but you may need to get comfortable with the way it behaves, which would be softer, smoother, and more subtle. Having gone from a stiffly-sprung autox setup (from 375/250 to 550/350 and as high as 700/300) I'm of the belief that rates in the middle of that range will provide reduced movement of the sprung mass without diminishing road holding. A stock Miata can often be hustled around a track surprisingly quickly.

If you can locate a complete set of Bilsteins for your NB and send them to me I can tune them for your needs. That way you can see which setup works best for you. Of course, I'd love to come out and try your car at the track as well ;)

Shaikh

I took off a set of Bilsteins to put these on. Mine is a 10AE and came with them. The Bilsteins were actually pretty good. It just had a load of roll in the turns. I then added the RB front and rear sway bars and that cured the roll but, when you hit the end of a reasonable stright and smacked the Goodwin brakes, the nose dived pretty bad. So I added the JIC's. That cured the nose diving under hard braking.

When I installed the JIC's, I just barely preloaded the springs. Basically pulled the plates up snug and two turns on the nut. The ride height we measured before taking off the bilsteins and set the JIC's to be the same. Street and track I run the damper setting at 50%. Stop down and take it for a ride anytime. The day we finished installing the JICs, I got in the car and drove to Cleveland to visit a friend. 2100 miles in 36 total hours. I really don't find them bad on the road. A few days later I drove it back to Phoenix in roughly the same short time.

[socal pat]

Socal Pat and I have almost identical cars (suspensionwise)- 99 with old FM springs and KYB AGX shocks. Hell, we even have the same colors 99s.

With that said, I've had the FM spring/KYB combo for around 1 1/2 years and 10,000 miles on a new set of Azenis and I have had zero problems with the tires cupping. I've also had "Lanny's Alignment" for around 2 years.

The FM springs/KYB are a great improvement over the OEM (worn out) shocks and OEM springs. However, they seem to lower the car too much. Also, If I had to do things over again, I'd buy a set of real coil-overs right from the beginning.

Now that my car is around 200~210HP, I'm starting to think about the susension again. Maybe Tein SS this time around?
This cupping issue isn't wide spread, but those few people who had seen the problem before each said it was the fault of this combo. All 3 were experienced tuner/racers. I tried a Lanny's alignment, Icehawks', and now somewhere between Lyle and Moti. Same result each time.

[chuckerants]

This cupping issue isn't wide spread, but those few people who had seen the problem before each said it was the fault of this combo. All 3 were experienced tuner/racers. I tried a Lanny's alignment, Icehawks', and now somewhere between Lyle and Moti. Same result each time.

Pat, your car is the first I've heard of (and saw) this problem with the FM/AGX combo. I find it hard to believe that no one else has complained of this in the 1 1/2 years since I've had my set up.

Then again, no one said crap when BRP claimed OEM like drivability with their hotside kit either. :(

Besides, I don't think I actively searched for a problem with the combo either.

[Serpico]

I've had the old FM springs/AGXs for over 2 1/2 years (20,000 miles) now and I've been happy with them. I managed to get over 12,000 miles out of a set of Azenis 215s using the Icehawk alignment and the ride height is just about perfect IMHO.

I too am starting to think of upgrading to something with slightly higher spring rates and better dampening.

Maybe Tein Flex's or perhaps the new Eibach coilovers from Goodwin.

[Steve in VC]

Tom,

The JICs are a well-matched setup and are well-regarded for a reason. I think the car must be very stable and predictable at the track. You want that for high speed manuevers.

You may be losing some ultimate grip with such stiff springs.. in fact, I'd almost say for certain you are, but sometimes the trade-off in predictability is worth it. My personal preference (and the advice I've heard from tuners with more experience) is to softer the rear to get the traction you want and stiffen the front to get the turn-in you desire. I would definitely say that using the smallest rear bar possible will aid both traction and predictability. I've found that to be the case years ago.

Shaikh

Shaikh,

I want to be sure I understand.

The set up for bet G force on a skid pad is different than what makes for a quick responding autocross car.

Best traction requires the best contact patch under all conditions. This starts with the tire / wheel combination, as that defines how the tire will roll over in a corner. The spring / roll bar combination to allow the unequal length wishbones to convert body roll to the camber necessary to offset the tire roll under for maximum contact patch.

The required body roll makes the car feel less predictable, and it may be in autocross.

Stiff springs, and / or stiff sway bars keep the car flat, reducing body roll, so it feels predictable. But it requires adding camber to the alignment to maximize the tire patch in a hard corner. This give less than optimum tire patch when not cornering.

How far off am I on the dynamics?

Thanks,
Steve