robertdot

I can't find a decent post that explains what I'm looking for, and piecing the information together isn't going so well.

I've seen several posts on suspension upgrades. From Mazda / Mazdaspeed, we have rear sway bars, rear strut tower bar, front sway bars, sway bar end link (does this count?), front strut tower bars, lowering springs... am I missing anything (the J-spec Mazdaspeed '8 had some other stuff... cross bars on the under body, 4 point front strut bar)? Are there any aftermarket suspension upgrades that MS doesn't offer that others do?

I've several questions:

Should I go with Mazdaspeed parts or aftermarket? I doubt this will void the warrenty for any reason, so I have no hesitation with aftermarket if they are better quality products for the same / cheaper price tag.

I would be installing these myself since, again, they shouldn't cause any concern with the warrenty. Are any of them particularly hard to install (specificly front sway bars, as I think i saw a post that had them mounted in a weird spot)? The DIY install for the Tanabe lowering springs is available here.

Is the 4 point front strut worth finding? I know someone on the forum ordered the MS J-Spec 4 point front strut bar, but didn't know if it fits. Is there an aftermarket 4 point front strut? Does anyone have any opinions about this?

Is a 1 inch drop enough to improve stability? Is it too much? Specifically, does any one know if the appearance package and / or Mazdaspeed kit will suffer from lowering about 1 inch?

What after install work will need to be done? Obviously an alignment will need to be done after lowering (apparently about a week later to allow for setteling). Anything else?

Is there a best order to do these mods? Should I lower it first, then install various bars? Should I install each mod in a certain order, or could I just install them all at once and be in complete awe of the ride difference?

Basically, I want to know as much about this as I can before I start to buy parts, and I would like to have a decent thread for other people to look at when they start asking the same questions I am. I've read up as much as I can, and I want personal opinions of RX-8 owners, specifically auto-x folks, as I think they make the most use of such upgrades. What suspension setup do you recommend?

PUR NRG

Okay this type of question is starting to bug me almost as much as people who don't bother to search. However robertdot has been trying to search for answers so I'll cut him some slack.

Asking "what suspension setup do you recommend?" is about as useful as walking into a shoe store and saying "I want to buy new shoes. Which ones should I get?" You need to clarify your question before anyone can give good answers.

1. What is the primary intended application?
2. What (if any) is the secondary intended application?
3. How much are you willing to compromise one for the other?
4. What budget do you have?

Here are my answers as an example:
1. Primary use is street driving. The car averages 20k miles per year.
2. Secondary use is autocross. The car enters 30+ events per year with two drivers.
3. We have a (relatively) high tolerance for harsh driving in pursuit of performance. So we sacrificed daily drivability for increased performance.
4. While I would have loved to put Penske shocks on the car I couldn't justify their $4k price tag. For less money I purchased JIC coilovers, Racing Beat sway bars, and corner-weighted the car. That gives me what I consider good bang for the buck. We also sacrificed tire wear (higher and more frequent tire replacement) by going with a more aggressive alignment. Don't forget maintenance/replacement costs when factoring your budget.
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robertdot

I'll clarify, even though the last question wasn't really the important one (in fact, I should have left it out like I originally intended).

I don't plan on racing, though I really do enjoy pushing around curves, and there are plenty to go around in Alabama. The 8 was designed for this, and I'd like to take full advantage. I think anything worth doing is worth doing right. To me, until daily driving ride is "sacrificed by stiffness" (whatever that means to whoever has said it on the forums before... I have no idea as I've never ridden in an "overly stiff" car), the most race-modified suspension is the best.

So...

1. The primary application is plain-old driving to/from work, etc.

2. My seconday application is throwing the most speed at naturally occuring road curves as possible when I want to have some fun while I'm milling around the outskirts of town.

3. I'm still unsure what #3 entails. That is another (probably subjective) answer I'm looking for.

4. As far as budget, getting all the suspension parts from Trussville Mazda is well under $2K. So, lets set the bar at $2K initial investment, but that is flexible. I've got a job and time to wait.

If my search skills suck, and anyone has links to worth-while threads and / or websites, feel free to link to those, esp. if they offer definitions of some terms / jargon that non-autox people wouldn't understand.

PhineasFellOff

robertdot, you've done an AWESOME search job.

I wonder if you're like me. I had a Honda before and left it stock. I have never done any mods of any kind to any of my previous cars. This is the first car I've ever owned where it's worth considering modifying. I'm new to this world. I don't drive that hard. Mostly fwy cruising, but I still like to push the limits sometimes for fun and excitement. I probably can't drive like some of the autocross maniacs around here, but that doesn't mean I can't feel the differences in suspension setups and don't deserve superior equipment.

It sounds like you have a reasonable amount of money or you're not on a shoe-string budget. It also sounds like you don't have the background experience- JUST LIKE ME- of knowing exactly what each piece of equipment- sway bars, strut bars, different springs, spring height, shocks- can do for a car. To me, it just isn't practical driving all over trying to check out cars that already have this equipment or that equipment. I went to a rotary car meet recently and only one guy had a mod, which was an exhaust, and no one had a suspension mod.

This is why I am seriously considering getting the JIC 15-way adjustable coilovers with electronic height adjuster (so you can adjust height and possibly also dampening???? without taking the car apart). I believe Tein has a comparable product with about 9 or 10 adjustments. PUR NRG says he has the JIC's. Some guy from Las Vegas got them a while ago and wrote a report on this forum.

I believe they are between $1695 and $1795. I'm not sure if that price comes with the electronic adjusters. Sure they're relatively expensive (but not THAT expensive) but at least I can continuously adjust them and find out what settings I like best. With "set" springs and shocks, you have to know exactly what you like because you're stuck with what you buy and there is no room for regrets. Knowing what I like requires previous experience and, unfortunately, I don't have any.

After the JIC coilovers, I would get the sway bars, strut bars, endlinks, etc.

PhineasFellOff

PUR NRG,

I would love to hear what you have to say about the JIC coilovers (and the Tein coilovers, if you know about those as well). What about the electronic adjusters?

I noticed you said you only have the sway bars. How are sway bars different from strut tower bars in what they provide performance-wise?

PUR NRG

When I bought the JIC coilovers they did not have electronic adjustment capability. Electronic adjustment is only an advantage if you need/want to adjust settings while you are driving. It takes one minute to adjust all four manually with the car stopped.

Sorry I don't have experience with Tein, but you bring up a good point: if someone only has experience with one setup then take what they say with a huge grain of salt. Chances are they will rave about how much better it is than stock. But how much better (or worse) is it than a competitor's part? That's the real question. Unfortunately I don't know. I can say the JIC FLT-A2s with 10/7kg springs give better than stock handling but are probably too stiff for daily driving. I like them but that doesn't mean everyone else will or that they're the best price/performance shock out there. Upgrade parts are too new and it will take a while before worthwhile comparisons can be made.

Did you read this thread?

Have you ridden in a "luxury" sedan where the ride is very smooth? No bumps or jolts. Compare that to the stock RX-8 where on the same road you feel more bumps and jolts. The RX-8's suspension smooths out some stuff but not all. Now imagine springs so stiff if seems like you feel every surface irregularity. You are almost constantly feeling bumps and jolts ranging from noticable to jarring. That's what is meant by an "overly stiff" car and how much you can tolerate is very subjective.

And it's an answer that will only come with experience. The first car I modified was a BMW 540i. Stock it had good handling and an unbelievably comfortable ride. I put Koni yellows and Dinan springs on it and ride comfort was like an Integra but handling was superb. It still felt kind of tame so I went even farther with the RX-8. The 10kg springs front and 7kg springs rear are at my comfort limit--maybe even slightly above what I'd like in a daily driver. So the short answer is you have to try different suspensions to see what you like and can tolerate.

Don't forget installation labor if you don't plan to do it yourself. But I get the impression you plan to DIY.

Remember what I said about vague comments? What are "all the suspension parts" for well under $2k? And if $2k is for starters, how much were you planning to spend each year to improve the suspension? $2k total is a different proposition than $2k now and more later.

The general upgrade path I recommend (although others have disagreed) is wheels/tires, shocks/springs, sway bars, strut bars. I think strut bars are optional and at that point you're at diminishing returns that the money is better spent on other areas. If upgrading incrementally, you need an alignment after the first two.

Wheels: pick the widest wheels you can rotate front to back. Keep them at 18" diameter if possible. Bigger wheels means more weight. I think 18x9" wheels can fit but I'm waiting for some that have the style I want.

Tires: big tradeoff between grip and longevitiy. I like Potenza S-02s but they wear quick and are noisy tires. I also use S-03s. Huge disclaimer: these are the only tires I run so I have no comparison data to other brands.

Shocks: in this price range double-adjustable (aka two-way) shocks are rare. Double meaning rebound and compression are independantly adjustable. JIC FLT-A2s are single adjustable with 15 adjustment settings.

Disclaimer: I am not a suspension guru. I know enough to be dangerous but that's it. I highly recommend reading Fred Phun's book "How to make your car handle". It will teach you more about suspension than you care to know.
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PhineasFellOff

PUR NRG,

Awesome information. Thanks for giving me the heads-up on that thread. Apparently, it was just started, so I missed it. From that thread, it is apparent that the effect of the strut tower braces is subtler than the effect of sway bars (aka anti-roll or stabilizing bar), so it makes sense to deal with sway bars first. It's interesting that northern-8 stated that sway bars will also stiffen the ride, that they connect the left side of the suspension to the right side. Is this because, while the suspension is normally independent, the sway bars take some of that "independence" away? So with sway bars, you can't reduce body roll/lean without also increasing ride stiffness? Can you reduce body roll/lean without increasing ride stiffness too much with coilover adjustments WITHOUT installing thicker sway bars (i.e., with only the stock sway bars)?

Let me put it in some personal context, if it helps. For me, I think the RX8 in stock form leans too much in sharp turns. So my primary focus is to reduce the body roll/lean. If I can do it without affecting ride stiffness, then fine, although I can definitely tolerate a certain amount of stiffness as I used to drive a stock Datsun 280zx.

Omicron

I'm really liking this thread. Great questions and great answers and info flowing here.

What I really think would be really useful at this time would be to clearly define and explain the various upgradeable suspension components and what exactly they do. I'll try to list them here (in mo particular order) and explain them as I see them.

Pardon my pedestrian explanations, which are probably at least partly incorrect... I'll take a crack at this simply to get this part of the discussion going. I'm sure someone who knows a hell of a lot more than me about this will take great delight in correcting me. :D

Springs: Allow the car chasis to move up/down semi-independantly of the suspension, so the wheels and can absorb bumps and flex up/down as the car corners. Lowering springs just lower the chasis of the car, which can improve handling to some degree because it lowers the center of gravity of the car, and the lower the COG is the less "tippy" the car is when going into a corner fast. High performance springs ususally both lower the car and have a higher compression ratio, or "stiffness," which to a point can help the car handle better because one can go into a corner faster for the same spring travel.

Shocks/Struts/Coilovers: These augment the springs. Stiffer ones do the same thing as HP springs but within a different range and granularity of suspension travel. The springs do the gross ride control, and the shocks/struts do the fine control. Coilovers are usually adjustable for both nominal length (allowing one to adjust the ride height) and stiffness, although the most expensive versions also allow rebound adjustment.

Sway bars: As the car goes into a corner, the tires are gripping the road and trying to go the direction the driver has indicated, while the chasis of the car is trying to continue in the previous direction. Newton's first law. Sway bars limit the amount of side to side travel that the car's body/frame can make when taking a corner, because springs alone would allow it to move side to side. Larger sway bars are stronger and further limit the amount of lateral movement of the chasis to the wheels.

Strut tower braces: These reduce chasis flex at the highest possible point. In general, the stronger the chasis of the car, the more it resists the forces applied to it at each corner from the suspension. A strong chasis allows the suspension to work more efficiently as it doesn't have to contend with forces applied from the chasis to the suspension versus between the suspension and the ground.

Chasis braces: These do the same basic thing as the strut tower braces, except at the lowest possible point on the chasis.

Tires: Easily the most important part of the handling equation. "Sticky" tires grip the road with more force so the suspension can do it's job, but because they are usually made out of softer compounds, they wear out quicker. Lower "profile" (basically the sidewall height) tires have less sidewall flex, and therefore also allow the suspension to take more of the load and forces of handling, but give up some ride comfort. Wider tires provide a larger contact patch on the road, so the shear force between the tire and the road is distributed across more surface area. The trick with tires is finding a compromise between all of these things and what you're comfortable driving on.

Finally, as for the order to do these things, I suspect you're best off addressing whatever weaknesses of the car you can detect first. For instance, if you note the chasis flexing as you go over big bumps or railroad tracks (like the old convertibles used to do) then you'd want to look at bracing it. If the body leans excessively when cornering (like the old luxury sedans used to do) then you'd want to address shocks/springs/sway bars.

Hope this helps. Let's flush out all these definitions thoroughly for the good of all us suspension-noobs. :D

robertdot

I drove a 3 cyl Geo Metro for the past 4 years while in college. The Metro doubled as a tow car to my parent's RV. I think that is all I need to say.

I'm not "new" to all this. I've helped my friends install mods, but never any suspension and never my own car. I read alot on things I'm interested in, so I've got a good deal of theoretical knowledge. I've never been interested in suspensions until reading some of the autox posts.

It depends on what you mean. If you mean slowly upgrading over a few years to get where I want to go, then: I don't plan to upgrade THAT slowly. As I said I can get the aforementioned Mazda parts for under 2 grand. Not a big deal.

If you mean upgrading yearly like I upgrade my computer every 3-4 years, that opens another question. Obviously tires wear out and need to be replaced periodicaly. Shocks will eventually wear out, though I don't know the life on them (and this may be dependent upon brand... so, how long do shocks last on average?). Are suspension parts like computers? Do I need to upgrade on a cycle? Or, once I get them in place (e.g. strut bars and sway bars) they are good for life? In my ignorance, the only reasons I can think to upgrade are if a part wears out or a much lighter and much stronger product is available. But, like I said, I'm not planning to compete.

Is it that struts don't offer much additional performance, or that the performance is not worth the money? Or is the 8 just that well built that they don't help? I'm asking your personal opinion this time, not for generic information.

I've heard a good review of Mazdaspeed suspension parts. I like that they mount without modification to stock components. Is there any reason I should have some prejudice towards Mazdaspeed? Their catback doesn't offer any aditional power, from what I've read. That makes me question whether or not the rest of their upgrades are for appearance, which is why I am even asking about Mazdaspeed. While ease of install is a plus, if it doesn't do anything, I don't want it. Does anyone else have any opinions, esp. if you have the parts?

robertdot

Thanks, Paul. I think you've put us on our way to having an organized and useful discussion.

Omicron

You're welcome, that was my intent. :D

As for Mazdaspeed, the best thing about it is that no dealer can claim it voids your warranty. It's Mazda-branded parts are not only Mazda-warranty'd, but also designed to go on Mazda products. But other than this warranty thing, you can get as good or better parts elsewhere.

PUR NRG

To understand what a sway bar does it helps to understand how it works. Think of a sway bar as a U-shaped rod. It is connected at the ends to each wheel and in the middle to the car. Now consider what happens in a turn: newton's law states the car body wants to keep going forward while the wheels are trying to turn. Body weight is transferred from the inside of the turn to the outside. Less weight is on the inside wheel and the body rolls as it transfers more weight to the outside wheel. The gap between body and wheel is greater on the inside and less on the outside.

Now think about the sway bar. It is attached to each wheel but the brackets that attach it to the car body allow the bar to rotate. So the arms can rotate up and down relative to the car body. If both wheels go over a bump at the same time then both arms go up simultaneously and the sway bar has no effect.

If you had the car body on jacks and tried to jack up one wheel, the sway bar will try to lift the other wheel an equal amount. If my explanations so far made sense then that would sound logical.

In a turn it's a different situation. The inside wheel moves farther away from the car body while the outside wheel moves closer. This causes the sway bar arms to move in opposite directions, which twists the bar itself. Naturally the bar resists that force and wants to keep straight. Thicker (aka stiffer) bars have more resistance.

Now let's combine it all together. You go into a turn and the inside wheel moves away from the car body. The sway bar transmits that force to the opposite side and tries to push the outside wheel an equal distance away from the outside car body. This helps counteract the weight transfer which tries to push the outside car body closer to the wheel and results in less body roll. Less body roll means the inside wheel has more weight on it which then means it has more grip. The end result is you can go through a turn faster.

So why not slap the thickest solid bar on that you can find? Take that argument to its logical (and rediculous) conclusion and you'd remove the shocks and springs altogether. Sway bars actually reduce the total grip you have on that axle.

In an oversteer condition the rear axle loses grip before the front axle does. The common solution is to put a stiffer sway bar up front. This reduces the level of grip on the front axle so both front and rear lose grip at the same time. Most people use the "bigger must be better" theory without thinking about this.

A Penske racing shock installer (arguably the best shocks available bar none) stated his goal is to adjust the suspension to use the smallest front sway bar possible and ideally have no rear sway bar at all. Why? In a RWD car the rear wheels put power down to the road. You want the most grip possible in the rear to do this or the wheels will spin. Since sway bars reduce grip it follows that ideally you don't want a sway bar on the rear at all.

Unfortunately idealism and reality don't always mesh and most shocks are not up to the task. That's why rear sway bars exist. They reduce grip so you can't accelerate as quickly but help you go faster overall in a turn. Suspension design is full of compromises like that and one component can affect several parts--and vice versa. That makes tuning suspensions a tricky proposition.
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robertdot

Brilliant post.
Do you mean "off the line" speed or "accellerating out of a turn" speed? It seems like it would reduce grip while in a turn, but on a straight you'd be fine. I just wanted some clarification in that area.

PUR NRG

Again, I highly recommend Fred Phun's book to understand basic and advanced suspension design. However to answer some of your questions:

Moving parts will eventually require replacement. Shocks (depending on usage) may last as little as one year or as long as 90k miles before requiring replacement or rebuild. Not all shocks are rebuildable.

Springs should last forever, along with sway bars. Braces definitely will last barring accidents.

Braces are designed to reduce body flex. Hold a piece of paper with both hands. Twist the paper. That's flex and that's what braces reduce. While reducing flex is always a good thing it's a question of diminishing returns. Most new sport cars have fairly little body flex, so a strut brace won't make much of a difference. That's why I consider them optional.

You didn't mention shocks in the list of MS parts, and out of everything you mentioned that's the biggest part--both in terms of suspension handling and price.

Like computers there are two different upgrade paths: either you upgrade a single part with the best you can (thus blowing your immediate budget) or you buy a number of good quality parts with the intention of replacing individual components with better ones later on. Both approaches have their advantages and disadvantages as I'm sure you know. Regardless of which approach you take--or even a mix--use the component priority list I gave earlier to make your decisions.

Again, let's take my experience as an example. My priorities are handling first and power second. However there's a point of dimishing returns where I feel a given amount spent on an incremental improvement would give a better total improvement if spent elsewhere.

Since I place handling first I started there. Wheels? I'm looking at $2-4k for the type of wheels I want which is beyond my immediate budget. S-02 tires at $200 each are acceptable however so I put those on the stock wheels. For shocks/springs I wanted a coilover for corner-weighting and ride height adjustment in addition to "normal" shock advantages. JIC FLT-A2s seemed the best choice for price/performance. JIC likes the Racing Beat front/rear sway bars so I got those as well. However their choice of staggered wheel setup calls into question their reasons for adding mods. I think they did that to appeal to the import tuner scene. But I digress. At that point I think I've gotten a good bang for buck in the suspension department and I then moved to power. Canzoomer's chip is good value. I also got a Racing Beat exhaust but primarily for looks/sound not performance so it doesn't count.

At this point the handling/power pendulum (also taking into account price) is swinging back to handling. Alas I have spent my initial budget and will have to wait before installing StopTech brakes. That isn't necessarily a bad thing however as I'm hoping they will sell a front/rear caliper setup for the car in another year. At that point I will probably swing back to power again and choose a lightweight flywheel or maybe forced air. And on and on it goes...

Side story on the StopTechs: I purchased them for the BMW 540i when they first came out. Great brakes, highly recommend. Technically speaking upgrading the rear calipers is strictly for show but I like the look. (Yes there's some ricer in me as well.) A year after I buy the front caliper set they produce a front/rear combo. However the combo uses a different front caliper than the front-only set. So it isn't cost-effective for me to ditch the front-only set and buy the front/rear combo I wanted to begin with. This illustrates an important lesson on cutting edge gear--there's a chance you will get cut. I recognize this with upgrading the RX-8 so soon after its introduction but I'm too impatient. Those upgrading in a year or two will have a much wider and better selection of gear to choose from, and probably at cheaper prices to boot.
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PUR NRG

You are correct. Sway bars have zero effect in a straight (level road) line. Since the topic deals with suspension and handling, that's what I'm referring to.
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PhineasFellOff

PUR NRG,

What about the question I have in my most recent post above?

PUR NRG

Don't confuse effects with causes. Body roll is a side-effect and yes anything you do to reduce/eliminate roll will increase ride "stiffness". You could take out the shocks/springs entirely and weld the control arms in place. That would completely eliminate body roll but I can guarantee that won't give you a better handling car.

Making a better suspension is all about compromises and trade-offs. Ultimately however the goal is to get better handling and if does so with increased body roll then why does roll matter? Remember that example I gave with Penske shocks? If the ideal is to have no rear sway then that means the rear will roll more than if you had a rear sway. Yet you have a better handling car.
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rlfletch

What I would like to control is the "Floatiness" the car has between fast transitions. I'm fine with the grip and balance, Nor do I want to negatividly impact the ride quality too much. My first thought was a sway bar kit but how do those JIC Coilovers affect the ride? My friend is rather unhappy with a coilover kit he put on his WRX because even at it's softest shock setting it is way choppy for the street.

PUR NRG

Sway bar has no impact on "floatiness". That's all shocks. Springs bounce up and down, shocks control that movement.

The WRX problem sounds like the springs are too stiff for his preferences. Shock settings will have little impact on that.

Progressive springs improve ride quality (over linear ones) but aren't as good for precise handling.
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rlfletch

Yes, we figured his springs are too stiff. My question is: How are the springs on the JIC coilover kit day to day? So you don't think sway bars will help with steering response and keep the car flatter in quick transitions? I'm not talking Autocross quick but I do want more responsiveness out of the chassis.

PUR NRG

As I have mentioned before personal preference is very subjective. I have the 10kg/7kg springs and that's the limit of my tolerance. Your limit may be lower in which case the 7kg/3kg springs may be more appropriate. Then again you may consider even that too choppy. The only way you can find out is by trying. What were the spring rates in the WRX and your opinions regarding the ride?

I misread your floatiness comment and thought you were talking about straight line handling over dips and bumps. As a general rule sway bars will increase steering response and reduce body roll in a turn but those should be considered in the context of improving overall handling. Focus too narrowly on one subject and you might improve it to the detriment of others. If body roll is the only thing you're concerned about then go for the sway bars.

rlfletch

I don't know his spring rates but it crashes pretty hard over bumps. How does your kit compare to stock ride quality? I didn't know different spring rates were available. ~$1500 + installation is a bit much to find out I might not like it. Just trying to gather info before I jump. Sway bars are a lot cheaper.

The body role seemed to be the obvious reason the car was unsettled in the transitions but maybe I'm missing something. That was my only complaint with car, other than the soft brakes, so I'm trying not to upset the ride/handlng balance in correcting it. Thanks for the input BTW.

Japan8

Weeell. I wasn't going to post this yet, but since you guys have brought the subject up, I'll see what I can do about posting the suspension reviews in the RX-8 Sports Magazine...

They review 15 different coil-over kits. Their two favorites, Tein Cruising Master TYPE CS and Cusco Zero-2 are allotted 2 pages each (with a side bar on the Tein Super Street), which Ohlins PCV Supsneion Kit, Bilstein BSS Suspension kit, Knight Sports Aragosta Kinght Special, and Fujita Engineeing FEED F801 Suspension kit get a page each. The rest of the pack is Quantum RE Amemiya Spec., Revolution Suspension System, AutoExe Tunable Suspension Kit, RS Active SRE Suspenison System, Alpha Rigid Jim Carna Suspension KIT, Original Rundunce Original Suspension KIT, Leg Motorsports Hi-Spec Damper, RSW Sports Spec KIT, and last but not least Kei office Erfolgkei type XT.

There's quite a bit to go over so it may take me awhile to finish this post... please bear with me and stay tuned for more...

PhineasFellOff

PUR NRG,

rifletch is talking about the very noticeable body roll in slalom-type transitions. Many of the magazines mention explicitly that the RX8's body roll reduces its slalom performance.

PhineasFellOff

I'm surprised the JIC's aren't in the review.