TracerRX-8

Ok I've got a little money burning a hole in my pocket and want to put it in the suspension. I just got the Tein spring installed and have been reading about sway bars. I'm takin the short bus to school regarding suspension so talk real slow and use small words when you reply. lol. I'm taking it that I need front and back and what about those bars that tie the tops of my shocks together? I've noticed a huge price difference in them too. What about the beefer things they tie to in the back....should I get those too? I'm going to be racing this thing but I want the most bang for my buck in handling. Where do I start and which brands should I get? Thanks a ton! T

PUR NRG

Short word reply: did you try a forum search? This has been talked about before. Many, many times.
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Ophitoxaemia

springs will be the best bang for buck. get the RB ones then you dont need shocks. the stock shocks are very good.

hey robin, will you be out on the 13/14th at oakland? im tied into driving the cobra for slush, but some others will be racing my 8.

james

PUR NRG

It's doubtful. I'm in the final crunch to get the house completely unpacked and settled in before Thanksgiving. We're expecting 30+ guests...
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rev-2-9k

The biggest problem you have tracy is that most people buy the Tein S tech just to lower that car. I do not know of a matched shock or sway bar for this spring. Like Oph said the best bang for your buck would have been to get the RB kit with springs and sways as they are matched to the stock shock and all the pieces work together.

Sway bars will help you more than tower struts, they will transfer weight left to right during cornering and keep your car flatter. Tower struts will stiffen the chassis. You already have a front tower strut and the back is already stiff without ...

There are 3 sway bars most people get...

RB, but they may have to large of a diameter for the TEIN's and mess with your steering. Tanabe has a set that may work best with the TEIN's.
The Mazda Speed ones are kinda expensive and matched to the MS shock and spring.

I would get both front and rear sway bars.

Getting larger end links is certainly an option. RB has a larger diameter front but you have to drill out the A-Arm up front. Vivid racing sells a tougher one for the rear. I did not put the upgraded end links on my car, I guess if I bend them then I will get the RB ones.

brillo

Does tien normally make sways for other cars? They might comeout with some soon if you wait. I believe sport compact car had an article about the tien rx8 with the adjustable suspension coilovers, and they were using the racing beat bars, not sayin they are a good match, they might be, I'm not sure, but its worth looking for that article online.

rev-2-9k

Well brillo with adjustable shocks and springs you could match to the RB sway bars. Tune to your taste.

I am sure the car would corner flat the question is if he would get to much oversteer with this setup. Or understeer.

brillo

good point, I guess you could tune with or around the sway bars if you had adjustable sways, to be honest, I see alot of writeups in car mags on cars that have sways that are made by a different manufacturer than the springs/shocks/coilovers, so if done correctly, I don't think it will matter that they are not all form the same place.

I'm geting around this by going all Mazdaspeed, you could also go all RB and wait for the koni's that are matched to the RB springs. I'm not as familiar with the S-tech springs in terms of their benifits and drawbacks, I got the impression that they were more for lowering than handling, but obviously any spring that is stiffer and lowers will aid in handling somewhat.

Ophitoxaemia

there is no magic in sway bars or springs. they are both springs and for the most part are defined completely by one number: lbs resistance per inch of movement.

shocks are a different matter and are complex.

sway bars are just springs that only work to resist body roll during cornering. so it doesnt really matter for most people to mix and match.

what starts to matter if if you put really stiff springs on a soft shock (or visa versa). and actually, the stiff you go, the less bars help you since you get roll resistance from the springs. you can also get a case where you need to remove the rear bar because it will pick up a rear tire during corner entry (torsens hate this).

james

Spin9k

Ok. Are you saying that as stiffness is additive among springs and bars, you can more easily than you think get to a 'too stiff' stituation? So that would recommend smthg like the RB Susp Kit as it is a moderate (matched overall) stiffness kit?

Stock RX8 6spd Racing Beat
F 155.61 lb/in F 187 lb/in (20% Stiffer) Unknown sway bar stiffness vs OEM? 20%?
R 112.86 lb/in R 136 lb/in (20% Stiffer)

But my question is, OK you've moderatly stiffened up the car - But NOW at the same time ADD in new 17"wheels (lightweights ~16lbs) - decreasing total/wheel unspung by 48-39 or about 9lbs. Does this make the spings and shocks now treat the lesser unsprung weight with 'more stiffness' because it was designed to control a heavier OEM weight? And if so, isn't that even more reason to stay with a less stiff kit - as this unsprung weight reduction will ADD to the total stiffness?

Seems lightness and flexibility is a virtue

Ophitoxaemia

>Ok. Are you saying that as stiffness is additive among springs and bars,

yes, but springs contribute the same rate of stiffness in dive, squat and roll. sway bars are specially attached so they only contribute roll stiffness. the only reason we dont just use really stiff springs is so we can control the body roll without making the ride crazy stiff. in racing terms there is a limit where there is so much spring the car just jitters over bumps and you cant get any traction. if you rely on the sway bars too much you will start to pick up a front tire (too much front stiffness) or a rear one (too much rear roll stiffness).

the unsprung weight doesnt have a direct effect on stiffness. the springs are there to hold up the chassis (the sprung weight). it has an effect on how the shocks will work though.

you can calculate almost exactly how much roll stiffness you need. i did this for my race car. there is (an imaginary) lever arm that exists between the center of gravity of the car and the line that connects the front and rear roll centers of the suspension design. with the car turning at the maximum G force, the weight of the car pulls on this lever. you can then figure out how much force you need to limit the body lean to, say 2 degrees.

how to distribute the roll resistance front versus rear is more complex. then we add shocks and dynamic weight transfer and it gets too hard to caluculate.

a 20% increase all around wont cause any problems. whats important is to keep the front versus rear roll resistance about the same. about means like 20-30%.

james

BaronVonBigmeat

I *think* there was a guy somewhere here who had both the Tein S-techs and the Tanabe (?) sways too, and raved about the combo. But now I can't find his posts. I have the S-techs collecting dust in my garage for now, I figure I might as well go ahead and do sways while I'm at it. But I'd prefer to copy someone else's setup first, and let them be the guinea pig.

TracerRX-8

[you can calculate almost exactly how much roll stiffness you need. i did this for my race car. there is (an imaginary) lever arm that exists between the center of gravity of the car and the line that connects the front and rear roll centers of the suspension design. with the car turning at the maximum G force, the weight of the car pulls on this lever. you can then figure out how much force you need to limit the body lean to, say 2 degrees.
/QUOTE]

Yeah thats what I was thinking....about 2 degrees. LOL Thanks James now I feel like a retard! Dynamic weight transfer indeed! LOL.... I'm glad there are people like that out there but I'm a put this thing on your car it will make it "Sweeeeet" kinda guy.

Ok let me ask one more question..... When I put the Tein's on I had it aligned as I was told I should have but if I put sway bars on do I need it aligned again?

Oh also.... I havent read much in this post about the thing that ties the top of the shocks together that is the engine compartment. This question is for James or someone like him...what does that do compaired to what sway bars do? Do I need both?

Thanks, T

AlexCisneros

You will not need to re-align the car for the sway bars. They have no effect on suspension geometry like springs do. I have the front and rear Tanabe sway bars and think they are the best investment I have made to the car.

As far as the front or rear strut-tie bars... You do not need them in conjunction with your other mods. They only stiffen the chasis which, unless you are with a full race suspension and slicks, you don't need.

*on a side note* the MS front strut-tie bar should have special mention. This bar has a bracket that supports the brake master cylinder. This support has been reported to increase pedal feel during threshhold braking.

Ophitoxaemia

alex is right on.

other cars might benefit more from the strut bars (that tie the strut towers together) because many cars 1. are less stiff and more importantly 2. are mcpherson strut, so flex in the strut tower direct affects the suspension. the rx8 with a duel a-arm front design is much less senstitive to displacement in the shock towers.

i get the feeling that the MS bar, if tied to the master cylinder might qualify as a 3 point bar, which is likely a ticket to e-mod in autocross.

james

Dark8

The MS bar doesn't bolt to the master cylinder, it has a bracket that sits right up against it as a brace. I don't think that would count as a mount point.