donny

I was thinking of buying a new front and rear sway bar set-up, is it worth it. Can you tell a difference? Also, what is a good kit to buy, how are the 3-piece(adjustable) front sway bars???? I dont want to spend the money if it hardly makes a difference....

artowar

iTrader: (1)

Depends on a lot of factors, but some more info would help people give you their opinions. For starters:

-What have you done to the wheels, tires, & suspension already?

-What do you want to use the car for?

donny

18" Volk Te37, 235front and 275rear. Tokico 5 ways' with Eibach springs. The car is street driven, not daily, nver auto-crossed. I just want it to handle the best it can....

kyle@insight

Sway bars will definatly help you out. Don't mess with the adjustable sets since you aren't a hardcore auto-x/roadracer. Just get a nice set of Suspension techniques swaybars.

artowar

iTrader: (1)

donny, unless you need to replace the swaybars (e.g., they're about to break), if I was you, I'd just leave it alone for now. Your wheel/tire setup will bias towards understeer, which is more forgiving. Also, you can always play around with tire pressures and damper settings to even things out a bit.

That $$ you save on these mods is IMO better spent on maintenance items. However, if you really want to spend the $$ on suspension components, then I'd suggest asking someone local for a drive of their already-modified car. Hell, if you were here, you could ask me. Of course, I would say "NO,” but that’s because I'm a selfish bastard that doesn't let other people drive my car Seriously though, someone local can probably show you some installed components and hopefully let you try driving.

Now to answer your original questions:

Is it worth it?
It was for me, but my car is mostly used on the track now, and I run R-compound tires year round. I also upgraded my springs & shocks. My car is street-legal, but I think that most (non-track oriented) people would consider my car too harsh as a daily driver.

Can you tell a difference?
A huge difference in the way that the car handles. I find the car a lot more responsive (i.e., it responds more quickly to inputs from me or the road). Overall, I find that it makes the car more fun to drive.

Also, what is a good kit to buy, how are the 3-piece(adjustable) front sway bars?
I bought Tri-Point's 3-piece front bar. Great quality, and in my hands the day after I ordered it (okay, I live 1/2 hour away, but the point is that they shipped it immediately). I use it in conjunction with David Breslau's Widefoot swaybar mounts. I also have M2/Advance Design adjustable shocks with aftermarket springs.

I dont want to spend the money if it hardly makes a difference...
It makes a lot of difference in how the car handles, but it won't improve your driving abilities. Remember that bone stock, this is one of the best handling cars ever produced. Assuming that your goal is to be a better driver, you can better spend your money on car maintenance and driving instruction. I’d be a lot faster now if that’s what I had done J

One more thing: The mods are probably going to move this to the suspension section. Search there to find a lot of info on available parts, etc.

spyfish007

I'd only recommend a rear bar upgrade for 2% of RX-7 owners. Get the front only.

Howard Coleman

iTrader: (6)

sway bars do not change lateral weight transfer. they do change the rate of transfer and body roll. since the rx7 was engineered to have negative camber gain body roll doesn't hurt the car's lateral grip as it would a bmw w it's inferior macphereson strut front suspension. changing swaybars effects the roll couple and as such does make a major impact on how the car handles. what we are talking about is front to rear balance. oversteer ("loose") comes from too much rear roll stiffness, say, too stiff a rear swaybar... /too stiff in relation to the front bar/. understeer ("push") comes from too stiff a bar in the front in relation to the rear. other factors effecting handling dynamics are cornerweight.... (get all the weight off the front tires... battery behind seat, remove all the engine accessories p-s, a-c etc), shock adj (soft in rear), spring rate (ditto), suspension geometry and settings, wheels, tires and lastly one of the most important: tire pressure. i like around 30 front 28 rear cold. with most rx7s the challenge is making the rear stick. i run lots of suspension in my car but am happy w the stock bars and Widefoot mounts. other than racing around cones stiff is not fast. it reduces tire compliance w the track. watch the nascar cars while they warm up their tires prior to a restart and you will see some body roll. if you are serious about making your car handle a pyrometer is extremely helpful.
i do agree with the preceding advice from kyle,artowar and spyfish007
howard coleman

DamonB

Why do cars need sway bars? As Howard points out weight transfer across the car will happen regardless of roll stiffness, even go karts have weight transfer and they have solid suspensions. It's true the FD does have plenty of camber gain as it rolls and body roll in and of itself is not bad, but there are big reasons to try and eliminate it.

I see no need to change the sway bars unless the car is going to see some performance driving, to me that means some sort of track or autox use. For performance driving the front FD bar is too soft. Again as Howard points out the FD tends toward being loose in stock form. A stiffer bar typically removes some grip from the end of the car it is on, so by adding a stiffer front bar to the FD we actually make the car more neutral along with some other positive results as well:

Less body roll is always better than more for several reasons.

First, the car can change cornering attitudes more quickly (think esses or slaloms) because the chassis is not heaving around as much and therefore the tires will more quickly respond.

Second, body roll uses up suspension travel. In a hard right turn with lots of roll the right side of the car approaches full droop and the left side approaches the bump stomps. Things can get dicey while turning, braking or accelerating while turning over bumpy surfaces as you can easily bottom out the side of the car you most need to be working for you. When you hit the bump stops the spring rate will instantly go infinite and you'll find yourself running out of pavement. Hopefully there is enough to keep you out of the weeds.

Third, as the suspension compresses the geometry creates camber gain. The less suspension travel we use in roll the more tightly we can control the camber of the tire as the suspension will be working inside of a smaller envelope so to speak. We can make our camber settings more "perfect" for many different corner speeds because the suspension will not roll as much. Our camber compromise can be smaller with increased roll stiffness.

Fourth, a stiffer front bar helps with getting the power down on corner exit by keeping the inside rear tire planted more firmly while cornering. This is the biggest positive attribute I find with my setup as I can be much more aggressive with the throttle after the apex and yet not break the rear tires loose.

A sway bar is merely a spring that connects the left and right sides of the car. This spring only comes into play when one side of the car experiences an action that the other side does not. The reason a sway bar fights roll is because as the outside tire is forced up in compression, the tire must compress it's own coil spring and at the same time twist the sway bar since the opposite wheel is trying to droop. The sway bar adds spring rate only during cornering. Obviously you can also add spring rate by changing the springs to something stiffer, this would also result in less body roll. In stock form the FD springs are pretty soft and therefore it takes a stiffer roll bar to make the car work. On the other hand adding stiffer coil springs would not require as much bar to make the car work as the springs themselves are helping with the body roll.

Again this is all a tradeoff. You can easily make the car so stiff in roll it would have less grip. The goal is to have the least amount of roll that still gives maximum grip, and the sway bars are by no means the only mechanism available; shocks and springs also play a prominant part.

duboisr

My mechanic has Suspension Techniques bars and their lowering springs . The car is street use only and handles the way he wants it to . Turns are very flat and stable, no over or under steer . any one can drive the car hard with out fear of slideing out . The ride is not to harsh but it is a sporting car if you will . Tie in a good engine torque brace , pick up a girl, turn up the radio, go for a ride .

DavidDeco

I have the RB Front one and it's definitley worth it.

You won't need or want the 'matching' rear. It will promote too much oversteer for the car.

donny

I am kind of confused. I only drive my car on the street but I want it to be extremely responsive, not necessarily like an Indy car, but very quick. I am gathering from the info above that a simple Suspension Techniques kit would do the job, front and rear. Orwith my wider tires in the rear, (275/35/18) , do I only need a front bar so that oversteer isnt a huge problem. My front tires are (235/40/18) and I have Tokico 5 ways' with Eibach springs.. I dont care if the ride is a little worse, it is a sports car....

mjw

iTrader: (1)

Your staggered tire setup will not induce oversteer (that is unless you are into the throttle too much in a turn), it will have a tendency to understeer more. It is very hard to notice in street driving though.

Howard Coleman

iTrader: (6)

donny,
giving your objective additonal thought (more responsive car) my first mod after your tires/wheels would be springs not sway bars. i have both a shock dyno and a highly accurate electronic spring rater and have done lots of research in the area. the stock rx7's springs are about 263 pounds per inch in front and 195 in the rear (average of 10 sets tested). some people run 550 front and 450 rear. i run 432 front and 378 rear. for the majority of rx7 owners driving in the real world of potholes etc but still wanting greatly (and i emphasize greatly) improved performance i highly recommend the Eibach ProTrak springs. they measure out at 350 front and 255 rear up 33% from stock) and provide a near perfect compromise between stock and race-only. they also drop the car to just about perfect ride height (25 inches at the top of the wheel well.) the stock shocks work well w the springs. you will need to reset your camber after installing the.... about 1.2 degrees neg front and rear. enjoy!
howard coleman

ptrhahn

iTrader: (9)

The short answer is, yes they are worth it... sway bars are fairly cheap and contibute greatly in improving the responsive "feel" of the car. Since yours is a street-only car, balance will be less important than feel. (balance is subjective to driving style, course conditions, and each individual corner anyway, and you won't explore the limits of the car in this way on the street.).

matty

i only upgraded the front. I cant believe how neutral my car handled when i brought it to the track. love my car!!

matty

this is is true....i couldnt even explore the limits of the car on the track....takes some practice. My own limits are lower then the cars. Trust me unless u have driven an fd on a track you have no idea what they can do. It was a real eye opener!

matty

opps

rx713bt

iTrader: (4)

Thanks for the info guys. Last time I was at the track, the rear end felt too loose and I had quite a bit of body roll. Time for the Addco sway bar up front. They want $140 for the front at www.shox.com.

-Jeff