Necessary to Replace/Upgrade Sway Bar Link when Installing Aftermarket Sway Bar?

[3002 tii]

I understand the need to typically upgrade sway bar end links if you're lowered, but are these oem components in general durable? Reason I ask is because I will be putting on a new front sway bar (while maintaining stock height) and figured I should replace everything in one shot if that is in fact the case.


And if so any feedback on GC or the TMS end links?

[F360C]

You don't "need" them but it helps to have them especially if you plan to corner balance the car. Having adjustable endlinks allows you to be able to take pre-load out of the bar.

[Serious]

They are necessary if you want to either remove the preload or corner balance the car (which you can't unless you have height adjustable suspension)

Personally if you're near stock suspension I would run the stock endlinks.

[mfanatic325]

Hey Dubbed, wouldn't upgrading only the front sway bars induce more understeer? I thought if anything, you would want to upgrade the rears, with all else equal?

[Nikki]

Originally Posted by mfanatic325

Hey Dubbed, wouldn't upgrading only the front sway bars induce more understeer? I thought if anything, you would want to upgrade the rears, with all else equal?

This is what I've been told as well. I'm planning to upgrade the rear sway once I see one come around in the for sale forum.

[3002 tii]

Originally Posted by mfanatic325

Hey Dubbed, wouldn't upgrading only the front sway bars induce more understeer? I thought if anything, you would want to upgrade the rears, with all else equal?

Less body roll especially in slaloms during auto-x, and not looking to swap for higher spring rates, not yet at least.

[Serious]

Originally Posted by mfanatic325

Hey Dubbed, wouldn't upgrading only the front sway bars induce more understeer? I thought if anything, you would want to upgrade the rears, with all else equal?

Typically that is the rule of thumb... but remember not all suspension setup's are the same and sometimes suspension tuning is a black art, what may work great for person X may hurt person Y because of differences in tire compound, wear, pressure, differences with other suspension components or wear, driving style etc. Sadly there is no such thing as flow chart to a proper handling car.

The reason many people run a stiff front sway in BMW's is due to the macpherson strut style front suspension and how the camber changes throughout the travel.

Essentially stiffing up the front of the car helps turn-in dramatically, although IMO it also causes an increase in mid corner/exit understeer.

To be honest I don't like using swaybars to effectively increase the spring rate, and don't feel the car needs them. Additional negative camber is the most important thing to improve the handling and reduce understeer on any BMW, after that you should be using stiffer springs and better dampers to increase the wheel rate, then and only then should you be looking at different sway bars and only using them to tune the handling not dramatically change it.

A big rear bar, and stock one up front is only going to further enhance the lazy turn in while increasing midcorner/exit oversteer. beware.

[mfanatic325]

ohh interesting. Thanks for the heads up.
I like how my car currently handles. I'm sure that I would need plenty more seat time on track and got more leveling-up to do before my setup will come anywhere close to being insufficient
I currently have TCK D/A's with 500 lb./in. front and rear springs (I heard that it's more advised to have a different front to rear ratio, but thus far it's felt fine on track), stock sway bars, stock end links.
The coils are corner-balanced and my current alignment specs are as follows...

Fronts:
-3 degrees camber
"0" toe
full positive caster provided by TCK's camber/caster plates (I believe it's around +6 degrees?)

Rears:
-2.2 degrees camber
3/16" toe-in

I'm currently still getting acquainted with the car, and am still using crappy General tires. Have only run two track days so far. And thus far, even the crappy General Exclaim UHPs have been surprisingly decent on track
I attribute the wow factor to the car though of course
I'm currently running 32psi fronts and 30psi rears on track (hot temps).
30 and 28 respectively (cold).

What would you suggest for me to try out? Or should I just keep at it, keep working on my driver skills, and not worry much about actual tuning of the car until I'm fast enough to? =P

I suppose we could turn this into a track thread if no-one else minds? lol

Originally Posted by Nikki

This is what I've been told as well. I'm planning to upgrade the rear sway once I see one come around in the for sale forum.

Do you go tracking Nikki? I feel that the bars on the Z4M are plenty good, even for track use. Perhaps upgrades aren't needed at this time?

My MR2 already had the sway bars done when I bought the car, and it was ridiculously stiff. Stiffest crap out there for that car. It was notorious for ripping end links, end link tabs, sway bar mounts, etc.
Reinforcement plates welded directly to the chassis were highly recommended. I felt that the car handled well from the four times I took it to track, but perhaps some of its initial understeer was caused by the overly-stiff sways *shrug*. That's just a hunch of mine.
In any case, the Z4M blows that car out of the water lol. I will not track the MR2 again out of sheer cowardice hahaha

[nlink720]

Correct Above: a stiffer rear spring rate is necessary to balance the car due to the different lever arms of the front and rear suspensions. The fronts spring perches are farther out than the rears, so for a given spring rate the front is more effective. I heard somewhere that the front is about 0.95 while the rear is like 0.75. That's why the rear springs must be stiffer to maintain a neutral balance. 500 on all corners will understeer unless you are running a very stiff rear bar and relatively soft front.

I have my bars equal, and 550F and 700R is neutral to very slightly understeer at the limit. 550F/650R was great all around until the limit, when it understeered annoyingly enough that I went up 50lbs, and it was resolved nicely. I use my car primarily for autocross, so a more neutral car may be desired for my uses more so than for a primarily tracked car. But, none of this is important until the limit -- there is no way to differentiate other than ride firmness -- the difference between a square spring setup and a softer front-stiffer rear setup in a street-only environment.

I've been through 440/550, 500/650, 550/650, and 550/700.