mVP

Hey guys,

I figured I would ask the professionals for some advice before I go buying things blindly.

After reading about how evil sway bar preload is, I'm looking at some adjustable sway bar endlinks (likely SPL from Concept Z Performance but open to recommendations). Is it recommended to get endlinks for both the front and the rear? Or is the front enough?

I have an 06 Z that is currently on BC Racing coilovers with a slight drop to accommodate 275/35/18 ZII Starspecs front and rear. No camber arms/toe arms yet. Car is a nice-weather driver and used for autocross and occasional HPDE.

I'll also be getting an alignment soon, would you recommend installing the endlinks before or after the alignment? Or does it not matter?

MicVelo

Do both F&R. Especially if you are running adjustable bars. Sure, it might end up being set and forget (if you like the setting and/or you don't have adjustables) but why not if you are going to the time and expense of swapping out end links. One less thing to worry about going forward. (I'm a strong believer in "maximizing lift time".... why not just get 'er done while it's up there?)

I'm also a believer in maintaining balance F&R. New end links MAY alter the roll stiffness up front (doing only the links front) because your old, tired rear links may have a little more slop in them than the new ones up front, leading to possible understeer. Not a highly likely scenario but you never know until you get it out on the road/track; then you gotta go and lift the car again. (There's that "maximizing lift time" thing again.)

You are wise in knowing that the pre-load is important. So, do your final torque-down while the suspension is loaded under settled, static weight (on the ground - yes, a PITA.... or on a platform lift/alignment rack - much preferred.)

Generally speaking, ANYTIME you make suspension changes, it is advisable to at least CHECK alignment following or just have it done to correct what you can - in our case, toe adjustment with stock components or all factors with adjustable gear.

So, while installing bar endlinks won't necessarily affect any of the alignment specs (but, technically it could since you are changing the load on the suspension with new bars), do the alignment AFTER.

For street, you want the best compromise for handling AND to save your tires, so alignment is an absolute must with any change.

Mic

mVP

Thanks for the good information Mic!

I'm currently running the stock sway bars, mainly looking to relieve pre-load from lowering the car. In the future I might swap out the front sway bar but had no plans for the rear as I've seen many people on the forum prefer to run without it!

Makes sense to do front and rear though as both sets of endlinks are likely under tension. Any recommendation on SPL vs Whiteline? I've been digging through the forums a bit but can't seem to get a straight answer regarding quality.

Manny

monztr

The sway bar does not load or preload the suspension with the car sitting flat. A sway bar simply connects one side ot the other, so when one side is compressed it leverages against the unloaded side to increase effective spring rate at the loaded corner during turning, when flat, nothing. Stock end links work great, if they are old and bad you replace them. If you are "all stanced out yo", you might need adjustable links to gain the needed clearance due to the modified suspension geometry.

MicVelo

Manny, I am still (after some 3-some decades of suspension tuning) in a state of confusion over the commentary about running without a rear bar - especially where there was one to start with. It goes counter-intuitive to everything I've ever read and DONE to any of my cars.

Generally speaking (and highly dependent upon the type of suspension being run, e.g. 4-way independent, front independent-live rear, etc.), removing a rear bar will promote UNDERSTEER, which is probably fine if the car is driven conservatively. (Most production cars are set by the mfgr to understeer slightly to keep them safe from product liability issues due to some g'ma swapping end-for-end while running late for bingo).

Even our Z's have production understeer consciously built into them as delivered.

But specific to the Z33 (and pretty much all Z cars), the cars aren't too far "below" neutral steer. Adding a SET of specifically tuned sway bars push it closer to that theoretical "zero" line of absolute neutrality and in some cases, can be tuned to go over that line into the area of oversteer.

As an example, I've tuned my '03 Enthusiast for slight oversteer by running the front bar (aftermarket - Hotchkis adjustable) soft (first hole attachment) and the rear slightly stiffer (second hole attachment).

Likewise, both of our Nismos are equipped with larger-than-all-other-Z-trims REAR sway bars to get them to neutral steer which I wrote about in this post.

So, someone needs to explain to me (seriously) the rationale for NOT running the rear bar. I am NOT saying anyone's wrong and maybe I'm missing the point but in my "traditional chassis tuning" mind, dumping the rear bar is a recipe for off course disaster (at least from my type of driving's perspective).

Maybe it's an autocross thing? (Which, admittedly, is NOT my forte.... my preferring road tuning - hills, road course, that sort of thing).

Anyone want to comment on this? I'm sincerely interested in knowing why this works and contradicts everything I've ever learned! Heh heh.

EDIT: Oh, forgot, you asked about brands.... SPL is considered good stuff but Whiteline actually has a pretty good rep as well (and a lot lower price point). But I've no experience with either as I'm running factory sway bar end links with a modestly lowered suspension (no coilovers). I've not experience any link wind-up or complications with my bars in 18 mos. of running them.


Mic

MicVelo

monztr, I'm pretty sure that Manny (OP) wasn't talking about suspension pre-load (and I know I wasn't). We're talking about the effect of lowering on the sway bar attack angle itself because changing the geometry of the suspension (lowering on coilovers) can impart a difference in the sway bar lever angle. Going with adjustable (length) end links enables one to get the sway bar back to its proper geometry, that's all.

Mic

terrasmak

iTrader: (8)

Typically you will corner weigh and align the car with the bars disconnected. Sway bars at 0 preload do not affect alignment. If they have a slight preload on them it's not enought to matter unless you are racing at a Grand Am level.

mVP

Thanks for the replies everyone; I was talking about sway bar preload (not preloaded suspension).

On another note (I'll post here as not to crowd the forums), I'm looking for some feedback on a VLSD vs LSD. I've seen too many threads on people converting the open diffs to LSD, but none on the benefits of an LSD over the VLSD. Is it worth the $1200+? Again, my car is used for sunny weather driving, autocross, and occasional HPDE.

My other option is to go hard on the suspension setup (adjustable front A-arms, rear camber arms etc...) to get the alignment dialed in. Basically, what is going to give me the best results on the autocross course for the money?

LeonardiZ

From what I understood, running no rear sway bar for autox is actually not uncommon. Its supposed to all the car to roll and plant itself on corner exit. The guys who do it usually compensate with harder springs in the rear. I haven't tested out this set up but I may give it a shot... For now I'm running the Whiteline bar with the adjustable links in the front only. The car is slightly dropped on Petit racing custom valved coilovers. Lets see how they do

04 Z33

eye-5

My 2 cents, aftermarket endlinks usually clunk pretty bad. I went back to stock just to get rid of the clunking. It was driving me crazy.

jledford

iTrader: (1)

I have Whiteline end-links on a front Hotchkis bar with no clunking. I do not run a rear bar at this time.

eye-5

The stock viscous diff sucks. If you are running in a class that allows diffs, a 1.5 way clutch type would be ideal. OS Giken is probably the best out there. Helical work well until you lift a tire and then they act like an open diff.

eye-5

I know the stock one sucks because I'm a one wheel peel all over the autocross course. I run in a class where you can't change it out. I might put a new stock VLSD in to see if it helps as I hear the stock one doesn't last very long.

LeonardiZ

Maybe you need to put slight pre-tension on the aftermarket links so they have to room to wiggle and clunk.

Also, if you're gonna run the stock VLSD then look into adding some friction modifiers so it holds better. A buddy of mine drifts his Z on the VLSD but he changes the fluid with every oil change basically and he adds some kind of friction modifier to it.

eye-5

I thought the stock unit was sealed.

armt350z

iTrader: (6)

It is. The viscous fluid is unaffected by friction modifier.

terrasmak

iTrader: (8)

Sounds like a huge waste of money, the fluid is separate , and friction modifier will never actually touch the LSD

Glenn350zHR

iTrader: (5)

dont waste your money on a stock VLSD. if your doing autocross and making the eventual switch from street to street touring get a real Diff. It is the single most important upgrade to the whole setup next to tires. I had a hard time making a Quaife diff work for me but others have got it to work fine. I prefer the OS Giken diff. Little bit more money but 100% worth every penny.

Glenn350zHR

iTrader: (5)

regarding the end links I liked the quality of the whitelines. i only had them for the rear bar that i almost never used in autocross. I ran custom ones up front but only because we had the parts available to make them when we did the alignment.

The whitelines have a nice anodized threaded collar that u dont necessarily need to completely disconnect the link to adjust length which is cool. Again your probably adjusting this but once when u do a corner balance and alignment but still convenient. Also u dont need to go full crazy on the torque specs because they use a lock nut which is probably the most important. Horror story - I had one of my custom links loosen up and the car was misbehaving up front and didnt realize what was going on till it was too late. This happened at Nats this year and ruined the thread bolts so i couldnt fully tighten the link back up. Also ruined my chance of a trophy **sigh***

eye-5

This is why I went back to stock endlinks. Even with locking nuts & Locktite, the Circuit Sports adjustable endlinks would always loosen up. The stock (actually AC Delco stock equivalents) are working great without loosening up.
A little note, I did have to bend the stopping tab on the stock ones to allow them to work with an aftermarket bar.