z-u-later

iTrader: (43)

Does anyone have the SPL front end links installed? My front end links are very loose when I have the front sway bars set on the tightest setting. I have the Tein S springs & stock shocks so I'm just wondering if the SPL front end links will work for my setup since they recommended it for coilovers.

daveh

iTrader: (9)

Ok guys, TC Design will use my car to make some adjustable end links. He says a project like this is very easy for him and he can do it in about a week.

I'll post back with all the info in the next week or so when he's got them ready. As I mentioned, Tony does great work and has built some very fast machines. He did my custom rollbar and upper shock mounts. Check out his work here.

http://www.tcdesignfab.com/

Dave

Z1 Performance

iTrader: (564)

we're purposely not doing the adjustables for the sets we are going to make - I've had too many issues with them from various makers in the past on other cars and prefer a solid design

z-u-later

iTrader: (43)

I agree, the design should not be too difficult. Although with the custom end links, I just hope the cost is not more than the $100+ end links that are already currently on the market. If things work out (quality & cost), I will be one of the first ones to purchase a kit.

abui01

iTrader: (68)

Let me know the minute these are ready, my handling is going to hell w/ OEM endlinks.

ksj

Can you be more specific about the type of issues you've encountered? You're the first person I've heard say there was an issue with adjustable end links using heim joints.

Thanks!

Z1 Performance

iTrader: (564)

It's simple - we've had them (from various manufacturers) loosen up, causing sway bar walking and in some instances, flipping (had this happen on several STi's using a well known endlink, and as a result, we stopped selling them altogether). The adjustable ones are a relatively easy way for manufacturers to make 1 link that fits several cars.

I've also had the bearings fail, causing the links to make a racket, and, we've had the center "ball" sections pop out as well (also by a seperate well known manufacturer). As a result of this, the only type endlink we now will sell is the type we posted above. In the 3 years we offered that style (by 2 seperate manufacturers) we have not once had a failure, a complaint, or an instance of any noise of any kind - in our eyes, they are the best of all worlds and allow a link to be tailored for a specific application.

The heim designed once can be made to work very well, but doing so is very expensive and having not had any luck with them on any car we've run them on (from BMW's to Ferrari's to Vette's to STi's) , we vastly prefer a one piece CNC'd unit with a quality bushing.

abui01

iTrader: (68)

Could you explain what exactly happened when those end links snapped? I am experiencing an odd "swaying left and right" motion... while driving in a straight line! Yes that is correct, straight line driving, not during cornering. My end links are still in place and nothing is broken. My first guess was perhaps a loose bolt ever since I installed my suspension? (Cusco Zero II's dropped 0.5 inches, Hotchkis sway bars - hard front med rear, GT Spec front/rear lower tie bars, tanabe underbrace) However, a loose bolt would make a noise from the extra play or at least a *clunk* when it sways, in my case, there is ZERO noise... the car drives straight, the wheels are straight, but the body itself leans from left to right. The shocks are basically brand new and the up/down rebound motion is perfectly fine. My BEST guess was because of the sway bar.. but what could possibly be wrong with a sway bar besides the... END LINKS! I just received my SPL rear links in the mail the other day and will install them by the end of today, but until then, any suggestions? BTW: I just had my alignment done 3 days ago and my mechanic got everything back to spec and he noticed this odd swaying motion, 3 days later (today) it got worse than ever. Hopefully end links will solve the issue.

I've been reading about people who "hit a bump on the highway and the rear end seems to lose control" this happens as well, perhaps it's all part of the same equation, who knows, any suggestions guys?

Z1 Performance

iTrader: (564)

I'm not even going to wager a guess as to what could be wrong - it sounds serious though

you would know if the endlink went bad immediately - it is quite loud over every single bump, big or small and the bar will physically not stay in the same place

z-u-later

iTrader: (43)

So, are you still looking at designing and selling these end links? I seriously think there is a huge market for these new end links if the concerns you outlined are resolved with these new end links for the Zs.

Z1 Performance

iTrader: (564)

yes we're in process of designing the prototypes - once we're satisfied that they will fit the needs lacking in the stock pieces, we'll put them into production

z-u-later

iTrader: (43)

Yeah!!! If you need someone to test the prototypes, I'll gladly volunteer!!! I am looking forward to this new product.

Z1 Performance

iTrader: (564)

no problem - we actually have 2 Z's in house as well as several local cars we'll be doing testing on once the prototypes are done

kuah@splparts.com

iTrader: (10)

The reason the endlinks are made adjustable is to allow them to eliminate (or in certain cases set) sway bar preload. A fixed length endlink cannot do this, so if after corner balancing you find your suspension heights are different from left to right, that means you will end up with sway bar pre-load with a fixed endlink, and you have no option to dial it out.

From a performance standpoint, heim joints are always preferable to bushings for sway bar endlinks, since the compliance of the bushing means the first few mm of roll goes towards compressing the bushing rather than twisting the sway bar. Also depending on how the endlink is attached to the suspension, it may have to accomodate changes in angle which is better performed by a spherical bearing than a bushing, the bushing basically starts binding as soon as you start twisting it. So an endlink with bushings reduces the effectiveness of the sway bar, it would be like going to a slightly smaller diameter bar. Keep in mind the endlinks on the 350Z have no bushings stock, they are all ball joints (spherical bearings), abliet not the strongest bearings .

It sounds like sway bar walk is the problem causing those endlinks to fail on those cars you mentioned. A heim jointed endlink will not resist sway bar walk, compared to a endlink of the style you posted. The endlink with the bushing will bind more and more as the sway bar tries to shift, so it will resist that movement. The endlink with bearings will not resist the sway bar walk until the endlinks end up at an extreme angle, where it reaches the limit of the ball misalignment -- the ball hits the housing which puts a hard stop to further movement. This could cause the ball to pull out, or something to break. However that is not the fault of the endlink itself (unless it is poorly designed), the endlink should not be used to prevent the sway bar from walking; the sway bar can be prevented from walking with appropriate collars, clamps, etc.

The endlink loosening up is almost always due to the ball reaching its misalignment limit. This could either be due to care not being taken when tightening it to allow for maximum misalignment, or it could be due to the sway bar walking problem above, or that the endlink was just not properly designed to allow for all the movement that goes on with that suspension.

I have sold alot of heim jointed endlinks for the 300ZX, 240SX, etc, and I use them personally, they have all held up perfectly for years and never loosened or broke in use.

abui01

iTrader: (68)

just installed *one* side, my OEM end links were definitely toast because as Z1 mentioned, it made a loud noise over any bump and would chatter the whole ride. I replaced one side with an SPL end link and the noises were completely eliminated! However, when I looked at the factory end link I replaced, it seems perfectly functional... no broken pieces or anything.. very odd... The other end link had a rusted bolt and I couldn't get enough leverage under the car to break it loose and ended up stripping the bolt, so I'm gonna go take it up on a lift in a few hours and get back to you guys with the results. So far only 1 side sways back and forth and the one I replaced and fixed with the SPL seems to be pretty solid.

Z1 Performance

iTrader: (564)

kuah - I totally understand the purpose of the adjustable link mind you - we've used them on some of our track cars for years. But we've had so many issues with them on street cars, that we simply choose not to offer them. Like many other track parts that find their way to street cars, they are a maintenance item in my eyes, and that's not something the average street car customer or even occassional track day guy will live with (at least not our customer base).

I've also yet to run into a customer car that had an issue being cornerbalanced with this style link - probably because most of our serious track guys use 2 way adjustable coilovers for track cars (so preload can be adjusted independant of rideheight).

The cars that exhibit the swaybar walking (most notably Subaru's and specifically STi's) do so for 2 reasons - improper install or stock endlinks - once we fit the solid endlinks, the problem is completely gone in our experience (I've yet to have a sway walk with the above endlink installed). even the Heim joint ones have proven utter junk (at least the ones currently made) and we got so tired of taking returns, we dropped them from our offer list altogether and went to strictly the solid ones. Sti's have very beefy mounts and collars to them from the factory and I've never had to upgrade the stock ones at all.

So, while the bushing might be a slight compromise in performance for the all out race car, I've found them to be the preferred method, both in terms of noise and longevity, to the heim joint style. I've just found them to be a much more "install it and forget it" setup that needed no special care while installing other than making sure the bolts are tightened down properly. The bushing compound used is a a "group n" type compound and is quite rigid. Companies like STi and Ralliart, among others, use it for upper strut mounts, and a variety of other Group N (rally) bushings.

It could be that thes SPL ones are an awesome piece - I honestly don't know enough about them to comment one way or the other - they certainly look well made from the pics. It's just from a pure personal experience standpoint, I've never had any luck with links of that style, which is why we strictly use the bushing type now.

GTNPU Z

iTrader: (17)

I think you hit it right on the head on what I'm looking for with what you have said above since this will be on my daily driver. Looking forward to this...

sfarrah

iTrader: (4)

I'm confused by this statement and would like to clarify for everyone. The preload you're referring to on 2 way adjustable coilovers is spring preload. The preload Kuah is referring to is swaybar preload - these are two different things. Spring preload cannot make up for the sometimes necessary adjustment in end link length to remove sway bar preload due to different ride heights at different wheels that can occur during corner balancing. Please correct me if I'm wrong here.

kuah@splparts.com

iTrader: (10)

Well certainly heim joints require some maintenance, but rubber or urethane bushings wear out too Personally I have had a different experience with urethane bushings on sway bar endlinks where they create a lot of bind under travel and IMO cause unpredictable handling. In general I do not like urethane bushings being used as suspension bushings due to their lack of compliance to misalignment, the one example I always think of is the urethane tension rod bushings on the 300ZX/240SX, the urethane bushings bind so bad under suspension travel that after about 1-2 years they cause the control arm to fracture from metal fatigue.

I agree the type of endlink you prefer is simpler to install and setup, its hard for me to agree on its benefits though but I admit I am biased against bushing type endlinks. I guess we all develop different preferences based on our experiences

Z1 Performance

iTrader: (564)

sfarrah - yes I know he was talking about swaybar preload, I was merely referencing the cornerbalancing aspect of it, that's all. We're not setting up oval track cars or cars who's center of gravity are biased to one side in an exaggerated manner, so swaybar preload is not something we ever mess with, nor have I encountered on the bars we use. While we don't cornerweight cars day in and day out, we do run several cars in house and have done several other customer cars that all have been cornerweighted and I've yet to enounter swaybar preload. Alot of this could be due to the fact that the cars we've done all ahve endlinks that literally sit at the end of the swaybar, not at some other point, so it's much more difficult to even induce preload to the swaybar in this manner. I think that is a case of some cars being more prone to it than others based on a variety of factors. I also have never messed around with running different sway positions on the left side vs right or anything of that nature - again, none of us here are professional drivers and as such, there are so many other factors that can crop up at a track day, and the car is generally capable of more than anyone here can dish out unless the starts are perfectly aligned and we don't run into traffic (or hit a wall!)

I hear you on the rubber bushings wearing out. While wear was a concern of ours initially, I've yet to run into a situation on these endlinks where the compound used needed to be replaced (we've offered these type of endlinks now since 2002). There are some very practical, real world reasons we've only offered the type of endlinks we do. What you cite as a weakness, is really what we feel is the strength - the compliance of the bushing. Through proper bushing mount design and using a bushing of the proper durometer rating, you can achieve an endlink that is both rigid enough to allow the sway bar to do its job without binding, as well as have an endlink that won't make noise and that won't cause premature failure of other components down the road.

As you know, the modding game is not zero sum - there are benefits and trade offs to anything you change from the factory. I'm confident that the links we'll offer will meet the needs that I believe the marketplace has. I know I've experienced the failure of the stock endlinks once already, and replacing them is a bottomless pit, as they same things will happen over and over again. On the flipside, I do not want a heim joint type link on my own car due to the reaons outlined above. So, that leaves me with the one last solution - build the better moustrap