240sx swaybar upgrades: a technical article

[tastyratz]

This is a Page I have typed for the 240sx Performance modifications Wiki.
(http://en.wikibooks.org/wiki/Nissan_240SX_Performance_Modification)
Before it gets tainted and torn apart with inaccurate information from the general public I wanted to post it here to preserve the information in its original form


*PLEASE* do not post useless posts in this thread. Please keep legitimate relavant inquiries in intelligent form if need be so this can retain a professional and informative feel. Anything I deem relavant I can go back up and edit the post to include.




==OEM Sway Bars==

S14 chassis:
S14 Base model: Front bar is 27.2mm, there was no rear swaybar equipped.
S14 (SE and LE package): Front bar is 27.2mm, 15.9mm in the rear bar.


S13 chassis:
S13: (Abs/lsd package) Front bar 25mm, 21mm in the rear.
S13: (se without Abs/lsd package) Front bar 25mm, 17mm in the rear.
S13: (non se) Front bar 24mm, 15mm in the rear.

All are tubular steel


==S13 Aftermarket Sway Bars==

Largus - Front bar 31.5mm, 27.5mm in the rear. 3 way adjustable front only. Tubular steel construction. Stock type endlinks.

Largus includes new bushings with purchase

Whiteline - Front bar 27mm, 22mm in the rear. Solid steel construction and 3 way adjustable. Whiteline users their own

specific blade type endlinks

Tanabe - Front bar 30.4mm, 22mm in the rear. Tubular chromoly construction. Stock type endlinks

Progress - Front bar 27mm, 22mm in the rear. 3 way Adjustable front & back. Tubular steel construction. Progress supplies a heims type endlink on all swaybars.

Cusco - Front bar 28mm, 18mm in the rear.

Suspension techniques - Front bar 27mm, 20.64mm in the rear. Solid steel construction. Stock type endlinks

==S14 Aftermarket Sway Bars==

Largus - Front bar is 32mm and 2 way adjustable, rear bar is 28mm non-adjustable. Tubular steel construction. Stock type

endlinks. Largus includes new bushings with purchase

Whiteline - Front bar 27mm, 22mm in the rear. Solid steel construction and 3 way adjustable. Whiteline users their own

specific blade type endlinks

Tanabe - Front bar 30.4mm, 27.5mm in the rear. Tubular chromoly construction. Stock type endlinks

Progress - Front bar 30mm, 24mm in the rear. 3 way Adjustable front & back. Tubular steel construction. Progress supplies a heims type endlink on all swaybars.

Cusco - Front bar 30mm, 27.5mm in the rear.

Suspension techniques - Front bar 28.6mm, 20.64mm in the rear. Solid steel construction. Stock type endlinks



==Notes to be considered when selecting a swaybar upgrade==

-Stock swaybars are hollow as well as several aftermarket replacements. Testing has found the tube is the strongest shape and while maintaining a proportionate wall thickness a tubular swaybar will provide only 5% less stiffness for one made out of
solid metal in the same diameter but will have a significantly lower weight, sometimes a reduction as much as 10-20lbs. This has no heavy polar impact since its so low on the chassis but will impact braking/acceleration respectively.

-Adjustability is something to weigh in consider if thats a concern for you.

-Stock endlinks are actually very well designed but due to the age of the cars tend to have rotted bushings. Replace them with eurathane bushings from energy suspension kits, or the universal swaybar bushing kit available at local auto parts store. Note when using the universal kit the bushings must be sliced in half using a razor blade as they are twice as thick as what is needed.

- Whiteline swaybar blade type endlinks are not as well designed as the OEM supplied endlinks so that does impact the functionality vs stock links with eurathane bushings or aftermarket replacements. If using whiteline swaybars it is recommended that aftermarket replacements are taken into consideration

-Splparts.com produces a heim joint based replacement endlink solution for both stock and whiteline type bars. This will improve the performance of a swaybar by removing give/squish with bushings.

==Swaybay Bushings==

Energy suspension produces full bushing replacement kits for the 240sx so that all the old worn rubber bushings can be replaced with polyurethane.

[m072514]

good stuff... +1 for intelligent people!

[FRpilot]

i vote for faq and archive

[slideways2004]

S13: (Abs/lsd package) Front bar 25mm, 21mm in the rear.

is that a hicas equipped car?

[vutony]

anyone got specs on the nismo swaybars ??

[drift freaq]

S13: (Abs/lsd package) Front bar 25mm, 21mm in the rear.

is that a hicas equipped car?
yes it is.

Tasty, you should also mention the fact that though heim joints improve performance by eliminating mushy or squishyness they also transfer body torque straight to your chassis. If your chassis is not stitch welded or reinforced with cage it will cause wear and tear on the factory chassis, thereby shortening chassis life.

[Wiisass]

==Notes to be considered when selecting a swaybar upgrade==

-Stock swaybars are hollow as well as several aftermarket replacements. Testing has found the tube is the strongest shape and while maintaining a proportionate wall thickness a tubular swaybar will provide only 5% less stiffness for one made out of
solid metal in the same diameter but will have a significantly lower weight, sometimes a reduction as much as 10-20lbs. This has no heavy polar impact since its so low on the chassis but will impact braking/acceleration respectively.



This is a gross generalization which just shouldn't be in something like this. You can't just throw out numbers like that. The difference in stiffness depends on the OD and ID of the hollow bar. If you're comparing a solid bar to a hollow bar, both having the same OD, the hollow bar gets softer as the ID decreases. Also, your weight reduction numbers seem really high. That's something that you can calculate with just an estimate of the overall length of the bar and what material is being used.

Also, I don't know what you mean about braking and acceleration being affected. Is this just a comment because of the slight decrease in weight of the overall car. If not, I wouldn't talk about acceleration and braking when talking about sway bars. That just introduces several other things that you need to consider, including bending moments on the bar, friction in the d-mount bushing, etc. Things that most people don't need to be worried with.


-Adjustability is something to weigh in consider if thats a concern for you.


Does anyone know if the non-adjustable aftermarket bars are the exact same dimensions as the stock bars. If not that's something that should be considered. If that moment arm length is longer or shorter on the new bar, the comparison using the bar size can not be used anymore.


Tasty, you should also mention the fact that though heim joints improve performance by eliminating mushy or squishyness they also transfer body torque straight to your chassis. If your chassis is not stitch welded or reinforced with cage it will cause wear and tear on the factory chassis, thereby shortening chassis life.


Do you mean this for a general note on heim joints or a specific note to heim joints as sway bar endlinks. Because if it's just for sway bar endlinks, I doubt that it's really an issue. If anything it could shorten the life of the LCA, just because of the more direct load path of the bending moment right into the middle of the arm. Otherwise, you can't really say that sway bar endlinks being solid joints rather than soft bushings can shorten the life of the chassis.

Also the word to use for "mushy or squishyness" is compliance. By elimating this compliance you are more effectively using the sway bar. A sway bar generates a certain spring rate, when using soft bushings some of this effect is absorbed into the bushings and not realized at the point it should be which is at the tire.

[s13coupedrfter]

I'm running the Tanabe f/r sways with stock end links on my s13 and love them, they give the car a nice neutral feeling. The car is equipped with Tein HE coilovers and I was still getting body roll with stock sways. After the Tanabe's were installed the car feels much more crisp and responsive. Amazing cornering ability!

[tastyratz]

yes it is.

Tasty, you should also mention the fact that though heim joints improve performance by eliminating mushy or squishyness they also transfer body torque straight to your chassis. If your chassis is not stitch welded or reinforced with cage it will cause wear and tear on the factory chassis, thereby shortening chassis life.


Wiisass pretty much summed it up with his response. The heims joints wont cause the chassis to really be absorbing any real extra force, it will mainly be on the lca. If that was the case saying the heims joint will negatively impact life... means that larger swaybars would do the same thing.


slideways2004: the largest swaybar was included in a "handling package" (I dont know what the exact title was) which included hicas.



Wiisass:
The generalization on hollow vs. solid tubing was actually from the hotchkis site. By proportianate wall thickness I meant the average, most manufacturers seem to use a very similar wall thickness in proportion to the diameter.

When I commented on the weight of the bars as much as 10-20lbs I was going on shipping weights from some different websites. So yes, you ACTUALLY can save that much weight.

When I spoke on braking/acceleration I was making a statement based on the fact that you are removing weight from the car. That was my only point of reference. It isnt obviously a huge impact that will give you .3 in the quarter mile, but it all adds up when your shaving it off. If you buy a carbon fiber hood for weight, then something like this for weight is in the same ballpark.

Absolutely correct the length of the sway bars will impact the overall spring rate but we only have so much data provided to us to base things off of.


I wish swaybar manufacturers developed some sort of a standard for testing. For example, clamping 50% of the bar and testing the spring rate where the endlink attaches. Doing so on both sides of the bar and averaging the rate.

[usdm180sx]

Heads up, the Largus front swaybar will not clear greddy sr20det oil pan.