comment on nismo subframe bushings design

[hai1206vn]

I've been running MMR UHMW bushings in my s14 for a year (http://www.mmr-direct.com/catalog1/S13/index.htm). These are very hard plastic so consider them equivalent to solid aluminum. Noise was one thing, but i've been displeased by the lack of rear traction due to drivetrain shock.

This year I decided to give the Nismo ones a try, since there's no other option softer than solids. Left (black) for the rear, right (gray) for the front



The pics are there for a reason. I never noticed that although the front and rear inner steel cores are of the same length, they are at different height relative to the outer sleeves. The inner core for the front is about 1/4" taller (in picture, a - b = 1/4"). I'm assuming the stock bushings are also like these (I didn't take notice when I set them on fire last year).

Now compare the stocker/nismo design to the typical solid bushings where all 4 are identical


What this means is compared to a solid setup, the stock/nismo bushings actually tilt the front of the subframe downward a little bit. Does this mean anti-squat characteristics are different? Which one has more?

I've got a lot more rear traction with the nismo. I wonder if the rubber's compliance or the slightly different subframe geometry that contributes to this change. Totally happy though.

[cdlong]

tilting the front of the subframe down will give you less anti-squat (more pro-squat?) i haven't looked at the bushings close enough to comment more than that. the nismos aren't really your only option though, i found this thread a while ago and book marked it, but haven't gotten around to doing it.
http://forums2.freshalloy.com/showthread.php?p=1494207

[AceInHole]

Can anyone confirm that the stock bushings are offset? I'd love it if my current subframe bushings (solid aluminum, even height all around) are illegal, as fixing them would actually give me an advantage :P

H. Subframe bushings may be replaced with bushings of any material
as long as they fit the original location. Offset bushings may
not be used.

It looks as though the 300zx subframe is also offset front to back:

Photo stolen from importnut.net

Looks like I need to measure up some stock bushings and fix mine accordingly. So much for the solid bushing advertisement of "retains stock geometry".

Yay for less anti-squat

[hai1206vn]

They make these for s14 but the 4 look identical http://www.frsport.com/Energy-7-1117...d_p_14988.html

instructions for s14 http://www.energysuspension.com/pdf_instruc/17486.PDF
instructions for z32 http://www.energysuspension.com/pdf_instruc/17303.PDF

@ cdlong: I looked at these urethane ones initially but they both require preserving some original metal sleeves, which were all gone when I installed the solid bushings. I was too chicken to try them so nismo was it.

@ aceinhole: looks like z32 ES ones are better suited than s14 version given the offset, though you might have to cut the core a bit so the nuts thread in better (not really necessary, the guy in the link below has a hack). And yay for less antisquat. If my observation is right, all these solid bushing makers have been screwing us all over

z32 bushings into s14 FYI, nothing new: http://www.240sxforums.com/forums/in...-anti-56k.html

[AceInHole]

Well, my problem is that I have to run stock location for the subframe. If the ES setup is right, then I'm stuck with what I have

[hai1206vn]

i've thought of this combination to stiffen things up without adding metal, but it costs waaayyy too much for questionable value:
- Nismo bushings
- s13 ES inserts or windo-weld to fill some inner gaps
- peak performance urethane collars to fill top & bottom gaps

ace, in your case it might easier to shave down the rear aluminum ones by 1/4" to tilt the subframe back to stock height

[Def]

I window welded the stock S14 bushings when I swapped subframes a while back. It feels like there is still a bit of movement back there, and the window weld is really soft so I wonder how much it is helping.

I should have just made my own offset subframe bushings from delrin or aluminum when I had it out, but it seems like too much of a PITA to change them out now. I didn't really notice the bushings being different heights, but it is possible.

[hai1206vn]

I window welded the stock S14 bushings when I swapped subframes a while back. It feels like there is still a bit of movement back there, and the window weld is really soft so I wonder how much it is helping

did you just fill the gaps within the rubber? that reduces lateral & front-to-back movement but there's still plenty of vertical play that requires collars

[e1_griego]

They make these for s14 but the 4 look identical http://www.frsport.com/Energy-7-1117...d_p_14988.html

Phase2 lists these same bushings for 89-98. My friend just got done putting a set in his car. Seems like they should work just fine for s13. Just as an aside...

[cdlong]

well, doesn't the inner core sit up against the frame? if the core sits up against the frame and the lower washer sits against the other end of the core, wouldn't it sit in the same place, just affect the vertical preload in the bushing? the only thing that would affect the angle would be the amount of bushing material between the subframe and the unibody. just speculating, never looked at the bushings very closely.

[Def]

did you just fill the gaps within the rubber? that reduces lateral & front-to-back movement but there's still plenty of vertical play that requires collars

How would you use collars after filling up the subframe with window weld?

[AceInHole]

It probably depends on how much you fill the bushing. I'm sure you could just fill the pockets and still use collars to "cap" everything. It's easy and now cheap enough to just run aluminum bushings, which IMO have not made a significant impact on "harshness".


Anyways, can someone with a stock subframe measure up the offsets for me, chassis to subframe at the bushings? I need to know if there's an actual offset built in from the factory, or if the Nismo bushings are changing the stock dimensions.

[V1A]

I have an extra S13 subframe with stock bushings that I can measure tonight. I don't know how comparable it will be to an S14 setup, but at least we'll have some data to look at.

Maybe someone can confirm that the only changes S13 -> S14 were the pickup point locations? I don't really remember what is different between the two.

[AceInHole]

That'd help a lot. I wonder if I could use that as part of the update/ backdate rule within Street Prepared, or as at least general evidence pointing towards some factual numbers. Pics would help out a lot, too.

[Def]

If I get a little time away from work this week I'll measure both(s13 and s14 stock subframe bushings).