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"long" coilover shocks for IRS
Bob C - 19/11/03 at 12:52 PM

Gents,
I'm intending to use mazda mx5 rear uprights on an IRS locost. On the donor car the spring/damper bolts to the bottom wishbone. I can do that but would need a very long unit! Where should I look for such an item? I need to connect to the proper top mounting as that's what the whole chassis design is aimed at.
Alternatively I could extend the caliper bracket to pick up the shock mounting, but the bolts are well inside the wheel so it soes not look nice.
If I pick up the top wishbone instead (like everybody else) I'll be compressing the top rubber thingy in a way it was not designed for - and - you guessed it, the rubber thingy is in the upright, not the wishbone.....
Ideas, URLs etc. welcome!
Thanks
Bob C


jcduroc - 19/11/03 at 03:24 PM

quote:
Originally posted by Bob C
Gents,
I'm intending to use mazda mx5 rear uprights on an IRS locost. On the donor car the spring/damper bolts to the bottom wishbone. I can do that but would need a very long unit! Where should I look for such an item? I need to connect to the proper top mounting as that's what the whole chassis design is aimed at...
Thanks
Bob C

Bob
Why not bolt the upper shock joint to a properly designed triangulated chassis apex?
Joćo Rescued attachment WESTFIELDSPORTSCARREARSUS2.jpg
Rescued attachment WESTFIELDSPORTSCARREARSUS2.jpg


jcduroc - 19/11/03 at 03:28 PM

...or this Rescued attachment TritonIRS.jpg
Rescued attachment TritonIRS.jpg


jcduroc - 19/11/03 at 03:33 PM

...or this Rescued attachment Striker_RrSusp2.jpg
Rescued attachment Striker_RrSusp2.jpg


jcduroc - 19/11/03 at 03:52 PM

If I'm not mistaken this is the MX-5 rear susp... Rescued attachment REARTHU2.GIF
Rescued attachment REARTHU2.GIF


jcduroc - 19/11/03 at 03:53 PM

...and this is MK rear susp Rescued attachment RearUpRight.jpg
Rescued attachment RearUpRight.jpg


Metal Hippy - 19/11/03 at 03:54 PM

JC... Are pictures 2 and 3 as easy to make as they appear to be...?


Alan B - 19/11/03 at 04:28 PM

With access to right tools, sure why not?


jcduroc - 19/11/03 at 04:34 PM

quote:
Originally posted by Metal Hippy
JC... Are pictures 2 and 3 as easy to make as they appear to be...?

I guess it is not more difficult (or easier) than putting the coilovers on the top of the uprights!
Alan's got a point there. I'll be sure within a few months (hopefully!).
Joćo


Metal Hippy - 19/11/03 at 05:05 PM

Well it looks like I've found out what I wanted.... Hoorah!


Noodle - 19/11/03 at 05:18 PM

quote:
Originally posted by jcduroc
...and this is MK rear susp

Picture 2 is also MK Indy rear.

Neil.


jcduroc - 19/11/03 at 06:49 PM

quote:
Originally posted by Noodle
quote:
Originally posted by jcduroc
...and this is MK rear susp

Picture 2 is also MK Indy rear.

Neil.

Well Neil, it doesn't look like their upright; it's very different from the one in picture 5

[Edited on 19/11/03 by jcduroc]


timf - 19/11/03 at 08:14 PM

picture 2 is an early triton rear upright


Alan B - 19/11/03 at 08:29 PM

Yep agreed..

1 is the Westfield XTR2
2 is the Triton
3 is the Silva Striker or Phoenix (I think)


Bob C - 20/11/03 at 12:24 PM

Ta for all the research JC. love the pic 2 upright (not keen on the rest of it..)(don't like the angle of the coilover or the fact that it's top mounting looks flimsy). Pic 3 looks most like my "vision".
my choices seem to be:
1) more chassis work to get a lower top mounting or
2) "extend" a stock shock
Any thoughts re [2]? Weld on a 40mm diam extension tube???
I''m finding it difficult to get dimensional information about coilover units - the spax & koni websites just bang on about their fiesta kits... Where should I be looking guys?
Cheers
Bob C


Bob C - 20/11/03 at 12:34 PM

Oh yeah - pic 4 is indeed an mx5 rear subframe - I note it has more extra bracing to the inboard lower wishbone pivots than I've seen elsewhere. FWIW these pivots are on "cam bolts" on the mx5 so you can adjust rear toe, track & camber.
cheers
Bob C


jcduroc - 20/11/03 at 03:30 PM

quote:
Originally posted by Bob C
my choices seem to be:
1) more chassis work to get a lower top mounting or
...
Bob C

In any case do not mount the coilover in the middle of a tube; make an apex of 2 or 3 tubes dispersing the load to the structure.

Cheers
Joćo


Noodle - 21/11/03 at 10:54 AM



Well Neil, it doesn't look like their upright; it's very different from the one in picture 5

[Edited on 19/11/03 by jcduroc]

Well spotted that man.

This is an MK Indy rear upright

Cheers,

Neil.


MK Indy Rear Upright
MK Indy Rear Upright


[Edited on 21/11/03 by Noodle]


kiwirex - 25/11/03 at 07:40 AM

Back to the long coilover question - some of the later jap cars have mcpherson struts with very narrow coils at the back, which is almost the same as a long coil over.

Different top mounts I guess, but I'm not an expert.

Talking 90-95 nissan sunny and toyota corsa (yep, not vauxhall corsa, different car altogether), and starlet II (or something).

Been thinking about using them myself because I can pick up a pair for $120, rather than the $600 (nz) two coilovers would cost me.

- Greg H