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Adjustable coil overs and rim size


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#1 Neuby

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Posted 26 August 2008 - 08:03 AM

I had a thought on the weekend while I was focused on my struts.  I know you can get adjustable coil-over sleeve kits so I measured my struts and the outside diameter was a bee's dick larger than 55mm.  Does anyone know if this sounds right?  My favoured end result would be 10" wide rims on the rear, with ZG flares and careful selection of rim offset.  Hopefully by using a sleeve kit I can reduce the radius of the spring hence giving more room for a rim.

#2 nat0_240_chevZ

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Posted 26 August 2008 - 12:43 PM

should be 51-52mm od. but not to say that they are this....

#3 sco_aus

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Posted 26 August 2008 - 05:25 PM

If you have a 260Z or 260Z suspension, then yes, that is correct.

#4 Neuby

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Posted 27 August 2008 - 07:26 PM

It's suspension on a 260 and thank you for comfirmation.  So, does anyone think 10" rims will fit?  ;D

I was pondering spring rates too.  I was thinking 7kg/mm fronts and 9kg/mm rear.  Would that be too aggressive for half street, half track use?

#5 Lurch ™

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Posted 27 August 2008 - 07:38 PM

I was pondering spring rates too.  I was thinking 7kg/mm fronts and 9kg/mm rear.  Would that be too aggressive for half street, half track use?

Ugh, quoting Japanese spring rates...

You need to figure out what your wheel rate is, and then a suitable recommendation can be made.


#6 sco_aus

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Posted 27 August 2008 - 10:23 PM

^^^^^uh huh^^^^, see the the thing is, a stiff spring rate isnt always best, if you are doing hill climbs, some of them will throw you way off, then it may be too much for track.  The best thing you can do is find a really good suspension place in your rea, ask them and see what they think.  You will need a 4 wheel weigh to determine the little things aswell, so its no where as simple as we wish it were. 
I have barely touched on the whole workings of suspension.

#7 Lurch ™

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Posted 27 August 2008 - 10:29 PM

Scott, generally corner weighting is done AFTER the suspension package has been setup.

Neuby, There's HEAPS of books available to help with suspension setup - anything by Carrol Smith is generally a good start ;)

#8 sco_aus

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Posted 27 August 2008 - 10:30 PM

yeah i know that :P you forget how much i have been through with this thing, like i said, there is way more to what i just sayed


#9 Neuby

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Posted 28 August 2008 - 08:20 AM

Thanks for the advice Lurch. 

Theory can only take you so far which is the reason why I ask you guys what you thought.  The maths that you work out on paper may not be best practice off paper.  I have no doubt the maths will get me close to the end result, I was just seeking people's experience.

I'm looking at roughly 2.75-3kn per wheel and just off my head, would the wheel motion ratio be near 1.3:1?  I might go do some measuring tonight.  It's a bit hard to determine my current spring rates by empirical means as the car is virtually a shell.

Has anyone seen the new fully adjustable caster/camber tops K-mac make for the zeds.....

#10 sco_aus

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Posted 28 August 2008 - 08:39 AM

No i havn't.  I had the TehnoToyTuning ones welded in, they are great, but if you can get bolt in ones, might suite you better.  In fact, it may save you money to just go to th Arizona zed car website and purchase their pre made coilovers that have it all anyways.  Machining is never cheap and you dont have to worry about where to cut the struts and all the other shit that goes with it.  Thats my advice.  While your there, buy the adjustable control arms, they are da bomb.  :D

#11 Zedman240®

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Posted 28 August 2008 - 10:04 AM

Neuby, with your original question, I have fitted 8" rims with coilovers but thats within the original wheelarch (slightly lipped) so I think 10" should be squeezed under with a massive dish though! As for springs alot of Z cars around the clubsprints settle around 300lb per inch. I had 350lb on my last daily 260Z and that was a spine jarring ride! If you ask Ash what his spring rates are in his race car you probably would faint.

#12 sco_aus

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Posted 28 August 2008 - 10:58 AM

P.S, i have 8 1/2 inch rims on the rear and then i added spacers..., they stick out about 15mm, but im installing flares.  I'm not sure on the offset of mine, i might be able to check for ya.

#13 nat0_240_chevZ

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Posted 28 August 2008 - 12:40 PM

Ugh, quoting Japanese spring rates...

You need to figure out what your wheel rate is, and then a suitable recommendation can be made.


translates too.......390lb/" fr & 505 lb/" in you ol fart'e syndrome!!!!

#14 nat0_240_chevZ

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Posted 28 August 2008 - 12:44 PM

Thanks for the advice Lurch. 

I'm looking at roughly 2.75-3kn per wheel and just off my head, would the wheel motion ratio be near 1.3:1?  I might go do some measuring tonight.  It's a bit hard to determine my current spring rates by empirical means as the car is virtually a shell.

Has anyone seen the new fully adjustable caster/camber tops K-mac make for the zeds.....

mmmm  NO, wheel to strut motion is approx 1.1 MAX to: 1 as struts are only on a slight angle, not like a wishbone where there can be up to 60* angle
nat0

#15 Neuby

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Posted 28 August 2008 - 03:11 PM

Neuby, with your original question, I have fitted 8" rims with coilovers but thats within the original wheelarch (slightly lipped) so I think 10" should be squeezed under with a massive dish though! As for springs alot of Z cars around the clubsprints settle around 300lb per inch. I had 350lb on my last daily 260Z and that was a spine jarring ride! If you ask Ash what his spring rates are in his race car you probably would faint.


Thanks Zedman! That's exactly the kind of input I was after.  Sounds like the guys who are using 300lb/inch are doing what I intend to do so that might be a good starting point.  I'll be using ZG flares and from reading people can fit 9.5" under so I figure why not try to squeeze a little more in there by using adjustable coil-overs.

#16 620Z

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Posted 28 August 2008 - 03:42 PM

I have 9" mags alround on my car with coil overs and fit under the wheel arches no problems. It's all in the Offset. I have now flared my guards by 20mm and will soon be getting 10" on the rear. So if you get the right offset 10" or even wider will fit with bolt on flares.

#17 nat0_240_chevZ

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Posted 28 August 2008 - 05:10 PM

Thanks Zedman! That's exactly the kind of input I was after.  Sounds like the guys who are using 300lb/inch are doing what I intend to do so that might be a good starting point.  I'll be using ZG flares and from reading people can fit 9.5" under so I figure why not try to squeeze a little more in there by using adjustable coil-overs.

yes they are doing it WITH coilovers. i have 9's on stock struts, they ever so slightly rubbed the perch, smash the perch with a sledgie, gives me 2-3mm cl now, without touching the guard lips they stick out a tiny tiny bit, but when you load the rear it just sort of tucks in a bit with camber gain!!

mind you i have 245/45/16's in simmons v4's, and have a huge dish outback
nato

#18 PZG302

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Posted 30 August 2008 - 01:36 PM

With 100mm back space I can fit 8" rims under my guards that have bben rolled and the fronts slightly flared. The spring seats have been dropped to give me a lower ride height with the same distance for travel and I use spring rates at around 420-450lb/inch. This is for a circuit 240Z with the weight at 960kg plus 100kg of me.




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