The original comp springs had fewer turns and smaller wire diameter and
were made in Japan and sold thru NISMO there and Datsun Comp/Nissan
motorsports here. When the US motorsports dept could not get any more out
of Japan they turned to a US manufacturer to supply the springs. I think
that the free length is about the same for both types and the rate is
supposed to be the same too. Probably the spring manufacturer had wire on
hand that was suitable to make springs that had the same rate and free
length without needing to buy a mill run of wire to produce the relatively
small quantity needed for roadsters.
The part number for the new springs is different than the old ones.
Recommend that springs of the same type be used in pairs. There was
someone on ebay auctioning the springs one at a time.
Stan
===========
At 02:23 PM 2/14/03 -0500, Mark Sedlack wrote:
>Just a guess but here goes - spring rate is dependant on OD, wire diameter,
>and the number of active coils. Two springs with the same OD and length can
>have the same rate even though one has fewer coils at a smaller diameter
>wire, and the other more coils at a larger wdire diameter. The main
>difference is the torsional stress seen by the spring wire ( and the solid
>height with the spring fully compressed). If the sorsional stress value for
>the material is exceeded, the spring can take a "set", or in worse case,
>fracture and fail.
>
>My guess is that over the years it was found that the springs with fewer
>coils were being overstressed so they changed the design to compensate.
>
>Mark Sedlack
>OROC
>Cuyahoga Falls OH
>66 1600 http://home.neo.rr.com/mark2000/images/datsun1600/
>77 280Z http://home.neo.rr.com/mark2000/images/datsun1600/Z.htm
>
>
>----- Original Message -----
>From: "RWM" <RWM@rwmann.com>
>To: "chriscoker@mail.comcast.net" <chriscoker@pop3.comcast.net>
>Cc: <datsun-roadsters@autox.team.net>
>Sent: Friday, February 14, 2003 1:51 PM
>Subject: Re: NISMO comp springs - how many coils should they have???
>
>
>> Interesting. Which ones are lighter, and by how much?
>>
>> - RWM
>>
>> "chriscoker@mail.comcast.net" wrote:
>> >
>> > I've had two types of NISMO comp springs side by side, the number of
>coils was different, as was the wire diamter. I worked through the math,
>and the spring rate was essentially the same. The spring with the larger
>number of coils will have a slightly larger wire diamter. I think the
>spring with the larger number of coils is a later design, as I recently
>bought a couple of sets of these from NISMO. I compared them with the
>'older style,' which has been on my race car for around 20 years.
>> >
>> > Either style of spring should work fine.
>> >
>> > Chris Coker
>> > www.risensonracing.com
>> >
>> > Original Message:
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