FWIW, the 13-coil spring (if it has the same wire characteristics as
the 10-coil sprint) will be softer. Springs in series add like
resistors in parallel. Assume 150 lbs/inch for the 10-coil spring;
the 3-coil additional spring would exhibit an equivalent rate of 500
lbs/inch. The 13-coil spring would (overall) behave as a
(500*150)/(500+150) = 115 lb/in Installed height will have some
effect on the initial load on the spring, but them's the numbers.
But, ONLY if the wires of the springs are the same diameter and
material characteristics.
Donald.
> From: "James Libecco" <jfl@neoucom.edu>
> Date: Thu, 2 Mar 2000 18:29:49 -0500
>
>
> If I remember right, as I reinstalled the stock spit springs last weekend,
> they were indeed 13 coils, counting the ends as the final coils. The
> heavier springs will certainly be not detriment to your spits handling,
> since the heavier springs will definitely work to decrease some of the
> horrible oversteer the spit tends to have at higher cornering loads. You
> could even consider using the uprated competition springs (multiple possible
> rates) or the GT6 springs (increases spring rate approx. 50 lbs/in. but by
> no means bone jarring), since you will have to cut them down anyway, if you
> want to maintain stock ride height.
>
> I have found that to be the greatest conundrum in finding new
> springs...compensating for the loss of spring sag with loads as the spring
> rate is increased. How much shorter do you need to go as the spring rate
> increases...
>
> So, finally, I say to use the 1500 or gt6 springs with a friend's press or a
> spring compressor. Find the ride height at full length, figure out how much
> lower you would like to be and then go and hack off that much spring. It
> will sit crooked on the perch, but that should be okay. OR, you could go to
> a spring shop and tell them how much needs to be taken off of the spring and
> they should be able to cut it at the proper angle to sit flat on the spring
> perch.
>
> hope this helps,
> jim
>
>
>
> Date: Wed, 1 Mar 2000 22:11:47 -0700
> From: "MikeC" <mikech@sprynet.com>
> Subject: front springs
>
> I just got some new springs for my 64 Spitfire from Spitbits. The car has a
> 72 1296 cc engine in it, so in talking with Spitbits they suggested I put in
> a set of springs from a 1500 model because the 1296 engine is slightly
> heavier than the 1147. Looking at the new springs today I can count 13
> coils, the old springs have only 10 coils. The coils look like they are
> the same diameter. It seems like the front of the car will be raised an inch
> or more. Has anyone done this swap before? What were the results? Can
> anyone with a 1500 count how many coils your springs have. I don't want to
> raise the front height any, in fact I don't want it any lower either. I
> guess I could cut the spring but then the cut end will not be flat. Any
> suggestions?
> MikeC
> BTW: the springs are marked "Spitfire 1500 - 75 on".
>
>
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