>>> Joe Curry <spitlist@gte.net> 06/13 11:17 AM >>>
>Please let this issue drop, I am gettting pretty tired of people ganging up on
>me on this trying to make me look like a fool on the list!
I'm sorry you're feeling this way Joe. From my perspective, I've been enjoying
a spirited thread about hopping up our cars and making them work better and
faster. Something near and dear to my heart, especially when it comes to a
Spitfire. I've picked up yet more information in the process, learning from
Carter about his extremely strong rear spring and Bill who used a binding type
of sway bar with good handling results on the track. All very interesting and
informative.
Truly I haven't seen anyone jumping on you trying to make you look like a fool.
I've seen disagreement with you on specific points of engineering, but I
haven't seen anyone saying you dress funny or that your mother is ugly. I
haven't seen you set up for a fall, or baited for attacks. I haven't seen
anyone smear the camber compensator as being bad, a rip off scam, or making
comments about you for remaking this very vital piece of equiment.
I do not agree with you on eliminating a very important conversation simply
because you are getting upset by it. You have always had the power to skip
messages and press the delete key. No one is forcing you to participate in a
conversation about Spitfire suspensions, their engineering, and experiences
with various modifications. Just as a person who likes blue Spitfires doesn't
have the right or the authority to insist we not speak of red Spitfires, I do
not think you've got the right or authority to insist that we the members of
this group no longer discuss Spitfire suspensions.
>The Z-Bars we were working with in the 60's looked like a Z and had to be
>twisted to pre load them in the istalled position. If they have since changed
>it's my mistake.
Like the camber compensator, the z-bar can be used to exert spring pressure on
the suspension. It is not an inherent function of either to act as a booster
spring, but both are capable of it. The only instance I'm aware of that the
z-bar needs pre-loading is when it is used in place of the regular suspension
spring (s). I've only seen this configuration used on some formula Vee's. A
very peculiar set up, of dubious effectiveness. Doubly so since it never
seemed to catch on.
As a P.S. (because I don't know where else to put it), you've mentioned that
Kas only believed there was one type of jacking or wheel tuck as he apparently
likes to call it. That is odd to me, because I can think of three main ways to
cause it, each distinctly different. Two of them assuring you go spinning off
, with the third giving you the stability of a unicycle. The swing spring
addresses two of these conditions, while the camber compensator addresses all
three.
One is caused by sticky tires. Hit a turn hard enough and you can generate
enough force to pop right up over the outside wheel. Quick, violent, and not
so common back in the days of hard rubber tires. Though Beetles were good at
it. This is what you see if you've ever watched an autocrossing Spitfire
suddenly throw its rear end up part way through a turn and go spinning off
course, especially if the person backs off the throttle part way through the
turn.
The second is the jacking effect we've talked about in going through slaloms.
On the street, you can get into the same problem dodging dogs and little kids.
Swing the car back and forth fast enough and hard enough, and you can get over
the tire before it can settle, and then you hold the rear end in the jacked
position. Not as violent as the first, but just as disasterous. You see
Spitfires do this one in slaloms all the time, with each turn getting worse,
starting with the second turn usually. It's made worse by using stiff shocks
btw, particularly if they are stiff on compression.
The third one is from getting the rear end up as a whole, all by itself. Be it
hard braking with the nose diving and the rear coming up, coming over a sharp
crest, or getting a cross wind under the tail. This one gives you both wheels
on their sides and unstable. But since you're not always turning, you don't
inherently go spinning, you just find yourself with the darnedest feel car
until the rear end comes back down. This many of us have felt coming over a
sharp crest with a turn right under it. The car makes no sense for a second or
two until gravity pulls it back down and the rear suspension starts working
again in a good manner. This is the one that leaves us bug eyed, going "what
the hell was that about?" This is also the one that the swing spring does not,
and essentially cannot, address. At least not in street trim. A camber
compensator, limiter straps, shortened shocks, or a rock hard dearched main
spring are needed to fix this. Of the fixes, a camber compensator is probably
the best, particularly for the street.
I am sure there are some other jacking type conditions that I haven't thought
of that others could add.
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