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Scrubbing

To: "Greg Monfort" <wingracer@email.msn.com>
Subject: Scrubbing
From: "alfaki" <alfaki@bellsouth.net>
Date: Wed, 8 Mar 2000 01:45:14 -0500
----- Original Message -----
From: "Greg Monfort" <wingracer@email.msn.com>
To: "Bricklin" <bricklin@autox.team.net>
Sent: Tuesday, March 07, 2000 10:01 PM
Subject: Fw: need front end alignment specs

> I noticed that you're planning on using some Mustang
> headers. Is TT no longer offering his design?

No, he isn't.  Unfortuantely.  The moment of truth has arrived and the
headers are a tight go.  The drivers side went in after some grinding of the
collector flange, but the tough one is the pass side where the bracket for
the suspension and the strut arm interfere.  We're going to try a couple of
things before we give up.    I still have to get back with the guy who said
they'll fit, someone who owns a Mustang shop and a Bricklin.... maybe
somethings changed or maybe poor manufacturing tolerances.

>
> BTW, what's so special about a 4150 DP w/vacuum
> secondaries? They've been around since the late '60s.
> It's my street carb of choice.

This set up comes complete with elec choke ford a/t kickdown, center hung
floats and some other stuff.  Supposedly, Holley believes this is a new
rendition.  While 4150s generally came with mech sec  [TT didn't believe
that this one had vac secs.] I see no reason to doubt the existence of
earlier vac sec models.   What's nice about the new Holleys is the blow out
proof power valves, what's bad is the gaskets still suck.  Also had to grind
down the vac distribution fitting just a little behind the carb to clear it.
So my next question is now that I have 3/8" line from the pump to the carb,
what about from the tank to the pump.  Seems a little "a" backwards.

> ======
> > All their racing plugs were too cold, and the
> standard edel fitment spec was
> > too hot.
> ======
> Bummer.
> ======

Well, these should do the trick, or at elast get us toward a clear
direction.

> > > No, I've never bothered to measure it since I
> don't
> > > plan to significantly increase the track. It's
> pretty
> > > large though based on how bad it scrubs with
> stock
> > > rims. It's why I prefer the slight negative
> camber.
> > > =====
> > Now you lost me, scrub radius is basically the
> suspension geometry where the
> > centerline of the tire/wheel lines up with the axis
> of the ball joints
> > during travel [sorta, waaay over-simplified].  It
> basically determines where
> > the load is placed, and is determined to be either
> positive or negative
> > depending on whether the suspension axes are inside
> or outside the
> > centerline of the tire.
> =====
> I've never heard it called positive or negative, per
> se; but since a positive offset wheel gives less
> scrub radius, and vice versa, it seems reasonable.
> Less (positive) is better.
> =====
>   This is a critical measure, but one often
> > overlooked and not to be confused with tire
> scrubbing.
> =====
> True. The Bricklin has negative offset wheels, ergo
> it has a large scrub radius by default. Since you
> can't install wheels to improve it enough to
> matter, it's moot IMO, unless you plan to
> significantly increase track.

Well I agree, however, you can exacerbate the problem with the wrong wheel
offset,  so maybe not completely moot.  To really get to the scrub radius,
you have to change the pick up points of the suspension geometry.  Something
that was achieved by Daryl by desigining a new front crossmember for the
Fiero.

>
> The scrub radius is in part responsible for tire
> scrubbing, hence it's name.
My understanding was that the "scrub" came from the effect of the tire tread
scrubbing on road due to poor load placement / contact , not the tire
scrubbing on the wheel well.  Hmm, the tales....


> =====
>  And even rarer is the
> > alignment tech that has even a clue to what it
> means.
> =====
> No need for them to, unless they work at a high perf
> wheel emporium. I learned most of what I know from an
> alignment tech at Gene White's Firestone, the S.E.
> racing tire distributor at the time.

> Not anymore. They were custom ordered in '80. All my
> mags of the time are gone, but if you have access to
> Hot Rod, etc. of the time, they were pictured in ads.
> That's how I found them.

Damn, I really want to maintain the stock look, but these wheels really
bite.
TT said he once sent some out to get "trued" and got half of them back with
a letter pleading not to send anymore.....
stephan


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