[DeTomaso] Impressive grip

[Charles Engles]

Dear David,


        You're forgiven just as long as you didn't hurt their ego nor impugn
their species.


                 Warmest regards,  Chuck Engles



-----Original Message-----
From: detomaso-bounces at poca.com [mailto:detomaso-bounces at poca.com] On Behalf
Of David Fisher
Sent: Monday, July 15, 2013 10:11 PM
To: JDeRyke at aol.com; poca list
Subject: [DeTomaso] Impressive grip

I took the car out for a spirited (as in my neck hasn't compained this much
since karting) drive down my favorite, very twisty back road early Sunday.

I had the benefit that the local cyclists were few, and the traffic was non
existant - although the suicidal gophers were a plenty. (what is it with
gophers playing chicken?!)

Well, the long and short of it is that this 40 year old car is pretty darn
entertaining!  I still have a rather lazy motor out back, but the new sticky
rubber up front along with a rebuilt suspension makes for car with pretty
darn high cornering forces, and it is actually feeling like a mid engine car
now.  I have mild understeer at the limit, but the limit is pretty high. 

Two gophers gave their lives for my Sunday drive, and I would like to hold a
moment of silence to thank them for making it even more entertaining.  ;-)


Sent from my iPad

On Jul 12, 2013, at 11:05 PM, JDeRyke at aol.com wrote:

> Stock alignment #s were designed for narrow, hard, belted-bias tires;
radials didn't come into use until the mid-'70s. So most factory settings
are wrong for good handling especially with wide radials. But Camber, the
amount a tire leans in or out from the vertical, should still be pretty
close to zero for best tire life. Running -1.5 degrees will wear the inside
edges faster than the rest of the tire. It will also improve cornering power
noticably. If you're happy with the way the car rides and handles at this
setting, and you periodically rotate the tires on the wheels (not side to
side on the same wheels)  to compensate for inner edge-wear (or can afford
to replace them when the edges are worn throug), then go ahead. 
> 
> With understeer in corners, you're running into the stock-fendered
Pantera's main weak spot: you simply cannot hang enough front tire under an
uncut front end to balance ultrawide rears. Thats why the GR-4 racers got
big flairs. Your rear meats are more than 1.5X as wide as the fronts, so
even if you've realigned things to compensate for our car's designed-in
understeer, ultrawide rear tires will only intensify the understeer. Several
things come to mind that you may already have done (in increasing order of
cost):
> 1)- run a 1" rear swaybar with a stock or slightly smaller od front bar. A
hollow 7/8" front bar is 10% softer than a stock solid 7/8" bar. Poly center
bushings intensify any antisway bar's action, and sphere-balls on the ends
of both will improve the action noticably. 
> 2)- Check your ZF to be sure its not a 75% locker with 4 friction clutches
per side. Most Panteras got a 45% locker (three discs per side) but not all.
Unfortunately, disassembly is the only way to positively tell, but testing
may give a clue. Too much rear lockup will cause corner-push in any car.
Adding some Antislip agent to your ZF lube may help the push a little.
> 3A)- Use a 245-35x 17 front (8.4" tread width). Your current fronts are
8.0"
> 3B)- Use a 315-45 x 17 rear (11.4" tread width) . Your current rears are
12.2"
> If you change both tires as above, the mismatch in width will only(!) be
1.35 and your odometer will read closer to correct, too. I'm curious about
how all this plays out; most guys that mount giant rear tires don't much
care about cornering. Keep me informed- I'd like to know if you solve the
issue. Maybe I can learn something, too. 
> FWIW, I run 245-50 x 15s in front (8.9" tread) and 295-50x 15 rears (10.9"
tread) with a 3/4" hollow front bar & a 1" hollow rear bar, both with poly
bushings & sphere-balls. Those tread size ratios are 1.22:1. Stock ratio was
only 1.09:1
> Cheers- J Deryke
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