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Tiger suspension

To: "\"'<tigers@autox.team.net>'\" <"<tigers@Autox.Team.Net>
Subject: Tiger suspension
From: Bob Palmer <rpalmerbob@email.msn.com>
Date: Wed, 28 Jan 1998 21:27:24 -0800
Guys,

I tried to post this a few days back, but was not quite up to speed with 
Microsoft Outlook versus Outlook Express and other arcane aspects of the 
Win95, etc. protocols.  Anyway, here's a few of my comments regarding the 
subject of Tiger Suspension:

Pardon me if I re-name this thread as I don't think we're talking about the 
Tiger ID manual any more ( at least for the time being).  Anyway, having 
tried a lot of different setups over the years I have a few comments to add 
to the already extensive comments on this topic.

First of all, I've come to the opinion that the place to start with 
controlling suspension is with SPRINGS.   Dick Guldstrand and others with a 
lot more experience than any of us have the philosophy that springs are the 
primary way to control suspension travel and roll stiffness, NOT sway bars. 
 The purpose of a sway bar within this philosophy is to fine tune roll 
stiffness.  Accordingly, use BIG springs and a small sway bar up front.  By 
BIG springs I mean at least 400 #/in.  Depending on a variety of factors, 
including your relationship with your chiropractor, you may want to go to 
450 or even 500 #/in.  The 400-450 range is still reasonable for the 
street, again depending on your personal tastes.  I am using 425 #/in and 
use a 7/8" sway bar (3/4" is stock and went with very weak stock springs). 
 Recently, I have found a cheap and easy way to adjust front stiffness. 
 Buy a set of the rubber coil spring helpers from Pep Boys, etc., for about 
$5 and add them to the front springs to increase stiffness.  Changes ride 
height scarcely at all and allows easy installation and removal to adjust 
for street versus autocross (in for street, out for autocross).  The 
problem with using a big stiff sway bar (front or back) is that it takes 
the "independent" out of you independent suspension.  Granted, with a big 
stiff sway bar you won't lean in the turns (good), but now both wheels are 
essentially tied together and go up and down as a unit instead of 
independently following the contour of the road/track.  If you have soft 
springs and the car wallows like a Buick, then after adding a big sway bar, 
it will still wallow; just straight up and down.  Now 400-500 #/in springs 
might seem kind of stiff, but if you are running a track at high speed 
(>100 mph) and hit even a fairly small bump the compression of your 
suspension will be considerable if not controlled by rather stiff springs. 
 I think the principle here is to try and keep as many wheels on the ground 
for as much of the time as possible, which independent suspension does 
best.  I advise not to use 330#/in (CAT) springs because they are too weak 
for autocross etc., they sag, and other reasons I could mention.  Go to 
Coil Spring Specialties, Dale's Restorations, or other good source and get 
a set of top quality springs.  I think the cost is still not much over $100 
bucks for a pair.

Now on to the rear suspension:  The key here is to match it to the front  
 suspension.  It's harder to adjust the rear roll stiffness directly if you 
don't have an adjustable sway bar.  This would be the only valid reason, in 
my opinion, to install one.  Most people like to set up their suspension 
with a lot more roll stiffness up front because it gives them a more 
predictable feel.  Basically, with soft rear springs, the rear end just 
follows the car around.  However, if you want more cornering capability out 
of your car, increase the rear springs and/or sway bar stiffness relative 
to the front.  Guys who race Porches complain bitterly about the car's 
tendency to oversteer, but they do win!!  A really neutral handling car is 
a bit scary.  Where to set the balance is a matter of what your are willing 
to cope with and how good your reflexes are.  I think about two more leaves 
added to the stock rear springs is more-or-less about right, but you will 
have to play around and, again, the rear setup depends on how stiff you are 
up front (sounds like the basis for a bumper sticker).  I could get into 
the issue of roll steer in the back, but will defer this topic to a later 
date.

Regarding the torque arm:  A  lot of folks out there like this approach. 
 Bolt-on traction bars have been a very good option and have the advantage 
of being "stock" on a Tiger.  My problem with the torque arm is that, 
contrary to what you suggest, it adds to the tendency of the front end to 
dive during braking.  If you read Dan's tech notes he alludes to this fact 
and the related tendency for the rear end to lose traction in reverse gear. 
 Also, I don't see any relationship between the torque arm and the Panhard 
rod or Watts link.  The torque arm does nothing I can see to limit 
side-to-side motion of the axle.  I've tried mine with and without the 
Panhard rod and prefer it without.  Can't really explain why, but it just 
feels better without it.  I know Dale tried a really nifty Watts link on 
his vintage racer and took it off immediately after he tried it.  He can't 
explain it either, but then hardly any of us take the time to research 
these issues.  With the torque arm, or any other nifty new gadget, there's 
a tendency to view it as a "magic bullet" that's going to solve all our 
problems.  Truth is, success is more a matter of getting all the parts to 
work together which involves a fair amount of good engineering, 
trial-and-error, and just plain hard work.

Now, I have a question for you.  Can you please tell me a little more about 
the "over-riders running on top of the springs"?  I've been thinking about 
something along these lines and would like to know how it is implemented in 
some other vehicles.  Thanks.

Bob Palmer
B9472134, SHO, etc.





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