Re: Suspension questions (Thanks)

[Iain Mannix <mannix@privatei.com>]

> To answer (and ask) a couple of more specific questions back:
> 
> My alignment setting are at stock, and were done last year.  Perhaps I
> should dial in more negative camber as suggested? (Thanks Jim)
> What would this do for tire wear on fairly sporty rubber?  Is this something
> I could do myself? 

Alignments are not hard, but tedious.  Somewhere, maybe here, there was a
recent discussion re: home alignments.  IMHO, $40 is cheap, unless you
have NO money, tons of time, and boatloads of patience.  Try a 1.5-2d
negative and some toe out - 1/16" total?  Something like that.  The hard
part of aligning at home is not so much the actual adjustments, but the
measuring/preparation.  I suck at it, maybe that's why I don't like it.  I
can get camber fairly equal side to side, but measuring toe is a hassle,
and I am not good at it yet.  Front wheel alignments are typically fairly
cheap, you might be able to find coupons.  Problem is finding a place that
will adjust the car beyond manufacturer's specifications - they'll tell
you it is dangerous, that there is no warranty, it might not stay adjusted
- all a bunch of crap.  If it does not stay adjusted, it is because they
are idiots.  Tell them that.  I once took my car to a Badyear for a
quickie alignment - my normal shop was too busy/alignment guy was sick,
man, what a hassle.  Told them 2.5neg/1/8" toe out, they bugged.  "No,
bad, dangerous, tirewear, etc."  Finally, they did it, it sucked, the
camber was not the same side to side, es muy horrible.  Oh well, we're
lucky to have the Tire Source here in Boulder for alignements - whatever
you want, they'll let you sit in the car if you want, and friendly.  Cool.
I got mine aligned yesterday and a new set of R1s.  Yeah.  I am poor.
That's OK.  

> 
> Andre mentioned that I could adjust the tire pressures to reduce potential
> oversteer.  Currently I'm running about 42lbs all around, max pressure 45lbs
> on my tires.  Any suggestions here?

42psi sounds good for the fronts - to tell, use shoepolish on the sidewall
up onto the tread - measure rollover - drive around some corners, see how
far the shoepolish wears off.  It should wear right to the edge of the
tread, but not onto the sidewall.  Then, adjust the rear pressures up or
down to decrease understeer - if you go down, you're allowing the rear
tires to roll onto the sidewall a bit, reducing contact patch, reducing
understeer.  If you go up in pressure, beyond optimum, you'll be reducing
the contact patch, reducing understeer.  I prefer to go up in pressure, as
I don't like the feel of a tire mushing under, rolling onto the sidewall.
YMMV.  For autocross, I have heard of people going as high as 58psi in the
rear tires - this seems high to me, but on a stock car or mildly modified,
one might not have any choice.  Dunno.  Probably not a good idea to run
that far beyond the max psi rating every day.  

> As far as my driving style goes, well I could be better, but who couldn't? :-)
> Mannix and Shawn had some great suggestions here and I'll try and put them
> to good use as soon as possible.  Those were some very helpful pointers. 
> I'll keep you up to date if things start to work better. 

Glad you did not take offense.  It is always enlightening when a Stock
class car with a good driver smokes me - it happens more than I'd like -
but it lets me know that all the gofast stuff in the world does not
automatically make a fast car.
 
> What's this about stock upside down bars again?

Take your 25mm bar off, lay the stock bar on upside down, on top of the
axle beam, drill two holes for the brackets on the axle beam, mount stock
bar upside down on top, then reinstall the 25mm rear bar.  Works great.

> Because the Eurosport bar is so inexpensive, and no-one mentioned that it'll
> HURT, I'll add that to my setup as soon as I can.  Again, I'll let you know
> if things start to work better.

The Eurosport bar is good, but IMHO, the addition of the stock bar is
going to make a bigger difference.  If you are prioritizing, do the
swaybar first.  

> 
> Ah, Shawn, how'd you know that I was coveting the Velocity diff kit...<drool>
> When I get it, I'll talk to you more, I'll need a little hand holding to do
> it myself.  Hey, I've done clutches, so I know which end of a wrench to use. :-)

Like Shawn said, I have the 40% kit - I got mine before the StageII/80%
kit was available, and the 40% is good.  A competitor locally has a Quaife
in their car, and while it helps, I still can beat them.  I was really
worried when they first put it in, but their times did not drop noticeably
after they got it.  FWIW.  


> So, the bottom line is that I feel pretty good about my suspension set up, I
> guess that I failed to mention that I have the car lowered with Hor springs and
> Boge ProGas shocks.  After adding the Eurosport rear upper tie-bar, what's next?
 
Another thing to consider might be stiffer springs.  The Hor springs are
really not that stiff, and might lower the car too much.  Are your control
arms parallel to the ground?  If not, if they are pointed up to the front
wheels, the car is too low.  IMHO.  See, what happens is this - there are
two theoretical points relating to body roll/handling.  The center of
gravity and roll center.  The roll center is the axis about which the car
rolls, the pivot.  Think of a frozen bolt.  The bolt is the roll center,
the end of the wrench is the center of gravity.  The longer your wrench
is, the more leverage you have on the bolt(roll center).  Now, in the case
of the car, the roll center changes in accordance with the control arms
and other things.  With the control arms parallel to the ground, the roll
center is about 3" off the ground.  With the arms pointed up, the roll
center goes underground - remember, the roll center is a theoretical point
that the car rotates around under cornering forces.  So, if you lower the
car 2", you have lowered the CG 2", BUT, the roll center has dropped
considerably more, so the distance between the RC and CG is *longer*,
meaning cornering forces have more leverage on the car - cornering forces
have a "longer wrench," meaning more leverage, and the car will roll more
easily.  Also, if the c-arms are pointed up while static, any compression
of the suspension will result in loss of static negative camber.  Bad.  

Typical lowering springs are too soft and too low.  Look at your control
arms to see where you are.  It is possible to use a stiff enough spring to
counter the lower rollcenter, but I have not figured out how stiff that is
- my fronts are 280#/in (Nspeed race), and the arms are just about
parallel.  If I went lower, I'd have to increase my spring rate, which is
bad, as far as I can tell - the car is already fairly stiff.  Turn in
would suffer, too.


> MORE POWER! <Grunt>
> 
> That costs real money, so I'll probably go after the diff kit first. What'd ya
> all think?

Honestly, I'd spend my money on a SoloII school, learn to use what you've
got to its fullest first.  They are typically $20-40 dollars, and if you
spent $100 in schools/events for practice, you WOULD be faster than if you
put in the diff kit.  I think the kit is a good idea, but more speed is to
be had with driver adjustments almost every time.  A diffkit would let you
make certain mistakes, and you would be faster, but you'd still be making
the same mistakes.  Learn to drive better, and when you do the diffkit,
you'll be able to use it to its fullest, rather than letting it hide
errors.  I did a similar thing when I started solo - bought race tires
after 5 or 6 events, went faster, but only because the tires let me go
faster.  I still sucked.  Once I learned to drive the tires better, drive
the car better, I went truly faster.  I have become a big believer in
learning to drive better *before* spending millions of dollars on go fast
stuff - it gets frustrating, because if you don't have the fundamentals
down, you buy R1s or a diff kit, and you're still not keeping up.  It
becomes all too easy to doubt the car, when in reality, a school or two to
 be shown what to do is far more valuable.  People say "turn in early."
Cool, and you do, or you THINK you do.  Then you go to a school, the
instructor tells you to turn in HERE, huh?  Yeah, HERE.  You do, and it
all becomes clear.  Oh, EARLY.  Stuff like that.  The driver is the
cheapest and most effective part of the car to modify, bar none.  

Case in point - there is a father/son "team" here in Denver.  The son,
Jay, drives an HS Honda Accord, roughly 82 vintage, spray painted 3
different colors, 170k miles, ummm, sorta a piece of crap.  He worked on
the driver, got race tires, started going fast.  His father drives an 83
911SC in ASP, it has Bilsteins, R1s, swaybars.  Guess who consistently was
faster?  That's right, JAY was faster, in the POS Honda.  Awesome.
They're both really nice people, but Jay is a better driver than his dad.
Jay has no cash.  Jay worked on the driver.  Roger, his dad, has enough
cash to mess with the Porsche, and he does - little things here and there,
but Jay keeps beating him.  Which car is faster?  The Porsche.  Why does
Jay win?  Because he is a great driver.  He was second in Rookie last
year, second to a person in a 96 Camaro SS, which is *the* F Stock car to
have - the rookie class is indexed, so the person in the FS Camaro is at
an automatic advantage - the Camaro is fully capable of matching the
index, whereas the Honda is outdated and not so competitive, even if it
had 100k fewer miles.  Jay was really close to the FSR champ, who would
have been second in FS/open class.  Anyhow.  Driver driver driver, car
does not matter.  That's not to say we should'nt modify and have fun, but
if you are truly looking to improve speed, the driver will be the biggest
difference!


Mannix(I've wasted hundreds of dollars trying to figure out how to go
faster, but now I know.......)


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