Drag racing tips.....Phantom402

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Drag racing tips.....Phantom402

Postby h-bot » Mon Mar 18, 2002 12:11 am

From: darthvegagt_REMOVE_806270_THIS_@yahoo.com


I am buying a set of the Summit brand drag shocks
tomorrow, so that should help out weight transfer better. I
just installed a '97 S10 rear that has 4:10 posi and I
am confused on exactly where to set the pinion angle
or how to decide, whats the key to determining? the
higher the yoke the less it will hook or something??? I
dunno, just wondering. I was just going to make the rear
straight with the driveshaft and see how it worked. What
is the easiest way to set it without special tools
and what should I set mine at??? I do drive the car
on the street so I am gonna try taking the end links
off of the swaybar. thanks Jordan


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Drag racing tips.....Phantom402

Postby h-bot » Mon Mar 18, 2002 12:28 am

From: Phantom402_REMOVE_613900_THIS_@yahoo.com


How did you mount your rear end in the car?
I
just cut down s10 springs and bolted them on to rear
axle,welded the spring mounts on too and did away with the
torque arm and had some very good results and traction
too and I had severe negative pinion angle.
On a
coil spring car you want anywhere from 1.5 degrees to
4.5 degrees down pinion angle as the pinion(nose of
the rear end is tring to raise)i was going to build a
pinion snubber to mount on the car but wrecked it before
any testing could be done.
lee


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Drag racing tips.....Phantom402

Postby h-bot » Mon Mar 18, 2002 3:26 pm

From: darthvegagt_REMOVE_251705_THIS_@yahoo.com


I mounted the rear by cutting off all of the 7.5"
GT Vega brackets and welded them exactly the same
onto the S10 rear. I have to do away with the torque
arm as well but have been thinking about building a
set of ladderbars for it. What keeps your rear from
flopping around without a torque arm or ladderbar setup??
Your running leaf springs on yours, is that what your
saying? My new rear is setup like the stock rear, the
stock suspension worked incredibely well when I took it
to the track this last month, so I am sticking with
it. I think by adding the 4:10's, 3-way adjustable
drag shocks, bigger cam, and MSD ignition and nitrous
retard setup the car should run a good 11 second pass.
It ran 12.24 @113mph with 2.93's and stock
everything. lol. Jordan


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Drag racing tips.....Phantom402

Postby h-bot » Mon Mar 18, 2002 3:31 pm

From: darthvegagt_REMOVE_212258_THIS_@yahoo.com


So how much is 1.5 to 4.5 degrees down pinion
angle, in inches say??? I don't understand degrees.
Should I just aim the pinion down a little from the
neutral position (where the pinion and driveshaft are
straight with each other) and try that?? If you could
clear that up and explain it to where I could do it to
my car, I would appreciate it. I want the car to
hook hard, so that I can get my 60 foot times down
from a 2.0....I'm sure you understand lol!!!. Thanks
in advance Jordan


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Drag racing tips.....Phantom402

Postby h-bot » Mon Mar 18, 2002 3:33 pm

From: billy_b_85222_REMOVE_948251_THIS_@yahoo.com


Hi Jordan.Try making one change at a time.You might surprise yourself with the results.Have fun! Bill in Casagrande.....


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Drag racing tips.....Phantom402

Postby h-bot » Mon Mar 18, 2002 5:22 pm

From: vegadad_REMOVE_638890_THIS_@yahoo.com


Jordan,
What you need to do is go to your
nearest Home improvement store and Buy an Angle finder.
Really handy instrument to have in your inventory. This
will need to be held perpendicular with the centerline
of your pinion shaft and will give you the pinion
angle. It isn't a very expensive piece, but well worth
the bucks. I'used it to determine the angle cut I
need for my rollbar downtubes. Really handy. Good
luck.
john b. (in Virginia)


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Drag racing tips.....Phantom402

Postby h-bot » Mon Mar 18, 2002 8:15 pm

From: darthvegagt_REMOVE_972575_THIS_@yahoo.com


thanks I will have to go get one and see how it goes. Jordan


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Drag racing tips.....Phantom402

Postby h-bot » Mon Mar 18, 2002 8:36 pm

From: CJBIAGI_REMOVE_667802_THIS_@yahoo.com


I will admit that I am a little confused on
driveline angularity. On one hand everything I have read
says to have the output shaft of the trans and the
input of the pinion parallel to each other. When
checking with a angle finder the two measurements should
add up to 180 degrees. This minimizes any chance of
vibration. However at the same time a slight negative pinion
angle is also desireable. The way to achieve this of
course would be to have the trans output shaft slightly
higher then the pinion shaft in the rear end so that the
driveshaft is on a slight downward angle toward the rear
end. However with a torque arm attached to the trans
and to the rear end, THAT seems to maintain the
relationship between the trans and rear end. So how would you
go about adjusting the pinion angle with a torqu arm
rear? For those that are confused about pinion angle it
refers to the angle between the driveshaft and the
pinion, not the angle of the pinion to the ground. Clyde


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Drag racing tips.....Phantom402

Postby h-bot » Mon Mar 18, 2002 9:56 pm

From: Phantom402_REMOVE_764804_THIS_@yahoo.com


i used a cut down set of s10 springs bolted them
onto the rear end and slid the spring eye end into the
stock lower control arm mounts.
The rear end just
swings in an arc.I welded a plate with a bracket on the
back of the spring pad and set my shock angle at
nearly the same as the stock angle.
I used a set of
monroe sensa tracs for a 70 Monte carlo #5802 and on
front on my monza I used a set of Monroe Reflex for a
94 and up s-10 #911129.
good luck.
lee


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Drag racing tips.....Phantom402

Postby h-bot » Mon Mar 18, 2002 10:15 pm

From: Phantom402_REMOVE_643488_THIS_@yahoo.com


OK you can use a dial type protractor from
craftsman or one thats digital if you can afford it.
Set
front end and rear axle on jack stands(set rear on the
axle tubes so springs are supporting car or have it on
a drive on lift.
Make sure its level, put the
protractor on the drive shaft and read the angle, then you
measure at the pinion on the ujoint( remove the ujoint
snap ring and put a good ,clean square socket or get a
slug of metal made that will set level on ujoint cap
and read the number on that one.
You have to
remember that the drive shaft number is considered "level"
and subtract/add the change.
Do you understand ?
if not email me back.
The idea is that as the
pinion is twisted "up" by the pinion gear trying to walk
up the ring gear, the action is that the upper bars
square the axle to lift the car by the lower control
arm/ladders bars/torque arm.
If you look in S&W race cars
they build a neat tubular torque arm for 82 up f
bodies because it is taking the torque and allowing the
lower control arms lift the car/ plant the tires.
To
understand how a rear supension is supposed to work, look at
your index/middle finger as you make a sissior action
with them and figure it this way,if your rear
suspension seperates(sissors opening) you are planting the
tires if your rear suspension closes(sissiors closing)
you are lifting the rear tires and not hooking
up.
Lee


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Drag racing tips.....Phantom402

Postby h-bot » Mon Mar 18, 2002 10:19 pm

From: Phantom402_REMOVE_740485_THIS_@yahoo.com


move the pinion by raising or lowering the front of the torque arm.


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Drag racing tips.....Phantom402

Postby h-bot » Mon Mar 18, 2002 10:49 pm

From: SWT_Racing_REMOVE_921876_THIS_@yahoo.com


Jordan,

What you raelly need to do is get
an angle finder as John B. suggested. On a factory
4-link H-body, I would shoot for 2.0° down. (If you need
further explanation on what this angle is and how to
check it, either myself or someone else in the club
would be happy to help you.) Ideally, you want the
pinion angle to be 0° while the car is going down track,
but since the rear suspension has some rotational
'give', you add pinion angle so that under acceleration
the angles come out to 0°. In my experience, pinion
angle has nothing to do with traction, rearend rise,
anti-squat, tire 'hit' or otherwise.

I can tell you
what worked for my Vega (YMMV), when it still had the
factory 4-link. The setup was as follows: no front sway
bar, Lakewood 90/10 drag shocks, new rubber bushings
in the rear contol arms, boxed lower rear control
arms, cheap 50/50 factory type rear shocks (not gas
charged), factory rear sway ber to combat "corkscrewing"
(body roll) and the most important thing. . .26x8.5 M/T
slicks. This setup gave consistent 1.72 60' times. I
think it could have been better, but my front end rode
fairly high, and the front suspension only had about
2.5" of rise until it hit the stops.

That being
said. . .nothing is written in stone. Real world
testing is the only way to reach your goal.

Hope
this helps,

Andrew
SWT Racing/Hangar18
Fabrication
<a href=http://home.socal.rr.com/swtracing target=new>http://home.socal.rr.com/swtracing</a>


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Drag racing tips.....Phantom402

Postby h-bot » Mon Mar 18, 2002 11:12 pm

From: CJBIAGI_REMOVE_870538_THIS_@yahoo.com


Lee, you are right about moving the front of the
torque arm to move the pinion angle. I noticed when I
was reinstalling my torque arm that because of the
length of it you have a lot of leverage to move the rear
end angle with very little effort. I would imagine
that there is a designed in angle that the arm
provides with the stock mounting position. Has anyone
found a easy way to adjust the front of the torque arm
and has it made any difference? Clyde


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Drag racing tips.....Phantom402

Postby h-bot » Mon Mar 18, 2002 11:26 pm

From: cliffhangeriii_REMOVE_737875_THIS_@yahoo.com


You'll have to shim your trany & engine mounts.


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Drag racing tips.....Phantom402

Postby h-bot » Tue Mar 19, 2002 9:45 am

From: twelve_second_vega_REMOVE_443561_THIS_@yahoo.com


Andrew,
I agree with you 100%. I have found
pinion angle to be just that; an angle without influence
on tire 'hit' or anything else.

Stock
setting on a Vega 4-Link is 1.0 degree negative at rest.
Range of motion with this system is about 6.o degrees
total.

When I raised my upper control arm pivot points,
I also lengthened my tubular upper 'bones' or
control arms.

This created a geometric change
that resulted in less pinion angle deflection. I am
now reading only 2.0 degrees total range of motion,
from full extension to full compression.

I
think the most important aspect of driveline angle
adjustment is knowing the angle of the ouput yoke on the
gearbox. This serves as a baseline measurement.


Once established, the angle on the pinion yoke should
be within 3 degrees of this with at least one degree
of continuous angle for lubrication.

I will
use my Vega as an example:

Angle @ Gearbox
Yoke: 3.5 Degrees Negative

Angle @ Driveshaft:
3.5 Degrees Negative

Angle @ Pinion Yoke: 2.0
Degrees Positive

Your individual angles may very
well be different and I suggest pulling the rear
springs and checking the pinion angle over the
differential's entire range of motion.

This will let you
know exactly where to begin. Andrew's suggestion of
2.0 degrees negative sounds just about right to me on
a stock 4-link system.

Best of
luck...Robert (bigbadvoodoovega@aol.com)


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