Author Topic: Caster Master Setup  (Read 11425 times)

Offline justfreaky

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Caster Master Setup
« on: July 20, 2010, 01:37:26 pm »
Just reposting this for Geoff.

step 1

Set the lower control arm lengths to 16.5 inches for the right side and 15.5 inches for the left. Take the measurments from the center of the heim joint to the center of the grease fitting.

step 2

square and level the rack to the inner control arm bolts.

step 3

change the 12'' tierod to 11'' adjust the the steering so that the rack turns the wheels further to the left than to the right not by a lot but at full lock the left wheel should touch the header when we are done .this set up is a bit heavy to steer so make sure you dont have any stiff hiems .
install a 3/4 spacer between the outer hiem and the steering arm to take care of some bump steer.

step 4

install a 3/4 spacer between the inner control arm hiem and cross member on both sides.adjust the hiem on the back of the control arm out until the front part of the control arm rubs the cross member on the right as you move it up and down take it back a little to give about 35thousands gap.install a 3/4 spacer at the back of the arm .use longer bolts to make this easier . go to the left side and make it about the same length with the same spacers. go back to the right side and remove the upper strut rod take it to the vice put the clevis end in the vice spin that cheap locknut back as far as you can it will go way past the thread then turn the rod to it.turn the hiem all the way in.centre to centre should be about 13 3/4'' re install and do the same to the other side with the shocks unbolted adjust your hiems so they don't bind through travel.

step 5

lets do the springs now and Iwould like to say that what makes this deal work is not soft springs its the fact that we are causing camber gain under static or not rolling which is controlled buy the driver and at the same time steering the rearend through roll and dewedge in the turns. as we roll along I'll try to explain my theory the best way i know how.
I use58% cross as a base so to get your ride height in the ball park I'll give you measurements off of my 34 coup
I mount the shocks strait up not upside down.
rt front 300 with 2 inch from the bottom of the spring holder to the bottom of the adjusting nut go ahead and install it but now you dn't need a spacer on the upper bolt because your shock can lay back due to all that caster we installed.
lf 275 1 1/4 from bottom of holder to bottom of adjust nut go ahead and install leave out the spacer.
RR 225 1 1/4 from bottom
LR 200 1 1/4 from bottom go ahead and install then let he car down on the floor.
lets do the tire pressure RF35 RR32 LF23 LR 20 now we want to check the run out in the wheels on the right side only since we are squaring with a string jack it up and spin the wheels mark the widest point and put it to the bottom so that we don't get any false readings.
now lets go back to the front end and apply our caster camber gauge to the right front lean the top in until you have 4 1/2 on camber
lets go lock to lock for caster and we should have about 16 degrees check the camber gain when you turn the steering wheel and by the way you will need a 17'' wheel to handle the heavier steering . go to the other side and apply your gauge lean the top out until you have 1 1/2 degrees adjust the top rod forward until you have 13 degrees caster lock to lock .now take a look at the camber gain on this wheel when you turn the steering I like the feedback I get going in with this .
lets do the ride height RF 3 7/8 LF 4 RR 3 5/8 LR 3 3/4 to check wedge jack up the back place a jack stand under the rear end to the left at the point of half way on the battery let the jack down and the rear wheels should come off the floor even that should be about 58 % mark that spot on the rear end for reference I will use as much as 61% on flat like charlotte or 56 % at orlando.most tracks 58 is just fine
getting back to the ride and rear end 3 degrees pinion
on the third link I install a 3/4 spacer on the front and take the spacer out of the back so that when the body rolls the link is pulling strait instead of to the right.
the 3 5/8 ride is very important because is the limit you can go to be safe in tech at this height the front pickup is lower than the rear end pickup which means that when the body raises going in it pushes the right rear back and on coming out in squat it pulls it ahead the left side being 3 3/4 is high enough so that the back lifts going in it pulls the left wheel ahead and when coming out in squat it pushes the left back to steer you off the corner; when you get up over 4'' the opposite happens
that being said the theory all that caster on the left will let us control the roll steer by turning the steering wheel to change the left rear ride height and when we raise it we knock out some of that 58 %to let the car turn and at the exit of the turn when we straiten the wheel the wedge comes back to get us up off the corner and combine with that roll steer in squat.
Just a couple of things left check your bump steer because those 3/4 spacers under the tyrods might be to much depending on how high that rack is Ilike to see about 10 thou on both sides for bump.
lets square it off the right rear wheel only heres how I do it tie a good string around the outside of the rear bumper and draw it tight up across the middle of the front and rear wheels move it out away from the front wheel as you bring it back in take note of where it hits the front of the back wheel if it hits before it touches both sides of the front wheel this means that the rear end is towed out and needs to be either brout ahead on the right or back on the left if it touches the front and back of the front wheel and does not touch the front of the back wheel it has to be adjusted the apposite. during this procedure check your wheel base on the right side only it is very very very important to keep that string just barly touching that back wheel when you get your wheel base correct it tricky to get but if you play with it you will get it once you get the right side squared and wheel base legal go to the left and check the wheel base with your wheel base gauge make it legal by adjusting upper and lower front control arms ahead or back both at the same rate so as to not mess up your caster and bump steer .
brake bias to rear brakes I like the flip handle type with the rear brakes not set up to much so the bias valve will work better .I've been on tracks where Ihave had to use all rear at one end and no rear at the other .I
Ithink thats about it except the toe which i run at 1/8 out .
there is a little test you can do to see if you like it . go to a flat spot on the pavement go about 5 miles pr hour then cut the steering wheel hard to the left hit the gas to put it into a spin feather the gas to steer the back when you get the feel of it you can turn it all day to bring it out back off the gas and point the front where you want to go, go ten feet and do it again this will send the kids in the crowd crazy and if you have to spin it on the track you will be able to bring it out of it without stopping. I don't believe we are doing anything against the rules and don't knock it til you try it.
I have won with this set up in the winter nationals at inverness and albany it also keeps me in the top 5 year after year in orlando hell not to brag but I have even passed cotton spry with it
let me know what you think or if I have to explain myself a little more clearly cy37


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Offline Racingtrader.ca

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Re: Caster Master Setup
« Reply #1 on: March 04, 2011, 04:05:28 pm »
I have run this set up a few times over the last couple years. It works good if you have the arms to turn the wheel. On a friday night last season by lap 15 I was beat falling over in the seat and went back to the shop that evening and removed 1/2 of the caster but kept everything else the same. I was able to finish the 50 laps with no issue on night 2.  Just need to get more track time this year to fine tune it for myself .
Mark Williams
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Offline justfreaky

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Re: Caster Master Setup
« Reply #2 on: March 04, 2011, 08:00:12 pm »
I had the opportunity to view a chassis set up video that Cy Harvey and Geoff Bevan were working on. Don't think it ever got produced. Cy never once claimed that his set up was the end all answer, or that it would work for everyone. It did show basic set up techniques though. I thought it was a well done video for information. Not showy. And the sound was not the best quality. Overall, much better than the dwarf car video produced by Steve Smith. Only my opinion.

This set up is, I believe, still a work in progress. It will likely not work for everyone... But is food for thought, and the old trial and error that everyone must go through to fit their driving style to a chassis set up. Geoff's last question was if anyone had tried this set up? I appreciate your input; And, would like to hear from others who have tried this set up or variations of it.

Steve
Better to be hated for who you are, Than to be loved for who you are not.


Offline Racingtrader.ca

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Re: Caster Master Setup
« Reply #3 on: March 04, 2011, 08:09:20 pm »
It's a little out dated now. I have the benefit of living local to CY and have seen his set up progress over the last few years. I read once the reason he posted the set up was to help new and back marker cars run a little better so they didn't run into him lol.  

I have never watched the video but heard about it. I may have to see if he has any left kicking around.
Mark Williams
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Tel: 902-448-6903

Offline justfreaky

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Re: Caster Master Setup
« Reply #4 on: March 04, 2011, 09:29:28 pm »
I believe the original thread was from 2008. It got deted by mistake. I re-posted the info that I had saved for my personal files.
Check with Cy or Geoff. They may still have the video saved somewhere. I have a copy, but will not copy it or share it with anyone because I was asked not to.

Steve
Better to be hated for who you are, Than to be loved for who you are not.

 

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