Swing Arm ?

[4bangerhotrod]

sorry racin6mod but you are wrong up on the frame adds sidebite but kills forward traction and down takes away sidebite but keeps the traction in the car. the purple bar attach's to the left side of the rearend so when it is high on the frame it is pulling the LR tire up which in return plants the RR tire, but when it pulls the LR up it takes the traction away from that tire. when the bar is down on the frame it is pulling straight across and not trying to pick up the LR tire which holds more weight on the LR tire adding traction to that tire. if people are going to give advice you should really know what your talking about before you do. all you have to do is have a mechanical mind and visualize what the change is doing this is the reason some of us can setup a car and when big races and some cant. take a pencil lay it down, tie a string to the left side of it and hold it to the right side about a inch above the pencil and pull on it, it will try to pick the left side up. then hold the string down against the pencil and pull on it, it will not try to pick the left side up. this is the same thing the purple bar is doing to the rearend.
thanks,
4bangerhotrod

[dualdj1]

4 banger you're partially right, the purple bar is a pulling action. as the car goes into the corner, the axle is trying to move left to the driver side, and in turn the purple bar applies tension between the right side frame and the left side of the axle. This can effectively cause a slight lifting on left sid axle, and extra downward force on right side frame. On the opposite side, J-bar or left side straight bar applies pressure outward between the left side frame and the left/right side of the pinion as the axle tries to move left. This can effectively cause left side hike, and extra either LR (left short) or RR (j-bar) force.

When you change mounting points on the panhard bar, it raises or lowers the moment (roll) center of the rear end. the height is the middle of the mounting points. The higher it is, the more resistance to roll the rear suspension applies. The lower the height, the more efficient the suspension works allowing for "easier" roll. Less roll generally equates to more side bite, more roll to more forward drive; but it is also dependent on other settings.


Believe Steve is still on the purple bar, but not positive.

[RACR_73s]

Here is how this week went...

LF650 (same) RF450(was 500)
LR300(was 350) RR600(was 500)
pull bar left 1(same)
purple bar 2 1/4" up on frame(same)
RR swing arm down 1 hole(4th hole from top)
LR 7/2 Pro compression shock(was standard Koni)
#158 LR(been anywhere between 140-186)
2 1/2" stagger(same)
12" fuel

Car was much better going in, first time that I felt that it was putting the RR in the track. Led 1/2 the heat before caution and never could get rhythum back and faded to 4th.

Feature changes....
RF 375
pull bar left 1 more
LR rear bar down 4 to bottom
RR rear bar up 2 to top
4 round out of LR
grind rear tires
No fuel added(less rear to tighten, correct ???)
forgot(ran out of time) to lower purple bar.

Track was the best it has been all year for the feature so can't compare apples to apples but car was good in feature. Started 8th and after a couple of laps started to come to the front. Got caught in lapped traffic(new driver all over the track and didn't want to dump him or wreck car any worse than what he was doing to it...lol) for a few laps and lost several spots. After caution started moving back up and spun with a few to go trying to get under another car.

washeduptoo - Thank you for telling me what the swing arms will do. I was wanting to lower the RR but wasn't sure if that was right.

dualdj1 - not sure on front spring and compression shock but it seems to be a step in the right direction. Going to leave 600#RR spring, 375# LF and 4 rounds out of left rear at start of next week and move everything else back. Maybe this will be a good starting point.

[wishiwasfast]

So you went down on RF, down on LR, and up on RR, but the LR bite # stayed pretty much the same? All that should've taken quite a bit of LR bite out of the car, right?

[dualdj1]

wish, there's really no way to measure bite at the track, but yes taking rounds out of the left will take bite out.

Glad you're making progress. On the fuel thing, add fuel to tighten. More rear percentage = more drive, by planting both rear wheels more so you get more straight line "push". less fuel/weight will loosen you. So if it felt good without putting more fuel in, you may need to go back up on that RF since you may develop a push with a full(ish) tank of fuel.

Just keep good track of all your settings. That way next week if you try something different and it's better/worse, you can have a better chance at figuring out what changes actually gave you the effect you wanted.

[racin6mod]

sorry racin6mod but you are wrong up on the frame adds sidebite but kills forward traction and down takes away sidebite but keeps the traction in the car. the purple bar attach's to the left side of the rearend so when it is high on the frame it is pulling the LR tire up which in return plants the RR tire, but when it pulls the LR up it takes the traction away from that tire. when the bar is down on the frame it is pulling straight across and not trying to pick up the LR tire which holds more weight on the LR tire adding traction to that tire. if people are going to give advice you should really know what your talking about before you do. all you have to do is have a mechanical mind and visualize what the change is doing this is the reason some of us can setup a car and when big races and some cant. take a pencil lay it down, tie a string to the left side of it and hold it to the right side about a inch above the pencil and pull on it, it will try to pick the left side up. then hold the string down against the pencil and pull on it, it will not try to pick the left side up. this is the same thing the purple bar is doing to the rearend.
thanks,
4bangerhotrod

Well hell I only post my oppinion and what worked for us.and when ever I lowered the bar on the rside it helped side bite.but like you said I've never won a $100,000.00 show and most likely never will.

maybe you could post your big when on win....

[4bangerhotrod]

it might have helped sidebite but it was most likely from other factors and not the panhard bar angle

[RACR_73s]

So you went down on RF, down on LR, and up on RR, but the LR bite # stayed pretty much the same? All that should've taken quite a bit of LR bite out of the car, right?

I did all those changes @ home on the scales. The only thing I did @ the track that would change the LR bite was change the RF spring(which I reset the ride hight on the RF when I did...shouldn't change it much) and take 4 rounds out of the left rear(which should put me around 130-135#). I will find out the exact #'s when I put it back on the scales later this week.

[RACR_73s]

wish, there's really no way to measure bite at the track, but yes taking rounds out of the left will take bite out.

Glad you're making progress. On the fuel thing, add fuel to tighten. More rear percentage = more drive, by planting both rear wheels more so you get more straight line "push". less fuel/weight will loosen you. So if it felt good without putting more fuel in, you may need to go back up on that RF since you may develop a push with a full(ish) tank of fuel.

Just keep good track of all your settings. That way next week if you try something different and it's better/worse, you can have a better chance at figuring out what changes actually gave you the effect you wanted.

I have always added fuel for feature but I was sure CJ told me to take rear % out for feature(That's what I wrote down anyway). That is why I questioned it in my post. We don't run a long feature(15 laps) so I hope it didn't hurt me too much. Usually go through about 7 gal. of fuel a night. I make a setup sheet(Longacre) every time the car goes out. I log what I did different for the coming night as compared to the last race. When I am at the track I log what I did there and what I thought of the car at the end of the night. ~Thanks~

[dualdj1]

cool thanks for the info. we're gonna try a different setup this week too if it slicks, so I may try leaving fuel a little lower and see what it does.

[lil jimmie]

Well whatever Lance jr.is doing in the late models and Bauman jr. is doing in his limited late models those two Rayburns sure have been running good. Sorry to hear that Bauman jr. is done for the year due to havimg surgery. I would ask those guys for a little imput.

[RACR_73s]

Took the RR off the swing arm and put it on the birdcage...

Went with
LF550(546#) RF500(525#)
LR400(771#) RR400(631#) on birdcage
52.2 cross
53.2 left
56.7 rear(12.5" fuel/move weight to back)
pull bar left 1/ 3" blue spring(usually on 2" green)
purple bar 2" off frame
Both lower bars 15 1/2" uppers 17"
rearend left 1"

The difference of being on the birdcage was not as big a difference that I was hoping for. I went with a 400LR just to be safe(Not to tight) and have some adjustability. Car was still tail happy loose.

Feature time
LF650 RF500
LR350 RR50014" of fuel(should be around 57.5 rear)
pull bar left 1 more
LR rear bar down to bottom
car was ok but not enough to get into top 5(started 5th), ran just outside of it until crash. Still can't keep tail of the car under me.

Going to run with the LM next week if the car count is low enough to ensure a feature start. No idea what I am going to do for a setup!!!!

Now that I am on Z on the RR is there any way by moving the front lower bar that will keep the rear of the car straighter and tighter on entry???? What do you see that I did wrong? What can I do to make it better?

~Thanks~

[washeduptoo]

Again I'm a mod guy but I don't think you need that high of a spring when its on b/c, probably around 175-225 range would work. Hopefully someone will with better knowledge will help you. Good luck.

[fox1162002]

Ill tell you that Rayburns are a trip to work on our car was super free and we put a 6/0 & 9/0 afco behind with a koni shock and spring on swing arm then we use a 600lb spring on rr to help tighten it in. Ours was real free and when we put the compression shock behind it freed it up but driver was able to pick the throttle up real quick said it wasnt an un nerving feeling.

[abe_05]

Track bar to frame on right normally loose on entry and tight coming off, J-bar to left frame normally tighter entry looser off. Normally start out with 500's on front, 400 lr, and 275 rr on swing arms with j-bar. Normally as track gets slick I drop left rear trailing arm and go up on lf spring to 550 or 600 and drop track bar on rear end. I have all side bite I need with j-bar. I do run afco m2 from envy and crank up the compression.