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Author Topic:   RR spring placement.
FlyNLoIMCA17
Dirt Forum Champ
Total posts: 753
posted March 15, 2005 01:18 AM  
I have a 4-bar car, the LR is on the 4-bar with the spring behind on the cage. The RR birdcage is locked to the axle housing and the upper bar is removed (basically a 3link RR) I currently have the spring in front of the housing on the cage. I was wanting to put the RR spring on top of the housing but I was thinking if I move the spring behind the housing what will it do??

I know on a regular 3-link you run the LR in front and the RR behind. But with mine having the 4-bar LR spring behind I was kinda afraid to put the RR behind also. Has anyone tried this???

I know that you stagger the springs to increase wedge on accel. and decrease wedge on decel. but how much does it effect???

Thanks for any help!

dirtbuster
Dirt Forum Champ
Total posts: 2007
posted March 15, 2005 07:25 AM  
The LR behind on he BC is doing the same thing as the LR clamped in front but instead of increasing bite with the throttle directly it increases bite with body movement, which can be tuned with pullbar angle, bar angle etc. So by putting the RR clamped behind you will be similar to having the springs staggered on a 3 link car. But putting the RR behind clamped up might make the car really tight on the gas, but you never know without trying it. On top will keep it pretty neutral.

FlyNLoIMCA17
Dirt Forum Champ
Total posts: 753
posted March 15, 2005 04:06 PM  
Thanks, I'll try it. What I'm needing is bite all the way around the track LOL!! The car is ok going in but really needs more bite coming out. I found that my pullbar was hitting the diff under accel. So that is killing my bite. Also my car was built by an idiot that wouldn't know a race car if it hit him in the @#$ !!!! He put plenty of holes for the adjustment of the upper 4-bar but only 2 holes for the lower bar! I'm going to build a bracket to add a few more holes. The top hole on the bottom bar only gives me about 2-3 degrees uphill angle, so of course thats not gonna work on a dry slick 1/4 mile track. Or at least won't work for me.

Thanks for the reply dirtbuster.

dirtbuster
Dirt Forum Champ
Total posts: 2007
posted March 15, 2005 04:55 PM  
If you keep the spring behind on the LR then lowering the bottom bar should tighten the car and make the LR bite harder because it will increase the amount of indexing of the birdcage. put more anlge in the top bar and it will bite even harder.

Are you talking bite as in LR bite like to tighten the car off, or bite meaning traction in general?

FlyNLoIMCA17
Dirt Forum Champ
Total posts: 753
posted March 15, 2005 05:25 PM  
pretty much both!! Bite off the turns and a little more traction all around which I think both will be greatly increased when I fix the pullbar clearence problem. Say lowering the LR lower bar will give more bite with the spring behind??? I always thought raising it would do that? I guess I see how because it indexs the cage towards the spring. Never really thought of that.

I seen a car at the track this past weekend that was 4-bar both sides and noticed the RR spring was behind and noticed that the lower link had ALOT of angle on it. That kinda tripped me out being on the RR. I guess thats why. Or am I way off here? Thanks dirtbuster.

bauman
Dirt Roller

Total posts: 11
posted March 15, 2005 10:55 PM  
If you have the right rear clamped up behind the housing when you de-accelerate it will actually index the spring and should tighten the car up on entry. Then when you accelerate it will let tension off the spring. That is the way I understand how it works but I could be wrong.

FlyNLoIMCA17
Dirt Forum Champ
Total posts: 753
posted March 16, 2005 12:09 AM  
That sounds right. Thats what I'm looking to do is tighten entry and also if when you accel it releases the RR spring that should tighten the car on exit, I think. The reason I say that is because I broke the RR spring cup before, and the spring dropped down to the cage before the chassis could compress it (therefore acting like a weaker spring) and the car had a TON of forward bite. So I'm gonna try it and see what it does. Thanks guys!

[This message has been edited by FlyNLoIMCA17 (edited March 16, 2005).]

zeroracing
Dirt Forum Champ
Total posts: 1875
posted March 16, 2005 06:22 AM  
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