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Author Topic:   4-bar LR
A&M Motorsports
Dirt Maniac

Total posts: 117
posted April 13, 2005 04:56 AM  
It seems as though people have different opinions about the spring placement and options when running a 4 bar on the left rear? When do you use the following and why?
On the cage in front of the axle clamped
On the cage in front of the axle
On the cage behind the axle clamped
On the cage behind of the axle
I understand how everything moves dynamicly
but just need a little more help.

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Artie Perilloux
A & M Motorsports

Xtreme12x
Dirt Forum Champ
Total posts: 874
posted April 13, 2005 10:44 AM  
1.On the cage in front of the axle clamped
2.On the cage in front of the axle
3.On the cage behind the axle clamped
4.On the cage behind of the axle


1. You cannot clamp the cage, the spring will be mounted on a separate bracket off the front of the housing-
Use this on tacky tracks or stop and go tracks

2. Never see it done, it will unload when the birdcage indexes

3. Never seen it done on a 4 bar or 2 bar car. It again will unload the spring

4. This is how 65% of the 4 bar cars are, and how most Late Models are. This creates bite when the birdcage indexes. Around here we perfer number 1, but when it gets super slick and dry number 4 works well..

Kromulous
Dirt Forum Champ
Total posts: 796
posted April 13, 2005 10:56 AM  
On the cage behind, heard of it referred to as " on the hook ".

Clamped, infront, on its own bracket is really popular as well.



A&M Motorsports
Dirt Maniac

Total posts: 117
posted April 13, 2005 01:55 PM  
X-treme it musta been too early in the morning when I posted, I meant:
1. Clamp bracket in front.
2. On the birdcage in front.
3. Clamp bracket in the rear
4. On the birdcage in the rear.
Sure screwed that one up dis morning.

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Artie Perilloux
A & M Motorsports

rocket36
Dirt Freak

Total posts: 209
posted April 14, 2005 02:55 AM  
spring in front of axle and clamped to axle tube is definitely only for tacky tracks or very rubbered up. it reacts really hard with the throttle and is really sensitive to how much bite you run, so you need to be a pretty **** good driver to be consitent with this, but it can be real fast.
(3 piece birdcages can be clamped without mounting shock/spring on seperate bracket.)

spring behind, floated on the birdcage i have found to be alot more progressive and easier to drive. will only really increase drive with body roll. i use this on all track conditions now (on our "open" engined late model). the only time i have found it to be a bit of a hand full is if the track gets really rough. but thats just the way it is some times LOL.

i don't know of anybody who still uses the left rear in front and un-clamped anymore.

A&M Motorsports
Dirt Maniac

Total posts: 117
posted April 14, 2005 05:35 AM  
Rocket or anyone, what will running the spring behind clamped on the on the left rear
produce?

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Artie Perilloux
A & M Motorsports

Kromulous
Dirt Forum Champ
Total posts: 796
posted April 14, 2005 06:44 AM  
Clamped behind would be loose off probaly really loose in, soon as you hit the gas it would index away (extending the spring, basicly unloading the car.

It may be worth expierementing on a really rough paper clip track. So when you get on the gas hard the chassis / suspension doesnt get so stiff so you can still absorb so bumps.

Never seen anyone run it.

A&M Motorsports
Dirt Maniac

Total posts: 117
posted April 14, 2005 07:58 AM  
Krom, I don't remember where I heard this but I think some folks are running the spring clamped behind and yes it does unload and allows the car to get on the bars real quick. When it's up on the bars all of the available wieght is on the left rear. I would assume that this would induce a lot of cross weight. Am I thinking about this correctly, low split between LR & RR, going in tight and coming off tight on the bars????

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Artie Perilloux
A & M Motorsports

Kromulous
Dirt Forum Champ
Total posts: 796
posted April 14, 2005 08:03 AM  
Usually i walk around the pits during day light and "observe" very closely what people are running. Never seen this run, but will look for it. Would like to see it go around the track.

I guess it would stand the reason thou, once its up on the bars the spring is out of the equation. all you need is the spring in the right place to assist in getting the car up.

I made provisions on our car for clamped in front, no reason i cant put it on the back, maybe i'll get it a try this year.

A&M Motorsports
Dirt Maniac

Total posts: 117
posted April 14, 2005 09:52 AM  
Krom, I am in the process of finishing the chassis on my newly built mod and I have designed all of my suspension pick up points on 1.5" clamped brackets so I can run just about any kind of suspension you can dream of. Down south a lot of people don't like you to look at their cars. When they ask you if you need a flashlight you know it's time to leave.

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Artie Perilloux
A & M Motorsports

Kromulous
Dirt Forum Champ
Total posts: 796
posted April 14, 2005 10:24 AM  
LOL, you know it, sometimes i get some looks.
Some have caught on and they back there cars in to the trailer so you cant see the rear suspension.

I can really rattle some, usually when they see me with a camera the all stand around the car and give me the look. Now days, i do it just to stir the pot a little.

A good tactic, send a kid around with a camera. I gotta 9 year old niece, she is good at it. Tell her what you want to see and she gets it.

Anyway back on topic, i plan to try it this year as well. Like to hear from somebody that has already.

NJantz
Dirt Forum Champ
Total posts: 755
posted April 14, 2005 01:19 PM  
tell her get pics of all the hot girls.

dluna
Dirt Freak

Total posts: 334
posted April 14, 2005 03:05 PM  
Hot girls in the pits at the dirt track? Huh? What track are you going to???

I tried that angle with my friends to try and get them interested in coming and helping out...they only come once and want me to refund their $25.

[This message has been edited by dluna (edited April 14, 2005).]

Ego Racing
Dirt Forum Champ
Total posts: 724
posted April 14, 2005 07:47 PM  
What do you think of this:
LR 4 link: 250# spring behind on dummy shock/ 94 shock in front.
RR 4 Link: 225# spring 94 shock in front/ 150# spring 94-2 shock behind.

dirtbuster
Dirt Forum Champ
Total posts: 2007
posted April 15, 2005 07:25 AM  
seems like a lot of spring on the RR to me.

Kromulous
Dirt Forum Champ
Total posts: 796
posted April 15, 2005 08:35 AM  
2 springs on the RR?

Rocket runs 2 on there LM's, they run on clmaped infront, and one behind.

I would like to try one in front clamped and one on the housing, with a Z-Link.

Ego Racing
Dirt Forum Champ
Total posts: 724
posted April 15, 2005 10:25 AM  
Both of these are on the cage. The front spring catches the car comming off of the bars when dropping off of the pedal and it keeps the car from upsetting so much. We run a 17 inch straight bar when we goto this setup.

dirtbuster
Dirt Forum Champ
Total posts: 2007
posted April 15, 2005 10:48 AM  
I dont see how more spring on the RR will catch the car off the bars??

Teh LR dummy shock behind with real shock in front will help that. I dont think that LR setup llooks bad at all. I just think 375# total spring on the RR is too much.

rocket36
Dirt Freak

Total posts: 209
posted April 16, 2005 07:35 AM  
i can't say that i've tried or heard of anyone clamping the left rear behind.

the dual right rear spring setup is something that both rocket and grt have standard setups for. my car doesn't have provision for this but in the 2004 rocket manual i have, it does give a baseline setup for this. and uses something like 2x 125lb springs from memory. i don't have it with me right now so i can't say for sure.

the 0 valve "dummy" shock on the back of the LR birdcage with the spring and the real shock on the birdcage in front is common. the real shock effectively becomes "stiffer" because the shaft speed is increased with the birdcage rotation. usually recommended for very fast, high banked momentum tracks.

with the left rear clamped in front, our rocket manual says to run a softer (180lb) spring, longer torque arm length and definitely a 9/1 axle damper on top of the rear end. i think this is because it is so aggressive and can produce a huge amount of traction (if there is some in the track) at the slightest touch of the throttle.

Ego Racing
Dirt Forum Champ
Total posts: 724
posted April 17, 2005 07:54 PM  
Rocket isn't it funny how in Nextel stuff trickles down but in our cars it trickles up! We have been messing around with this setup for about 4 years and now it is in the books!

rocket36
Dirt Freak

Total posts: 209
posted April 22, 2005 01:59 AM  
ego, it doesn't surprise me that you have tried this setup. i learned a while back, that it doesn't matter what idea we can ever come up with. somebody, somewhere has already tried or is using just that. there are plenty of smart people out there.
you modified guys seem to try all sorts of stuff trying to find that extra advantage over your competition. LOL.

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