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Author Topic:   Pull bar & 6th coil ?
Kromulous
Dirt Forum Champ
Total posts: 796
posted April 14, 2005 07:57 AM  
Anyone familar with them Skyrocket Mods? i am wondering what pull bar do the run with the 6th coil / lift arm combo?

I mounted the Lift arm, and a pull bar brkts on the car, now i need to figure out what pull bar to use. I guess they use one with not brake biscuit in it so the 6th coil can do its thing.

Anyone ever seen one? or got any pics of it? Maybe somebody out there has some pics of a Skyrocket LOL.

wfoondirt
Dirt Forum Champ
Total posts: 505
posted April 14, 2005 08:36 AM  
I don't know what Kelly is using on his cars now but I always just took an afco bar and removed the brake biscuit.

dirtbuster
Dirt Forum Champ
Total posts: 2007
posted April 14, 2005 09:38 AM  
I dont think they are using a 6th coil. Most likely it is just a chain from the frame to the torque arm. You can only have 5 coils on the car 4 at the wheels and 1 in the pullbar thats it.

Any pullbar will work,the cars that leave kelly's i am about 99% sure have the new AFCO pullbar on them, not the 2 way prostyle just the redesigned linear bearing or whatever.

A&M Motorsports
Dirt Maniac

Total posts: 117
posted April 14, 2005 09:58 AM  
I have an x-factor pull bar, so does that mean I could run a spring for braking on the torque arm.
I saw a new Pierce car setup and it had a chain on the end of the torque arm.
What's the advantage?

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Artie Perilloux
A & M Motorsports

Kromulous
Dirt Forum Champ
Total posts: 796
posted April 14, 2005 10:08 AM  
A&M, the pierce car had a chain from the lift arm / torque arm to the chassis? and no 6th coil in there?

The rumor is, that a Pull bar has the best FWD bite, and a lift arm has the best braking effect. So some are running both. Skyrockets run it this way i am told, and some other cars around here (never seen a Skyrocket, love to own one LOL).

I didnt think it would be very effective if the pull bar was working both ways, braking and power, so i am looking for one that is one way, and will leave some room to move fwd so the 6th coil can work.

No idea if its legal or not in UMP, but i plan to find out.

A&M Motorsports
Dirt Maniac

Total posts: 117
posted April 14, 2005 10:13 AM  
Krom, as preciosly posted, I may just remove the braking biscuits from my pull bar and do some investigating on installing a spring for braking at the end of the torque arm.
Anyone out there have any info on this?

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Artie Perilloux
A & M Motorsports

dirtbuster
Dirt Forum Champ
Total posts: 2007
posted April 14, 2005 10:16 AM  
At least in IMCA or IMCA 'type' rules, You are allowed 5 springs so in your case you cold run the 5th spring on the torque arm, BUT make sure you are allowed 2 different traction control assemblies, i.e. pullbar and torque arm. I beleive IMCA only allows 1. Some tracks will follow IMCA rules but allow both. Our track only allows 5 springs but you can run both a bar and an arm, along with a chain. IMCA wont even allow the chain anymore.

Yes the skyrockets set up for non IMCA stuff have a pullbar for acceleration and a torque arm for braking with a simple chain from the arm to the frame. No spring or bushing to cushion it just the chain. Pierce cars are presumably the same. We ran the same setup on our DW car last year. Doesnt matter if the brake biscuit is in there because the chain only allows so much travel anyway. We would set it to where the chain was just tight at ride height. So under braking the brake biscuit had no effect at all.

wfoondirt
Dirt Forum Champ
Total posts: 505
posted April 14, 2005 10:32 AM  
I beleive UMP has the same 5 spring rule or something to that effect. I always ran a chain. I just lump the chain in with references to 6th coils sorry.

The reason the 6th coil/chain setup works better is due to the fact that the svsa length is longer on the torque arm than it would be on a pull bar. Its pretty commonly accepted that short svsa lengths create wheel hop/unloading under braking.

The only reason I remove the brake biscuit is to make it easier to check preload on the pull bar/torque arm.

Kromulous
Dirt Forum Champ
Total posts: 796
posted April 14, 2005 11:21 AM  
So basicly the chain connected to the chassis, is just pulling against the suspension.

Being long, i just it would pull against the front suspension more on than the rear since its so far fwd.

wfoondirt
Dirt Forum Champ
Total posts: 505
posted April 14, 2005 12:22 PM  
I'm not sure if I follow your reply but the chain goes in the same orientation as the 6th coil would. Vertically from the end of the TA to the chassis.

You set the pinion angle with the chain tight then preload your pullbar. Its a pretty simple and effective setup.

Kromulous
Dirt Forum Champ
Total posts: 796
posted April 14, 2005 12:30 PM  
What i mean is, when you get on the brakes, something has to give. The chain has no give in it, so it pulls against the chassis, it has to give, that or you break something or bend it.

So when you get on the brakes, the chassis should sink into the track, or get pulled down onto the track or against the track etc, by the lift arm.

Since its connected more towards the front of the car, it should have more of an affect on the front end.

At least thats the way i figure it. I guess the adjusting point would have to be the connection point on the chassis, fwd versus aft.

dirtbuster
Dirt Forum Champ
Total posts: 2007
posted April 14, 2005 12:39 PM  
kromulous,

thats sort of the idea except in most cases it isnt that far forward... more like in the middle of the car. Ours was only about 36" long. So it will affect the whole chassis more equally, not just front or rear. It in effect uses the braking forces tranmitted through the torque arm to load the suspension and keep it planted. The harder your on the brakes the more pull there is on the chain which plants the car harder. Even though the springs give you still need to keep an eye on the torqua arm brackets and bolts as all that force snapping tight on a chain can create problems, bending stuff.

Theoretically with a long pullbar that mounts near the tailshaft, you should be able to accomplich the same thing. Thats what the AFCO 2 way pro style pullbar was designed around. Allowing you to have a little cushion like a 6th coil, but only use 5 coils on the whole car. And at the same time you get rid of the torque arm and chain altogether. With a short pullbar I think you could run into some wheelhop problems, but the longer pulbar should help that.

Kromulous
Dirt Forum Champ
Total posts: 796
posted April 15, 2005 08:39 AM  
I dont like the idea of putting just a chain up there, seems violent.

So last night i got an idea, i took an old 6th coil i had, and put a rubber (quickcar) biscuit in there, works good, and it adjustable in length.

Now the tech guys cant say i am running 6 coils, i just got 5 coils and a biscuit. That should be a good arguement, LOL.

dirtbuster
Dirt Forum Champ
Total posts: 2007
posted April 15, 2005 09:03 AM  
thats one way around the 5 coil rule. I'd definetly say go and try it. But try it both ways with and without the biscuit. I know guys that tried the same thing and they liked the solid chain better. but could be driver pref.

ACtually i dont think it feels as violent as it sounds. Keep in mind that any cushion you put in it either by biscuit or spring will delay the effect. Just like a pullbar, if you want instant effect you need a solid bar.

zeroracing
Dirt Forum Champ
Total posts: 1875
posted April 15, 2005 09:09 AM  
check your pm's krom

Kromulous
Dirt Forum Champ
Total posts: 796
posted April 15, 2005 09:40 AM  

 
Check this pic out, this guy is running a Pull bar, 5th coil and the 6th coil.

This seems abit much, is this how the skyrockets are?

dirtbuster
Dirt Forum Champ
Total posts: 2007
posted April 15, 2005 09:53 AM  
No the Skyrockets are like I posted above. Pullbar for acceleration and torque arm with a chain for braking. Thats it.

Unless its an IMCA car then no torque arm.

spde
Dirt Freak

Total posts: 243
posted April 16, 2005 02:19 AM  
IMCA rules are 1 traction device per car. Either a pull bar or a lift arm. not both. It doesn't matter if you are running a rubber biscuit or a spring, same idea and purpose. You cann't run a 6th coil either per the 5 springs per car rule, also a springs have to be 5" dia. IMCA rules got to love them. As for Skyrockets his cars wern't the first with this setup Pierce was the 1st modified. Thought this might help. ltr gl

[This message has been edited by spde (edited April 16, 2005).]

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