Anti Roll bar questions

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fourtenposi
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Anti Roll bar questions

#1 Post by fourtenposi » Tue Oct 19, 2010 9:34 am

Is there any indications of when to use one.

I have a 74 nova, 3200 pounds, Runs 6.30s. I run a 9 inch slick. I notice that it does wear the left side tire faster then the right, and in pictures of the launch, it shows the body rolls a tad the right side.

I have tried to get it to level out but no luck. The fact that it is wearing the tires differently suggest to me that I am not loading the tires evenly.

The left side has approximately 75 more weight on it then the right side.

So would an anti roll bar benefit me or should I look elsewhere?

Here are some videos

http://www.flickr.com/photos/simpkinsfa ... 361026491/

http://www.flickr.com/photos/simpkinsfa ... 361026491/
Bill Simpkins
74 Nova
SBC 406
3240 pounds
Speierracing heads

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60 1.29 (10/15)
1/8 6.05@111 (11/15)
Best 9.87@131 on the rev limitor 1 Feb 201

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John_Heard
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Re: Anti Roll bar questions

#2 Post by John_Heard » Tue Oct 19, 2010 9:48 am

I don't see it rolling over any, in fact I don't see it doing much of anything? Maybe you ought to try softening the extension a bit on the shocks. It don't appear to be hitting the tire very hard at all IMHO. Are you foot braking it? Sounds like a tight converter, what's it flash to?

fourtenposi
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Re: Anti Roll bar questions

#3 Post by fourtenposi » Tue Oct 19, 2010 9:55 am

Yes I am footbraking , Converter flashes to 6000, launching at 3800 rpms. I have the rancho 9 ways and they are set at 4 right now. The car was sixty footing about a 1.40-1.41 all day.
Bill Simpkins
74 Nova
SBC 406
3240 pounds
Speierracing heads

Image

60 1.29 (10/15)
1/8 6.05@111 (11/15)
Best 9.87@131 on the rev limitor 1 Feb 201

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John_Heard
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Re: Anti Roll bar questions

#4 Post by John_Heard » Tue Oct 19, 2010 10:24 am

Does the track turn to the right on the return road? Maybe it's just an issue of scrubbing the tire turning right all the time? Really if the car is repeating like that, it doesn't sound like it's got a launch problem.

Are you trying to lower the 60' or is the main deal to get the tires to wear evenly? How many passes on them?

fourtenposi
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Re: Anti Roll bar questions

#5 Post by fourtenposi » Tue Oct 19, 2010 12:19 pm

Interesting idea about the turning right, All the tracks I race at turn right. I also have noticed to that when I get back to the pits, the left side tire always looks cleaner.

I am looking for more consistancy, At one of the tracks I race at, car for no apparent reason, will drive out 4-5 feet and spin the tires. Catches me off guard and cost me races. Talk to others and no one has experianced this that I talk to. I know I can point my figure at the track but it will stll cost me rounds. Sunday, I was .007, to my opponents .027, car spun and run a .10 off.

This probably seems to have started since I put my 6000 converter in. Until then, I can't remember the last time I lost a race because the car spun.

So just looking for ideas.
Bill Simpkins
74 Nova
SBC 406
3240 pounds
Speierracing heads

Image

60 1.29 (10/15)
1/8 6.05@111 (11/15)
Best 9.87@131 on the rev limitor 1 Feb 201

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John_Heard
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Re: Anti Roll bar questions

#6 Post by John_Heard » Tue Oct 19, 2010 12:26 pm

Well from watching the video, I don't see it hitting the tire all that much - very little separation between the tire and the back fender from what I can see. I'd suggest loosening the shocks a little - click or two and see if it doesn't improve some.

How many passes on the tires? Might be time for a fresh set...

fourtenposi
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Re: Anti Roll bar questions

#7 Post by fourtenposi » Tue Oct 19, 2010 12:33 pm

The first time it happen, I was on old tires, chocked it up to that. The tires that were on it this weekend only had 20 passes on them. It happens right after the peak g-force on the logger.

I guess I will try it and see what happens.
Bill Simpkins
74 Nova
SBC 406
3240 pounds
Speierracing heads

Image

60 1.29 (10/15)
1/8 6.05@111 (11/15)
Best 9.87@131 on the rev limitor 1 Feb 201

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BillyShope
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Re: Anti Roll bar questions

#8 Post by BillyShope » Thu Nov 25, 2010 6:13 am

fourtenposi wrote:...it shows the body rolls a tad the right side.
Look closely and you'll see that every RWD beam rear axle car is doing the same thing, to a greater or lesser extent.

The driveshaft torque tends to unload the right rear and load the left rear. The reaction to that driveshaft torque, taken at the engine/transmission mounts, is distributed, front-to-rear, in proportion to the front and rear roll stiffness. If the front roll stiffness is twice that of the rear, two-thirds of the driveshaft reaction torque goes to the front suspension and one-third goes to the rear. If it all got to the rear, the driveshaft torque effect (that unloading of the right rear) would be canceled and you wouldn't have the body roll.

The ARB greatly increases the rear roll stiffness, meaning more of that driveshaft reaction torque finds its way back to the rear, meaning that the rear tires are more equally loaded and body roll is decreased.

So, the short answer to your question is, yes, the addition of an ARB will decrease body roll. In addition, since the performance of a tire pair...whether in traction or in cornering...is maximized when the tires are equally loaded, your dragstrip performance will be improved.

fourtenposi wrote:The left side has approximately 75 more weight on it then the right side.
This isn't helping. Try to shift some weight to the right side, if possible.
http://www.racetec.cc/shope

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johnh
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Re: Anti Roll bar questions

#9 Post by johnh » Thu Nov 25, 2010 10:03 am

those vids didnt even look like a 1.40 launch at all... No hit as John said..
I would try full soft on the Ranchos if your footbrakin it...
6.01 @ 116 on 9 Inch Slicks

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Dave Morgan
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Re: Anti Roll bar questions

#10 Post by Dave Morgan » Sat Dec 18, 2010 10:30 am

The car looks over-sprung to me.
I suggest you attend my Dallas seminar and workshop and bring the car with you. That event is Jan 22-23.
Author of "Doorslammers: The Chassisbook"
Drag Racing Chassis Seminars and Videos

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