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When going thru corner the car would hug bottom real well. But, we noticed that when we straightened the wheel up some the car hooked up and had a lot better forward drive. At times with counter steer it got loose on throttle until, I was trying to drive car so I could straighten wheel up to drive off corner for the better drive. So, with all that what do I need to look at to fix my issue. Caster, camber? Thanks for any help.
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Increasing caster will add more dynamic wedge when you back steer and load the lr. -
I'm not understanding what you mean by "straightened the wheel up." Was this an adjustment you made to the car, or the way you were driving? If the latter, I think you answered your own question. In understanding the spindle roll effect Punisher88 is talking about, straightening up the wheel (which I take to mean not turning it to the right) would reduce the spindle roll on the RF.Comment
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I have noticed a lot of touring guys have so much drive in the cars now that they are actually turning the wheels (front) to the left (towards the infield) a lot coming down the straights.
Something i have never seen considered on here, so... but when your counter steering to a great degree the contact patch of the tire is considerably aft of the ball joints / spring shock. So that would tend to artificially soften the RF spring.
When your straightening up the wheel your giving the LR something to push harder against. Otherwise its to soft and the LR can overpower the RF and just pin it to the ground, once you achieve so much excessive hike the car looses drive.
Seems plausible to me, try stiffening the RF spring 25 lbs and see if you notice the same thing happening.
Just say no...Comment
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I have to disagree somewhat Krom. The motion ratio affect on what the contact patch feels in terms of wheel rate it not affected by where the wheel is. It is only affected by where the lower ball joint is relative to where the inner pickup and shock are. That being said, the change in contact patch vertical location relative to the lower ball joint vertical location due to the combination of scrub radius and the insane amount of camber gain we get these days CAN have an affect. But if you assume no camber gain, you can put the contact patch 10 feet from the spindle and it won't change the wheel rate relative to the spring rate. Only shock/spring location on the lower control arm matters.Comment
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We've got so many jacking forces in the cars these days, I'm a big fan of running minimal caster to keep the thought process a little simpler. That being said, think about what the angle of the spindles is relative to the track when the car his hiked the way it is. We do a lot of measurements on these cars sitting on the shop floor but the car is NEVER in that attitude on the race track at speed. Just something to think about.Comment
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Yeah, I have been rethinking this the past couple of days. The added effect of castor as you noted all hiked up, could really impact the RF spring rate. Making it quiet stiff under full counter steer. So turning left slightly could allow the LR to hike more against a softer RF without the added castor via counter steer.
I hope the original poster could post some follow ups, and see what change did what, very note rested myself.
Just say no...Comment
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Havent looked at late models lately, however, I would look at scrub radius. if scrub radius is zero or near zero, the effect of caster as a weight jacker is diminished or nill on the right front. the left front is a different story.Originally posted by Kromulous View PostComment
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Sorry guys don't get to run every weekend. Trying to decide what to try because we r running more caster than the norm. Is there a point that when might have to much caster that during counter steer that the spindle rotates back and maybe unloads the LR? Just thinking out loud. Haven't had a chance to put it on scales yet.Comment
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do you have a spindle checker you may have bent spindle or balljoints in the RFComment
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hrt, is this a blue gray rocket, sound typical to the way they drive they don't like to be thrown around , the ones ive driven like to be driven straight and smooth so to say, soon as you hang them out forward drive is gone.Comment
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Yep, that was my experience also. I had a rookie driver that I thought was breaking it loose until a veteran driver drove it. I did about 6 or 7 adjs and after the feature, he said we were only halfway there.Originally posted by rakracing View PostTurn LEFT, Vote RIGHT!Comment
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How are you controlling drop on the lr? Are you at the spec 13.25" with bars in correct race position and lengths? ......What I'm getting at is , less rear steer to reduce backsteer.Comment
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Just to make sure we're talking the same language.Originally posted by HRT2332 View Post
Steering = to the left.
Counter Steering = to the right.
Typically counter steering, thru the caster effect jacks weight into the LR, thus promoting drive, not decreasing or causing a loose condition. Could it be that you have too much rear steer in the car and when your counter steering, you are already loose and throttling up doesn't produce enough drive to overcome the excessive rear steer.History doesn't always repeat, but it does often rhyme.Comment
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Counter steer caster assistance only helps with forward drive if you have weight transferring from front to back. If you are counter steering at mid corner while weight is still transferring from left to right, you're unloading the RR which will make the car looser. This is one reason I'm in favor of less caster than most "baseline" setups call for. The baseline setups are mostly calling for the same caster that the cars had in the 80s with no power steering. I think it's time to start rethinking why we need caster and caster split and what it is good for.Comment
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