installing a set of the moog K791 upper control arm bushing..

per the moog instruction:
to attain maximum positive camber bushing must be installed with the arrow, on the bushing, pointing towards the ball joint

per Tom Condran's book
install the front bushing with the hole away from the tire, but the rear bushing with its hole toward the tire,
believe he is saying the rear bushing should have the arrow point away from the ball joint..

so from the folks that have done this,, how are you installing them?

thanks

You don't need a lot of positive caster for good handling. If you're going racing you'll want both bushings offset and the holes closest to the ball joint to shorten the UCA for the most negative camber. If you want a little more caster and street levels of negative camber one offset bushing in the rear of the control arm with the hole closest to the ball joint is fine for most cars.[/u]

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Joshua

The OP should let us know what he wants to achieve. More caster? Correct a wrecked front end?

For more positive caster, rotate the hole in the rear towards the ball joint and the hole in the front away from the ball joint; that moves the ball joint towards the rear of the car and increases caster. If you rotate them the same amount but in opposite directions, the camber will not change.

(BTW I edited what I first wrote as I had it backwards.....)

Merry Christmas!

You absolutely want as MUCH caster as possible. Camber is the sacrificial number for a well handling car. Caster is what keeps the tire flat in a turn. Camber just gives the tire a head start.

thanks for the responses,
wanting to set the car up for good street handling..

the moog off set bushing,,

when installed with the holes away from the ball joint allow for additional positive camber.
however,,
when installed with the rear bushing hole towards the ball joint and the front bushing hole away from the ball joint allows more positive caster


more positive caster is what I want,, believe I have it right now, thanks.

I have always done what Condran describes. I run +2 to +4 caster and -0.75 to -1 camber on the street, with about 1/16" toe.

Lou

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Home of Slant6-powered fun machines since 1988

Caster is overrated. If the steering axis inclination is adequate negative caster will still steer well. Our cars with manual steering have the factory alignment with negative caster settings to reduce steering effort.

Negative camber is what keeps the outside tire contact patch flat on the road under lateral acceleration.

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Joshua

You couldn't be more wrong again. Maximum caster 8-10* is desired and the norm on most modern performance cars, and even on the most aggressive setups we rarely exceed 3* Camber. Without writing a novel I can't prove you wrong, however I suggest you pick up a couple books on how to make cars handle.

I've read the books and road raced A bodies. Caster is overrated. I would rather have zero caster and 3° negative camber (and the car will be faster through turns) than with 3° positive caster and zero camber. Show me one performance vehicle with alignment specifications of more than 5° caster. Caster gains steering stability, but doesn't do anything for lateral grip. Yes, there is some negative camber gain when the wheels are turned, but with too much camber you risk the change in the cross weight and unbalancing the car.

The fact of the matter is you exchanged your terms. You described camber and used the word caster. This is why I posted the picture. Another fact is you don't know me and decorum suggests that you take a kinder tone.

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Joshua

I'll tell you what Mr. Skinner. I prep championship winning SCCA, vintage, Open Road Race and autocross cars for a living. Feel free to google
Dan Weishaar Racing
or DTM Racing Yuma

We'll have to agree to disagree but the best part is, I know I'm right. Feel free to declare your opinion in any pit from a professional team and they'll either nod and walk away or walk away laughing. Feel free to bring up factory alignment specs for an ACR Viper, Z06 Vette or performance model. You'll find caster is king.

I'd love for you to show up to one of our events and prove me wrong, but I'm sure you won't. Now you'll have to excuse me, because your post is so hilarious, I'm going to share it on a racing forum so we can all have a good laugh the next time we're in the pits.

Dan, I went to your Facebook page and found it most interesting. I am glad to know it is there. I noticed that you appear to be using the stock looking K member for the Yellow Duster you are building. Have you modified it at all/ And, what caster are you running?

I have the adjustable, tubular upper control arms on mine with all late model A body steering box and linkage. At one point I was running as much as 9 degrees positive castor and my mechanic talked me out of that. I was getting an unhealthy oscillation, rebound with an interfering sway bar link that is now resolved by welding a sway bar tab to the control arm instead of using the aftermarket shock mount tab supplied with the kit. He thought the problem was caused by too much castor. I think that was not the problem, but took his advice anyway.

I am now running 4 degrees, and do not like the feel as well. It feels fairly numb on the highway. I prefer the feedback you get from more caster. I do not race this car, and never push it in any way. I just enjoy driving it. Do you have any insight into why he felt the way he did? Was he correct in any way? And what caster spec would you put into it? This gentleman went on to open his own street rod company elsewhere, and the alignment guy there now will do whatever I ask for.

Thanks.

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The 74 Duster was put together for a friend on a budget as time allowed; however we did do a bit of beatifacation as we went. I'm a big fan of using the factory K frame and LCA's as much as possible. They are a good design and hard to improve on. I generally go through a pretty extensive process of cleaning and use the Firm Feel kits to reinforce them. With that car we used the factory control arms with the Moog offset bushings. With the bushings installed for maximum caster we got 4.5* caster and 1* of camber. The car handles well and drives really nice.
With my wifes car (62 Dart full Hotchkis TVS) we run 7.5* of caster and 1* of camber since she only autocrosses her car from time to time and drives it everyday to and from work. That car cruises really well and we drive it to LA and Vegas a few times a year each. The car gets about 7500-9k miles annually.
My Road Runner is course dependent and runs 8.5* caster and 2.7* camber. that is for competition only and has won everything from hillclimbs to autocrosses.
The 67 Valiant we just finished for a customer runs 8* of caster and 2* of camber (needs a touch more of each). The driver has won the last two regional SCCA Championships in CAM against 12-15 other cars. Last time I co-drove the car with the owner I was about 2 seconds faster than him in the car. It's REALLY good. we are finishing a sister car to that one right now, a 68 Dart that will have a higher level of fit and finish than the Valiant.

As to your car, I would seriously give the suspension a good look and check for anything shot or blown out. depending on the quality of your suspension/alignment guy, your results may vary. Unfortunately with most modern guys/cars they are "toe and go" jobs. I would as around the local car clubs or SCCA guys and see who they take their cars to for work/check ups/tuning. Bonus points if they actually know how to adjust a mopar.

Recent model Dodge Challenger's use around 9-10 degrees +/- positive caster; I would assume that qualifies as a modern performance car, but opinions may vary on even that.... LOL.

These arguments are not of much use; like so many things, 'it depends'. Experiences and cars and drive format and tracks vary. With high HP RWD in a steady radius corner (circle track), with power applied and the rears slipping out a bit, extra caster induced camber is not of much use, becasue the front wheels are not turned or may even be counter-steered; in that case, actual camber is the only camber you have. But the same car on a road course may benefit from added caster on turn-in.

Just as an example that I know very well, in RWD rally (what I race) excessive caster is not desired because:
- You are always cranking more degreees into the wheel to make a certain turn as the slip angles on dirt and gravel are far greater than pavement and so the camber gain with caster gets exaggerated
- With a stiff rally tire, no real grip to distort the tire into complying with the surface, and too much caster induced camber, you can end up with just the inner tire edge making any real contact. You end up turning the wheel and getting no more cornering force. (Time to grab the hydraulic rear handbrake or slam on the throttle if you are brave!)
- Large caster amounts don't help in giving much centering action because the surfaces are too loose anyway

I don't find road race or paved circle track guys readily relating to rally (and a lot of rally related suspension factors), but that is to be expected; their racing world is entirely different. The same with circle vs road race, etc; you don't find road racers putting negative camber on the right and positive camber on the left.....

So when someone says they think they have the right answer, then that should be qualified a lot based on the car, racing format, etc. ad nauseum.

Wish I could explain you caster situation for you Sam. The change in feel is understandable, but heck, I run the stock 0 to -1 degree caster on my '62 Dart. I want it to drive like an original car. It does not wander because the steering and suspension are in top shape, but you do lose the tactile feedback at small steering angles; it is a learning curve to adapt to the steering input without that aspect of feedback to your brain. How long have you driven it that way?

Thanks for the replies. Everything in my car's suspension is essentially new, or recently so. The rear springs are new with new rubber in front, and urethane at the shackles. The front suspension has the late model A body suspension throughout with solid bushings on the front struts. The upper control arms are tubular with turnbuckle adjustments to put the uppers anywhere I want. The LCAs use stock rubber bushings with a welded on sway bar tab. The torsion bars are the stock 340 bars (whatever that is). The brakes are the standard Mopar disks (11"?). The steering box was new (not rebuilt) about 20K ago and is the larger late model pittman, idler and drag link. Ball joints are about 10K old. The wheels are Cop Car wheels.

I would like to know what you guys think of rear sway bars. I like the way the car feels in modest driving with the sway car on. The bar however, at the urging of some is currently hanging on the wall. With or wthout it the car oversteers seriously when pushed. Keep in mind I do not race. I just don't want to find myself traveling backward all of a sudden in the middle of a turn. I reduced this tendency some by going to 6" wheels in front and 7" in the rear. I think I could help it more by putting 215's on the back and keeping the 205s in the front. The car also has rear disks from TSM and they work well.

The poor road feel could be caused perhaps by the adjustment on the box being a bit tight. I did not change it when I put everything together. Power steering could of course be a part of this, but it had better road feel with higher caster. I've had this car 20 years, and in that time had perhaps 4 different suspension set ups, with various size wheels and brake setups with each.

For what it is worth, my DD is a Honda CR-Z with electronic power assist, and while it is amazing in the twisties, I do not particularly like the road feel of this car. I can live with it, and understand the logic of using that technology. But if I had my druthers I would stick with hydraulic. The best feeling car I have owned is my '97 BMW 328.

Thanks for your thoughts here.
Sam

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Yes, I see that caster has been increased by leaps and bounds. I understand why you think this is funny, but is it (are you) kind? And yes, the Challenger is too heavy.

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Joshua