70 Dart. Looking for More Castor, QA1 arms or Moog bushings?

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340doc

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1970 Dart with large ball joint uppers. The QA1 arms state 3 degrees more castor. How much can I get with the Moog offset bushings? Anyone use these QA1 arms? What's the quality? QA1-52301 Thanks.
 
Doc, After you get it done let us know how it drives. It has to help give the car some road feel to make up for Mopar's over zealous power steering.
 
1970 Dart with large ball joint uppers. The QA1 arms state 3 degrees more castor. How much can I get with the Moog offset bushings? Anyone use these QA1 arms? What's the quality? QA1-52301 Thanks.

The QA1 arms are the nicest tubular arms on the market. They also allow for clearance of high offset wheels should you desire to go wide. I run 18x9s on the front. The offset bush ings do not allow as much positive caster and are rubber which allows a lot of flex.
Furthermore, don't get too caught up with excessive caster, 3 degrees is fine. Most guys with high caster don't realize there is a jacking effect in turns which is very unsettling at speed. I run my car on the track occasionally and run about 4 degrees.
 
Thanks Gmachine. For the people who use the offset bushings, are you able to get, say 3 degrees castor?
 
I've used over 1/2 dozen sets, never failed to get 2* caster, they may do more, I never tried,
The couple I couldn't get enuff had bent stuff.
3* caster is an awful lot, you're sorta starting to shooting at the moon then, your wheels are toed kinda up, and there's other issues.
 
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I've used over 1/2 dozen sets, never failed to get 2* caster, they may do more, I never tried,
The couple I couldn't get enuff had bent stuff.
3* caster is an awful lot, you're sorta starting to shooting at the moon then, your wheels are toed kinda up, and there's other issues.
Thank you. I was wondering what numbers were within reach with the bushings.
 
I only align to 2*, so I never tried for more cuz it causes a really heavy steering wheel to turn at slow speeds, in parking lots, etc. as a daily driver.
I run lots and lots caster in the RF of my racecar to help turn left.
What is your goal for the car, road-racing ? ?
cheers
 
I'm just looking for a fun street car. Just put on some good 17" rubber and want to keep going. The car needs to go for an alignment and I want to have everything in place for a one and done on the alignment. I've heard many times on this site, that not enough caster is available with all stock pieces. That's why I was inquiring about the arms and bushings. Do you know what the most caster you can get with all stock pieces?
 
You won't get much more than +3* of caster with the offset bushings, I certainly wouldn't count on getting more than that. Depending on the ride height, you might not be able to get that much.

+3* is not "an awful lot" of caster. Most modern cars run between +6* and +8* of caster. Yes, how much you want is dependent on the suspension design, so that's not strictly an apples-to-apples comparison. But +3* still isn't a lot for the A-body suspension.

I've run everything from about +3* up to +8* of caster on my Duster, starting by using stock UCA's with offset bushings and now running SPC UCA's from Bergman AutoCraft. I'm currently running +6.5* of caster. There is a "jacking" effect, but the additional positive caster also increases the negative camber on turn in (which is where that jacking effect comes from). It's a bit of a balancing act, and it does depend on driving style and preference too, in addition to how the rest of the car is set up. Peter obviously likes to run less, and I'm sure he has a great reason for it because I know he can get more caster if he wanted it. I personally like where my car is at with +6.5*, but I also wouldn't say that's the right answer for everyone.

For a street car with decent tires I think +3* is the least that I would want to go. That's just me. And that would be pretty much the limit of the stock UCA's and offset bushings.
 
Please describe what a Jacking affect is.

When you turn the steering, the inside front wheel is lowered, and the outside front wheel is raised. That in turn raises the mass of the car, and puts more of the weight on the inside front and outside rear wheel.

There's a bunch of things that effect how much jacking you get, caster is one of them, but so is the scrub radius you have up front and the amount of camber you already have dialed in. Typically though the more caster you have, the more jacking you get (unless the scrub radius is zero, but it isn't).

On turn in the caster is a good thing, but if you have a large amount jacking you can get a significant weight shift, which tends to destabilize the car right after turn in. There are a ton of other effects too, it depends a lot on the rest of the suspension geometry. So the amount of jacking you get depends on how your car is set up, and how much it effects handling depends on what you're doing with the car.

Like anything in suspension, there are trade-offs, and getting the car to handle right for what you're doing with it is a balancing act. Some jacking is good, it tends to counter the overall weight shift to the outside and keep weight on the inside front tire. Too much is bad, you end up moving too much weight around as you enter the corner and you can get an opposing weight shift right after turn in, which is bad.
 
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When you turn the steering, the inside front wheel is lowered, and the outside front wheel is raised. That in turn raises the mass of the car, and puts more of the weight on the inside front and outside rear wheel.

There's a bunch of things that effect how much jacking you get, caster is one of them, but so is the scrub radius you have up front and the amount of camber you already have dialed in. Typically though the more caster you have, the more jacking you get (unless the scrub radius is zero, but it isn't).

On turn in the caster is a good thing, but if you have a large amount jacking you can get a significant weight shift, which tends to destabilize the car right after turn in. There are a ton of other effects too, it depends a lot on the rest of the suspension geometry. So the amount of jacking you get depends on how your car is set up, and how much it effects handling depends on what you're doing with the car.

Like anything in suspension, there are trade-offs, and getting the car to handle right for what you're doing with it is a balancing act. Some jacking is good, it tends to counter the overall weight shift to the outside and keep weight on the inside front tire. Too much is bad, you end up moving too much weight around as you enter the corner and you can get an opposing weight shift right after turn in, which is bad.
I get it. Thank you for explaining that blu.
 
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