Lengthening the LCA

[David Pozzi]

Check what you have now. I was told one of the Chrysler cars had a huge amount of neg camber gain stock. I don't recall if it was Challenger or Cuda.

[kp.touring]

I plotted out E-body suspension a few years back for a Cuda project. Don't use a taller spindle! As Dave stated Mopar's have a huge amount of neg camber gain stock and the tall spindle will add to this. The 1 of biggest problems with the front suspension is the lower ball joint/steering arms they're junk when new.

Kevin

[autoxcuda]

I plotted out E-body suspension a few years back for a Cuda project. Don't use a taller spindle! As Dave stated Mopar's have a huge amount of neg camber gain stock and the tall spindle will add to this. The 1 of biggest problems with the front suspension is the lower ball joint/steering arms they're junk when new.

Kevin

Bill Reilly plotted on a suspension geometry program the camber curves on the taller spindle (only 3/8"). He got camber gains. He used an A-body for the analysis though. Not an E-body/71-72 B-body front clip.

Article on that here: http://www.bigblockdart.com/techpages/spindles.shtml

What's the issue with the LBJ/steering arms?? What do we need to look out for?

[High Plains Mopars]

I plotted out E-body suspension a few years back for a Cuda project. Don't use a taller spindle! As Dave stated Mopar's have a huge amount of neg camber gain stock and the tall spindle will add to this. The 1 of biggest problems with the front suspension is the lower ball joint/steering arms they're junk when new.

Kevin

Huge is certainly a subjective term. 1.5* negative gain isn't too bad a thing to have, IMO. Especially when you consider other some cars that are the opposite, like a first gen camaro that generates positive camber under compression. So, 1.5* negative camber gain during body roll is a good thing for keeping the tire face perpendicular to the road.

Yes, shortening the upper control arm length by lowering the mounting point would have a big impact on this. Whether or not that is a good thing depends corner banking and body roll and those are big factors in how much you actually need. For a street car it is always debatable

Similarly, the taller spindle does raise the roll center slightly as well, which reduces the moment lever arm length, which increases resistance to body roll, another good thing. If the car has been signifcantly lowered, than this raised front roll center height can also be a good thing.

The stamped steel, pressed fit lower control arms are not great, but boxing them up does firm them up considerably, thus alleviating a significant amount of flex. So, I'll grant you they are not great in stock form, but they aren't awful and can be fixed easily for cheap. I'll agree that I don't particularly like the stock lwr balljoint/steering arm arrangement, but hey, some crosses you have to bear.


Now, just putting an A body lower arm under a B/E body would also necessitate a longer upper arm, or else you will end up in a situation where you have the upper arms adjusted all the way out and you still have too much static negative camber. You might be able to make it up by juggling the install of some offset bushings, but that might take some trial and error and may still limit your caster adjustment. The only real advantage I could see to making all the arms longer is like JRouche pointed out, larger arcs. You also could run a rim with more rear spacing on it too, if that is your goal.

Adverse effects of the tall spindle, IMO, not enough to worry about.

If you want to add some adjustability to the rear leafs, you can put pivots in the front eyes and add a panhard bar. This will allow you to change the rear roll center height to adjust the corner exit bite.

[JRouche]

Ideally you want a nice long lower control arm. It gives you a slower ratio on the circle. Think about all suspension components on a circle. Short arms have a smaller circle. Faster changes that arent good for dialing in the curves. Specially the lower control arms. In an ideal world they wouldnt be on the circle. They would travel lineally up and down on a straight line. Long arms. As the suspension travels through the circle short arms produce too much movement. Pulling the spindle in and pushing out. So a long lower arm is good, a lil shorter upper arm is needed to compensate for how high it is, at the frame mounts. If we could lower the upper arms frame mounts then a longer upper arm is good too. To the point where we like the camber change.

It would be nice to have some really long lower and upper arms. With the upper arm frame points low.

Problem starts up with packaging and bump steer. With really long lower arms the steering arms dont have any room. No place to put them. So they end up being too short. BAD. Bump steer issues.

It really becomes a packaging issue, and Im dealing with that right now. Give and take a lil here and there.. Its a juggling experience. Compromise and some really careful measuring. You end up with something that fits within a 1/4" on all the travel and doesnt touch. Cant have any touching of the members.. Its difficult.. JR

[kp.touring]

Yes longer upper and lower control arms are a good thing, but here is the rub if you lower the upper control arm mounting on a E-body Mopar you will increase the neg camber gain curve!

Kevin

[autoxcuda]

Check what you have now. I was told one of the Chrysler cars had a huge amount of neg camber gain stock. I don't recall if it was Challenger or Cuda.

Same exact front end between Cuda and Challenger. Think Camaro and Firebird. Only difference chassis wise is the Cuda is 2" shorter than the Challenger between the front and rear seats. The body platform is called E-body.

The E-body is basically a shortened 71/72 B-body (Charger/Satellite). The E-body and 71/72 B-body share the entire chassis from firewall forward. The angle of the steering box is slightly different for a slightly different steering column angle between the two chassis styles.

[rb70383]

So will there be any adverse effects? I saw the big block dart info. Yes it was ur old site about the LCAs. LOL So far I am thinking Hotchkis UCA's, various XV chassis stiffening (easy for me to buy and weld then try to bend up stuff for now). Still on the fence about the rear. Keeping the rear leafs though. Of course with the longer LCA I will need an adjustable strut rod to prevent the LCA bushing from binding. Any one got a suspension program that then could change the LCA length to see the basic affect it would have?

[autoxcuda]

So will there be any adverse effects? I saw the big block dart info. Yes it was ur old site about the LCAs. LOL So far I am thinking Hotchkis UCA's, various XV chassis stiffening (easy for me to buy and weld then try to bend up stuff for now). Still on the fence about the rear. Keeping the rear leafs though.

Up to your budget on the rear leafs. I don't get overly excited about trailing arms. It's not a leaf car is worthless. And some of the bolt in stuff has to take in for packaging issues and not 100% optimized.

When we were over at Hotchkis at their open house this summer, they were working on an A-body platform (71 Dodge Demon). So hopefully they'll have a rear leaf spring set for those too.

Of course with the longer LCA I will need an adjustable strut rod to prevent the LCA bushing from binding. Any one got a suspension program that then could change the LCA length to see the basic affect it would have?

The only reason I mentioned the longer LCA was for someone wanting to run lots of camber. When I mean lots, I mean like over 7+ degree. That was common for us to run in the right front of a hobby stock car. The circle track guy I mentioned only ran the longer LCA on the right front tire. It was more of trivia deal and maybe in very particular situations a person could take advantage of.

I don't think someone should run a longer A-body arm on an E/B body on the street. Not neccesary.