Aftermarket Front Lower Control Arms

[scoti]

on our circle track cars we would run 3.5° to 4.5° on the left and 6° to 6.5° on the right, the settings would depend on the degree of banking in the corners and the spring rate we were running. With more caster you get more camber gain as the suspension compresses so on the right side that also helps. Circle track cars always pull to the left on the straights. I have a Borgeson Delphi box and I like 5.5° on the right and 5° on the left, I like the split to compensate for the road crown....

Sounds like I'm in the right range w/my goals then.

I'm glad you posted your combo. I have been researching the Delphi 600 aftermarket boxes but had not seen what Borgeson offers. Is your box the 600 series or 800? I noticed quite significant variance on pricing between manufacturer & trying to figure out the 'what/why' of that.

 

[pontiacgp]

Sounds like I'm in the right range w/my goals then.

I'm glad you posted your combo. I have been researching the Delphi 600 aftermarket boxes but had not seen what Borgeson offers. Is your box the 600 series or 800? I noticed quite significant variance on pricing between manufacturer & trying to figure out the 'what/why' of that.

it's a 600 box

 

[scoti]

it's a 600 box

The 12.7:1 box? I see where some w/bigger tires are using a 10.1. That seems very aggressive.

 

[superbon54]

8° caster sounds like too much to me, stock specs are 2° to 5°. With 8° I would think the steering gets real heavy in a corner and you'd feel the road too much plus the steering wheel would center too quick

Many of my pickup points are changed, and subsequently the dynamic camber curve is completely different than a stock g body. For giggles I modeled the setup, and the simulation showed optimal front tire contact at about 8 degrees once factors such as KPI, dynamic caster and camber gain/loss and steering angle are factored in. YMMV depending on the setup, and the key for me to remember is that the simulation is optimized to tire contact patch, not drive ability or comfort. I may dial the caster back if the steering is too heavy or if it tram lines like crazy but to me, the tinkering is the fun part.

On a separate note, g body front suspension actually isn’t too bad once the camber curve and bumpsteer are fixed, both of which aren’t complex or expensive to do. The rear geometry kind of sucks for handling and is much more complex to improve, but that’s a topic for a different thread.

 

[ssn696]

Define 'tram line'. Trampoline?

 

[scoti]

Define 'tram line'. Trampoline?

It likes to follow moderate crevices or ruts on the road surface like they're train tracks vs. where the steering wheel is aimed.

 

[ssn696]

Ah. Motorcycle on a grating deck bridge. Scary in the rain.

 

[Kelvin's80442]

Here's my .02 (actually. 0005): first, I'd lean towards the upper arm manufacturer because they may be designed to work together. If you really like the ones that have a drop spring pocket, go that way, ditch the lowering springs and get some Moogs for ~$50.


What is the drop spring pocket?
That additional clearance to allow for a taller spring?

 

[scoti]

What is the drop spring pocket?
That additional clearance to allow for a taller spring?

The drop pocket is for 1" additional lowering and/or "tuning" the ride height by adding shims back in (under the coil) as desired up to a certain amount. So technically you can run a taller spring vs. a drop spring & get a similar ride height.

 

[scoti]

Local u-pull it yards want ~$20ea. for G-body arms.

I went to my local Smileys today @ lunch to check out some new Metric chassis lower arms. Brand new arms are $85ea. Add the cost of bushings ~$50pr x2. So new OE is $135 + tax each or ~$146 a pop. My thought was possibly do a lower BJ mod like I've done on C10 trucks. After looking (staring) @ the arm, I know its probable but it still would be a project.

After going back & looking @ pics of a past Malibu, I pulled the trigger on SpeedTechs lower arms. Powder coated, loaded (lower BJ, Delrin bushings, bump-stop, & sway-bar link) are also included in the $750 (or $375ea) cost for the delivered S.T. arms gives me a known product w/engineered layout vs. me doing the math to determine how much would be needed. It allows me to continue progress on my coil-over conversion I'm in the middle of on my 64.

Notice where the wheel is in the opening? The lower BJ def needs to come forward so the upper arm doesn't require as much adjustment to achieve modern Caster settings which allows the wheel to remain closer to center. Thanks for the insight & input on the topic.