Besides weight, are there any real specific advantages to buying the aftermarket lower control arms? How much wieght difference could it possibly be? I mean, is it an aluminum vs. steel thing.
Whatis the census opinion?

 

I've got no complaints on the boxed factory LCA's on my Firebird or the Z28 Autocross car.
IMHO, the weight difference is minimal, and the price was right(a friend welded them for free). If they have to be 'pretty' or weight is a real issue, then buy aftermarket ones.

I have a pic of the ones on the racecar if you want to see them

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Redbird
Bayou Motorsports
87 Firebird-Daily Driver/Autocrosser
84 Z28-Full bore Autocross car
Delta Region SCCA
#00 C Prepared

 

LCA's w/ one or more spherical rod end allow the the rear to pivot more freely, such as when one wheel goes over a bump. The factory LCA's will twist easier than a boxed one. I don't think this is a problem though, it just sounds bad in theory. I have boxed lca's on mine and have no probs.

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87 IROC 350
13.94@103mph
Check out my new web page.
http://austinsiroc.homestead.com/Home1.html

 

thanks for the advice. Red Bird, I'd like to see the pics. Do you have a website?

 

I have boxed LCA's also w/poly. I have no problems.

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82Z 305 w/comp 270 magnum cam,Edelbrock Performer RPM,Holly 1850-4,serpentine belt drive.TH700R4 w/B&M holeshot 2000 converter,& megashifter.1LE front brakes, 9bolt 3.27 w/1LE rear brakes.Aluminum driveshaft,boxed rear susp.poly everything,IROC swaybar+wonderbar. 70mph@2200rpm ASE Master Tech plus L2
also recently obtained a
'69 chevelle SS396 w/Turbo 400,3.31 posi,11.0 to 1, headers,etc. Latest project car,'86 IROC stock 305TPI hit on left side,but not too bad

 

Andy, this shows one of them decent enough. I was actually taking a pic of the exhaust for someone else. They are boxed, have poly bushings, and have a piece of 1" cold rolled steel welded into the 'channel' in the LCA. The only reason the cold rolled is there is because of the size of the slicks and the HP the motor puts out. We didn't want it to flex at all, and it doesn't. There's no wheel hop at all.
The ones on my Firebird are only boxed.


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Redbird
Bayou Motorsports
87 Firebird-Daily Driver/Autocrosser
84 Z28-Full bore Autocross car
Delta Region SCCA
#00 C Prepared

 

RedBird, did you do anything special to the paint inside the u-channel before boxing the arms? I want to box mine, but I'm a bit worried about rust.


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
---Think your car could be pic of the week? Visit http://www.f-body.net for details!

 

Yes, they were sprayed with a John Deere rust inhibitor before welding. My friend works for a John Deere dealership.

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Redbird
Bayou Motorsports
87 Firebird-Daily Driver/Autocrosser
84 Z28-Full bore Autocross car
Delta Region SCCA
#00 C Prepared

 

Heh, cool! Did you do any spraying after the welding was done? Wouldn't the rust inhibitor bubble up from the heat?


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
---Think your car could be pic of the week? Visit http://www.f-body.net for details!

 

I just got done welding up my LCA's. I used .125" (1/8") plate steel, and cut it to fit just slightly down into the curved portion of the LCA's. after a little trimming, and some hammer work to invoke the proper curves to the steel stock, I then began the welding process. I alternated the welds every 2" skipping to the other side every other time, until I had a completely welded LCA. (This is important so as to not warp the LCA's).

In the picture you can see a bushing still installed. This was an old bushing, and was simply used to make sure I didn't tweak out the metal too much when I had the LCA and piece of steel stock clamped down for welding. MAKE SURE that you don't install your new bushings before you weld. This should be done after welding and paint.

Also, it's difficult to see my weld quality since I took a grinder to the welded areas to provide a smooth clean appearance.

I'm going to take the LCA's to work tonight and sand blast and paint them. Most paint (even the high-temp stuff) will burn or lose it's rust prevention properties if you weld after paint application. The best bet is to apply a good coat of high-temp paint to the inside, and then when you are done with the welding, wirebrush (or sandblast in my case) the entire assembly and apply a quality paint. I'll be using Rust-oleum #7777 Satin Black. It probably wouldn't hurt to saturate the internal part of your newly boxed LCA with your paint prior to bushing installation. Just point the spraypaint nozzle inside and spray away.

If there are any other questions, I'm sure Redbird or myself would be glad to add further to this thread.




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86 Trans Am WS6 Black with tinted windows, shaved door handles
ZZ4, Mini-ram, true duals
***Too many other mods to mention***

"In the future, cities will become deserts,
roads will become battlefields, and the hope of mankind
will appear as a stranger" The Road Warrior

 

Steve nailed it!

That's exactly what to do in detail.
And exactly what happened with the ones in the Firebird. The only difference in the racecar LCA's was the pieces of 1" cold rolled steel that was added into the channel.
The channel was cleaned thoroughly prior to welding in the cold rolled, and painted with the rust inhibitor after it cooled. The excess paint was removed from the edge of the channel prior to welding on the plate steel. It was then painted inside(after removing the old bushings) and outside with the rust inhibitor and then with Kubota orange paint. Then PST's poly bushings were installed.
The 1" cold rolled steel is NOT necessary on a street driven car, Hell it probably wasn't necessary on the racecar, so don't include it as part of your 'box job'

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Redbird
Bayou Motorsports
87 Firebird-Daily Driver/Autocrosser
84 Z28-Full bore Autocross car
Delta Region SCCA
#00 C Prepared