socorob Posted June 9, 2015 Share Posted June 9, 2015 My car is a 78 with full interior. I have the plates to stiffen up the sway bar area from bad dog welded to the chassis. I have done 2 track days and an autox so far this year, and the few pictures I've seen of my car in the turns, and what it feels like from inside the car, shows I am getting a ton of body roll. I have the stock bar up front and no rear bar. I have konis all around with 300 springs in front and 250 rear. I was looking at upping the front bar to help with the body lean, but not sure whether to go with 1 inch Addco or 1 1/8 inch st front bar. There's a chart in the black dragon catalog that shows the percentage of how stiff each bar is over stock and shows the 1 1/8 bar to be a lot stiffer than the 1". I don't want to go too big and have the car act more like a solid front axle. I'm not even sure with these bars if that's even an issue. Is one size recommended over the other, or is bigger better? I've read in the suspension faq and it seems a lot of people use the 1", but those are on much lighter cars than mine. What would be the better choice for a heavyweight 280? Quote Link to comment Share on other sites More sharing options...
jhm Posted June 9, 2015 Share Posted June 9, 2015 Search on John Coffey's advice regarding sway bars and suspension stiffness. Your post didn't mention what kind of power and torque you're putting down; but generally, you'll want to move roll resistance rearward for lower power applications and move it forward for higher power applications. (Are you currently running an LS1, as indicated in your build summary?) A 1 and 1/8 bar is pretty big, particularly if you have nothing in the rear. Consider adding some kind of rear sway bar before installing a huge bar up front. You've already got good springing and damping, so don't go crazy with the sway bars until you're sure you need that much roll resistance. Lowering the car's CG also reduces roll tendency. Hope this helps. Quote Link to comment Share on other sites More sharing options...
deja Posted June 9, 2015 Share Posted June 9, 2015 All I can suggest is based on what I did to my car. I have '77 280z with an LT1. Tokico 185 and 200 pound lowering springs and struts. After the engine swap I had the stock front bar on with the rear bar removed. A friend of mine offered me a 1 1/8" front bar at an awesome price so I took it. I reinforced the frame and installed the bar. I was shocked at the difference it made as far as body lean and balance. Also I am running Yokohoma drive S 225/50-R17 tires on 17x8 inch rims. Going to low profile tire made a huge difference over the 14" 60 series that used to be on the car. Again this is based on my experience and not on any science. Quote Link to comment Share on other sites More sharing options...
socorob Posted June 9, 2015 Author Share Posted June 9, 2015 http://www.mingdom.com/Cars/Motorsports/SCCA-Track-Night-NOLA-5615/i-S7dwhHr/A http://www.mingdom.com/Cars/Motorsports/SCCA-Track-Night-NOLA-5615/i-KHFZ8FP/A http://www.mingdom.com/Cars/Motorsports/SCCA-Track-Night-NOLA-5615/ I am running a stock LS1, T56. I have the body stitch welded from wheel well to wheel well, with an angle brace welded in going from near the front strut top down to in front of the bottom of the door inside the fender. In the pictures above, you can get an idea of the amount of lean the car is getting in the turns. This was with used clicks, -1.4 camber in front, -.9 in the rear, I think 4 degrees caster. I was staying behind an MR2 that stayed really flat in the curves. We were running about the same lap times, but he would pull away from me in the turns, and I would catch him on the straights. I had bought a rear bar, but ended up sending it back before I even opened it after reading the suspension FAQs. Seems like a lot of people there use 1", but their cars are probably much lighter than mine. Quote Link to comment Share on other sites More sharing options...
rjracin240 Posted June 10, 2015 Share Posted June 10, 2015 I went from the 1" to a 11/8" bar that I found at a wrecking yard, honestly felt no difference, car does roll a bit as pictured. But does feel very stable, and predictable. Have the old AZ springs with the Koni 1152 shocks in front and some Koni's that AZ Z Car was selling, urethane bushings all around. Power output is probably pretty low considering I have a 30+ year old wrecking yard motor in it. So sounds like advice JHM gave is in keeping with my set-up Quote Link to comment Share on other sites More sharing options...
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