quote:Originally posted by Bosswrench:
Wanna go further towards good handling, OZ?
1)- two 5/16" thick flat bars between the rack and the trunk floor mounts removes most of the bump steer. You can just slip them in (with longer bolts) or, by cutting down the tops of the split clamps in the areas that touch the bolt heads (that mount the rack) by 5/16", you avoid needing longer rack mounting bolts. If your car has the late rack-brace between the rack & right side subframe, the cuts avoid needing to redrill two extra holes in the frame.
2)- add polyurethane bushings to the front a-arms. These tighten up the handling with no extra noise inside, and if you order offset flanges on your bushings, it adds to the max caster possible and vastly reduces tramlining on crowned or rough roads. Offset upper bushings add an extra 1-1/2 degrees negative caster for -4 degree total per side. Even more (to 6 or 7 degrees!) is possible by also using offset bushings in the lower a-arms (biased in the opposite direction), but remember, steering effort goes up with extra caster.
3)- gas-charged Konis can be mounted upside-down for a little bit less unsprung weight, with no downside to this positioning. Set the car with the nose down a little (2 degrees is enough) for better high speed stability.
4)- a 7/8" rear anti-swaybar will reduce the car's understeer. I recommend using polyurethane bushings on the center mounts and sphere-balls on the ends. The stock front bar size is fine- also with poly center bushings and sphere-balls.
5)- add a square-bar brace with a clevis across the bellhousing, to replace the non-adjustable stock one. This doesn't help handling much but does help prevent paint (and sheet metal!) cracking from rear body flex with giant tires. Be sure you choose a bar that has long enough ends to jam firmly into the back of the stock bar mounts; this allows the whole weldment to take cornering loads instead of trying to deliver them through thin sheet metal tabs with slotted holes.
There's more that can be done, but that should get you started. And you can do it all yourself with hand tools, and it's all reversable if by chance you don't like the results.
Note- all this assumes a completely stock suspension; you may already have some of this stuff on board. And wheel alignment should be checked if by chance you do the changes piecemeal. Let us know what you think of your improved handling. You'll be ready for Bathurst in 2011!
Whew, good list. Fortunately I'm nearly there.
I'm sure that the steering rack hasn't been modified and this has to go to top of the list. It's pretty savage at the moment and could catch you unawares on some of our roads, especially swerving to miss a kangaroo and copping a pothole.
I'll check out Mike's page for the pictures and come back to you with the results.
I have full new poly bushes in the car from Bob at Precision Proformance.
I did the Johnny Woods modification to the upper control arm and was really pleased with the castor I attained straight up from that modification. Also made camber adjustment easy thanks to the small bolt that pushes the ball joint and locks it into place.
I have a 7/8 sway bar with all new mounts, but it's not mounted with sphere balls. I need more understanding of this?
I have an adjustable square brace accross the rear. I adjusted it until I heard the smallest of creaks and then locked it off. I figure that way I know it isright at the tightest point where it will do the most good.
The springs are Front: 400 Rear: 650 with brand new fully rebuilt Alden Eagle shockers which they set up for road/targa use.
I'm running 12/12 rebound and 3/6 compression on the rear and 6/12 rebound and 3/6 compression on the front. To me the front springs seem too hard and occasionally you can hear the springs rattle in their seats when you hit a sharp bump. On smooth roads (freeways) it's fine, but it could be a little more comfortable on the back roads.