suspension stuffs

[Spiv]

Apparently no one on supraforums know the answers to these, so feel free to show them up

I'm sure it's no suprise that the stock suspension is craptastic for road race conditions, but I know some of you are in the sport. I've been searching through the archives for a couple days, and still came up with a mess of unanswered questions, so here they are:

*stock sway bars: are they solid or tubular? And anyone know the answers to that for the various aftermarket ones? (ST seems to be most popular)?

*high rate springs: I'm a big fan of driving a car around the course with a very stiff spring and no added preload. I know a lot of you are against progressive rate springs too (word), but is there anything with a very short soft side before it kicks into the harsher rate? Always nice to get the quality handling that won't bottom out and still doesn't have a tendency to rattle the rest of the suspension (and my teeth) on every little bump. I'd obviously rather not have to get a progressive rate spring and preload the poo out of them, because, you know, I like my suspension to go both ways.

* significant weight reduction and ride height: I'm guessing knocking 600lbs out of the car is going to make lowering the center of gravity an extra challenge. Any suggestions besides coilovers?

 

[IJ.]

1: Stock bars are tubular, I had a set of solids made for mine and they made an ENORMOUS difference. (+3mm)

The suspension is a brilliant design and can be made to work well but you're fighting the overall bulk of the car every step of the way.

 

[ma71supraturbo]

*stock sway bars: are they solid or tubular? And anyone know the answers to that for the various aftermarket ones? (ST seems to be most popular)?

See IJ's post

*high rate springs: I'm a big fan of driving a car around the course with a very stiff spring and no added preload. I know a lot of you are against progressive rate springs too (word), but is there anything with a very short soft side before it kicks into the harsher rate? Always nice to get the quality handling that won't bottom out and still doesn't have a tendency to rattle the rest of the suspension (and my teeth) on every little bump. I'd obviously rather not have to get a progressive rate spring and preload the poo out of them, because, you know, I like my suspension to go both ways.

I subscribe to the higher spring rate, softer sway bar - school of thought. The car will ride more like a BMW than a ferrari, but still hand very well. Firm, but not harsh. For I'd recomend 18kg/mm front springs and 12kg/mm rear springs on stock swaybars.

* significant weight reduction and ride height: I'm guessing knocking 600lbs out of the car is going to make lowering the center of gravity an extra challenge. Any suggestions besides coilovers?

It will certainly make a huge difference in the acceleration, braking, and slaloming of the car. But it will also become unpleasant to drive everyday (still very fun on the backroads). I dropped almost 600lbs from the mk3 and its a totally different car. To achieve such loss, take out everything that isn't needed to control the car. Seats, carpet, sound deadening, radio, interior panels, wiring, AC, etc etc etc. Just keep going until you get to the point you wonder why you didn't just start from scratch and built a tube frame

 

[1sic7]

It will certainly make a huge difference in the acceleration, braking, and slaloming of the car. But it will also become unpleasant to drive everyday (still very fun on the backroads). I dropped almost 600lbs from the mk3 and its a totally different car. To achieve such loss, take out everything that isn't needed to control the car. Seats, carpet, sound deadening, radio, interior panels, wiring, AC, etc etc etc. Just keep going until you get to the point you wonder why you didn't just start from scratch and built a tube frame

lol im already there with the dropping extra wight part all i have is 2 seats dash and a steering wheel

 

[Wiisass]

Solid sway bars of the same diameter won't make much of a difference over a tubular sway bar depending on the wall thickness of the tube. For example, a 25mm solid bar is only about 8% stiffer than a 25mm tubular bar with a 6mm wall thickness. Of course that number is higher with a smaller wall thickness and lower with a thicker. But the weight increase in going with a solid bar really isn't worth it. For the example above, I think the weight increase comes out to about a 37% increase in weight. This is all given the same materials and sway bar dimensions.

Also about the spring stiffness, you should get a higher rate spring and match it with some well valved dampers. The dampers will make the most difference in ride quality. Besides you really don't preload a spring anyway. Adding any preload would be on the damper.

 

[IJ.]

Post edited to include WA's "correction"
(didn't even imagine someone would have Solids made the same diameter as stock)