Suspension and Balance

Before I go in for my alignment, I had wanted to run some figures through my simulator to see if I can't make some improvements here or there. Please, feel free to respond if you have the answers to any of the following:

Weight split front-to-rear.

Centre of gravity in the y-axis (Height).

Toe spread at 100KM/H (Or if not, stock toe figure).

Stock spring rate.

Stock ride height.

Thanks in advance!

Dawg wrote: Moog makes an adjustable upper ball joint for chamber.

Don't confuse the boy. That would be "camber".

The mentions the primary issue with alot of positive caster being overcome by modern cars. It should be noted: It will not be corrected by our cars. The article was written for cars with power steering, something our cars lack. Any increased effort will be the driver's job to fight with our cars.

Caster makes the steering wheel hard to turn for two reasons: One, it directs the weight ahead of the tire patch, which causes the tires to want to stay straight. This can be demonstrated with, of all things, shopping cart. Push the cart normally; The tire will follow behind the pivot point, where the weight pushes down. Now, try and turn the wheel 180 degrees out and push forward. It will almost immediately spin around and continue to follow the weight instead. This is due to a phenominom called implied weight. The other reason caster makes the car harder to turn, is because you're essentially turning one tire "into the ground" and "lifting" the other tire. This can only really be thought of if one thinks in the extreme. Using the diagrams from the site, one can see that at zero degrees, the steering ONLY turns the tires. At forty-five degrees half the effort is to turn, the other half is applied to "turning the tire over" (Altering camber). At ninety degrees, the wheels wouldn't turn left or right, but only lean back and forth while still pointing forward.

It is that final "problem" which is also the most beneficial in terms of performance. By causing the tires to lean, this adds in negative camber, which helps correct for tire roll-over (The tires will try and lean opposite the direction the car turns) by adding negative camber to the outside tires, and adding positive camber to the inside tire, helping to flatten both out.

I believe the use of eccentric camber bolts does offer more adjustment. However, they may or may not actually be required on lowered Fieros. (Probably depends on the amount of lowering that's been done.)

Colby, did you bother with them (even for just the added ease of adjustment)?

Alrighty, well, based upon word-of-mouth estimates on what the Fiero GT's spring rate is, I've plugged in the ride height, weight balance, roll-characteristics and tire type, and run through the simulation, and from the speeds at autocross (And highway) the best camber angle would be -0.9 degrees on the front and -1.7, which brings it to about .15 degrees front and -0.05 degrees rear under acceleration at 60MPH, 0 front and rear without acceleration or deceleration, -0.4 degrees front 0.1 degrees rear under deceleration.

The only thing that concerns me is running -1.7 degrees on a daily driven car... Begging for tire wear.

No, the first figures are the static set rates, the last three are what will actually be translated at the bottom of the tire under the circumstances listed, due to caster, tire roll over and body roll.

And you don't find it wears quicker with the -1.6?

Cheese wrote: Romeo wrote: No, the first figures are the static set rates, the last three are what will actually be translated at the bottom of the tire under the circumstances listed, due to caster, tire roll over and body roll. How can the camber be 0 deg under a constant velocity but -.9 and -1.7 deg when stationary? Is there really enough drag (and anything else I'm forgetting) at 60mph to cause the front end to lower and the rear end to get higher, and enough to cause that much change? Or is there something else happening? Romeo wrote: And you don't find it wears quicker with the -1.6? Not sure, I've only had it there for a couple weeks and less than 400km. I guess I'll find out eventually.

And alright. Will wear slower than the way I have it now anyways. lol