Funny, somewhat, but not constructive in the least.

To everyone else, thanks for the feedback. I think i am going to go with 1/16th total toe in this weekend when I am off, and the next time I have some spare cash laying around, I'll have them verify it on the alignment machine.

This thread has been very informative and hopefully the wealth of information contained in it will help others, like me, who get a weekend wild hair.

 

and when he said +-.25 he meant degrees. generally on a street car the best settings are as folows:
camber: 0 +-.5 really should be even on both sides
caster: usually above 5, it really depends on make and model
toe: 0 +-.25 for tire wear

but dude, -3.5 degrees camber up front? dear ******* god, but its autox, so thats somewhat understandable

as far as doing the alignment on the ground, i used to build and restore VW's, and theres pretty much no machine that is programed for a 65 bug LOL. the shop would do everything by hand, the good old stanley method, lots of measurements, but we would do 1/4" toe in. always right on, never any weird tire wear

there is a general rule about rwd vs fwd vs awd as far as the general toe settings, i cant remember for the life of me what they are, and im ASE cert'd for it. LOL

Lloyd

 

When I said +.25 I meant inches, not degrees, to clear that up. So 1/4 inch total.

This weekend I am going to set it at 1/16 or even 1/32 of an inch toe in. I'll do 1/16 first then try 1/32 and see how it is. I have rather pricey tires so i don't want to wear them out earlier than necessary.

 

um the simple answer is yes, the complex answer, especially if you go racing is no.

i think if you had no book, and had to setup a car something like 1/16th of toe in would be fine on the street. racing we like to start @zero.

the complex answer, and this is more for racing, is that it depends on the tires, and then the suspension geometry.

the best example is the FC, actually. the DTSS is setup to be optimal with a bridgestone RE71, if you put pirelli p7's on there, like mazda did with the efini, then the toe control may no longer be optimal. those cars actually had a different DTSS bushing.

or the other example is the E46 bmw race car we just picked up, its got -4 camber in the front and wears the outside edges still....

 

You bring the beer again and I'll work around your schedule.

 

You'll never see me claim that this is an optimal street setup. But I have two other cars and a motorcycle and the RX-7 doesn't see THAT much street time.

The problem (the problem? One of the many problems) of the FC chassis is that when you lower it at all the front roll center goes subterranean. The front gains positive camber as the car rolls. So the static setup has to maintain the contact patch shape when cornering. This is done by running a lot of static camber and a high front roll stiffness.

On my Z06 I only had to run about -2.2 front camber and that car had a great camber curve with its upper and lower A-arm suspension.

I'm still chasing the best setup for our local venue, so this probably won't be where I end up. I am still learning a lot.

 

last time we ran an FC race car, we set it up with the butt dyno, so to speak. we've got 3 (!) in the pipeline and it'll be fun to set em up with actual instrumentation, not to mention the drivers are way better too.

if you allow me to speculate, the front is just a matter of getting the best compromise between ride height, camber etc etc

the rear is the big puzzle...

 

We have datalogging (DL1) so we use that as a tuning tool to some degree. The clock is the most important tuning tool for us anyway.

The rear of the FC actually works pretty well if it isn't set up to be way too stiff. If you ditched the DTSS there isn't much toe gain through bump so your static toe setting becomes more of a tuning tool.

Our general philosophy has been making changes to the front to get the nose to bite and not skate mid-corner and adjusting the rear to rotate off throttle without being too loose in transitions. But again this is for autocross. I'm sure I'd pursue a completely different setup for a racetrack.

I'm finding that the rear ride height is a very useful tuning tool. I'm running no rake right now, but if I got to a venue where the rear was too planted I could easily raise it, removing some negative camber and moving the Cg forward, which makes the car a bit more lively.

 

Speaking of which, I have been toying with the idea of lowering the front a bit, maybe an inch to give the car some rake. Any benefits on a street driven car. Should improve (lower) the drag coefficient a tad right?

 

If you're going to lower the car, lower both ends. You don't want the handling that will come with rake on an FC.

 

With that said, I'll just lower the front and back an inch. Why is rake so horrible on the FC though?

 

seems to be some pretty good info here.
i have just been trained on street cars, align them for the best ride and least amount of tire wear. i would love to get into high performance suspension, but i have nothing around me to get into that.
thanks for the clarification about the toe. again, street is what i know

Lloyd

 

It's not just the FC, but lowering just the front moves the Cg forward, lowers the front roll center and will make the car twitchy and prone to snap oversteer.

 

Indeed. Keep the rake in the garden.

 

nothing wrong with that at all! the thing i notice the most about the zero toe is the steering response is amazing, its razor sharp.

 

For those (like me) that like toe-out for autocross, but also drive on the street, you can make a temporary adjustment to the toe yourself.

From '89 FSM, page R-7:
"b) One turn of the tie-rod (both sides) changes the toe-in by about 6mm (0.24 in)."


So, for example, if your alignment is 1/8" toe-out, you can make one full turn in to each side, to give you 1/8" toe-in.

Just think carefully about which way to turn, and remember what you did, so you don't get lost...

I read where a guy suggested just changing one side, so you remember to change it back because the wheel won't be centered.

Another thing to keep in mind when figuring how much toe you want, is that on the highway: rear wheel drive cars with rubber bushings have a rearward force on the front wheels that will reduce the toe-in (or increase toe-out). This will be less with polyurethane bushings, and about nil with delrin.

 

you need to really know what you're doing when you align your car without a modern machine.