miatauser884

iTrader: (11)

If you had to give up rear toe to get your desired rear camber numbers, which is better. A little less rear toe, or a little less rear camber?

hector

Good question. Which one would make you faster or would it be a wash? I would probably go with the toe as it might increase my comfort level with the car. Although I guess you could say the same of having added camber which would plant the rear better. I dunno. Have you tried making changes?

Seefo

iTrader: (5)

rear toe is good for keeping exit power-oversteer in check (and possibly a bit of stability under braking). Camber generally helps during turn in. If you aren't making a lot of power (I don't have any rough estimates), I would get rid of the rear toe in.

Otherwise, I would try to get a little lower in the rear (you can drop the front to keep the rake you need) and see if you can get the camber you want with the toe you like.

ChrisGriffin

You will never have the perfect setup. You will always be chasing it. The better you become at driving the easier setup will become. Pro race teams are forever making changes to their setups while at the track.

You need to be able to read what the car is doing and then understand what the changes will do. Give it some thought, make a change and see how it effects your car. Then repeat.

Gryff

iTrader: (6)

Alright, so... Im pretty sure this is on a hill but,
LF:



LR:



RR:



RF:



I have measured the ride height before, and it did not seem to be near that off. I highly doubt it has shifted, but it is a possibility. I am also going to remeasure everything in a different spot as soon as I get the opportunity to do so.

I also found this while taking pictures:




Might this have an effect on anything? I dont think it would, but there is always a possibility.

Braineack

iTrader: (62)

typical.

Seefo

iTrader: (5)

haha wtf, is the bolt sheared off in the hole or is that just rust?

Gryff

iTrader: (6)

they are studs. and it sheared halfway in.

scott, whats typical?

sixshooter

iTrader: (12)

With those soft spring rates, lowered ride height, stickier tires, and only factory sway bars I'm going to say that you are hitting the bump stops and your FRC % goes right out the window at that point. I'm running heavier springs than you with FM sways and less sticky tires and I am just on the bumpstops in certain corners.

I also have photographic evidence I would like to present to the ladies and gentlemen of the jury of Collin's car on the track.






I submit that the front outside suspension is firmly against the bumpstops in this picture and that the inside front is at full droop:












The prosecution rests, your honor.

Gryff

iTrader: (6)

I dont doubt that I am hitting the bump stops. please tell me what you mean by lowered ride height. mine is pretty much right where it should be according to 949. But I do realize that my car is much lower than yours...

Braineack

iTrader: (62)

the sheared bolt and ride height.

Gryff

iTrader: (6)

Ah. the sheared bolt wasnt there a few months ago. aka last time I was under the back of the car. if 4.5 in is too low, what should it be set at?

sixshooter

iTrader: (12)

It isn't that you are too low, per se, but that you are too low for your spring rates. Oversimplifying for the sake of illustration: If you have 400lb per inch springs and one inch of travel before the stops, then you can only corner with enough force to generate 400lbs of force at the spring before you lose all effectiveness in your suspension. With the same 400lb per inch springs and two inches of travel before the stops, you will be able to generate 800lbs of force against the springs before engaging the stops. Likewise, with 800lb per inch springs you would only need one inch of travel to reach the same 800lbs of force on the spring.

I would like for my ride height to be a little lower but I need the suspension travel with the spring rates (and sways) that I have. Think about coming down the hill through turn 12 at Road Atlanta, a fast, off-camber right hand turn. if you are completely on the bumpstops with your outside tires at 80-100mph and you drift onto the rough outside gators exiting the turn, you will have no suspension motion left. Your car will be completely released from the ground. The only movement you have left is flex in the sidewalls of your tires, which won't help you at that point. At that point you might end up as a greasy spot on the wall up under the flag stand.

This is why it is really important to have a little suspension travel left after your tires can't hold anymore lateral force. On rougher tracks like Sebring it is recommended to use more travel and a lighter spring, and on the smoother tracks like RA to get lower and run a higher rate spring. Additionally, if you add more tire width or stickier compounds you need to add more spring (also works with sway bar) to keep you off the stops at max cornering adhesion.

Seefo

iTrader: (5)

^props, great explanation!

Gryff

iTrader: (6)

Yeah, it makes perfect sense. My friends and I raised the car a half inch for the time being, we will probably raise it more tbh. but we found some interesting discoveries...

Firstly. the left rear shock body is much lower on the threads to keep a consistent ride height. This is the first time I have actually moved ride height since I have bought the car, so were like 85% sure that there is an issue with the subframe, which could be causing some of my issues.

Secondly. the metal sleeve in the rear swaybar endlink actually managed to pull itself out somehow, so my rear swaybar was disconnected at some point...

Thirdly, and also most obviously, I am on the bumpstops, just me in the car, and 140 lbs of person on the rad support almost bottomed out the front suspension (before raising it)

Seefo

iTrader: (5)

hahaha bumpstops ftw.

not sure how much you mean by "much lower" but you have less weight on the right side of the car, since you have a driver on the left. check out my corner weights:
http://www.miataforumz.com/showthread.php?t=433&page=2

you should be able to find any subframe damage anyway, if it effects the shock height it should be around the LCA...unless you have done some serious serious work to the subframe.

Gryff

iTrader: (6)

Height was checked with no driver. so with no driver. and the left rear wound down probably at least an inch lower than all of the others, the car sat level. That, and if there is any damage, it was done before I got a hold of the car, cause I have never set the ride height before yesterday.

sixshooter

iTrader: (12)

It wouldn't be difficult to see if the unibody or some of the framing is tweaked. Use 4 jackstands and set them at the same height. Put them under equivalent locations on the left and right side of the front subframe and equivalent locations at the rear subframe. I like using the steel flange just beneath the lower control arm mounting points at all for corners. If you are on a dead-flat concrete pad and there is a bend in the car it wil rock ever so slightly from corner to corner if you push down on the rear corners. If it is tweaked it shouldn't have firm pressure on each of the four points.

the front and rear jackstands don't need to be the same brand or height as long as they are the same left to right.

Gryff

iTrader: (6)

Thats brilliant! Ill be doing this next weekend for sure!

sixshooter

iTrader: (12)

I wouldn't say brilliant, but it works. Just thinking about it, check your lower ball joints and wheel bearings while it is up there if you haven't before. Most people don't.

Are you on NA or NB tophats?