Miata Turbo Forum - Boost cars, acquire cats.

Miata Turbo Forum - Boost cars, acquire cats. (https://www.miataturbo.net/)
-   Suspension, Brakes, Drivetrain (https://www.miataturbo.net/suspension-brakes-drivetrain-49/)
-   -   rear sway vs no rear sway FCM calculator (https://www.miataturbo.net/suspension-brakes-drivetrain-49/rear-sway-vs-no-rear-sway-fcm-calculator-62319/)

miatauser884 01-01-2012 04:03 PM

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 01-01-2012 04:30 PM

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 01-01-2012 05:19 PM


Originally Posted by djp0623 (Post 813688)
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?

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 01-01-2012 06:29 PM

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 01-06-2012 03:49 PM

6 Attachment(s)
Alright, so... Im pretty sure this is on a hill but,
LF:
https://www.miataturbo.net/attachmen...ine=1325882969


LR:
https://www.miataturbo.net/attachmen...ine=1325882969


RR:
https://www.miataturbo.net/attachmen...ine=1325882969


RF:
https://www.miataturbo.net/attachmen...ine=1325882969


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:
https://www.miataturbo.net/attachmen...ine=1325882969

https://www.miataturbo.net/attachmen...ine=1325882969

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

Braineack 01-06-2012 03:52 PM

typical.

Seefo 01-06-2012 03:54 PM

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

Gryff 01-07-2012 01:14 AM

they are studs. and it sheared halfway in.

scott, whats typical?

sixshooter 01-08-2012 07:11 AM

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.

http://www.miataforumz.com/picture.p...&pictureid=367

http://www.miataforumz.com/picture.p...&pictureid=364


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

http://www.miataforumz.com/picture.p...&pictureid=363
http://www.miataforumz.com/picture.p...&pictureid=361

http://www.miataforumz.com/picture.p...&pictureid=359

http://www.miataforumz.com/picture.p...&pictureid=358

http://www.miataforumz.com/picture.p...&pictureid=377
http://www.miataforumz.com/picture.p...&pictureid=376


The prosecution rests, your honor.

Gryff 01-08-2012 11:15 AM

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 01-08-2012 11:35 AM


Originally Posted by Gryff (Post 816285)
they are studs. and it sheared halfway in.

scott, whats typical?


the sheared bolt and ride height.

Gryff 01-08-2012 11:47 AM

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 01-09-2012 08:10 AM

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 01-09-2012 09:54 AM

^props, great explanation!

Gryff 01-09-2012 12:33 PM

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... :facepalm:

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 01-09-2012 01:31 PM


Originally Posted by Gryff (Post 817274)
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... :facepalm:

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)

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 01-09-2012 03:11 PM

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 01-09-2012 03:12 PM

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 01-09-2012 03:21 PM

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

sixshooter 01-09-2012 04:42 PM

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?


All times are GMT -4. The time now is 01:59 PM.


© 2024 MH Sub I, LLC dba Internet Brands