remove rear roll bar?
01-04-2008, 02:38 PM
#26
Registered User
Join Date: Nov 2006
Posts: 987
Likes: 0
Received 0 Likes
on
0 Posts
fwiw, it's just a list of generalities (copied from another site), as stated, but they're a guide of generalities at the very least, which I've found consistent in their response when tinkering with my setups for track use.
Last edited by SouthFL; 01-04-2008 at 02:41 PM.
01-04-2008, 02:42 PM
#27
I am in no way anywhere nearly sophisticated enough to speak on the intricacies of tuning the suspension like you guys are.
However, I will point out that in my own meager efforts to play with the balance between over and under steer on my car, I have found that increasing the rear tire pressure reduced oversteer and that there is a balance point that is pretty subtle in the adjustment of the rear dampers. Full stiff might be loose, but full soft is also loose. Somewhere in that upper middle had the right amount of push.
All of this is just to point out that the traditional check list as posted above is very general and the actual response might be quite different than what is expected.
However, I will point out that in my own meager efforts to play with the balance between over and under steer on my car, I have found that increasing the rear tire pressure reduced oversteer and that there is a balance point that is pretty subtle in the adjustment of the rear dampers. Full stiff might be loose, but full soft is also loose. Somewhere in that upper middle had the right amount of push.
All of this is just to point out that the traditional check list as posted above is very general and the actual response might be quite different than what is expected.
01-04-2008, 03:18 PM
#28
Registered User
Join Date: Nov 2006
Posts: 987
Likes: 0
Received 0 Likes
on
0 Posts
I am in no way anywhere nearly sophisticated enough to speak on the intricacies of tuning the suspension like you guys are.
However, I will point out that in my own meager efforts to play with the balance between over and under steer on my car, I have found that increasing the rear tire pressure reduced oversteer and that there is a balance point that is pretty subtle in the adjustment of the rear dampers. Full stiff might be loose, but full soft is also loose. Somewhere in that upper middle had the right amount of push.
All of this is just to point out that the traditional check list as posted above is very general and the actual response might be quite different than what is expected.
However, I will point out that in my own meager efforts to play with the balance between over and under steer on my car, I have found that increasing the rear tire pressure reduced oversteer and that there is a balance point that is pretty subtle in the adjustment of the rear dampers. Full stiff might be loose, but full soft is also loose. Somewhere in that upper middle had the right amount of push.
All of this is just to point out that the traditional check list as posted above is very general and the actual response might be quite different than what is expected.
TO REDUCE OVERSTEER or INCREASE UNDERSTEER:
Front tires:
- Decrease tire pressure in 2.5psi increments
- Decrease Section Width
- Install higher Aspect Ratio tires
- Increase front tread depth
Rear Tires:
- Increase tire pressure in 2.5psi increments
- Increase section width
- Reduce aspect ratio
- Decrease rear tread depth
Front tires:
- Decrease tire pressure in 2.5psi increments
- Decrease Section Width
- Install higher Aspect Ratio tires
- Increase front tread depth
Rear Tires:
- Increase tire pressure in 2.5psi increments
- Increase section width
- Reduce aspect ratio
- Decrease rear tread depth
As for extremes of damper range adjustment, that's something I've never ventured to toggle with.
01-04-2008, 04:21 PM
#30
Registered User
Join Date: Jun 2002
Location: Misinformation Director - Evolv Chicago
Posts: 3,086
Likes: 0
Received 0 Likes
on
0 Posts
Having some torque would allow more ability to steer with the throttle, so to speak, but how would it change the turn in, mid turn and (with throttle modulation) off turn...i.e. how would it change the actuall balance between front and rear grip? I can't imagine it...if the suspension is working, within it's geometry and design parameters' capabilities, it is working...throwing more power at it isn't going to make it "work" differently. I guess if you had a ton of torque, with a big hit, you might want to change some things (like rear toe) to make it easier to keep the back end under you, when the tires were spinning and grip was being lost...
OD, don't know what tires you use at the track but maybe think about a more aggressive compound???
01-04-2008, 04:50 PM
#33
tire pressures are a tweak only, you aren't going to correct for a large increase in WHP with it
shock adjustments will depend on what shock with what valving, again you aren't going to correct for a large increase in WHP with it, moreso if you don't have high end racing shocks
same for most of the other things being suggested
You'll either need larger wheels and tires which addresses the issue directly, or you can play the waiting game with throttle input vs steering angle. For high speeds you can use a rear wing to assist the situation.
Unfortunately I just sold the spare pair of 18 x 10.5" +45 SSR Comp wheels I had laying around ... the person who bought them is mounting them up with 305 tires for the rear
shock adjustments will depend on what shock with what valving, again you aren't going to correct for a large increase in WHP with it, moreso if you don't have high end racing shocks
same for most of the other things being suggested
You'll either need larger wheels and tires which addresses the issue directly, or you can play the waiting game with throttle input vs steering angle. For high speeds you can use a rear wing to assist the situation.
Unfortunately I just sold the spare pair of 18 x 10.5" +45 SSR Comp wheels I had laying around ... the person who bought them is mounting them up with 305 tires for the rear
01-04-2008, 04:51 PM
#34
Banned
Join Date: Sep 2007
Location: Waukesha Wisconsin
Posts: 2,643
Likes: 0
Received 0 Likes
on
0 Posts
01-04-2008, 04:55 PM
#35
Registered
Join Date: Sep 2006
Posts: 1,363
Likes: 0
Received 0 Likes
on
0 Posts
You'll either need larger wheels and tires which addresses the issue directly, or you can play the waiting game with throttle input vs steering angle. For high speeds you can use a rear wing to assist the situation.
Unfortunately I just sold the spare pair of 18 x 10.5" +45 SSR Comp wheels I had laying around ... the person who bought them is mounting them up with 305 tires for the rear
Could you ultimately go faster with wider tires? Yes.
Would the car be easier to drive? Yes.
Would it handle better? No, it would just have more grip
btw, 305 section rears on a RX8, unless you are running a serious motor, is just overkill...might even be slower, depending on the track, gearing and how modified the motor is...or, if it has an LS2 conversion
Last edited by mwood; 01-04-2008 at 04:58 PM.
01-04-2008, 05:31 PM
#36
OEM
Join Date: Dec 2006
Posts: 44
Likes: 0
Received 0 Likes
on
0 Posts
Would it handle better? No, it would just have more grip
Running wider tires should increase handling (going to WOT earlier) without changing the balance at turn-in and mid corner.
If you change anything else you might improve rear traction but you will also change the balance of the car.
From what I have read guys who want more grip from there drive axle's
1. Reduce the drive axle's sway bar
2. increase the non drive axle's sway bar
3. increase the drive axle's spring rates to compensate for the changes in sway bars.
And to figure all this out without changing the cars balance is beyond me. Thats why I think the tire option make sense. Unless you are racing and have to conform to certain rules.
Last edited by ThecdnRX8; 01-04-2008 at 05:44 PM.
01-04-2008, 06:13 PM
#38
Registered User
Join Date: Nov 2006
Posts: 987
Likes: 0
Received 0 Likes
on
0 Posts
What environment was this, AutoX or Roadcourse? If you're decreasing the rear pressure from overinflation on purpose (for autocross), then yes, the car will rotate less.
01-04-2008, 06:23 PM
#39
Road course and street driving.
Over-inflation is kind of relative. Recommended pressures are a range from safe to most fuel efficient. A tire's rating is all over the place.
So, is 37 PSI over-inflated? How about 31? 28? Where is that line. There are people out there driving on 42 PSI or more and the tire is rated to 50 PSI or more.
I played around with the pressures on the OE tires for a while. The OE recommendation was 32 PSI. It picked up lateral traction until about 35 and lost it again. Dropping to 29 it would lose it as well.
On the current tires, 37 is the sweet spot. That is over-inflated.
Over-inflation is kind of relative. Recommended pressures are a range from safe to most fuel efficient. A tire's rating is all over the place.
So, is 37 PSI over-inflated? How about 31? 28? Where is that line. There are people out there driving on 42 PSI or more and the tire is rated to 50 PSI or more.
I played around with the pressures on the OE tires for a while. The OE recommendation was 32 PSI. It picked up lateral traction until about 35 and lost it again. Dropping to 29 it would lose it as well.
On the current tires, 37 is the sweet spot. That is over-inflated.
01-04-2008, 06:26 PM
#40
Registered User
Join Date: Nov 2006
Posts: 987
Likes: 0
Received 0 Likes
on
0 Posts
Road course and street driving.
Over-inflation is kind of relative. Recommended pressures are a range from safe to most fuel efficient. A tire's rating is all over the place.
So, is 37 PSI over-inflated? How about 31? 28? Where is that line. There are people out there driving on 42 PSI or more and the tire is rated to 50 PSI or more.
I played around with the pressures on the OE tires for a while. The OE recommendation was 32 PSI. It picked up lateral traction until about 35 and lost it again. Dropping to 29 it would lose it as well.
On the current tires, 37 is the sweet spot. That is over-inflated.
Over-inflation is kind of relative. Recommended pressures are a range from safe to most fuel efficient. A tire's rating is all over the place.
So, is 37 PSI over-inflated? How about 31? 28? Where is that line. There are people out there driving on 42 PSI or more and the tire is rated to 50 PSI or more.
I played around with the pressures on the OE tires for a while. The OE recommendation was 32 PSI. It picked up lateral traction until about 35 and lost it again. Dropping to 29 it would lose it as well.
On the current tires, 37 is the sweet spot. That is over-inflated.
01-04-2008, 06:29 PM
#41
I see a lot of (too many) generalities being thrown around in here. SouthFL just touched on what my feelings are. It's hard to toss these things out there without knowing the baseline.
As Team said you need to balance the car properly. That may or may not include larger tires. It is just going to take some instrumentation and butt dynoto make the car run as you would like it it. For every driver that means something different.
OD, we can try to head you in the right direction if you give us more information about your setup, but no one will be able to dial in the suspension to your liking.
I tend to disagree with Team on what are (my) preferential alignment settings, but I would never argue that his are wrong. He seems to do pretty well for himself the way he sets up his car. We will see how well my pants seat translates to hard statistics once the snow melts.
As Team said you need to balance the car properly. That may or may not include larger tires. It is just going to take some instrumentation and butt dynoto make the car run as you would like it it. For every driver that means something different.
OD, we can try to head you in the right direction if you give us more information about your setup, but no one will be able to dial in the suspension to your liking.
I tend to disagree with Team on what are (my) preferential alignment settings, but I would never argue that his are wrong. He seems to do pretty well for himself the way he sets up his car. We will see how well my pants seat translates to hard statistics once the snow melts.
01-04-2008, 07:01 PM
#42
Alignment is Voodoo! Especially camber. The break-over point seems to lie in a range of just a few tenths of a degree in the rear.
Toe is another matter. The rear toe seems to do a lot for feel, but not a ton for actual traction. I just run no toe at all because I don't like the way toe feels anywhere.
Highly unscientific.
Toe is another matter. The rear toe seems to do a lot for feel, but not a ton for actual traction. I just run no toe at all because I don't like the way toe feels anywhere.
Highly unscientific.
01-04-2008, 07:24 PM
#43
Chassis tuning in general seems to be the culmination of the dark arts.
And good F-ing luck when you want to setup a track/race car for multiple drivers!
As long as I can keep the tire temps/wear reasonable I am going to dial in a shade of toe in on the back end. But then again I prefer a bit of a tail happy car opposed to something that feels like my old FWD.
chassis alignment setup - ultimately - is about maximizing your tires in relation to the driver being comfortable with the car. If it feels right in the cockpit, its a good setup for you.
With all the adjustability Mazda gives you out of the box you can sure **** it up like a wet dream though.
And good F-ing luck when you want to setup a track/race car for multiple drivers!
Originally Posted by MazdaManiac
Especially camber. The break-over point seems to lie in a range of just a few tenths of a degree in the rear.
Toe is another matter. The rear toe seems to do a lot for feel, but not a ton for actual traction. I just run no toe at all because I don't like the way toe feels anywhere.
Toe is another matter. The rear toe seems to do a lot for feel, but not a ton for actual traction. I just run no toe at all because I don't like the way toe feels anywhere.
As long as I can keep the tire temps/wear reasonable I am going to dial in a shade of toe in on the back end. But then again I prefer a bit of a tail happy car opposed to something that feels like my old FWD.
Originally Posted by mazdamaniac
Highly unscientific.
With all the adjustability Mazda gives you out of the box you can sure **** it up like a wet dream though.
Last edited by mac11; 01-04-2008 at 07:30 PM.
01-04-2008, 07:31 PM
#44
I purchased a camber device and a set of really nice lasers a while back. When I'm feeling perky, I go out to the garage and set 'em all up and look at stuff. Its amazing to me how much the setup changes from day to day.
I pick up and lose a bit of camber here and there and jouncing the suspension sometimes makes it change.
I've tried this on some other cars and it is about the same.
If you align for optimum conditions, you can only drive in optimum conditions.
I pick up and lose a bit of camber here and there and jouncing the suspension sometimes makes it change.
I've tried this on some other cars and it is about the same.
If you align for optimum conditions, you can only drive in optimum conditions.
Last edited by MazdaManiac; 01-04-2008 at 07:37 PM.
01-04-2008, 07:56 PM
#45
What "issue" are you talking about? The car is either set up well or not, is it not?
Could you ultimately go faster with wider tires? Yes.
Would the car be easier to drive? Yes.
Would it handle better? No, it would just have more grip
btw, 305 section rears on a RX8, unless you are running a serious motor, is just overkill...might even be slower, depending on the track, gearing and how modified the motor is...or, if it has an LS2 conversion
Could you ultimately go faster with wider tires? Yes.
Would the car be easier to drive? Yes.
Would it handle better? No, it would just have more grip
btw, 305 section rears on a RX8, unless you are running a serious motor, is just overkill...might even be slower, depending on the track, gearing and how modified the motor is...or, if it has an LS2 conversion
The issue is he went from around 200 RWHP to 300 RWHP. Lateral balance alone isn't going to stop excessive wheel spin exiting the turn. You first address wheelspin, then address balance. It will likely take an iteration or two.
Further, I never said he should use 305s, only that the person who bought the wheels from me intended to do so. I never asked what that guy was running. For all I know that person has a 500+ hp 20B setup
I'd seriously be considering 285s at a minimum for 300 RWHPMore importantly, powerful rotaries are different in how they put power down. I learned the hard way running in a limited size street tire class. Funny how all the serious rotary race cars over the years have larger rear wheel/tire setups. Guess they should have all consulted you first ...
01-05-2008, 01:31 AM
#47
Registered
Join Date: Sep 2006
Posts: 1,363
Likes: 0
Received 0 Likes
on
0 Posts
The issue is he went from around 200 RWHP to 300 RWHP. Lateral balance alone isn't going to stop excessive wheel spin exiting the turn. You first address wheelspin, then address balance. It will likely take an iteration or two.
Further, I never said he should use 305s, only that the person who bought the wheels from me intended to do so. I never asked what that guy was running. For all I know that person has a 500+ hp 20B setup I'd seriously be considering 285s at a minimum for 300 RWHP
More importantly, powerful rotaries are different in how they put power down. I learned the hard way running in a limited size street tire class. Funny how all the serious rotary race cars over the years have larger rear wheel/tire setups. Guess they should have all consulted you first ...
Further, I never said he should use 305s, only that the person who bought the wheels from me intended to do so. I never asked what that guy was running. For all I know that person has a 500+ hp 20B setup
I'd seriously be considering 285s at a minimum for 300 RWHPMore importantly, powerful rotaries are different in how they put power down. I learned the hard way running in a limited size street tire class. Funny how all the serious rotary race cars over the years have larger rear wheel/tire setups. Guess they should have all consulted you first ...
But, from my perspective and experience, which includes a lot of track time in "overpowered" vintage race cars like my Tiger, I was pointing out that you can have well balanced handling in a package with relatively low grip and still have a very driveable combination...
I guess the smile I made my comments with wasn't visible.
01-05-2008, 04:41 PM
#49
Wow--lots of info and opinions guys---appreciate it all.
Basically what all are saying is what I plan on doing.
1- learn the car again
2- change one thing at the time.
I have only spoken with one other rx8 owner with the s.c. about a track set up and his 1st suggestions centered around the rear sway. This guy has been around the track longer than some of us have lived
My set up is as follows ( with it i was running approx 1:50 at road atlanta and a 1:26 at Roebling road in the NA form) driving 8/10 in full nanny mode.
Wheels/tires -- R6 hoosiers 225/45/17 (hoosiers are wide they are as wide as a set of 235 RA1's i have). Weight 40lbs a corner. gears me down a good bit
Suspension--koni yellows 1 turn up from full soft on the rear and usually 1 to 2 turns up from full soft depending. Springs are tech H series, RB sways with endlinks.
alignment --cant remember --think 1.5 -1.6 neg up front and 1.8 in rear and over 7 caster. Due for an alignment before track time in march!
I have ran the same alignment settings for 1.5 k track miles
My driving style is to drive as less as possible---this may have to change some before i am used to the increased power.
My 1st thought is bigger tires---a 245 R compund. I have an 8 inch rim on a 17" wheel. i really like good sidewall support.
I wll go out 1st however on what i have--hell they are almost new.
my goal is -since i have more power now--i want to get it to the ground---it is corner exit i am the most concerned about.
oldscdragger
Basically what all are saying is what I plan on doing.
1- learn the car again
2- change one thing at the time.
I have only spoken with one other rx8 owner with the s.c. about a track set up and his 1st suggestions centered around the rear sway. This guy has been around the track longer than some of us have lived
My set up is as follows ( with it i was running approx 1:50 at road atlanta and a 1:26 at Roebling road in the NA form) driving 8/10 in full nanny mode.
Wheels/tires -- R6 hoosiers 225/45/17 (hoosiers are wide they are as wide as a set of 235 RA1's i have). Weight 40lbs a corner. gears me down a good bit
Suspension--koni yellows 1 turn up from full soft on the rear and usually 1 to 2 turns up from full soft depending. Springs are tech H series, RB sways with endlinks.
alignment --cant remember --think 1.5 -1.6 neg up front and 1.8 in rear and over 7 caster. Due for an alignment before track time in march!
I have ran the same alignment settings for 1.5 k track miles
My driving style is to drive as less as possible---this may have to change some before i am used to the increased power.
My 1st thought is bigger tires---a 245 R compund. I have an 8 inch rim on a 17" wheel. i really like good sidewall support.
I wll go out 1st however on what i have--hell they are almost new
.my goal is -since i have more power now--i want to get it to the ground---it is corner exit i am the most concerned about.
oldscdragger
01-06-2008, 10:17 AM
#50
Rotary wanabee
iTrader: (1)
Join Date: Jul 2007
Location: Long Island, NY
Posts: 1,978
Likes: 0
Received 0 Likes
on
0 Posts
my tire pressure is 1.5 under recommended pressure in the front and 2 psi over in the back. I dont know why ... but it works for me. i used absolutely no science in these results ... just a portable air compressor