I'm sooo confused....

Budman · Post by **Budman** » Thu Nov 27, 2008 10:49 am

So there is this guy on a forum that I frequent that is running some suspension #'s for me on some sort of higher math calculator thing-a-majig. His calculations are based off of a car in a steady state 1G turn.

My current setup shows the inside front and outside rear with more weight on them.

Inside front: 477 Lbs
Outside front: 1046 Lbs
Inside rear: -149 Lbs
Outside rear: 1096 Lbs

He is suggesting a setup that would give these #'s.

Inside front: 382 Lbs
Outside front: 1141 Lbs
Inside rear: -56 Lbs
Outside rear: 1003 Lbs

Maybe I'm not looking at this right, but it seems that setup #1 has the front weight distributed more evenly and should plant the inside front tire better. In my mind that should equate to more traction for the inside front tire which should result in less push and better traction off the corner than the 2nd setup would, right? Also, with more weight being transferred to the outside rear wheel and the inside rear wheel being lifted quicker the should mean the rear end should be looser/rotate easier, right?

Any knowledgeable insight here would be much appreciated!

Scuffcakes · Post by **Scuffcakes** » Thu Nov 27, 2008 11:27 am

It's gonna depend on what you're going for. Do you want it to rotate easier or be more stable in a steady-state turn? Looks a little like setup #1 will allow you to drive out of the turn harder while setup #2 will allow you to drive into the turn harder. It's pretty easy to make a case for either one. Does that help any?

Budman · Post by **Budman** » Thu Nov 27, 2008 12:45 pm

Doug and I co-drove my car at WS and we both agreed on some things we noticed.

1. The car turns-in great...even better than his car. Car is a little tailhappy when aggressively entering a corner, but feels fast. I really don't want to mess that up if I can help it.
2. At mid-corner when you start to pick up the throttle or at neutral throttle while in a sweeper the car develops a push that is present thru corner exit making it hard to get on the gas. The car's biggest strength is it's torquey power so it is important that I get the car setup to be able to get the power down on corner exit. That is where the car is at it's worst right now. I have negated the effect of the front swaybar to try and decrease the action of the front bar trying to lift the inside front tire when cornering which should have given the that tire more grip. I tried to adjust for the lack of a front bar with stiffer front springs, but it isn't working as well as I had hoped. I don't feel that I can go with even stiffer springs as I feel I am already bordering on them being too stiff.

I put this issue out on SCCA Forums and the feedback I got back was pretty unanimous...not enough front roll stiffness is the problem. They suggested as big a front bar as I can find, and then work from there with springs and rear bar to adjust the balance....i.e. start from scratch all over again.

Here's a link to that thread...
http://sccaforums.com/forums/thread/331438.aspx

MARKP · Post by **MARKP** » Thu Nov 27, 2008 2:16 pm

Post number one: I think you are on the right track. I don't see how more weight transfer to the outside front tire is going to help anything.

Post number two: I am very reluctant to put a honkin front bar on any car that is front wheel drive and has no limited slip. You tend to end up with a car that transitions very well and has lots of wheelspin. I would love to see pictures of the car with the two setups at similar points in the turn. I'm curious if you are getting too much camber change in the center of the turn (max load) which is causing you to lose grip because you aren't keeping the tire flat any longer. IF that is the case, MAYBE more spring would help. No guarantees. I think you have gotten the car between 80 and 90% on the suspension. The other 10-20% will be tough to get and require a lot of experimentation. It is highly unlikely that any one change will get you everything you want.

Post by **thrdeye** » Thu Nov 27, 2008 4:18 pm

If you can learn to drive it, I bet you're gonna be faster if you make it more loose in the rear.

Get that thing swinging around the cones and mash the throttle to pull it straight. Your car has pretty good torque, so I think this approach is worth a try.

Dstan · Post by **Dstan** » Thu Nov 27, 2008 8:35 pm

John do what I am thinking of doing and get a damn 89 honda civic

J/K

My thoughts on my setup is leave it alone on the most part and learn to drive on the same setup. Especially LEARN to drive.
I do have some more poly and powers mods coming this winter but I plan to keep the existing settings.

steverife · Post by **steverife** » Fri Nov 28, 2008 11:00 am

One thing that I've learned with the Mazda is that the car is very unpredictable when the inside rear is in the air. In a perfect world (one without wheelspin and uneven surfaces), I would make the outside front stiff enough to keep the inside rear planted and then use alignment and rear bar to make the car rotate. I think that is the same train of thought you get from the calculations.

No such thing as a perfect world exists, but if I were running FSP in the Mazda and had the time and motivation to really experiment, I'd try that to see what happens. As it is, I only have to worry about front bar or not.

gbwrx · Post by **gbwrx** » Fri Nov 28, 2008 11:30 am

Rife just put a passenger in the rear to help weight it down.

Budman · Post by **Budman** » Fri Nov 28, 2008 1:20 pm

I've really been thinking about this alot over the last few days. There is probably a better way to do this, but after Doug and I each drove the car a few times we felt the front tire temps and the seemed to be pretty close to even temp across the tread but just a bit warmer on the inside edges. It seems that the camber is reasonably close to right then?

I wonder what would theoretically happen if I left the stiff springs in, put a big front bar on and a big rear bar. Would that limit body roll to the point that the front end would stay planted enough that it would seriously reduce the front inside wheelspin on corner exit? That is the problem I've really been trying eliminate from the get-go. In Doug's car it seemed like the turn-in wasn't quite as good, but you could get on the gas earlier/harder without much wheelspin or push. My car also felt more tail-happy than his in quick transitions like in slaloms or the chicago box.

I'm starting to get a little frustrated with this. I don't know enough to figure out what I should do. I wish there was someplace I could just take the car to, have them drive it and they could just tell me how to make it better.

I think my options are....

1. Go up on spring rate to try and control body roll better. This may put the spring rate in the area of too stiff though.

2. Install the softest front bar I can and stiffen the rear bar. I may try this option 1st since I have front bars, but not stiffer springs.

If I could find an LSD I'd put it in there and run either STX or DSP and quit fussing with this stupid wheelspin issue once & for all!

lcoleman · Post by **lcoleman** » Fri Nov 28, 2008 2:08 pm

What diameter sways do you have, and what diameters are available? Maybe I'm missing something obvious, but if you haven't already, I'd get the stiffest front and rear I possibly could and back either front or rear rate down from there...more roll stiffness isn't going to hurt a car than already lifts the inside rear wheel.

Post by **thrdeye** » Fri Nov 28, 2008 3:39 pm

Stiffen the springs before adding bars. More bar=lees independant suspension.

Budman · Post by **Budman** » Fri Nov 28, 2008 4:56 pm

thrdeye wrote:Stiffen the springs before adding bars. More bar=lees independant suspension.

I know that's the right direction to go in as long as you don't get to the point where the suspension is too stiff. Since I am on street tires that limit is lower than those that are on R-comps. Do you think going up 50 Lbs on each corner would do much or should I try going up 100 Lbs per corner? I am currently running 550 Lb springs in the rear and 500 Lb springs in the front. The wheel motion ratio is .97 : 1, both front and rear and the car weighs approx 2280 Lbs. Think it will be too much spring?

Budman · Post by **Budman** » Fri Nov 28, 2008 5:07 pm

I found this site and towards the bottom under "solving handling problems" it states that corner exit understeer is caused by rear struts too soft in bump or front struts too stiff in rebound.

http://www.wtrscca.org/tech.htm

My coilovers originally came with 335 Lb front springs and 450 Lb rear springs and the struts adjust rebound only. Could it be that the struts aren't able to handle the stiffer springs I have installed?

lcoleman · Post by **lcoleman** » Fri Nov 28, 2008 7:18 pm

Well, a 335f/450r spring rate is a .7444 front/rear spring rate ratio, and a 500f/550r combo is a .909091 ratio...it's possible that could be part of your problem. This assumes, of course, that these springs are designed specifically for your car, with that being close to the ideal ratio...if memory serves, you have GC's, so you probably picked your own springs rates--making this meaningless.

Budman · Post by **Budman** » Fri Nov 28, 2008 7:51 pm

lcoleman wrote:Well, a 335f/450r spring rate is a .7444 front/rear spring rate ratio, and a 500f/550r combo is a .909091 ratio...it's possible that could be part of your problem. This assumes, of course, that these springs are designed specifically for your car, with that being close to the ideal ratio...if memory serves, you have GC's, so you probably picked your own springs rates--making this meaningless.

The coil overs are custom made with some no-name asian made strut inside them. The reason the spring rates got closer together is that I negated the front swaybar to try and reduce inside wheelspin. That allowed more body roll so I compensated for that by increasing the front spring rates more than the rear spring rates.