Fastest color!

 

The first event with the new coilovers is done. I am pretty happy with the car but there is a lot left to be found. We ran at Pellissipi States in Knoxville, TN. The lot is pretty sloped and sealed asphalt so it was difficult to get a good read on how the car has improved.

Couple of things...

1. I got to get the fenders rolled! Can someone point me toward a fender roller to do the fronts? I think the rears are okay. We really ate the front liners up. I bent the tabs up with my finger as best I could for now but before 7/31 in Nashville I got to get it fixed. I see an Eastman roller for $50 that might work.

2. The roll control is much better. The car was a tad pushy on turn-in. Overall, transitions were markedly improved but I think more roll control is going to be in order. Not sure where to go from here. I am going to give it another event before I start really changing/tuning things. BTW...I am on stock roll bars and 10k/8k springs w/the Ohlin DFV's.

 

I guess I might be talkin to myself.

This weekend is the second AutoX event for the new setup. I spoke w/Jeff @ Ohlins and he suggested adjusting rebound to increase rear dampening by a few clicks to help with initial turn-in push. I will see how that works.

I need some input though on the rubbing issue I am having and suggestions.
- I have the car lowered 35mm. I have rolled the front fenders but still am getting rubbing on the liner. A couple of things come to mind. Do I need to increase the spring rates to prevent this? My only issue with increasing spring rate is how do I balance that with the rear rate? Right now with stock bars it is handling nicely so I would rather not mess with bars till I have too. I have a Saner Front and Miata rear bar that I have not installed yet because I am not sure I need them.
Thanks for the help, Berry

 

The Saner bar will help with the body roll, keep your OEM rear bar. If your car is already pushing there is no reason to soften the rear.

Note: it is very popular here to disconnect the rear bar, but, popular opinion doesn't always equate to correct. I believe having a way stiff front and too soft rear unbalances the car.

http://farnorthracing.com/autocross_secrets3_5.html
The rest of this book is going to be about how to meet one of these two goals:
1.Enlarge the Grip Circle; and
2.Balance the Car
The purpose of both of which is to maximize grip, and with it, lower times - and win!

http://farnorthracing.com/autocross_secrets4.html
You can see that using our example tire from earlier: Load both tires with 200 lbs of load each, and you get 2 x 150 lbs = 300 lbs of grip. But move 100 lbs of load from one tire to another - still 400 lbs total load - and you get 100 + 175 = 275 lbs of grip, or 25 lbs less grip than with both tires equally loaded.

http://farnorthracing.com/autocross_secrets5.html
The primary goal of the suspension, from a racing point of view, is to do all these things in such a manner as to maximize the amount of time that the tire spends in its "happy place" where it is making maximum grip. A secondary goal is to perhaps induce behaviour conducive to balancing the car or affecting responsiveness - things like toe and roll steer come into play here. But for the time being, we'll limit discussion to the primary goal.

The first (and most important) consideration is that no suspension can "create" grip. The maximum amount of grip is produced when all four tires are equally loaded and in their "happy place" from a temperature, pressure, camber, and slip angle point of view. That's the best you can do. Suspension tuning can "unlock" potential grip, and a poorly tuned suspension can indeed lock away a lot of grip, but a happy tire is a happy tire.


http://farnorthracing.com/autocross_secrets7.html
There are two primary philosophies on balancing the car:

1.Make the end of the car that isn't sticking (eg, the front for understeer problems) stick; or
2.Unstick the end of the car that is sticking too much.
Using our twin Grip Circle balance model, Option 1 is to grow the smaller of the two Grip Circles to match the bigger, where Option 2 seeks to shrink the larger Grip Circle to match the smaller.

Of the two options, Option 2 (unstick the sticky end) is by far the easiest, and if it is crunch time, can be used to tame an ill-handling car. But it has the drawback of slowing the maximum possible performance of the car, because the combined Grip Circle has been shrunken. Option 1 ultimately results in an overall faster car.

 

I am not sure of the Saner rates but wouldn't stiffing the front bar compound the pushing problem by increasing the rear grip?

 

If you are pushing now, dont put the saner on.

 

Yes, using the Saner Bar will increase understeer on your S2000, but, will address the body roll.

If you've got push and too much body roll you can:

Increase the stiffness of your front sway bar and increase the size of your front tires.

Increase the stiffness of your front sway bar and increase the stiffness of your rear springs.

Increase the stiffness of the front springs, and increase the stiffness of the rear springs even more (not the best way to address body roll).

Increase the stiffness of your front sway bar, and reduce the stiffness of your front springs.

Leave the front alone and increase the stiffness of the rear sway bar (heresy).

You can also adjust your driving style to avoid overdriving the car on corner entry.

I'm sure others will chime in with more ways to address it.

 

Im wondering if its alignment causing push...

 

Very thorough! The car is 99% AutoX and I am at the max tire size for STR so increasing tire isn't an option to address the push. I like the current balance of the car. With the 10k/8k setup I currently have I feel the ride is really soft for a car that is used like it is. But then feeling it is "soft" isn't really a good way to guage the performance. From reading the STR thread it appears my springs are very light. With the current valving I can go to 700/600 which will put me more inline with the collective (which isn't goal ) I imagine then I will have to hit reset and start over addressing the bars. I am trying one other thing first....


....At the last event I was at -2.1 front and -2.6 rear. Since alignment was the easiest way to go, I had it adjusted. At Nashville tomorrow I am going to run -2.5 front and -2.6 rear.

 

OK, now I think I see it... Most of the STR cars I know of (mine included) run more camber up front than in the rear... My personal set up (for example not necessarily suggestion) is 700/600 springs, Saner front bar, no rear bar, RS-3's, -2.8 front -2.2 rear with only a little toe in in the rear... Saner bar on medium I get awesome balance for sweepers and hair pins but am slightly loose in transitions. On full stiff it transitions amazingly but has slight push on hairpins and sweepers, so I can adjust to the course and surface. I find with lower rear camber I put power down better off the line and out of tighter corners, and the extra camber up front really makes the front bite.