It's not so much the grippy front tires but just the overall grip of R-comps compared to street tires, combined with a rear swaybar that tends to lift the inside rear wheel.

In general, you can't really cure this by simply changing the overall grip of the car (except with a drastic reduction, i.e. going back to street tires). This is because the wheelspin is a *dynamic* condition (occurs only during weight transfer), not a static condition (after weight transfer has occurred, i.e. after car has "taken a set"). There are, however, several ways to address it:
1) Clutch-pack LSD (ideal cure, illegal in stock)
2) Remove rear bar (rather effective, illegal in stock)
3) Adjust damper settings (somewhat effective, legal in stock)
4) Adjust driving style (somewhat effective, legal in stock)

As we've said, you're pretty much restricted to 3) and 4). For damper settings, since you want to stabilize the rear in corner exit, you'd want to try increasing rear compression and decreasing front rebound. Unfortunately, damper settings always have a complementary effect: they do the opposite thing under opposite conditions; in this case, these adjustments also make the car less stable in turn entry (trail braking). That's where 4) comes in...

 

Thanks. That's very helpful. I'm really limited to 4), since I have stock springs.

Which brings up the questions:

1. When you say "adjust driving style," what do you mean? I know that my car can go much faster as it is (I traded cars with another S2000 driver on Sunday, and he drove my car almost two seconds faster than I did, wheel spin and all), so I know that I can push it harder. But what driving style flaws cause exacerbate rear wheel spin that I can correct, realistically?

2. Would stiffening my front bar by 15% make a noticeable difference?

Thanks.

 

2: Yes
1: Slower inputs, especially steering

 

2: Generally, a stiffer front bar is a good thing just because it allows you to run more front tire. Not sure if I agree w/ payne that it'll be of much direct help with the wheelspin.
1: Just anticipate the wheelspin and "drive around it" -- smooth inputs are certainly key, as well as feathering the throttle when wheelspin occurs. Maybe even altering the line somewhat to get more of the turning done early for a straighter exit.

 

Unfortunately, I don't have my copy of Puhn's book handy, or I'd quote it directly. The paraphrase is that to alleviate wheelspin, you either reduce anti-rollbars on the end in the air, or increase on the end not in the air. Wheelspin relates to f-r balance, not absolute roll stiffness on the end in question.

 

Haven't read Puhn, but have read Milliken&Milliken...

Let's say his (static) handling balance is pretty neutral as is. Now he slaps on a big bar, with no other change -- I'd agree that this will alleviate wheelspin, but only because he's reduced front end grip, which has reduced total grip, which has reduced total weight transfer, which has kept more weight on the inside rear tire. So he's slower everywhere except where he was getting wheelspin; will it be a net gain? Maybe, but I wouldn't bet on it, especially with all that understeer.

I think another issue is that the wheelspin is occurring in a nonlinear region of the suspension response. The load on the inside rear wheel is not determined entirely by simple roll-stiffness and lateral g's: at some point, rather than allowing the suspension to droop, the swaybar just mechanically lifts the inside wheel.

 

just wondering if anybody has tried using a smaller bar in the rear such as the 04/05 bars and keeping the front as it is? that's in comparison with using a bigger front bar or removing the rear bar completely...

 

I am running the 04/05 bar and found the car to be more balanced at the track. While I am happy with it, I'm sure many wouldn't be. I am currently running 205/245 RA-1's.

However, I'm about to unbalance things as I have 225's on order for the fronts.

Cal

 

tell me how that goes w/ the 225/245 tires and 04/05 rear bar when you have tried it out...

 

what is a solid bar??