I ran in my first real Autocross yesterday with SCCA in the Great America parking lot. I have track experience, I have run at Thunder hill a few times with a 2008 WRX with Falken Azenis RT-615s, and those felt pretty good on the track. I now have a 2007 MCS that is completely stock other than running R84 x-lites with pretty worn Hoosier tires (older Rs I believe). They are down to the wear bars, but I read that they may be usable down to the depth of the holes that are molded into them. Maybe they've run out of heat-cycles? I know a lot of variables go into what I'm about to ask (especially the driver), but please bear with me.

During all four runs, I was having traction issues. I had DSC off, and had no real chance to warm up the tires. There were a lot of people in my run group, so it seemed like there was 10-15 minutes between each run. The wheels were constantly spinning when I would accelerate, especially around corners. The tires seemed to slowly be warming up. The front passenger side wheel slowly climbed from 120 degrees after the first run to about 140-150 degrees after the 4th run. Is this even in the ideal operating temp for the Hoosier Rs? I think I've read that the R series take longer to heat up, being ideal for track time, not autocross. Would that potentially be my biggest issue, or would stock suspension, and front wheel drive also greatly contribute to it?

Just to give an idea of relative best times:
06 MCS_____________43.9____D Stock
07 Impreza wgn______45.7____D Street Prepared
91 3000 GT_________46.6_____Street Tire - T2
03 Evo_____________46.62____Street Tire - T2
08 VW unkown______47.14____D Street Prepared
92 240sx___________48.3_____D Street Prepared
Mine 07 MCS_______48.74
08 Mazdaspeed3_____50.5_____D Street Prepared
09 Solsitce GXP______51.3_____Street Tire - T2

I ran as a fun run, because I expected to be a part of the DSP class, but had what I believe are T2 tires, and so I wasn't really sure where to run. I think next time, I will just get some autocross tires, like the Direzza star-specs on the R84 wheels, and will probably have a rear sway bar installed, putting me in DSP, right?

 

Pretty sure you would be in STX unless the tires throw you out. I doubt it.
DSP would only be with a tune, front mount, or catless exhaust. I'm pretty sure.

Tire problems... No clue. I have all seasons and mine don't hold for **** at autocross. Buying KDW-2's next month

 

I suspect your biggest issue is the need for a mechanical limited slip.

 

As the OP speculated, I am wondering more about how the tread depth may relate to heat cycles and how hard the tires may have become.

 

+1. If the tires are heat cycled out, they won't grip no matter how much tread is left in them, the rubber can only take so much heat, then it turns into a big hockey puck...

 

Sorry, but you're talking about a stock car right?

It really needs morenegative front camber, it really, really, really needs a limited slip. And it needs good tires, shaved to a useable depth.

 

If you have a bone-stock MCS you'd run in D Stock and be able to run DOT slicks. Adding a rear sway bar will put you into STX and you won't be able to run slicks. To get more front camber wil require coil-overs again putting you into STX. While an LSD is a plus it isn't absolutely necessary and you'd need to go with a stock unit not a quaife. Your tires seem to be the culprit here. As they say here in the Carolinas "They're slap wore out!". ;-)

As you may have found with the RT-615s there is a fine line between when the tread wears to the bars and you begin to lose grip. The same no doubt holds true for the Hoosiers. Some Kumhos will do you well in stock. They have given me seconds of improvement on the same car at the same track on the same day.

 

+1 more here for old hard hoosiers. I've run on plenty of hoosiers that were beyond their useful life- even with visable rubber left (but, I picked them up for cheap or free). Star Specs would be faster, easily.

 

hmmm....

I'm in the "slap wore out" camp on this one...

I ran Hoosiers in '05 and '06 before the Works kit was admissable in STX (I was banished to ASP thank you VERY much) and found that if the tires were cool I would just spin the car. Front grip wasn't the issue, but the back end was downright thrilling!

Get a bar and some Z1s and run STX - that would be my two bits...

I run a Quaife though so what the hell do I know.

Cheers,

Charlie

 

Great, thanks a lot for the responses, guys.

I think I'll start with different tires, not slicks, and the rear sway bar, and progress in steps as I continue to autocross and determine how serious I get about it. If I were to pursue the MINI LSD, where would I get one? Directly from a dealership, and then have them install it? I see the Quaife is about $1200, but I haven't found a price on a factory LSD.