RebekahsZ Posted July 29, 2012 Share Posted July 29, 2012 Boot me if this is not the right place to discuss this. I've only done two road race track days with my cousin at a really cool club track in his Wrx out near Dallas/Ft. Worth (can't remember name of track). He's also had a spec miata and a Radical, currently building a Caterham. I've only done some occasional autocross and drag racing myself. Loved the videos. My question: Why do folks seem to intentionally hit the inside curbing? Does that not really "upset" a car being driven at the limit of adhesion? Quote Link to comment Share on other sites More sharing options...
mark Posted July 29, 2012 Share Posted July 29, 2012 Shortest distance between two points is a straight line. Typically inside tires are unloaded to the point a mild bump will not upset he car. It really depends on the corner, the size of the curbing, speed thru he corner, car set up, dirVer preferences and probably several other factors I've left out Quote Link to comment Share on other sites More sharing options...
Mikelly Posted July 29, 2012 Share Posted July 29, 2012 Depends on the corner and the car. My C5 Corvette loved the curb hopping. It was wide enough and planted enough that it didn't seem to upset it much. The Porsche 996TT wasn't as wide and would get upset. You had to commit. The Spec Miata didn't like it much, and that was due to narrow wheel track and short wheelbase. I "think" the datsun will like it "some", but still I try to minimize it. But as Mark says above, it is often the shortest distance, especially in a series of "ESSES", like the climbing esses on VIR. And we're not trying to "boot" people, but rather get them to do as you just did... Ask "Why", rather than make some incorrect statement. Mike Boot me if this is not the right place to discuss this. I've only done two road race track days with my cousin at a really cool club track in his Wrx out near Dallas/Ft. Worth (can't remember name of track). He's also had a spec miata and a Radical, currently building a Caterham. I've only done some occasional autocross and drag racing myself. Loved the videos. My question: Why do folks seem to intentionally hit the inside curbing? Does that not really "upset" a car being driven at the limit of adhesion? Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted July 29, 2012 Share Posted July 29, 2012 In case I ever forget to say it, there is always an implied "why" in anything I post. I'm here for knowledge. Quote Link to comment Share on other sites More sharing options...
johnc Posted July 30, 2012 Share Posted July 30, 2012 Curb hopping reduces lap times. But, as mentioned above, the car setup is critical - in particular high speed compression damping (> .3 mps) on the shocks. Digressive valving reduces the rate of force increase based on piston speed and thus are more effective at controlling the chassis over curbs. Even better are blowoffs that significantly reduce compression damping force at high piston speeds. Even better then that are the custom Penske triples I had on the racing 240Z had Velocity Dependent Pistons (VDP) that had adjustable valving for high piston speeds. We could sorta adjust the high speed compression to allow for different height curbs so the shock would go open (blowoff) at > 3.mps for a certain amount of its travel. Before Buttonwillow was repaved the curbs in the esses were about 3" high. I could drive straight over them and there would only be a slight movement in the steering wheel. More the a few guys had a lot of trouble following my line. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted July 30, 2012 Share Posted July 30, 2012 Wow! I got a lot to learn. Quote Link to comment Share on other sites More sharing options...
johnc Posted July 30, 2012 Share Posted July 30, 2012 Don't curb hop with Tokcio HP or Illumina shocks. You car will get tossed a couple feet to the side. Had that happen years ago at Streets of Willow going through the kink. Found myself off track to the right and spinning back across the track to the left. Scared the crap out of me and the six cars closely following. Quote Link to comment Share on other sites More sharing options...
johnc Posted July 31, 2012 Share Posted July 31, 2012 An example of curb hopping from back when cars were setup with lots of compression damping, spring, and roll stiffness. Plus its an excuse for me to again post one of my favorite facing vids. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted July 31, 2012 Share Posted July 31, 2012 I like all of it except for the flipping and crashing. Wild, Wild West! Look expensive. Quote Link to comment Share on other sites More sharing options...
260DET Posted August 3, 2012 Share Posted August 3, 2012 Put this in the tool shed, way out of time, banned for having fun. BTW me and old mate kick Porche monkey arse, 59 second laps on Federal semi slicks. Against full slicks here, times do not lie, bullcrap fails http://www.natsoft.com.au/cgi-bin/results.cgi?30/06/2012.LAKE.P1 Quote Link to comment Share on other sites More sharing options...
HS30-H Posted August 3, 2012 Share Posted August 3, 2012 BTW me and old mate kick Porche monkey arse..... Doesn't matter how fast you are ( or how fast you think you are.... ) if you can't spell 'Porsche' you're still a loser. Quote Link to comment Share on other sites More sharing options...
Tony D Posted August 4, 2012 Share Posted August 4, 2012 More the a few guys had a lot of trouble following my line. "I don't know, the guy in the other old Datsun went right through there, I had the perfect line, then it just went away!" Quote Link to comment Share on other sites More sharing options...
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