Sept FasTrack

[Sebastian Rios]

Would you build an BM to the class minimum wheelbase, it being only 8" longer? Why are there limitations in D/E Mod on how much a builder can shorten (but not lengthen) their vehicle's wheelbase (besides possibly maintaining original look)?
In a high powered RWD autocross car, is braking traction more important than corner-exit traction in an autocross setting? Is the extra tractive ability gained from additional rearward weight transfer with a shorter wheelbase worth more or less than the (not-necessarily-negative) changes to handling balance in throttle application?

I guess I just happen to disagree, I'll take a shorter wheelbase any day and any way I can get it around the cones. Superb yaw control and stability is great in Turn 8 at Willow but not what I'm looking for in the parking lot.

that's cool. I'll agree to disagreeing. no need putting everyone to sleep over it.

I'm not asleep, keep it up you two.

[Giovanni Jaramillo]

Would you build an BM to the class minimum wheelbase, it being only 8" longer? Why are there limitations in D/E Mod on how much a builder can shorten (but not lengthen) their vehicle's wheelbase (besides possibly maintaining original look)?
In a high powered RWD autocross car, is braking traction more important than corner-exit traction in an autocross setting? Is the extra tractive ability gained from additional rearward weight transfer with a shorter wheelbase worth more or less than the (not-necessarily-negative) changes to handling balance in throttle application?

I guess I just happen to disagree, I'll take a shorter wheelbase any day and any way I can get it around the cones. Superb yaw control and stability is great in Turn 8 at Willow but not what I'm looking for in the parking lot.

that's cool. I'll agree to disagreeing. no need putting everyone to sleep over it.

I'm not asleep, keep it up you two.

I'm learning more and more as long as they speak in layman's terms.

[Curt Luther]

In a given turn, the longer the wheelbase, the greater the difference between turning radius of the front vs. rear wheels. And that means to clear the apex cone with the rear wheels (which is what matters if you're doing it right), you need to swing the front end around wider, increasing your *effective* track.

In addition, that front end that you're swinging around wider is *that* much closer to the next slalom cone once the rear wheels clear the current slalom cone, making the problem worse. Body overhang will have a big effect here, too.

So I think a good case can be made for shorter wheelbase having an autocross performance advantage.

...says the guy who got his ass handed to him first hand driving a long wheelbase Civic against the short wheelbase Minis at Nats last year...

[Jason Munchhof]

Walter Wong has been running his NSX down here with a 225/275 V710 setup and some suspension bits. I actually found it easy to drive in that config. No issues with snap oversteer at all. It was a little sluggish to turn in, and the gearing is a bit too tall like Randy mentioned... but overall it's a sweet ride.

[Marshall Grice]

In a given turn, the longer the wheelbase, the greater the difference between turning radius of the front vs. rear wheels. And that means to clear the apex cone with the rear wheels (which is what matters if you're doing it right), you need to swing the front end around wider, increasing your *effective* track.

In addition, that front end that you're swinging around wider is *that* much closer to the next slalom cone once the rear wheels clear the current slalom cone, making the problem worse. Body overhang will have a big effect here, too.

So I think a good case can be made for shorter wheelbase having an autocross performance advantage.

I submit my proof that a neutral steer car has the front and rear wheels tracking the same radius in a turn. 103" wheelbase car.
http://vimeo.com/6229233" onclick="window.open(this.href);return false;


also I wanted to add that for a RWD car you want it a touch oversteer to enable early throttle application in most cases due to the longitudinal weight transfer shifting the balance towards understeer.

[Will Kalman]

Fair enough, but not all of us have the good sense to drive neutral steer cars ;)