Destination SSM One Miata's Journey through Hell

12Sep/120

Nationals

Nationals was an ... interesting experience this year.  I originally didn't want to go, due to being broke, not terribly into the sport right now, and knowing the car wasn't ready, but was convinced by my dad and some friends to make the trip.  So, out we went.

At the Pro Finale, the car wasn't handling terribly well, and was bogging miserably coming out of slow corners again.  We tweaked some suspension settings and that improved the handling situation a little bit, but we couldn't figure out what was up with the bogging.  So, I finished out the pro in 4th place, 1.2 out from the win overall.  There were a bunch of slow digs that the car couldn't get out of its own way for, so that time was easily there, especially if I could have landed a left side run (I was only 0.3 behind the winner on the right, 0.9 on the left.)  I was generally happy with the car's performance at this point.  It was obviously capable of running the times, especially if I could fix the slow corner problem.

So, we spent Monday driving around the streets of Lincoln with a laptop, working on trying to smooth out the AFRs on tip-in.  I fixed a bunch of stuff, which made the car feel like it drove much better, and so my dad (who didn't run the Pro) took practice runs on Tuesday, and ... after a couple runs got the same misfiring under tip-in as before.  This time, I pulled data from the AIM system and saw that with each run, our intake temps were jumping by ~20 degrees, culminating in 180 degrees during our practice last (and very misfirey) run.

That seemed likely to be the problem, so we drove all over Lincoln, bought a hole saw and some tubing parts, and cut a hole in the hood right over the supercharger, put a 90 degree bend on the inlet, and popped the filter through the hood.  We bought some more practice runs for Wednesday morning, spent more time on the street and really got the tip-in working pretty solidly, and then had no problems with heat or misfiring Wednesday.  The filter through the hood isn't the most attractive part of the car, but it's certainly doing the job.

Thursday came and the car was awesome -- handling's still a little quirky, but better than the Pro, but after the runs, I was in 2nd, only 0.4 off Carter, with 3rd several tenths more behind me.  Joy quickly turned to disgust, however.  We were immediately protested by Jake Namer for an illegal splitter, which was later upheld, and gave us a 1 second penalty on all of our runs.  We then lazily shaved off enough of the splitter to be a couple inches under the limit.  I was disgusted enough by the whole process that I just went back to the hotel and caught up on work all night instead of walking the other course, so for Friday runs I didn't really know my way around, and coned all 3 runs.   It was a long drive home, but at least by 2pm Friday we were on the road instead of having to go to the banquet, and, as such, got home at midnight Saturday night, so I got a full Sunday to unpack and unwind.

For reference, the splitter in question is pictured at the right.  The green photoshopped area is the legal area of an SSM splitter (which we are almost a square foot below.)  The little green penned area on the chopped off part (3/8" deep by a few inches wide) is the illegal area of the splitter, as determined by the protest committee.  When Bill and I built the splitter, we measured it in my garage to be 5" from the bumper (a full inch under the max rule), but somehow since April, our mounting mechanism has bent out to bring it over 6", and hence illegal.  Turns out that using sliding forks to locate the splitter isn't a great idea for autocross, since there's the maximum forward distance rule.  We were hoping it would help absorb cone hits, but that turns out to be less important than staying legal.  Oh well.  That's autocross.  Live and learn.

On the bright side, the car is very competitive, even in its primordial form right now.  0.4 off Carter is better than I ever would have hoped, and the data showed that there was a lot more time on top of that run.  So, it's proof that the SSM Miata concept is viable, which was the goal of this year.

 

Posted by David de Regt

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