Golspie Sprint 06/08

Sunday, 05 October 2008

Kames Sprint 04/08
East Fortune Sprint 05/08
Kames Sprint 05/08
Golspie Sprint 06/08
Boyndie Sprint 07/08
Alford Sprint 07/08
Kames Sprint 08/08
Golspie Sprint 09/08
Boyndie Sprint 09/08


Golspie Sprint 7-8/06/2008

The weather forecast wasn't the best, with rain expected on the Sunday, but somehow it stayed warm and dry.  Everyone caught a bit of the sun and the cars were all going very fast.  The class A6 entry was very strong and it looked like good driving was going to be required to avoid finishing 6th and 7th.  In the end we were well pleased with 3rd and 4th in class on both days, and our PBs were well and truly destroyed on both track layouts.  In fact, david managed to get to 0.08s of the class record - just before it was lowered by over 2s!  Oh well, back to the drawing board.

Biggest change to the car for the weekend was the fitting of rear wheel speed sensors which meant the traction control firmware could now be tested.   as with the launch control earlier in the year, both drivers did their practice runs without the electronics just to test that the sensors were working reliably and to establish what sort of front/rear slip percentages we were using.  Then we set the traction control to allow 20% difference in speed front to rear, took a deep breath and turned it on.

There's not all that much you can say about the results really.  Most of the time the car behaved exactly as before, but there were a couple of points on the track where we could feel the system doing its stuff.  The biggest benefit in the dry is that it's now possible to get the car into a slight oversteer attitude through the tight hairpins.  Previously we couldn't hold that position without risking a spin, and backing off inevitably resulted in slow understeer out of the corner.  We were both surprised by this, since we hadn't expected any real benefit in dry conditions.  The second straight at Golspie also showed some benefit.  This straight has a very off camber left hand bend in it, and it's just enough that the back end of a powerful Westfield will break away as you approach the second hairpin.  The traction control did a great job of stopping this behaviour.  From inside the car, you can hear the engine speed rising, and you can feel the back end start to move, but the movement is never fast enough to be a worry and the throttle stays on the floor until it's time to brake.  In fact I had to look at the data logs to be sure it was the traction control doing this and not just great driving!

What the datalogs did show was that most of the traction control system's activity was caused by one rear wheel losing grip and spinning up.  Clearly our viscous diff isn't doing the job we would have wanted and it appears the traction control is actually just covering this up.  If data we collect during the rest of the season confirms this, then a new diff is a distinct possiblity next winter.

Enough rambling, here're some pics of the racing!





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