501x Novak gtb 4.5 finally thermalled. Gearing comparisopns..

[Colinevan]

Unfortunately my 4.5 finally thermalled in the blistering heat at Bury this weekend. My initial gearing of a 16 tooth pinion vs 91 tooth spur resulted in the car losing its top end 4 mins into racing and running at half throttle until half a lap and then going back to full throttle etc.

I decided to drop to a 15 tooth pinion with the 91 tooth spur which helped matters as when calculated is the optimal 13.000 ( or there abouts )overall ratio as reccomended by novak.

However im wondering if that could be too low etc as the car was no where near as fast etc. Would going to a 17 make maters much worse etc?? Anyone tried experimenting.

My previous car ran a 5.5 on 96 tooth and 16 pinion and was fine.
This was replaced with a 4.5 which ironically woked best on the same gearing and i believe to this date is still on this gearing ( sold on).
New car runs obviously on 15/16 with a 91 and seems to run warmer than the previous older speedo. I will however state that yesterday was a very hot day

What is everyone else running on?

Col.