Re: drag predictions
I predict 13.4 to 13.6 for the manual if you’re a novice; 13.0 to 13.3 if you’re experienced.
In the modified manuals you drop too much boost between gear changes compared to the auto, the T56 is not exactly a box that you can fast change gears, plus the ecu works against you. You really need a lot more rwkw in the manual to keep up with a modified auto. I have raced my T-56 manual (once only) at WSID against modified autos, and it’s interesting to see a loss of around 2 car lengths against the auto every gear change.
By my calcs in 4th gear you’ll redline at around 112mph with the 3.73 diff, so you’re going to drop off towards the end of the ¼. Get into 5th before the end of the ¼ and you’ll lose more time changing gear, and you won’t have enough grunt to keep accelerating hard. I’m using a 4.10 diff, and it seems to have made the situation worse, although I’m still a novice.
Ideally you don’t want to get into 5th before the end of the ¼, and in this heavy car you need up around 400rwkw to accelerate well with the 0.8 overdrive gear if you do get into 5th.
I’m about to raise my rev limit to 7500 revs, so I should be able to pull 130mph in 4th even with the low 4.10 gears.
Nizpro Stage 3 ... 360rwkw (482rwhp at Brisbane show) 6-speed Manual ref http://www.nizpro.com.au/customers/xr6t8u/xr6t8u.html