watts best

Watt,s racing or tarmac.
Panhard gravel rally

Sorry to raise an old thread but looking at my RS the diff pinion angle is more like 1.6 deg up - not 4. I have modelled my engine conversion around the 4 deg as I have seen elsewhere. I realise I should allow for maybe 1 deg up for acceleration which means maybe 2.6 down on the gearbox end?

Anyone measured the stock Mk2 diff pinion angle?

Does lowered reverse eye leaf springs effect pinion angle?

Reverse eye doesn't alter pinion angle as the rear hangers stay where they were , if lowering beyond that I expect the diff will go more nose down by a micro amount. I've always gone for about 4 deg nose down as written in the rally prep book

But my diff pinion is 1.6 deg nose up (+1.6).
Google says the angle between tail shaft and both flanges needs to be the same but opposite - meaning the output flange and diff flange need to be on the same vertical parallel plane. Hence if you have 4 deg pinion down on the diff you need 4 deg up on the gearbox which is impossible.
My thinking was 4 deg down on the gearbox and ideally 4 deg up on the diff during acceleration. Due to the forces during acceleration the diff pinion is rotated up meaning you need less than 4 deg pinion up at rest - but surely the pinion won’t move through 8 deg (-4 to +4) when accelerating.
What am I missing?

I think I’m on the right track going by this thread.

http://www.gmh-torana.com...336-diff-pinion-angle/

TREMEC have a driveline angle app