We are both sort of wrong....
At stock pulley ratios
Where you said
"The 21 tooth gear rotates the same speed as the pulley."
For the 1.6L - the 35 tooth (connected to the 5 lober) is
actually driven by the pulley at 12,986rpm
and the teflon coated rotor is then spun at 21,644rpm via the internal gearing.
For the 2.3L - the internal gearing spins the 5 lober to 14,288rpm or 10% faster and subsequently
the teflon coated rotor is then spun at the
much touted 23,813rpm.
This might be a surprise to some -
the 1.6L is spinning at almost the same speed as the 2.3L.
This also lines up with my other observation and that is the two kits are very similar in profile.
I would guess they are identical in shape, but the 1.6L rotors are cut shorter for the shorter motor.
I'll approach it from the 2.3L angle.
How much longer are the 2.3L rotors?
I dont have a 2.3L on hand but based up on my scale drawing in the previous post - the 2.3L about 278/220mm = 26% longer
Given it spins at 10% faster and is 26% longer - 1.6L x 1.1 x 1.26 = 2.2L - close and I'll take a cigar when the true 278mm length is verified.
So - my target is now to establish if the gearing snouts are interchangeable.
Given some (like Guran over at mbworld
here) have the SC pulley spinning at 65/185 x 6200rpm = 17,650rpm and hence the 3 lober is actually spinning at 29,410rpm!.....literally
screaming...(well that's always a relative term), and dont seem to suffer from belt slip to any significant degree, we can obviously spin these babies fast.
If we can interchange the snout from the 1.6L onto the 2.3L Rotors and body, then we get the extra 26% length, without the complexity of having to run a second belt.
We can then run the SC at a lower speed for the same volume and possibly improve the efficiencies somewhat....
TBA on that comment.
There is still the pro blem of actually fitting the cooler> intakes etc to the longer charger...but that's another challenge.
b22b