Lets clear this up:
Firstly, on the topic of a rear spool. yes, your theory is correct in a grip racing situation
. Providing the rear of the car has traction and both rear tires are hooked up. The car traveling in its traction circle WILL indeed require the outside rear to travel FASTER than the inside rear. True.
However, as i mentioned, drift setup is a little different. The whole idea is to LOSE traction. On turn in, a diff setup in the rear will allow the outside to complete its traction circle and the wheel stays hooked up and planted. This is at the detriment of turn in because it effectively increases rear grip.
A spool eliminates the tendency of the rear to hook up. How? By eliminating the ability to complete the traction circle, to compensate one of the tires MUST start to slip. This decreases traction and causes the rear of the car to initate a greater slip angle. (Aka. DRIFT)
As for drift angle, the same theory applies. Once sliding, unless both rear wheels are equally loaded, a diff WILL unload in the direction of the lighter sprung wheel. This facilitates outside grip at the expense of forward traction. If one wheel is unloading, then you have no forward drive. The slip angle decreases and your drift ends. So in this situation the Spool is also superior.
You state that this will result in a great drift angle. How can this be so?
You mentioned the diff unloads and allows the outside wheel to spin faster. When the rear of the car is sliding, it is undergoing a slip angle to compensate for its pointed direction. Neither rear wheel needs to spin faster than the other. The acceleration vector is inline with the rear of the car. Not pivoting on the inside rear as in a grip racing situation.
This is similar to what you stated, however. A diff will still have a tendency to unload as the rear of the car is dynamic and never evenly loaded. A spool effectively sums the difference and most importantly, provide forward traction to continue the drift regardless of angle. Something which cannot be said of a diff. As the slip angle increases, the higher the tendency of the diff unloading to the inside wheel.
An LSD by definition(limited slip differential) is not a spool.
So you are correct in saying this! However, if you read my post correctly i did not say it was. Please don't misquote me.
I did make mention of the fact that like a spool, it provides forward traction for the end of the car that is experiencing a large slip angle. Perhaps i should have made this more clear for you.
Why would you need to keep the outside rear wheel faster in a turn until you hit the apex? Even in a grip racing situation, once exiting a corner your rear diff is still providing conpensation for the rotational differential at the rear of the car. Only in a perfect unobtainable situation is the diff purely providing traction and experiencing a "locked" state. This statement is misleading in a grip situation.
In a drift, the rear of your car is experiencing a large slip angle as you point into the corner. If you were to follow the accleration vector, then the apex is irrelevant. Are you taking a racing line? Are you taking a line that best allows for drift angle? You tell me.
Finally, to quote:
"Something that you didn't mention is that well I would run open diffs front and back but keep the rear diff just a little tighter then the front and also keep the rear a bit stiffer (suspension)"
Of course i did not mention this!!
This is not something that i run. How could i possibly mention a setup that i don't run, from a person that i don't know?You are entitled to your opinion, as i am to mine. If you have a thought or comment please post it, but critising my post on the basis that i didn't mention something YOU prefer is absurd.
I hope this post clears things up for you. If not, please feel free to correct me!