Crossover shim

Joined
Jul 14, 2002
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#1
What role does the crossover shim stack play? I am playing with my base valve stack and I am just learning about stuff and this has me confused.

Thanks
 
Joined
Jan 2, 2001
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#3
you haven't done a search on this?
Crossover shims gives the stack above it a free float, untill it hits the stack below. Thicker crossover, more room to bend etc. It is a tuning device for the slower shaft speeds mainly.
 

bclapham

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Nov 5, 2001
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#4
shim stacks come in stages- no crossover is a single stage, 1 crossover is a 2 stage stack- it enables the tuner to separate both LSC and HSC (to a degree).

for example, the rm125 has a 2 stage passive valve stack- by swapping the 10.1 crossover to a 12.1 i was able to increase the LSC and leave the HSC somewhat the same.