I have completed the prototype for the m20 underdrive pulley. This is a slightly different concept than I originally intended, but it keeps the cost down and you get to keep your AC.
This kit required the modification of the harmonic damper. In short - we machined the pully off of the damper and balanced it. As this is for my motor, I also ground off all but 3 teeth as to use it with MSnS for ignition control. I did this instead of the 60-2 wheel reader because it was simple, proven, and reduced a little weight. I also didn't have to make any electronic mods to my standard MS box.
The pulley is 6061 aluminum. Everything is a 10-20% reduction in speed except the AC which stays the same as stock. Assuming testing goes well, there will likely be a harmonic balancer exchange program as well as the option to take the instructions to a machine shop and have the modification performed.
There is a slight gap between the pulley and the harmonic damper as to not interfier with the damper vibrations and function.
When comparing to the kits available for the m50, I am hoping for over 8hp gain. This will not be confirmed until it is before and after dynod on a NA m20.
Anyways... here are the pics...



What do you guys think?
This kit required the modification of the harmonic damper. In short - we machined the pully off of the damper and balanced it. As this is for my motor, I also ground off all but 3 teeth as to use it with MSnS for ignition control. I did this instead of the 60-2 wheel reader because it was simple, proven, and reduced a little weight. I also didn't have to make any electronic mods to my standard MS box.
The pulley is 6061 aluminum. Everything is a 10-20% reduction in speed except the AC which stays the same as stock. Assuming testing goes well, there will likely be a harmonic balancer exchange program as well as the option to take the instructions to a machine shop and have the modification performed.
There is a slight gap between the pulley and the harmonic damper as to not interfier with the damper vibrations and function.
When comparing to the kits available for the m50, I am hoping for over 8hp gain. This will not be confirmed until it is before and after dynod on a NA m20.
Anyways... here are the pics...



What do you guys think?
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