21/53 = 102KMH track speeds at 1-1 shift. If your running a 154 or 165 this is the ideal ratio if your running a tune or close to the Gen5 HP level.
19/53 = 92 KMH track speed at 1-1 shift. This is too low for a 154 or 165. Would work with a 175 tho.
Silber has a few kits built and tested on various models. Pretty impressive numbers for pump gas. 7psi of boost on 91 with options for better cams.
Let me know if you would like to order a kit.
The secondary builds heat with the 157/303 secondary spring and the straight 40 helix. For lower elevation riding, a multi angle helix is needed with a 160/310 primary spring. Slight increase of pin weight as well to get extra squeeze for the lower elevation. I have set ups available if needed...
The biggest surprise was the fact that they use the same clutching as the CTEC 800. If there was an honest 11% increase in power, the clutching would need to be altered to allow proper function of that new power. The weight has a slightly different profile, but springs and helix are the same...
If your looking for some Turbo R clutching, i have an impressive set up that takes away the initial over rev and stops the rpm fade on the top end when going to clicker 1 or 2. Its stronger in the mid range with more top end and lower belt temps. Back shift is greatly improved as well. It...
I dont know the exact changes Silber has made. I was told that the primary goal was to get rid of the lean emissions control from 5500-6400 rpm, along with adding some fuel and timing to make the sled run better over all. This tune works great in a G4 as well.