Gear set to convert to the shorter/closer ratio 5th/6th JDM gearing. Reduces the 4th-5th shift bog and allows for a more useable 5th and 6th gear. Best suited for use with USDM MY04-06 gearing. Kit includes 5th drive gear, 6th drive gear, 5th/6th driven gear cluster, and adapter keyway.
Gear Ratios: 1.062 (5th) / 0.842 (6th)
Usually ships in 2 to 3 days.
Does this kit come with the carbon synchros for 4th,5th, and 6th? No. We used to offer a kit with the carbon synchros but have split it up. The carbon synchros can be purchased separately.
Is it possible to install these gears on MY07 and newer STI or on Legacy Spec B models? Yes, its possible to install them but the ratios will not work well. These models have a taller 2nd, 3rd, and 4th gear ratios. The 4th gear to 5th gear ratio difference will be very small making the 4th-5th shift almost pointless.
Which is the better option: the close ratio 5th/6th kit or the tall ratio 2nd-6th kit? It depends on the application. The close ratio 5th/6th is more suitable for rally applications and shorter tracks. The 2nd-6th kit is more suitable for longer tracks and drag racing.
What are the effects of a shorter 6th gear on the highway? The 6th gear ratio difference is about 10% so there will be about a 10% increase in rpms for the same road speed. This will have some negative effect on the highway fuel economy.
What is the purpose of the "adapter keyway"? Subaru has changed the keyway width for the driven gear shaft from wide to narrow. They have discontinued selling many of the wide keyway gears and normally this would require replacing the driven gear shaft and 3rd/4th driven gear at the same time which is a significant additional cost. We are producing an adapter keyway that allows a narrow keyway gear to be installed on to a wide keyway shaft. Subaru began using the narrow keyway on the USDM Spec B and MY07 and newer STI models so basically all applications that this set is suitable for require using the adapter keyway.
