Tunnel Cover mod re short shifter
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Rennlist Member
Joined: Oct 2003
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From: Nova Scotia
Tunnel Cover mod re short shifter
After fitting a short shifter to a C4S ( and this will apply to C4 & TT) described here , there was the matter of making a relief in the metal of the tunnel cover to accommodate the 25mm additional length hanging beneath the car.
Common wisdom is to heat & beat a pocket into this cover without shrinking the attachment bolt spacing; however, I have read of incidents where lowly suspended cars have hit this 'dimple' on the track/roadway surface ... jamming the shifter in gear. Therefore, an easily removable cover plate looked more attractive.
As I had a spare tunnel cover, there would be no loss in chopping away at it, for it was already pretty twisted up. In mapping out the shifter left to right movement, an 'oval' of 4" x 2" was cut with a hole saw and a grinder. A similar oval was traced onto a piece of wood and relieved ~1/2" with a drill bit ( Forstner type). Then, a piece of lighter gauge galvanized sheet was convinced to fit this mould with a ball pein hammer.
Basically, the new bottom cover took the shape of the desired dimple: after trimming and some more hammering, a strip of sealant was laid in and 4 sheet metal screws pulled it together over the oval hole ... to finish, some racer tape made the edges aerodynamically correct
Anyway, an alternative trick to beating the crap out of your tunnel cover and permanently deforming it - and if I smack it, 4 screws and it's off ....
Common wisdom is to heat & beat a pocket into this cover without shrinking the attachment bolt spacing; however, I have read of incidents where lowly suspended cars have hit this 'dimple' on the track/roadway surface ... jamming the shifter in gear. Therefore, an easily removable cover plate looked more attractive.
As I had a spare tunnel cover, there would be no loss in chopping away at it, for it was already pretty twisted up. In mapping out the shifter left to right movement, an 'oval' of 4" x 2" was cut with a hole saw and a grinder. A similar oval was traced onto a piece of wood and relieved ~1/2" with a drill bit ( Forstner type). Then, a piece of lighter gauge galvanized sheet was convinced to fit this mould with a ball pein hammer.
Basically, the new bottom cover took the shape of the desired dimple: after trimming and some more hammering, a strip of sealant was laid in and 4 sheet metal screws pulled it together over the oval hole ... to finish, some racer tape made the edges aerodynamically correct
Anyway, an alternative trick to beating the crap out of your tunnel cover and permanently deforming it - and if I smack it, 4 screws and it's off ....
Last edited by Garth S; Feb 8, 2007 at 08:24 PM. Reason: pics added
Drifting
Joined: Dec 2005
Posts: 2,797
Likes: 12
From: FT. LAUDERDALE, FL
On a C2, for those interested, you reverse the bushing that supports the shift rod in the tunnel. If you don't, you have to dimple the tunnel as you did. Ask me how I know...
By reversing the bushing in the housing, your shift tube/rod should maintain its geometry and you shouldnt have to dimple the tunnel and your shift lever inside the car should sit about 1.0" higher than stock.
By reversing the bushing in the housing, your shift tube/rod should maintain its geometry and you shouldnt have to dimple the tunnel and your shift lever inside the car should sit about 1.0" higher than stock.
