Has anyone ever lowered the gearshift tunnel in front of where the shifter is? It's quite intrusive to cabin space

The centre tunnel is a key part of the GTM Coupe's monocoque structure.
I have seen a couple of examples where someone has cut away the closed bottom of the tunnel (to get access to the gearchange) and this has caused the tub to kink!
I dare say that it could be possible to lower a portion of the top so long as the full structure is replaced and the new part fully welded.
The 1980's general assembly drawing shows a stepped central tunnel.



My GTM Coupe has square holes in the top and sides for access to the gear change, I think these would be better if they had rounded corners.

As minitici says the tunnel structure is a major contributor to the strength of the monocoque so I don't think it could be removed -- I wonder if it would be possible to introduce a small indentation near the pedals to act like a footrest and broaden the pedal box area -- a bit like the modification Pete made to the tunnel on the Libra. The downside might be that there are pipes and tubes running in the tunnel that might be in the way. Anyone any thoughts on this?
Steve

I thought it may be structural. I wonder if a rounded tunnel would still be as strong? would make it look a little less agricultural and give a bit more comfort/leg room. I'm going to modify the wheel arch to give more clearance around the throttle pedal, would be nice do have a rest for the clutch foot too

I did a lot of work on this when I made my GRP chassis/tub.

Basically the chassis is just 3 box sections (the tunnel and two sills) connected together by 2 bulkheads and relies heavily on the tunnel for its rigidity.

Personally I would not make any modifications that weaken the tunnel in any way. It will certainly have a detrimental effect.

Slightly related query but does anyone have some measurements of the tunnel to hand?

specifically the Length from front to back (to the access panel) and width across the top?

Thanks

everything is always possible!!!!!!!! someone once said dont bring me problems bring me solutions!! so the solution involves the use of triangles but thats all im allow to tell you.

On my coupe I modified the panel by the wheel, instead of having it go to a sharp corner I ran a sheet across the corner that just misses the tire, then I removed the inner corner to widen the pedal area. This allowed me move the throttle pedal and brake across and away from the column. My pedals are all individually mounted so I could get the position exactly as I wanted. making enough room for my size 10-11 feet, I can even drive mine in safety shoes/boots.

Now I have considered a modification to the tunnel to allow me to move the seat over slightly which involves making the tunnel more triangular. I have some other plans brewing as well I really like the early chassis dropped front bulkhead and how this ties in the bulkhead better and would like to replicate that on my chassis one day as i feel its a better engineering solution.

If your going to do mods to the tunnel you need to be very careful with how and what you do, i.e supporting the chassis correctly while modifying.

Neil