SEAT Original setup (Scroll down to see
the REDO) Most Diablo builders opt to mount the
seats permanently with no adjustment due to high clearance. I am 5'11"
and I wanted to be able to adjust the seat and so my wife could drive it
too. I began to see what I could come up with. I tack welded
everything until I was satisfied It would work and my wife agreed. I
first started by finding the "center" of gravity of the seats and
determined where they could pivot the least but with the most
adjustment. I then marked that on each side of the seat.
I cut a
1/8th piece of steel about 15" long and 3in wide I cut slots on both
ends and welded a bolt in each slot.
made L brackets and tack welded them in to position to accept the bolts.
the 1st stage. The bolts act as a pivot and do not interfere with the
function of the seat rails from the original Fiero.
the seat was in place I checked for clearance and the height was not too
bad. My wife and I could both sit without hitting our heads.
had to devise a way for it to adjust and stay in a locked position.
to the original Fiero seats and removed the seat adjustment bracket and
assembly. I cut off the upper long piece and came up with this.
see that the adjustment will allow for the seat to be tiled forward or
back and locking it into position.
(Passenger Side) View
I plan to reinforce the seats with 1/2 in
square tubing (see yellow below)and a steel plate where the pivot bolts
to the seat. I think this will work out fine.
I installed 1/4" round steel on the back
side of each seat and then glassed it in. The seats are now very rigid
and stiff. I was worried about flex but it does not seem to be a
The yellow shows where the steel was
glassed in. It was done from the back so it is not seen. It should be a
great improvement in feel and rigidity.
Seat Redo #2
Ok a year later and the body is now mounted and i realized that the way
the seats were mounted were both unstable since there was only 3
mounting points and it sat too high with the seat rails. No matter
what I wanted to be able to move the seat and I wanted to be able to
adjust the "tip" so I began to see what others were doing for this and
decided to put together my own design incorporating some very good
ideas. First if you must have seat rails you are going to have to lower
the floor pan. There is no other way of doing this and I searched
for months for some type of low profile seat rails and there is simply
none to be found..
Step one, using my plasma cutter I
carefully cut out the floor pan. One of the things that you must keep in
mind is that this small area is what connects the front and the rear sub
frame. The Seat mounting is also used to reinforce this area.
Removing the floor pan will require you to reinforce this area again. I
cut just to the edge of the gas tank cross member and followed it just
near the end of the front sub frame. I cut along the out side and
then towards the back sub frame.
I reinforced the opening with 1 X 1 steel
and made sure I welded the sub frame together and connected it to the
outside frame.. I welded two new seat rail supports on the
underside of the new steel.
Another close up of the new steel. I
was able to mount the seat rails closer together to fit the seat better
and connected them with 3/16" flat steel.
I wanted to be able to raise and lower or
"tip" the seat if in needed to so I created a pivot point in the rear
and made it adjustable from the front.
The pivot is made from 7/16" rod and
I cut 1/4" brackets to hold the pivot bolt
The seat is upside down and is tack welded
to show you how the mechanism works
I welded the Threaded rods to the spacers
and then the brackets to the 1/4" flat rod that is bolted to the seat.
I thought about the rear pivot point for a
long time. I wanted a very sturdy and quite mounting point. I
found some strap hinges that had plastic bushings making the very quite
I bolted on end to the flat bar on the
rails and the welded the other side to the flat bar on the set.
(Both flat bar steel is 1/4" for rigidly and support).
You can see here how the rear pivot works
and how sturdy and neat it looks. It is slightly offset by design
however it does not affect the quality of the job. I offset
it because I did not want the spring to touch the side so I moved in
Here is an example of the seat installed.
You may have to re-welded the lever. You can see in the picture that
there is not much room to slide it over, however if you look in some of
the previous shots I actually cut it off and added some steel to move it
slightly over so that it would not hit the bolt when moving it.