Opel Manta 400 Turbo
Project Undertaken 3rd January 2011
This project was set to be something special from the outset! were approached with regard to building a Manta 400 'show' car... The brief was big power, and a look that will set it apart from the 'typical' Manta 400. Around the time we were first contacted regarding the build we happened to have a relatively solid non-sunroof coupe shell in our possession which we bought as an unfinished project (you may have seen it in Total Vauxhall magazine). This was decided to be a good shell to start from, and so plans began for the project!
The floors and chassis rails were a bit rough (typical Manta!) and this, in combination with the fact that a good chunk of the floor and bulkhead would need refabricating and strengthening anyway, led to our decision to refabricate the entire floor/chassis rail/bulkhead from scratch.
We started with the chassis rails which were made up using 60x40 box section, with gusseting on the joints. The sleeves for the subframe bolts were machined and welded in place with the subframe used as a jig (this was welded to other points of the shell before the old rails were removed to keep the alignment)
At this stage we are already designing in some of the later details of the build. The engine bay is to be super-minimal, and will be losing the raised 'bulge' that usually houses the pedals. We will be designing a floor-pivot pedal box for the brake and clutch, which will incorporate rear-facing master cylinders set into the floor. We are effectively replacing the Manta front jacking points (which tie the sills into the rails) with a recessed 'box' that will house the aforementioned cylinders.
As you can also see here, the inner sills have been cut away and 75x40 box section welded along the inside to add further strength to the shell.
With the boxes in place, the rest of the floor area is fabricated and welded in place.
Moving briefly back to more 'cosmetic' metalwork, the nose is to be changed to the '4-slot' type.... We had an excellent used Manta front-end in storage so this was used. The 'noses' were split at the original seams and spot-welded in place as per factory fitment.
At this stage we also had a trial fit of the 400 kit. The fit is outstanding! (thanks Martin!)
Next we offered up the engine and gearbox, so we could fabricate the mounts and also modify the sump to suit the Manta crossmember.
Now attention turns to the rear axle. We are going to bring the car relatively 'up-to-date' with a complete independent rear axle from an S14 Nissan 200SX.
The bulkhead and tunnel is the next area to get attention.
Two removable cross-members are added between the chassis rails for strength, which kick up at the end to allow clearance for the 3" exhaust system which will be going on.
In the meantime we've started on the panels. The boot has had the GTE spoiler holes welded up, and been smoothed out ready for paint. The doors have been de-handled and de-locked and the bodykit has been smoothed out. ONe door also needed the lower skin repairing. All these parts get a heavy coat of 'Reface' at this stage, ready for block sanding.
