Modifying a monster 450SEAC

By: Tim Lamont

In my line of work, if you can call it that! I design and generally muck around with various automotive components, to a large extent for TVRs. In nearly all cases for the ‘newer’ models ie. from the TVR Griffith onwards.

I have in the past however owned five V8 TVR Wedges, which surely qualifies me as a Wedge enthusiast so when Steve Charlesworth (aka stainless_steve on Pistonheads) asked me to supply just about anything I could to make his 450SEAC more outrageous, I was to say the least pleased. I had in the past modified four SEACs; two of which I owned personally but this one was going to be a monster.

Steve's monster 450 SEAC [ Enlarge ]		Rear, note large spoiler 'wing'

The modifications I employ have been developed considerably over the years on the ‘newer’ cars but Steve’s car was the first pre-Griffith model to have the twin carbon plenum system fitted to it – this should be interesting I thought.

For those who haven’t heard or seen a SEAC in the flesh, to put it mildly they are a tad outrageous. Back in the tolerant 1980’s they were shocking enough (that was TVR’s intention!) but in today’s politically correct EU governed climate ‘anarchy on wheels’ springs to mind. Having just said that the SEAC’s are outrageous enough, Steve wanted to give his silver beast even more, and be heard above the rest – what a bloke!…..and I was delighted to help.

Side view [ Enlarge ]		Interior with non-standard seats

The SEAC was a development of the 390SE; in fact the first prototype (the white press car) was really a 390SE under the skin. The model was produced with racing in mind. TVR had already been racing with the Tasmin series with some success but with the SEAC they had created a real monster with a power to weight ratio greater than that of a Porsche turbo. In fact the only production car that could match its off the line acceleration was the Lamborghini.

Not only was the car brutally fast but also featured a full kevlar composite body. This however only applied to the first ten or so cars, as kevlar proved to be very difficult to cut and work with and TVR were struggling to make any profit even at the initial price of £28,500 as it was. Optional extras were power assisted steering (£365 extra), air conditioning (£735), metallic paint (£135), English leather upholstery (£805 extra) and half hide seats (£373 extra) according to an October 1986 UK TVR price list below.
Cars built thereafter were a mix of kevlar and GRP glass fibre, they also experimented with carbon fibre for five or six cars. As well as an ambitious body construction some of the cars featured fully rose jointed suspension and solid lifter engines, although the majority had more down to earth rubber suspension mounts and hydraulic lifters.

Wind power....not!		Front

The body was different in many ways to the 390/400SE’s with a shorter, narrower transmission tunnel, rounded and softened nose cone being the most noticeable difference, the rear bumper was also deeper and the side skirts and wheel arches were also exaggerated to accommodate the wide wheels.

The engines were initially prepared by Andy Rouse, then back in 1987 NCK took over. Engines featured Cosworth pistons, forged con rods, tufrided crank shaft, stage 3 big valve heads and a fast road cam. Engines varied in their ‘state of tune’ from car to car, the 420 was rated at 300bhp and this was quite a realistic figure for some of the ‘hottest’ cars.

Total production was 56 this breaks down as 37 road going 420’s, 19 were road going 450’s and a one off special TVR production car racer (Jeff’s yellow 420).

Production for the 420 SEACs started in 1986 and the 450 SEAC range in 1988. The last SEAC – the very nice dark green J-reg was produced in 1991. By this time fully spec’d from the factory this would have set you back nearly a staggering £50k. With the arrival of the long awaited Griffith at under £25k the Big Bad Wedge days were truly numbered.

SEAC engine		Close-up of induction system

Steve’s car was originally the 1988 Motor show car and was one of the first 450SEACs built. The engine is a 4.4L Rover V8 and features Cosworth pistons & rods, stage 3 big valve heads with the road/race cam with solid lifters and has been fully blueprinted. The car also features a full hide interior and rare 16" multi-spoke wheels and has a partial rose jointed suspension. Steve wanted the ‘works’ and some of the modifications are detailed below:-

• Fully tailored exhaust including triple ceramic coated manifolds
  
• Twin carbon plenum induction system
  
• Magnecor racing ignition lead set
  

After the mods I am pleased to report that Steve’s car has now around 12% more grunt than a ‘standard’ 450SEAC and let’s say a bit more than 12% more exhaust noise!!

ACT carbon induction system [ Enlarge ]		Carbon plenum from rear

Some would frown upon modifying such a classic TVR, but all of the modifications can be reversed and put back to original as Steve has retained all of the original TVR parts.

My thanks go to Steve for giving me the opportunity to try our twin plenum system on a SEAC; I hope he is happy with all the extra grunt.

Tim Lamont.

Thanks to Tim Lamont for this article.