slide wrote:
........ Could always do a Vizard and have it poking up out the back of the bonnet. What are the legalities around doing this? Is it an absolute no no nowadays, or can you add a bulge or reverse opening scoop (bit like adding a bulge at the front of a round nose to accommodate a cross flow head, but at the other end).
The only people who can really answer this question are you rego authorities... However, before asking, I would get quite familiar with the relevant regulations....
I fitted an IDA at one stage and for that a hole is the only option. After some argument, my local RTA (as it was in those days) office was forced to admit that my set-up was legal.
They had two issues. The first being that the carb and its shroud must not obstruct the drivers forward vision. Luckily the rules have a specific test that a bonnet scoop must pass... which it did (because I started with a copy of the regs). Secondly, any protrusion from the bonnet must be an integral part of it. An air filter poking through won't pass (Ford shaker scoop anyone???) but a scoop bolted to the bonnet does meet the letter of the law..
My problem was that the K&N filter that came with the IDA was meant for a Chev and it was not easy (b&*^y impossible IMHO:) to design a reasonably aesthetic scoop to cover it. I got tired of helpful people reminding me I'd left my lunch box on the bonnet....
The IDA worked really well.. but not well enough so that eventually I got tired of looking at the ugly scoop and reverted to a pair of SUs.
Cheers, Ian
PS The IDA replaced a 45DCOE that I couldn't get a decent filter for.... Cutting an old bonnet seemed a lesser evil than chopping the firewall.