after getting the car mapped last week it was mentioned about the inlet manifold i currently have fitted to the 1900 isn't really up to the task. i kind of knew it wasn't great but i am not to botherd for the 1900. the 1800 screamer is a different matter, i want to make sure it's as right as can be. main issue is to get long trumpets on and the tb's sitting in a cooler airflow area. it seems to be mainly motorsport type mk1's i've seen where the inlet manifold has allowed the tbs/carbs to sit at such and extreme angle. does anyone know what manifold manufacturers have manifolds that give a rake as extreme as this?
There is a company called Bogg Brothers that might be able to make one to order. They do a lot of custom inlet manifolds for bike carb/tb conversions. Prices are mean't to be reasonable as is the quality. However, why not look to fit an airbox with pipework routed to a good spot? As long as you can get at least 25mm between the end of the trumpet and the internal face of the airbox. What's your goal, maximum cold air? Another idea would be to knock up an angled plate to increase the angle on what you have currently.
There's not an awfull lot wrong with the popular (mangoletsi) inlet manifold once it's ported out (it IS cack in standard form though). You have to open the ports out enough to break into the bolt holes and blend it into the head. The outer ports end up with a sort of egg shape at the port entry (givin away my secrets here !) as you curve the ports. The inlet manifold can't be tipped up like the pic above if yr running carbs because of the floats. The mangoletsi manifold has a slight angle to it which is ok 98% of the time but can sometimes cause hesitation & spluttering on very tight corners depending on the speed, mine got better as I developed the suspension but it'll never go totally... fuel injection (t/b's) would cure that, and could obviously be run in a semi downdraught angle as above. Bends in inlet manifold ar'nt as bad as most people think as long as the curve is gentle and not abrupt (anyone seen/remember the old swan-neck Mini inlet for D.C.O.E's !). I've got and old 8v hot rod inlet which is almost a straight port into the head, the only problem is it's for in-line applications only, we were going to try and make an adaptor to angle the carbs on this manifold but because of the change in shape/spacing figured it would be a bit of a mission, hence the ported mangoletsi. I'll have a word with a chap I know who does some great fabrication work, we've just spoken about some top mounts I want making, one off's wont be cheap but the price can obviously drop with quantities, depends how much interest there is in them (manifolds & top mounts for that matter). I think the throttle bodies in yr pic pol are Pierburg items (in fact the car looks familier.. mk2 sprint car with 2ltr 8v ?), maybe the same make for the inlet manifold, though doubt it's available new. I use a ported "bendy" type inlet manifold right over the top of the hot exhaust (with a stainless heat shield between) and get over 100hp per ltr (107 to be exact) so neither is such a problem really.
