i know you wasnt slating my work and i know where your coming from as regaurds to listening to people like lance . as i said lance is an expert and defo knows his stuff , but and its a big but , like ive said look at what you are going to pay for an exhaust manifold and see if it is worth the money in parts and labour and if it all adds up then you know your getting a product thats worth what your paying , then the next thing to do is see if there has been any testing on the manifold , if there has , again your getting the product that actually works . as regaurds to building one yourself then yes use the best materials possible if you can ,but i bet your looking at the best part of a £1000 to buy parts , build time and tig welding . the time that goes into cutting the bends to the correct lenght is quite a long process and to ensure that each header flows equal amount of air i pour water into each cylinder and measure every header . if they are a couple of ml out they get made again .
this is my manifold for my zetec turbo as now iam going 4x4 the over the gearbox type is useless
heres a list of parts and the cost
zetec flange 13mm thick £35
t4 turbo flange 13mm thick £30
x3 2-1 merge collectors 304 £225
x5 180 u bends £50
x1 1 metre pipe £10
x5 45 bends £35
x5 90 bends £40
x 4 1 3/4 to 1 5/8 cones £20
x1 wastegate inlet flange £20
x1 wastegate outlet flange £20
+ vat = £570 give or take a few pence
thats just to buy the parts
now the man hours
its at least 42 hours to build something like that for me as i want every thing perfect and every header indentical in terms of flow.
thats all in 304 stainless now imagine that in 321 stainless your looking at the best parts of £1200 just for parts , so now imagine the cost lance would want for building and welding it , i would say another £1200 for labour would be a fair price, your now at £2400 just for a manifold for a road car , i dont think many people would pay that , thats why lance does motorsport work , cause thats where the money is!
the collector is 1.5 mm thick but it is spun stainless and not rolled and welded which makes it very strong and very good with heat
cheers paul