Originally Posted by
botters
just had a look at all the above manifolds and i must say while i am no expert (even tho i do make manifolds and exhausts for a living i would say that on all the above manifolds the collectors are crap flow wise, the haywood ones have managed to siamese all 4 ports!!! and on the jamsport ones with the big triangular collectors there could be serious floe issues with the way the pipes enter the collectors as there is a big step up in size just after the primaries that can cause the gases to pulse back towards the engine causing all sorts of back pressure issues. however all thease manifolds should provide better flow characteristics than a standard manifold as the primary sizes on a standard manifold are too big anyway for good flow, i would reccomend 1 3/4 inch on anything up to 200bhp-230bhp and 2 inch an anything above plus there prices are way too high 700quid!!!!! i am looking into making a few differnt designs late this year eg/ standard turbo location and turbo above the box location, the flanges cost me 20 quid and are laser cut in surgical grade stainless which will never rust EVER!! and i cant see any of them taking more than a day or two to develop and i am happy to pass my savings onto other passion ford members probably looking circa 200quid for standard location and 300-350 for above gearbox that is with a new downpipe running down back of engine (efi will be required for this as mfi gets in the way) however i dont want to sound too much like i am slagging the above manifolds off as i am sure they make an improvement over standard as the standard rst manifolds are cack!!!
iam sorry to say this mate but everything youve just said is wrong. the manifold in stevenebm pic was made by me and is a bargain in my opinion.
i think you should price items before saying that everyones getting over charged. also this style manifold was used on my zetec turbo engine that produced 522bhp on the engine dyno i might add , this manifold has had years of development work done to it and powers some of the fastest fords in the uk. the collector cone is a good alternative to a merge collector , its made out of spun stainless steel for strenght and very good for the high temps that are involved in a manifold like this. its ok building something that looks good but with no testing in a controlled enviroment (dyno) you are never going to know when the manifolds reached its limits etc. as for the pipe size again your miles off , bigger is not always better fact! , the headers on my manifolds are 1 1/2 as the headers are long so smaller pipe to keep exhaust gas speed to an optimium. you say use 2" pipe above 250bhp well 1 1/2 did 522bhp and 2" headers you might find on a 5000bhp drag car ,definently not on a 300bhp car. things can always be improved upon , like my own manifold that did 522bhp was unequal , now all my manifolds are made with equal lenght headers to vastly improve on torque . also we are now offering a 4-1 merge collector instead of the cone , again helping slightly with flow design making it the ultimate manifold , but things come at a price and i can tell you that the merge collector alone comes in at £150 for me to buy so i think some manifolds are good value.
that my manifold that did 522bhp
note the unequal lenght headers
stevenebm finished manifold
notice the equal lenght headers
hope this helps everyone
cheers paul