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Title: Flange size 1 5/8 header small or BIG? Post by: Felix/DFL on May 19, 2009, 21:23:16 pm Hi Folks,
I yust recived a 1 5/8 +header from Turbo thomas for my notch. Nice piece of stainless steel, there is yust one point which cracks my head. Will the small flange (2") work on a 2,2l ??? Won`t it be a big restrictor at high rpm`s and let the engine run hot? Or will the fast travel of the exhaust gas due to a venturi effect benefit? So what ya think, or which experiences did you make? The flange change is no big issue so that would be no problem... Engine (still in progress): Stroke x bore 78,8x94; Valves 42x37; FK10; CR about 10,5-10,7; 48 IDA, should go up to 7000rpm easily Best Greetings, Felix Title: Re: Flange size 1 5/8 header small or BIG? Post by: Peter on May 22, 2009, 10:42:46 am Hello Felix,
I have a 2276 with a small flange header as well, i dont think the flange is too restrictive for a street car, my engine does not run hot with the external cooler, and you have to think: you dont drive at 7000 rpm all day. maybe you can get more power out of it with a big flange flat out, but then in low rpms, the power can drop I d say, just try it and if it doesn t run hot leave it like it is :) Title: Re: Flange size 1 5/8 header small or BIG? Post by: Diederick/DVK on May 22, 2009, 12:05:23 pm i thought tobi was the exhaust man in the club, felix ;)
didn't he modify his header? including the flange? Title: Re: Flange size 1 5/8 header small or BIG? Post by: dirk zeyen on May 23, 2009, 23:54:55 pm hi felix,
walter (bug-box) has done this long time ago, he posted on the old "DFL-Forum" ask him. dirk zeyen Title: Re: Flange size 1 5/8 header small or BIG? Post by: Felix/DFL on May 27, 2009, 21:10:15 pm Hi Ruff,
thank`s for the answer. Good to know that your 2276cc is not getting to hot. Of course 7000 rpm is not the all day operating point. But I don`t want that the D opened 044`s heads and welded mainfolds are for nothing as the exhaust is to restrictive. I maybe go with a flange between the small and the big "hole".I will look what some "normal" cars have in use and adapt it. As the merged section is pretty short I am afraid that a to big flange will destroy the scavening/venturi effect as I need to shorten it if I go to a biger flange... And that`s the big advantage of the merged headers. What I find really interesting is that most of the old & fast racers went with the small flange. Have a look in to the bible old and new testament or the pic`s of Fab/the living scanner ;) The A1 mufflers even have a neck just after the flange as the turbo mufflers... Just thinking before I cut ::) @ Diederick: Yes, Tobi has welded a 2.5 V Band on his header |