Originally Posted by Equilibrium Tuning
My leak theories are based on actually physically testing many cars for boost and exhaust leaks and finding major leaks in about 75% of tested cars and smaller leaks in about 90%. These are cars that have been built by "proffesional" shops as well as private parties. Because of this we always pressure test all cars that we work on extensively. No one believes their cars have leaks until they see it for themselves. I believe this sort of test should be common practice and especially so when doing testing and comparisons.
Ed, while I don't have your data regarding the effects of manifold leaks I can tell you that when we were researching manifold designs we came a cross a lot of "don't do this" material (same as when we designed our oil pan) and I will keep these manufactures nameless. One of those items that we didn't want to deal with was gasket leaks due to poor flange design and/or warping from welding. I've posted a few examples we came across during our what not to do search. one has obvious leaks due to finish and/or warped flange surface the other just has horrible finish that will likely leak at some level too. Of course the 2 bolt flange was never an option for our setup as they are horribly
unreliable from a gasket/seal perspective.
Not only a rough time saver finish, but you'll notice the top right hole is ovalized. This is not something you'll NEVER see in a Killer B Header.
product, we are not a shop, we're a manufacturer. You'll never find one of our welders installing parts or wrenching on cars one day and welding another. They weld, and only weld. They are welders and know how to spread the heat around to minimize warping. ALL of our flanges are CNC machined on all surfaces to our own spec to provide a flat smooth surface finish. Even at this, a 1/2" flange can still move some, and that's why we grind our flange surface flat as one of the final processes our headers go through.
The last variable we have no control over; who installs the product. Were new OEM gaskets used, torqued to proper spec, etc. That's up to you guys