MI-Roger
11-07-09, 04:47 PM
I ordered a new gasket to fit between my new (Mar '09) downpipe and my old (Oct '03) Saab/Remus system. I had originally installed a SS high temp Type 1 gasket with only a 2-inch diameter bore to stop my leakage problem at the flanges. Type 1 gaskets are flat on one side and tapered on the other, picture a truncated cone. The flat side mated to the down pipe flange and the tapered side nestled in the expanded neck flange of the Saab/Remus.
I know from my engineering classes that having a single point of reduced diameter in a piping or duct system will not be a big hindrance to flow (think of an orifice plate flow meter), but this small gasket has bothered me since I installed it. I did a lot of searching and discovered that the rear catalytic converter flange gasket for a 2004-06 Subaru Baja Turbo is a thick Type 1 high temperature gasket with a 2-1/2 inch diameter bore!
So now I will have a 3-inch downpipe with its reduced discharge flange, feeding into the 2-3/8 inch Saab/Remus, using a 2-1/2 inch bore gasket at the flanges. I will post pictures when the new gasket is delivered and I can lay it next to the old one for comparison.
I know from my engineering classes that having a single point of reduced diameter in a piping or duct system will not be a big hindrance to flow (think of an orifice plate flow meter), but this small gasket has bothered me since I installed it. I did a lot of searching and discovered that the rear catalytic converter flange gasket for a 2004-06 Subaru Baja Turbo is a thick Type 1 high temperature gasket with a 2-1/2 inch diameter bore!
So now I will have a 3-inch downpipe with its reduced discharge flange, feeding into the 2-3/8 inch Saab/Remus, using a 2-1/2 inch bore gasket at the flanges. I will post pictures when the new gasket is delivered and I can lay it next to the old one for comparison.