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I know this should be in the proper forum but I thought you guys may have answers and at the least find it interesting . This is the factory exhaust on my 2004 f250 v10 . Any ideas on why they would reduce it down like this ?
Why? No idea why Ford did that. I'm just a shade tree mechanic.
Traditionally, stepdowns help maintain some back pressure to keep exhaust valves from burning.
I believe it was Ford's solution to a "flutter" in the exhaust of the V10, essentially causing back pressure in order to give the exhaust time to sort itself out.
It just seems very odd . We've been trained to believe bigger pipes freer flow = more power so what affect would a 50% loss of area have ?
Have you ever seen the video where Engine Masters or some such, hits headers with a sledge hammer for clearance, then documents the HP difference on their dyno? Even with every pipe dented severely, very little difference.
Casper's theory sounds likely, V10s have some weird harmonics.
Strictly a guess. If they enlarged the pipe on each end of the cat to match the connecting pipes, then they’d have to enlarge the center section as well which may; make it too big for the underside, too big for the engineered exhaust flow, too costly.
These are the only spots on the exhaust ( each downpipe at the Y ) even close to that small . After some research online for v10 truck performance the general consensus is that exhaust upgrades are of some value but gearing and a tune is the best bang for your buck indicating that what looks to be an easy " fix " is not hurting as much as it appears . Still confused .
Being small going into a larger pipe the small pipe would have more force for the gasses to get into the larger pipe gasses.
It may be needed being it goes in at a 90* and not a 45* like some Y pipes do.
Oh I stayed in a Holiday Inn once
Not a clue like everyone else
Dave ----
