Some interesting reading on stepped headers
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iTrader: (43)
Joined: Nov 2001
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From: Pittsburgh, PA
Some interesting reading on stepped headers I have a 383 Stroker that I know is getting choked by the FLP Y pipe. I was considering new headers and a new Y pipe or True duals. Trying to obtain more knowledge, I stumbled across this web site. Please read it and feel free to comment...
http://www.headersbyed.com/stepped.htm
http://www.headersbyed.com/stepped.htm
Sounds about right..Pay attention to the last 1/4 of the page..Alot of people over-header there car.Seems like our 346's like 1 3/4 headers.That's why I'm going 1 3/4 stepped to 1 7/8 on my 422 instead of a straight 1 7/8 or 1 7/8 stepped to 2"..
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Joined: Jun 2002
Posts: 1,979
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From: Upstate NY
Excellent article, especially when written by a header manufacturer who could make money selling stepped headers. I agree with him.
The engines which probably benefit from stepped headers are tested and retested with various combinations of steps and diameters. Nextel Cup and F1 engines come to mind. F1 engines particularly appear to have very large primaries for their 90 hp per cylinder (or less) and a significant step at a length which appesrs to be the tuning length for their 18000 or so power peaks.
Cup engine exhaust testing keeps the header fabricators very busy. Remember these guys are looking for a horsepower or 3 or 4 in their testing which goes on 24/7. Their engines have a very specific combination which they are optimising.
Why are we still using 4 into 1 headers (stepped or not) rather than 4-2-1s like high-end engines (Cup) which often have a 3500 rpm operating range?
The engines which probably benefit from stepped headers are tested and retested with various combinations of steps and diameters. Nextel Cup and F1 engines come to mind. F1 engines particularly appear to have very large primaries for their 90 hp per cylinder (or less) and a significant step at a length which appesrs to be the tuning length for their 18000 or so power peaks.
Cup engine exhaust testing keeps the header fabricators very busy. Remember these guys are looking for a horsepower or 3 or 4 in their testing which goes on 24/7. Their engines have a very specific combination which they are optimising.
Why are we still using 4 into 1 headers (stepped or not) rather than 4-2-1s like high-end engines (Cup) which often have a 3500 rpm operating range?
