What size headers?
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From: Southern Indiana
What size headers? Just wondering what the advantage would be to go with the 1 7/8 primaries instead of the 1 3/4 headers. Im planning on saving for some h/c after headers just wondering what the advantage would be to go with the bigger size.
The 1 7/8 should make equal low to mid-range torque and more horsepower. Assuming the cost is about the same, the only advantage of 1 3/4 headers is they may have fewer clearance issues in the engine compartment.
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Joined: Dec 2003
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From: Cherry Hill, New Jersey State
I just wounder will be a difference between the 1 3/4" and the 1 7/8" headers primaries even the collectors of both are 3" size!!!
I done some calculations and found the following
1 3/4 " = 1.75" = 44.45 mm
1 7/8" = 1.875" = 47.625 mm
To find the size difference between the two headers primaries:
1.875" - 1.75" = 0.125"
or
47.625 mm - 44.45 mm = 3.175 mm
Thus, we have 8 primaries, with this addition:
8 X 0.125" = 1.0"
or
8 X 3.175 mm = 25.4 mm
But, would this addition of 3.175 mm (0.125") in each primaries affect the engine output power if the engine made in the way to deliver 500rwhp!!!
For myself, I couldn't find the answer, but from reading in the net, it look that engine to deliver up to 480 ~ 500 rwhp the 1 3/4" can do the job, and for engine to deliver over 500 rwhp the updage of 1 3/4" to 1 7/8" is required...
I done some calculations and found the following
1 3/4 " = 1.75" = 44.45 mm
1 7/8" = 1.875" = 47.625 mm
To find the size difference between the two headers primaries:
1.875" - 1.75" = 0.125"
or
47.625 mm - 44.45 mm = 3.175 mm
Thus, we have 8 primaries, with this addition:
8 X 0.125" = 1.0"
or
8 X 3.175 mm = 25.4 mm
But, would this addition of 3.175 mm (0.125") in each primaries affect the engine output power if the engine made in the way to deliver 500rwhp!!!
For myself, I couldn't find the answer, but from reading in the net, it look that engine to deliver up to 480 ~ 500 rwhp the 1 3/4" can do the job, and for engine to deliver over 500 rwhp the updage of 1 3/4" to 1 7/8" is required...
Last edited by LS6; Jun 17, 2011 at 04:09 PM.
Based on standard engineering gas flow formulas a 1 7/8 piping system will flow 19.5% more than a 1 3/4 piping system of the same design and length. So the difference is not huge.
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Verdad Gallardo It's not stupid for someone that's on a budget build. Esp when the average set of 1 7/8 headers is several hundreds more over a set of Pacesetters. That money saved there could go towards a bump stick 
Yeah, I forget about the price differential sometimes because for my 05 CTS-V headers from any particular manufacturer (e.g. Kooks, or B&B) usually cost about the same whether they are 1 3/4 or 1 7/8.
