3/4 or 7/8 Headers

[BRAPPPP]

I searched through quite a few threads and couldn't find any solid info other than marketing. For a naturally aspirated engine, are 3/4 primary or 7/8 primary headers going to be the most hp/tq? I realize that if your running a lot of boost in a SC engine the 7/8 will be the better option, but what about for NA ? I may consider doing a whipple in the future so i have to take that into consideration as well. From what i have heard the 3/4 will give better back pressure and increase the velocity of the exhaust scavenging. However, i noticed that companies like SW only sell the 7/8 for the 6.2 and most guys are going with the 7/8.

 

[NickPic83]

If u r seriously think about a SC then go 1-7/8"

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[XxWarEaglexX]

I agree with NickPic83, if know that in the future you plan on doing a supercharger go big or go home. Definitely 1 7/8.

 

[Dv8tor]

If you're worried about scavenging, they do offer the ceramic coating that should speed things up. Agree will Nick. If your contemplating supercharging, go with SW 7/8.

 

[BRAPPPP]

If u r seriously think about a SC then go 1-7/8"

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Did you go with the 3/4?

 

[NickPic83]

Did you go with the 3/4?

1-7/8" i keep tossing around the idea of a S/C. probably never do it but u never know

 

[Boris]

I'm putting a SC on my truck and I went with the Kooks 1 3/4
My vehicle will be a daily driver with some KICK !

IMHO

Unless you’re building the engine into a 600 plus HP
There’s no real reason to go with 1 7/8
You’ll never get the benefit of the bigger exhaust

Also don’t waste your money on any coating,
There’s a ton of air flow under your truck to cool every thing

UNLESS you plan on doing desert racing and beat the shit out of your truck
Constantly redlining her


My 2 cents

 

[BRAPPPP]

Well with the whipple they are putting 500 to the wheels so that's over 600hp at the crank

---------- Post added at 11:55 AM ---------- Previous post was at 11:54 AM ----------

Even with a supercharger will you get more down low torque with the 3/4?

 

[Deinonychus]

IMO the 1 3/4" primaries if N/A to optimize velocity. Just not enough displacement to warrant larger primaries.

Forced induction is another story. More gases to expel - greater cross-sectional area needed.

If 1 3/4" is too small for N/A, then you can probably predict that 1 7/8" is too small for forced induction.

 

[BRAPPPP]

Is the 3/4 going to optimize velocity that much more than the 7/8 or is it minimal?

---------- Post added at 02:14 PM ---------- Previous post was at 02:01 PM ----------

I'm running cats by the way. Is that creating the same back pressure 3/4 would?