Primary Size?

[Cory S]

I wonder how much he would pick up getting rid of the 2 1/4 inch choke point?

No idea. I run with the 2.25” choke point as well.

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[K4fxd]

Boost overcomes a lot of shortcomings.

 

[Angrey]

My bud just went 9.7 @ 141 on a bone stock 2019 exhaust on gasoline/meth. 1 7/8” full lengths are fine to 1300ish all day. We made 1560 through 1 7/8” at 33psi as well.

Because of or in spite of. This is like a Casino manager saying "We made $15M last year! That's a tremendous amount of money." When a better manager would have made $20M. Because of or in spite of.

My car made nearly 900 rwtq on 2" primary long tubes. It makes over 600 rwtq by 2800 rpm. So the natural question becomes, what would it have done with 1-7/8"?

 

[K4fxd]

My car made nearly 900 rwtq on 2" primary long tubes. It makes over 600 rwtq by 2800 rpm. So the natural question becomes, what would it have done with 1-7/8"?

From what I have found on the coyote platform it will be within the margin of error. A few posts back Elston gives an explanation of why.

 

[LethalPerformance]

1 3/4”
1 7/8”
2”

Kooks sells all 3 for 21 mustang. For a NA E85 car what’s my best option?

My personal experience is that the 1-7/8" are the best fit for most Coyote builds. NA or FI. With that said if you're building an all out drag car and plan to make moon boost with a blower the 2" primary would be better for that application. The 1-7/8" headers can support a lot of power. I went 8.64@157 with Kooks 1-7/8" headers on my 2018 GT that ran a Whipple 3.0L.

Feel free to give us a shout if there's anything we can help you with.

Thanks!

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