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Kook's longtube's

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steveespo said:
Go 2", bigger is better with these engines. Goes against all we were taught about displacement vs intake/exhaust sizing but the Coyote takes in as much air as you can give it and needs a way to get it out just as fast.
Steve

That's interesting.
 

steveespo

Lord knows I'm a Voodoo Child
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Just for perspective my car is making about 500 flywheel HP so 100 HP/Liter, a pushrod 302 would make on a good day with similar induction and exhaust mods about 300 FWHP or 60 HP/liter. That is like a 62% increase in efficiency, which I still find hard to believe but it is true. The Coyote heads just flow that well. So I ran a 700 cfm throttle body and 1-5/8" primary long tubes on my 87 5.0, now I run a 1500 cfm TB (uses about 1366) and 1-7/8" primary tubes on my '11 5.0. 2" primaries are the ticket, especially if you are considering add super charging in the future.
Steve
 
"bigger is better"

Kook's Tech Support disagrees, ...for a stock engine. They said unless you are building the engine up, you lose bottom end when the primary tubes are too big. They recommended no larger than 1 7/8 for a stock Boss 302 engine, and he went onto say that would include supercharging it.

I'm not trying to be argumentative, just don't want anyone relying on info that may not be 100% - for their application.
 

steveespo

Lord knows I'm a Voodoo Child
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No offense taken, When you add 750-1000 power producing RPM the flow paths have to increase in size because the timing events to intake and exhaust are accelerated. Stock GT power tapers off starting at 6500 rpm, stock Boss tapers off at 6800-7000, Tuned Cobra Jet setup makes power to 8000 rpm. I have 1 7/8" primary ARH headers and made 433 SAE 5 RWHP on a tuned GT engine with Boss intake. Following the Kooks logic I was over piped already, not the case. Mark Wilson when he was with Ford Racing explained to me that they tried both 1 3/4" and 1 7/8" tubes on the 302S cars and the bigger pipes were measurably better, this was also true with the CJ Intake but that packaging and cost were the reasons it did not make the cut for Boss program. It all depends on what other mods you plan on doing with the engine. The investment for headers and x pipe is big$$ and it is a painful install job that you would want to only do once so think of your future plans.
Steve
 

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