4-2-1 Vs 4-1 Headers

[Mach Number]

Hi,
we are the first year team and we are just on the stage of designing headers, having read the forums related with headers configuration, we have found that with 4-2-1 configuration we get wider torque band and is tuned for two rpm ranges, while using 4-1 we get max Power and it mainly tuned for a single rpm. So i need to ask some questions which i did not find in the forum that; Can the intake and exhaust be tuned on same rpm?

I have studied Heisler and Winterbone and didnt find much about the topic since i was trying to figure out the tuning length of primary and secondary.

Any help would be highly appreciable..
Thanks
Formula NED

[Mbirt]

Blair's "Design and Simulation of Four Stroke Engines" was an incredible eye-opener for me on this subject. I highly suggest checking it out. I don't believe he spends much (if any) time discussing primary vs. secondary exhaust length tuning, but remember that you'll have a stronger reflected wave with a greater discharge coefficient. Thus the higher power you found with the 4-1 setup.

To answer your question, the intake and exhaust can be tuned on the same rpm, but I see no reason to do this other than if the engine is designed to run only in a very narrow rpm range (cvt, governed engine). You can place the "peaky" tuning of the 4-1 exhaust where the intake ramming "trough" is between two intake ramming peaks. This makes a much more flexible power band.

[RollingCamel]

Rule of thumb: If it shoots fire then thumbs up! (j/k)

[Gruntguru]

Your generalisation is correct. 4-2-1 systems typically have a wider power band but lower peak power. Whatever you do, don't design for peak power, width is much more important at the speeds encountered in FSAE. Low speeds mean the cars spend a lot of time in the traction-limited regime so driveability and reduced gear-shifting are much more important than peak power.

[Mach Number]

Thanks guys for your suggestions and inputs.
@ MBIRT :
Thanks for suggesting the book.. Now we ended up the exhaust section of blair .. and we cleared our misconception and querries about the header design.. we are going for 4-1 headers..
Thanks..