# Kooks Sig Series questions



## smitty#131 (Dec 17, 2011)

Guys im confused about these headers. marylandspeed.com has two set of kooks headers. These 

Kooks "Signature Series" Stepped Headers 1 3/4" x 1 7/8" x 3" 

And

Kooks Long Tube Headers 1 7/8"x 3"

now i see the difference in size.. does this mean the sig series start by 1 3/4 and then flow in 1 7/8. 

and then the regualr 1 7/8 Lt's just start with the 1 7/8 size? 

Now another ? why are the sig series better?


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## svede1212 (Nov 1, 2005)

A lot of people suffer under the impression that bigger is better. For headers to work well it's more about velocity of the gases with minimum back pressure. At lower and mid RPM you aren't moving as much gas and if you dump a moderate amount into a large pipe the gases slow down. You then lose some scavenging effect. At high RPM (and with bigger the cubes or higher flowing heads, etc) you need a bigger pipe to not cause back pressure. With that volume of gas velocity stays high. Stepped headers attempt to make the best of both worlds and keep the torque curve up down low yet flow well up high. Straight 1 7/8ths work well near 450 RWHP and higher at high RPM but on a lower HP car or lower RPM you give up down low. The same misconception of size seem to guide exhaust pipes were the "bigger is better" mantra gets followed.


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## smitty#131 (Dec 17, 2011)

very nice description. Thank you.


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## ViperT4 (Jul 18, 2010)

They do also have the straight 1 & 3/4" headers as well for a bit less than the stepped. didn't seem like you saw that. Call Brandon personally for the best price.


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