Yet another 1-3/4 header question...

Not sure I'd really call that "low". 5 -7 psi would be what most call low boost. 10 - 14 lbs through good heads will get you much closer to 700-800 horsepower. The tri-y header design you inquired about above will kill the topend output close to 75 horses or even more and cause the EGT's to spike at extended WOT. My advice would be to have a custom stainless header built for another $400-$600 more than the steel coated version you're looking at above. At that power level and with the potential gains to be had.. seems like a decent bang for the buck even if you had to wait for another paycheck or two to clear the bank.

Yes they can support that much power but 1 3/4" primary is still just a bit too small for that much boost. A 4-1 conventional design with 1 3/4" to 1 7/8" stepped primaries.. or full 1 7/8" primaries would be more appropriate at 14 lbs. And the secondaries(the second tri-y step size) are entirely too small at only 2". Then there's the collector sizing at only 3" which adds even more potential power loss. The trick with blower motors is to get the exhaust out as quickly and easily as possible. Not as big a need to use exhaust scavenging tricks like tri-y and merge collectors to create depressions to vacuum out the next cycles waste products and tug on the intake charge. The exhaust cycles blowdown energy and volume of escaping gas is much higher than an N/A motor so the pipes can be bigger all around.

I would suggest getting together with a good header builder and have him run your engine spec's through one of the engine/exhaust design sim's to help you better understand what such a motor will need to adequately get the job done. You could also use Burns or some of the other big name shops consultation services to help you spec' the proper build dimensions too.

 

Wow! Thanks for the detailed response. I guess I considered it low boost because all of the guys I run with are 20+psi
I ended up going with a set of Accufab Bt-154. They are a true 4 in 1 design, with 1-7/8 tubes, and are mid-lengths! Yes, I know they aren't built specifically for a Maverick, but I feel fairly confident that I can tweak them to get them to fit. Plus George over at Accufab, said I could mark them, take pictures of them of where they were hitting and could send them back and he could make them changes to them, also. Some may say I took a gamble, but I say I did that a long time ago

Thanks for all the help guys!

 

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