flubyux2

ok well last summer i had a nice exhaust put on, for cheap. heres what its like:

manifold>precat 1 gutted>60mm race pipe>60mm out driverside>Arospeed bomb (like an N1, only MUCH lighter)

and i liek this set up. but as far as i can tell, all the headers on the market extend way under the car, and i would have to chop up my nice new exhaust.

so i decided that i can make my own, since i am handy w/ the welder and grinder. that way, i can make the total header length so that it eliminates the Precat 1, and will bolt up to the 60mm race pipe where the Precat1 meets up to it now.

i was basically planning on using cast steel Weld Els, as shown in Maximum boost, used to fabricate turbo manifolds. so i figure if companies use rolled steel tubing for headers, then cast steel tubes HAVE to be more durable. there is also a website for a company that shows how to make your own stuff.

www.SDSefi.com they actually show how to make a custom intake for an NA fc...go figure

anywho, i kinda need some tips on how to tune the lengthes of the primaries.

how should i route them?
how long should they be?

and i can make my own collector if i cant find a nice Y pipe from a muffler shop. any collector i make will be WAY nicer than what i have seen from Pacesetter anyhow.

thanks guys
chris

shows how to fabricate a turbo manifold http://www.sdsefi.com/techheader.htm

shows how to fabricate intake manifold for RX7
http://www.sdsefi.com/techinta.htm

Samps

Mazdatrix sells custom header piping and flanges. I would suggest making each tube as close to the same length as possible to reduce noise.

here is the link.

http://www.mazdatrix.com/fabricators.htm

flubyux2

thanks bro, youre just a weath of knowlege arent you?

the mazdatrix kit sounds like "the way", now i just need to know how the primary length affects the torque/HP curve and peaks.

chris

Manolis_D

iTrader: (2)

Not sure exactly what you're looking for, but as a general rule, the longer the primaries, the lower the torque / HP peak occurs.

flubyux2

ok yea, i just got an email back from Mazdatrix, and they say pretty much the same thing, and it makes COMPLETE sense to me.

the longer the primaries, the more exhaust pulses will be traveling inside at any time. and an exhaust pulse has a positive pressure wave (ahead of it) and a Negative pressure wave (behind it) so the more negative pressure waves inside that primary tube, the more it will scavenge the gasses out of the engine. the shorter the primaries, the fewer exhaust pulses will be in the tube at lower RPM, meaning a weaker negative pressure signal to draw the exhaust from the motor. but in the HIgher RPM's, the faster the exhaust pulses come out, and the more there will be in the short tube, then this will increase the negative pressure wave signal, and scavenging will improve in the upper RPM.

ive got it down pat. now i just need to figure out how to tune my header for a power peak of...6500 or 7000. depending on where my shifts will land my RPMS.

i know exactly how to do my header, just have to figure out how long to make the primaries to obtain my optimal power peak.

thanks guys
chris