donkayroo

I just want to clarify. Does everyone know what exactly headers are? I'm not flaming on anyone I just want to clarify things a bit.

Now most automotive enthusiasts know that headers for a N/A engine perform better than the low production cost stock exhaust manifold.

But, why do they perform better? Is it because the piping is larger? Is it because the bends are rounder (no/less abrupt direction changes) and retain a consistent diameter throughout the bends (mandrel)? Or, is it because the runners are equal length in order to time exhaust pulses to create or enhance the scavenging effect which results in more efficient flow? Is it possibly the ceramic coating which can aid in thermal efficiency?

If you believe all the previous questions contribute to defining how a header improves performance then you already know that YES, there are headers for turbocharged vehicles.

As we all know the turbine is powered by exhaust pulses. Most stock turbo manifolds just cram the pulses together which causes less responsive boost. Toyota tried to harness these pulses by using a twin entry manifold which was used in the 91+ Turbo MR2. This is the closest they came to enhance flow while keeping production costs low.

Turbo headers allow the pulse to follow in a "single file line" while sucking each other along from the vaccuum created in the tail end of the previous exhaust pulse just like N/A headers. Turbos therefore spool much more freely since each exhaust pulse has its own jab at the the wheel.

Imagine what happens if a crowd of people try getting through a rotating door of a hotel lobby during a fire evacuation. That's a stock manifold in action. Now imagine the crowd seperated into several lines awaiting their turn to exit through the rotating doors. That's kinda what the turbo headers would do, right?

Basically, headers allow the gases to exit at a much faster pace while sorting colliding pulses. This fast pace is acheived by a number of factors but mainly through runner length. Headers can also be tuned for a specific power band and that's why some headers look like snakes and others are very simple. A number of Japanese tuners used the N/A header concept and applied the concept to occur just before the turbo.





17900-turbo%20header.jpg

donkayroo

A few years ago I too never knew custom turbo manifolds were called turbo headers.

I've provided a list of sites that use the term turbo headers. A few of the sites have excellent pics of some well made turbo headers. Enjoy!

http://www.turbocelica.com/Autos/Whi...urboHeader.htm

http://www.arautosports.com/ttheaders.htm

http://www.bbtriflo.com/shopsite/911turbo.html

http://toyotaperformance.com/turbo_header.htm

http://www.houlster.com/amigo/turbo2/turbo_header.htm

http://www.rernetworking.com/1989__1...sche_c2c4_.htm

http://www.80tq.com/tube_header.html

http://www.kookscustomheaders.com/specialties1.html

Here's a site that sells the Pentproof Turbo Headers for the
tt z32.
http://www.dspracing.cc/penturhead.html



<P ID="edit"><FONT class="small"><EM>Edited by donkayroo on 10/04/02 11:26 PM.</EM></FONT></P>