The 230 Headerfold project

[maineSS]

MM:
Here are some URL's for for 6 Cyl jeep header images:
http://www.quadratec.com/Assets/Imag...9/36419-lg.jpg
http://www.quadratec.com/Assets/Imag...1/52221-lg.jpg
http://www.quadratec.com/Assets/Photos/p36410c.jpg
http://www.rocky-road.com/xjthorley.html

All of these are primarily aimed at restriction reduction rather than wave tuning as evidenced by the pairing and length of the primary pipes. I asked my friend about these layouts, and his opinion was that the lengths required for wave tuning at low RPM would be a royal pain to fit-especially pair 3&4. His recommendation was along the lines of the Thorley header (bottom of page)- keep the bends gradual and pair the pipes ASAP with as few collectors as possible. The stock Jeep header apparently had cracking problems, and was meant to be more of a tubular exhaust manifold than a header. It looks like you could pair up the pipes in the right order into a couple of triple collectors, but whether that would make a big difference is doubtful. The biggest fab problem will be the collectors, so designing something that can use manufactured units will save a lot of time.

[monkeymissile]

updated CAD file

for all interested folks, I have attached the updated CAD file of the port/stud layout. I am 99% sure it's all correct, but I plan to make a paper template to test it out first. Thanks.

[monkeymissile]

MonkeyMissile,

I printed your cad drawing of the intake/exhaust ports but I can not make out all the dimensions. Can you increase the font size for the dimensions? Also what is the dimension for "x", the verticle dimension from the center of the port to the center of the stud. I wanted to start the fab of the flange plate. Thanks

I still need to get that X dimension, will do so tomorrow since I'm still in NH with truck. I'll repost the drawing with larger dimensions too. I can also email you a copy if you want. Thanks.

[Sickcall]

MonkeyMissile,

I printed your cad drawing of the intake/exhaust ports but I can not make out all the dimensions. Can you increase the font size for the dimensions? Also what is the dimension for "x", the verticle dimension from the center of the port to the center of the stud. I wanted to start the fab of the flange plate. Thanks

[maineSS]

The "split" design could be constructed to have 3 consecutive pulses 120 deg apart from the other 3 cylinders by running 1,5,3 into one tube and 2,4,6 into the other, then joining the two tubes into a collector. If it were set up similar to the Jeep header, it wouldn't be so difficult to fabricate as a true Tri-Y. I'll ask my friend whether it would work as well.

[Cheyenne Dave]

so my design up until recently was to take pipes 1+2+3 and 4+5+6 down into (2) 3:1 merge collectors, then into a 2:1 merge collector and finally into the primary pipe. However it was suggested I try to pair pipes 1+6, 5+2 and 3+4 pipes so the configuration would be (3) 2:1 collectors into a 3:1 collector and into the primary. This design should, theoretically, provide much better flow like a true Tri-Y.
My issue is that I don't know how I'd keep those 3 pairs of pipes the same approximate length, seems like the 1+6 pair would be really long, 5+2 a bit shorter and 3+4 the shortest.
I was under the impression that you should try to keep all these pipes the same lengths, within reason, so that all pulses are traveling the same distances to the primary.
Is this true or not so important?
Thoughts on these two possible configurations?
Thanks and hope everyone has a safe holiday.

Justin

Equal length pipes have always been the goal with high performance bike exhaust systems, so it seems you are on the right track. Quite an undertaking you've taken on...

C.D.

[monkeymissile]

Headerfold configuration question #1

so my design up until recently was to take pipes 1+2+3 and 4+5+6 down into (2) 3:1 merge collectors, then into a 2:1 merge collector and finally into the primary pipe. However it was suggested I try to pair pipes 1+6, 5+2 and 3+4 pipes so the configuration would be (3) 2:1 collectors into a 3:1 collector and into the primary. This design should, theoretically, provide much better flow like a true Tri-Y.
My issue is that I don't know how I'd keep those 3 pairs of pipes the same approximate length, seems like the 1+6 pair would be really long, 5+2 a bit shorter and 3+4 the shortest.
I was under the impression that you should try to keep all these pipes the same lengths, within reason, so that all pulses are traveling the same distances to the primary.
Is this true or not so important?
Thoughts on these two possible configurations?
Thanks and hope everyone has a safe holiday.

Justin

[monkeymissile]

Well, I guess this is more or less the "official" start of my project to build a better performing exhaust system for my M43's 230.
My hope is to design and build a substantially improved, and possibly "tuned" headerfold that I can offer in limited quantities to interested people. I'll use stainless if I can, steel otherwise.

First of all a huge thanks to everyone who has taken the time to contribute all sorts of great information in the previous posts. Now it's time to put it all into motion and see where it leads. When I removed my cracked manifold a few weeks ago, I could plainly see the economy of it's design, but also it's shortcomings and fragility. I knew I could do better and after being relatively unimpressed with the aftermarket offerings, I started researching. With a tremendous amount of support (you know who you are!) I think I finally have a design worked out.

The first step was to get an accurate and precise drawing of the intake/exhaust ports and mounting studs. I carefully measured (and remeasured) my recently manifold-less engine with calipers and got a CAD drawing started. I posted it here and when complete, will be available to anyone who wants a copy.
The challenging part comes when I start a 3D model to figure out how to snake all those pipes together.
So let the fun begin and have a great holiday everyone.

Justin