[karism]

Afternoon Guys,

So i have been sitting down, and looking at some figures on header pipe length.

I have decided to compare two types of headers.

The Bosal/Hotshot type : Short primary runners(front and rear bank non equal length) ,collecting and into equal length secondary pipes.

Pacesetter type : Long primary runners, collecting and into unequal length secondary pipes.
Rule off thumb : The longer the primary pipes are, the more torque will be made at lower RPM. The shorter the primary pipe, the more HP it will make at higher RPM. Both of these laws point to gas pulse tunning.

The basic principle of pulse tuning on all engines is exactly the same. To try and extract as much of the exhaust gas as possible ,by means of using sound wave energy to “ pull” the gas out of the manifold.

One can tune with various different styles of pulse tuning. According to testing, it seams to work the best when tuning for the 4th sound wave, as sound travels at such a velocity, that it is very difficult to harness the first sound wave emerging out of the head(port).The 4th sound wave does have allot less energy than the first one, but still it makes a big difference! Also keep in mind that the exhaust gas also travels at quite a speed.

The primary and the secondary lengths of the pipes work hand in hand. They shape the “curve” of how the engine will produce torque. Now its not all about torque, but hp as well. All ways keep in mind that torque is what moves mass! That is why it is important to have torque within the everyday usage range of the engine(which differs from driver tot driver, and road conditions and sometimes gear ratios).

That is the foundation of designing exhaust headers that work where you want them to.

I have looked at both types of headers, and from what I have learnt over the years it looks to me like the Pacesetter headers will work better. (Not talking about build Quality, or fitment)


Please feel free to comment!!!!

I will continue to work on the numbers behind what I have said so far,to try and put it into graphs,and make it easier to understand.

Thanks for reading!

Karis

[Mr Loyyy!!!]

Great info! I learned something new today .

[blackshine007]

From what me and a buddy of mine were speculating on, yeah the pacecrappers would make the most power but sound the worst due to the unequal length pipes. What I suggested was buying some ebay headers and modifying the mid pipe (being that they kept the flange at 2.25 ID and decided to swedge up the end of a 1.75 inch pipe and merge it into a 2.25 inch flex pipe with a 2.5 inch outlet). I thought that was bass ackwards. I plan on using a 2.25 ID merge pipes w/ a 2.5 ID flex pipe merging mx3 style instead of trying to do it the way ours is from the factory. If you have the merge pipes at least somewhere near the same length then you can keep the sound quality and still make your power.

Here's ours stock


Mazda did some research and found you make more tq with our style. I'm gonna assume that it flowed better and made more hp on top end with the other. That's what I'm gonna do



I love the sound of my engine and I don't wanna lose that sound. I'm awaiting on a flex pipe and I'll be doing this sometime this year.

[karism]

my A Rayyan : Thanks! I`am glad I could show you some of the basic principles that it works on!

[karism]

[quote name='blackshine007' date='Feb 27 2008, 01:34 AM' post='264107']
From what me and a buddy of mine were speculating on, yeah the pacecrappers would make the most power but sound the worst due to the unequal length pipes. What I suggested was buying some ebay headers and modifying the mid pipe (being that they kept the flange at 2.25 ID and decided to swedge up the end of a 1.75 inch pipe and merge it into a 2.25 inch flex pipe with a 2.5 inch outlet). I thought that was bass ackwards. I plan on using a 2.25 ID merge pipes w/ a 2.5 ID flex pipe merging mx3 style instead of trying to do it the way ours is from the factory. If you have the merge pipes at least somewhere near the same length then you can keep the sound quality and still make your power.

Thanks for commenting.

hahaha,you jumped in front of my wagon!This will be the next step that i discussed!

My idea will be very similar to yours,as i also had a look at the SAE papers on the devepolement on the engine(the one piece which you showed)

Mazda spent allot of time with the design of the engine,i dont have resources they do,so i will have to work with what i have learnt over the years

I will be trying to get the best of both worlds.

My plan (so far) is to use the Pacesetter style header ,but to make the runners a little shorter (stll longer than the Bosal/SS Autochrome type)

So in effect it will consist of the following.

Standard type secondary pipes,in a larger size.(same config and angles as stock)
LongPrimary pipe 3-1 config with long taper collectors.

The rest of the exhaust will probably be 2.5".

Karis

Ps: My V6 Mazda has been sold allmost 2 years ago...I just love the engines so much that i decided to start working on an exhaust system that will (hopefully) work very good.

[karism]

Part II:
Halo there! Today we will start looking at some examples off how well the headers with downpipes work.
I`am attaching herewith an example of what the average KL03 engine will produce, before and after the addition of Bosal(SS Autochrome) headers, down pipes and nicer flowing exhaust.
Please refer to the attachment :
If we look at the areas the it made the biggest difference, that would be at the following RPM numbers :
3288 RPM = 5 Foot Pound
3699 RPM = 6 Foot Pound
4110 RPM = 6 Foot Pound

Now this is normally the RPM that most of us drive around town , shifting at roughly 4200 rpm or so. That’s nice difference these headers make here. It will feel like the engine gained allot of power, as it will help the (very very ) rev happy engine rev up even quicker!

What is the problem with any header that is used on a conventional V6 engine? The Pacesetter & Bosal headers are NOT pulse tuned. They have the same(or very close to) length pipes, equal and size etc but not pulse tuned.Its amazing to think it makes so much of a difference, and it isn’t even tuned properly!

On a conventional Ford Pushrod V6 engine that has the following firing order : 1,4,2,5,3,6 you CANNOT pulse tune the header using only one bank of cylinders. You will have to use cylinders from both banks of pistons. Why ?simply because it fires number 1 on the right bank ,and the next is no 4 on the left bank, next it fires no 2 on the right bank, and then number 5 on the left bank. Thus it is not possible.

Coming back to the KLO3/DE/ZE engine, their firing order is different : 1,2,3,4,5,6.Firing the one cylinder after the other in sequence. Right bank, and then left bank.(The firing order is one of the reasons that the engines are, and sound so extremely smooth!)

If we were to try and pulse tune the headers, we would have to take no 1 and then no 2, which would mean taking one from each bank(which is do able, but not in a production car).

Have a look at a pic of Race FORD GT40, and look at the crazy spaghetti headers it has, that is how headers are supposed to be tuned on a V engine.

Finally : How will I go about extracting more hp out of a Mazda V6 engine, without building crazy criss-cross headers?

Well: For starters : I would begin with the pace setter headers, making their primary pipes shorter, and changing the angles of the collector slightly.(Very important is that the front and rear bank will have the same length primary pipes. Next I will fabricate an equal length secondary pipe section, for both the front and the rear bank, the secondary pipes will be in the region of 1.75-2 “.
Why? At any given time, the exhaust gas flow will not be more than that of 1 cylinder. Going bigger will hurt low end and midrange torque. The collector of the secondary pipes will have angles aprox 15deg with a proper divider to separate the pipes.

I hope I have made some aspects of Pulse tuning more clear! Lets see if we can extract some more hp out of these lovely smooth engines!


Karis


Ps:I recently built a custom header for my beetle project.I can show it,if someone is interested?

Edit : Damnit!Cant get the pics to work,will attach them a little later

[blackshine007]

karism, on Feb 27 2008, 07:20 AM, said:

On a conventional Ford Pushrod V6 engine that has the following firing order : 1,4,2,5,3,6 you CANNOT pulse tune the header using only one bank of cylinders. You will have to use cylinders from both banks of pistons. Why ?simply because it fires number 1 on the right bank ,and the next is no 4 on the left bank, next it fires no 2 on the right bank, and then number 5 on the left bank. Thus it is not possible.

Coming back to the KLO3/DE/ZE engine, their firing order is different : 1,2,3,4,5,6.Firing the one cylinder after the other in sequence. Right bank, and then left bank.(The firing order is one of the reasons that the engines are, and sound so extremely smooth!)

I don't know if you know this or not, but the Ford firing order is the same as ours, they just number the cylinders differently. Bank 1 is 1,2,3 and bank 2 is 4,5,6 while ours is 1,3,5 and 2,4,6 respectfully. Technically speaking, you can pulse tune any engine, if you're willing to put the time and money into it. But you can pulse tune it similar to ours because most V6 have the same exact firing order unless it's an odd firing engine. Most even firing engines are usually gonna be 1,2,3,4,5,6 or similar. But please continue. This is pretty interesting.

[karism]

Morning guys!

Herewith the pictures as promised,sorry for the delay







Ok,so i got the firing order wrong?Thanks for pointing it out !!(Damb i feel like an idiot now...hahaha)

I have never had the oppertunity to look at a Mazda V6 crank yet,but have seen the Ford pushrod ones a few times.

The Rest of the pulse tuning theory still applies to the different pipes though.

Have a look at the pics,it might explain things a little bit better

Karis

[karism]

I decided to show a pic of the Header myself and a friend built for my beetle.



Things to point out :

The pipes are 42mm, (To large for other No Rotary engines to use)
The lenght of the pipes are allmost precisely equal ( differs by less than 2mm)Which means both cylinders will be runing equal AFR ,as the burn pattern will be identical.It allso makes tuning allot easier if the pipes are equal lenght

The collector angle is very shallow.which promotes the proper mixing off gasses without "confusing" the other pulse.

Pipes used is thickwalled mild steel,(weighs a hell of allot),but will not burn through with the extreme heat.

Next Up?

I will try and explain on a pic how according to theory (and some practice on my side) we should be able to build the ultimate Mazda V6 header.

Karis