Pairing headers?

[EGLITOM]

Great Illustrations Thank you

Keith is a similar picture for the 13726548 firing order available ( i could do it by myself, but if onwe is already available would be perfect).

Anyone managed exact equal lenght 180° headers ? please pictures ( Although i read Adam C´s great "volumetric efficiency post and see that there are also advantages in unequal lenghts).

Seems that no one knows any details about the car in the video. Can´t believe.

Thanks
TOM

[Russ Noble]

Originally Posted by tomschwab

Great Illustrations Thank you

Keith is a similar picture for the 13726548 firing order available ( i could do it by myself, but if onwe is already available would be perfect).

Anyone managed exact equal lenght 180° headers ? please pictures ( Although i read Adam C´s great "volumetric efficiency post and see that there are also advantages in unequal lenghts).

Seems that no one knows any details about the car in the video. Can´t believe.

Thanks
TOM

Tom,

Depends on your definition of exact!

My headers are all within half an inch or so. It would be possible to get them bang on but the extra work and time involved would not produce any significant returns.

My headers are laid out thus

Left Collector
2 3
5 8

Right Collector
4 1
6 7

Thus the left bank goes into the bottom. Right bank into the top. Just the way I had to do it to clear chassis tubes etc. It also means you can lift the heads off without having to remove the headers.

Pics here Kiwi scratchbuilt

Cheers,

[Keith Hardy]

Originally Posted by tomschwab

Seems that no one knows any details about the car in the video. Can´t believe.


TOM

This has come up before and I don't believe anyone identified it then, but, if you wanted an (un) educated guess I would say: original, 289, Webers, 180 degree headers..

[Mike Trusty]

Here are some pictures of the system that I'm building for my SPF. It is much different in arrangement than what you normally see but the intention is to have pipe within .25" in length and firing order rotating clockwise in the collectors. This is like what Keith described earlier but this is for the later firing order. The primary lengths are a foot longer than ideal but it's impossible to do otherwise. They are step with 1 7/8" to 2" and a 3" collector throat transitioning to a 3 1/2". This is the best guess that Burns Stainless and I could come up with. The exhaust pipes are intended for track events and can be easily changed to mufflers for street use. As you can see, ordered one to few U bends. Should be here next week and can finish. Then on to the cage. Just sharing.

[EGLITOM]

Thanks again for posting all the informations

Mike
What is the engine spec for this system ?

so your collectors for the 13726548 firing order would look like

1 => 7

4 <= 6
for the left one ( looked on it from the front of the car) and

3 => 2

8 <= 5
for the right one

but looking at your pictures the rotation is the other way around. I guess just defined by from which side of the car you looking at it ( front or rear). Anyway won´t make any difference or ?

From what i can see you did the step to 2" app 12 - 13 " away from the outlet and then an immidiate step up.

I personally thought more of a conical step up after app the same initial dia with going to 2" within a section of app 15" . Had very good experience with this kind of exhaust on my racebikes. What you think ?

What is more interesting, is the expected difference from your PANTERA system. HOw is this one performing anyway ? any dyno datas ?

[Scott Calabro]

Mike,

Is that a '69 Chevelle I spy with my little eye?

I just finished up a real 138 code 427 4 speed '67 SS Chevelle.

Where did you source those (V band) MARMON CLAMPS?

Cheers,
Scott

[EGLITOM]

Scott

As you are always very interrested in technical questions, any input on the thread ?

what configuration are you using ?

Tom

[Scott Calabro]

Well yes I do Tom.

Yesterday I was getting a headache reading this thread!

Personally I like kieth's diagram/picture.

720 divided by 8 = 90

Nice and simple.

All the other discussion seems like a hell of alot of work for only a little extra poop!

I primarily like the crossover header for the noise it makes! Not the extra power it may or may not make, depending on a particular engine combination.

Oh and Mike, you should go into the header business, those pipes are beautiful.

Nice work, top shelf.

Cheers,
Scott

[EGLITOM]

Thanks Scott,

but the 720 : x calculation is not so obvious.

I have a task for you:

Classic parallel english 360 Twin engine => Firing separation in °
Obvious it would be 720 : 2 = 360°

CORRECT !

Japanese parallel twin 180° Twin engine => Firing separation in °
is it 720° : 2
NO it is a #1 => 540° #2 = > 180° #1 separation

Now try an 90° italian v Twin is the firing separation 720° : 2 => NO

#1 => 270° #2 => 450°


A V8 Flatplane ? would like to be interrested in your result.

TOM

[Scott Calabro]

Tom

Does each cylinder have its own crank throw in your example engine?

Cheers,
Scott

[EGLITOM]

360 ° Parallel Twin = two crank throws
180 ° Parallel Twin = two crank throws
90 ° V Italian Twin = one crank throw

Flat plane V8 = does it realy matter, i don´t think so !

[Scott Calabro]

OK,

4 throws 180 apart.
2 cyl on a throw.
2 throws on each bank.
2 cyl's on separate throws but on the same bank fire at the same time.
180 later the same thing happens on the other bank.
Repeat twice.
Done.
Put the first four cyl pulses in the same collector, the second four in the other.

Or put them all in the same collector.

Did I pass the test TOM?

Cheers,
Scott

[EGLITOM]

Scott
let me think: "two cylinders firing at the same time"

I´m not sure, i think you definitely can make it work that way ( just need the correct cam and ignition). but than it would be more like a flatplane V4 .

Never mind !

Just knowing that the difference between a poor design and a good one, can result in a power output difference higher than just a "poop", i want to know and understand as much as possible, to do it right from the beginning.

Thanks for your constructive reply

TOM

[Scott Calabro]

Tom,

Well a flat V8 is two flat V4's! End to end.

Just think of two 180 degree crankshaft 4 cyl engines joined together, sharing a common crankshaft.

I you want to do it right, you are on the right forum.

Cheers,
Scott

[EGLITOM]

Scott

Correct, but there are two options of firing sequences:

firing distances could be like this one ( if the crank is one up, two down, one up )
and #1/#5 on 1st throw, #2/#6 on 2nd, #3/#7 on 3rd nd # 4/#8 on 4th.

#1--90°--#5--90°--#3--90°--#7--90°--#4--90°--#8--90°--#2--90°--#6

i assume i don´t have the order per bank correct ( for least harmonic amplitudes and reduced crank stress) but it is also a even 90° sequence

or it could be like this one

if two fire @ the same time, it is the following sequence
#1/#4 --270°-- #6/#7 -- 90° -- #2/#3 -- 270° -- #5/#8 -- 90° -- #1/#4 again

your choice.

I posted because i just like the sound of the car in the video and simoultanesly be interrested in high power outputs and would love to have both in a GT 40.

[Mike Trusty]

Tom: The motor is a aluminum block SVO motor with 416ci displacement, 3.9" stroke. The heads are C3H. It will have 58mm throttle bodies and distributorless ignition using an Electromotive ECU. As for the orientation of pipes at each collector, it is as you say, depends on how you look at it.

Scott: Thanks for the compliment on the headers but I must admit that I can only weld like that in my dreams. When I want something done right I take it to a good friend of mine that is a FAA certified welder. For many years now he has been a full time fabricator of race cars and in my opinion probably one of the best in the US. His Name is Bobby Shahan and is located here is Arkansas which is virtually in the center of the US. He is always busy but has expressed interest in working on these types of cars so if anyone is interested here is his contact information.

Shahan Race Cars
1100 Mt. Carmel Rd.
Cabot, AR 72023
501-605-9089

His real skill is chassis fabrication. Headers are just something that is part of the package.

The V-band clamps and all of the stainless in the headers are from "Burns Stainless".
They are very helpfull and have extensive header experience. Talk to Viney.
Burns Stainless

The flanges were cut by my best friend, Jack Houpe, on his water jet machine. He posts on this forum and has a Mark I SPF along with serveral other wonderful machines.

[Scott Calabro]

Mike,

Thanks for the info...

So what is the blue car in the background?

Cheers,
Scott

[Mike Trusty]

So what is the blue car in the background?

Cheers,
Scott[/quote]


That is Bobby's personal car. It is a '69 that he has converted to a Super Street car. It has a complete funny car style cage all chromemoly. The chassis is his design with a 665ci motor. Because this class is limited to 10" tires it actually looks like a street car from 50' away.