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Old 26th September 2010, 11:42 PM   #1 (permalink)
Jim
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bundle of snakes

Is there a order to the position of the pipes on the bundle of snakes? Looking at a lot of photos there seems to be multiple configurations.
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Old 27th September 2010, 02:28 AM   #2 (permalink)
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Re: bundle of snakes

As far as I know (I'm no expert), the order at the 4/1 collector doesn't matter (unless you're really trying hard for perfectly tuned lengths). What is important is that you end up with a "cross over" exhaust - in other words, it's important which exhaust pipe goes to which 4/1 collector.

Hope that helps.
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Old 27th September 2010, 05:38 AM   #3 (permalink)
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Re: bundle of snakes

Although there are a few myths around about the gases entering the collector in a rotational pattern to maximise performance, in reality this probably makes very little difference in outright performance, compared to ensuring that the collector s are paired to ensure even gas loading and the collector lengths are as close to an identical length as possible.

<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com<img src=" /><o:p></o:p>
Through my work, Ive got access to engine simulation software and the modelling we did on my proposed set-up (with correctly designed cross-over system) a shows 3-4 Hp improvement at 6000rpm over a non cross-over design.<o:p></o:p>
<o:p></o:p>

Regards<o:p></o:p>
Andy<o:p></o:p>
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Old 27th September 2010, 05:40 AM   #4 (permalink)
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Re: bundle of snakes

Hi Cliff

I believe that is the question he is asking.

Which pipes go into which collector?????

Everybody seems to have a different answer and to what end would be achieved.

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Old 27th September 2010, 05:53 AM   #5 (permalink)
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Re: bundle of snakes

If the maximum benefit from the perfect set-up is only going to be 3 - 4 HP, you couldn't even notice this. So go for what looks good (proper 40's have cross-overs) or even what sounds most magical.
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Old 27th September 2010, 07:10 AM   #6 (permalink)
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Re: bundle of snakes

Have a look through this thread Pairing headers?
I used the info to help build my own set. crossover exhaust question

Clayton
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Old 23rd October 2010, 04:09 PM   #7 (permalink)
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Re: bundle of snakes

You should take the firing order of your engine. Devide it in half using every other number. The 1st/3rd/5th/7th is the four for the side of the engine that has #1 cylinder on. The other four are for the other side. They should fire in sequence in the collector. This allows the firing cylender to scavange the previously fired cylinder. each primary should be as close in length as possible. the length of the primary's determine where your power band is. I made mine by hand and they are all within 2 inches of each other.
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Old 23rd October 2010, 05:18 PM   #8 (permalink)
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Wink Re: bundle of snakes

Quote:
Originally Posted by cobra1 View Post
You should take the firing order of your engine. Devide it in half using every other number. The 1st/3rd/5th/7thThats Chev- Ford is 1234 on RH Bank & 5678 on LH Bank is the four for the side of the engine that has #1 cylinder on. The other four are for the other side. They should fire in sequence in the collector. This allows the firing cylender to scavange the previously fired cylinder. each primary should be as close in length as possible. the length of the primary's determine where your power band is. I made mine by hand and they are all within 2 inches of each other.
That means 1467 in one collector & 5238 in other for 15426378 order or 1764 & 3258 for 13726548 firing order.
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Old 23rd October 2010, 05:36 PM   #9 (permalink)
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Re: bundle of snakes

I thought with the original firing order from the 60s that the pipes from the center two cylinders are the ones which cross over to the opposite collector. Every set of GT40 BOS headers that I have seen are arranged that way. Have I missed something?
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Old 23rd October 2010, 06:47 PM   #10 (permalink)
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Re: bundle of snakes

15426378 is the 60's firing order & 1/4 are the outer cyls from the right bank along with 6/7 being the center cyls from the left bank, you must be getting confused in the translation from Kiwi english via USA english Jim the 1467 is the sequence which the pipes fit in the collector so that the 180 pulses go around in the collector instead of a criss/cross fashion.
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Old 23rd October 2010, 10:48 PM   #11 (permalink)
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Re: bundle of snakes

Here are some Pix of my headers during making them.
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Old 3rd November 2010, 12:02 PM   #12 (permalink)
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Re: bundle of snakes

Unless you have an out and out racer I think the 2 main advantages of a cross over system are:-

1. To look like that on the original cars.

2. To make a sound like the original cars, which is quite unlike your normal big V8 rumble, sometimes sounding more like a V12 at high revs.
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Old 3rd November 2010, 02:19 PM   #13 (permalink)
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Re: bundle of snakes

If I am confused it's not the only thing I am confused about. I didn't realize there was an order to it.
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Old 4th November 2010, 11:13 AM   #14 (permalink)
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Re: bundle of snakes

Ford V8

260, 289, 302(5.0L)

up to and including 1984

Firing Order
15426378
To get the propper paring you put the two cyls together that are 180* apart, so it is
1542
6378

1-6, 5-3, 4-7, 2-8 Then you gather them into the collectors (1653) (4728), there you have it a bundle of snakes with 6 & 7 swapping sides
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Old 4th November 2010, 03:06 PM   #15 (permalink)
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Re: bundle of snakes

Hmmmm....mine were made using a set of Safir headers as a pattern. The center two cylinders from each bank cross to the opposite side and join the outer, or end, cylinders from that bank. All the other sets I have seen were the same. I did not know that it made a difference how they got into the collector. And frankly, mostly what I wanted was the engine to sound right- although at least one vintage GT40 (1008) has headers which do not cross over.
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Old 4th November 2010, 05:10 PM   #16 (permalink)
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Re: bundle of snakes

Jim, if the firing order is correct and forms a "circular" pattern from pipe to pipe, you get a rifling effect or vortex down the exhaust which speeds up the scavenging and gives back a little horsepower.
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Old 4th November 2010, 06:15 PM   #17 (permalink)
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Red face Re: bundle of snakes

Quote:
Originally Posted by RUFAZZ View Post
Ford V8

260, 289, 302(5.0L)

up to and including 1984

Firing Order
15426378
To get the propper paring you put the two cyls together that are 180* apart, so it is
1542
6378

1-6, 5-3, 4-7, 2-8 Then you gather them into the collectors (1653) (4728), there you have it a bundle of snakes with 6 & 7 swapping sides
Sorry, I put the wrong groups together
it should be (1467) & (5238)
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Old 4th November 2010, 07:52 PM   #18 (permalink)
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Smile Re: bundle of snakes

Look at the 3rd photo above you will see how they go for a 64 427 sideoiler
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