Exhaust header design question

[bnam]

PO had installed a 4-2-1 header on my 74Tii -- allegedly from IE. But, I could not find a matching pic on their website.

The header on mine has cylinders 1&3 and 4&2 paired together. IE site says (wrt shorty header) that 4&1 and 2&3 is the correct pairing. But, their stage 2 header shows 1&2 and 3&4 pairing. I initially thought I had the stage 2 header until I noticed the diff in the pairing (unless IE changed their design sometime).

So, which pairing is right and which one is worst?

Thanks!

Byas

[roadhog0]

Looks like an old Alpina bag of snakes copy. The design was to keep all the tubes the same length!

[TobyB]

For torque, you want 1&4 paired with 2 and 3-

it balances out the pulses over time, as your zundfolge is 1342, you know...

any other pairing in a tri-y will be a net loss.

t

[bnam]

Looks like an old Alpina bag of snakes copy. The design was to keep all the tubes the same length!

I found

http://www.alpinabmw2002.com/2010/03/schrick-bmw-m10-headers.html

had a couple of pics of Shrick copies of Alpina bundle of snakes. Though the first set has pairing similar to mine, while the second is 4/1 + 2/3 pairing.

If the 4/1 & 2/3 pairing is better for torque, why is the IE stage 2 paired as 2/1 & 4/3? Is that for peak hp?

Thx!

B

[c.d.iesel]

and if you like your air conditioning?

better relocate that hose away from the exhaust

[AceAndrew]

If the 4/1 & 2/3 pairing is better for torque, why is the IE stage 2 paired as 2/1 & 4/3? Is that for peak hp?

Thx!

B

Might be best to shoot Jeff/Jeremy a call. I know Jeff Jeremy, and a long-time slat-flat racing buddy did the initial design.

[Guest Anonymous]

You are mistaken. The IE short headers are designed with the correct 1&4 and 2&3 connections. See the description on our website.

Jeff Ireland

[bnam]

Sorry you have mis-read my post -- I said your shorty headers have the "correct" pairing, but was wondering if why your stage 2 headers have a different pairing.

http://www.iemotorsport.com/bmw/2002-exhaust/02stephead1.html

Thx!

Byas

[Guest Anonymous]

There is no such item as a "stage 2" header from Ireland Engineering. We do not make any 4-2-1 header other than the shorty. Our long tube headers are 4 into 1. You must have us confused with a different manufacturer.

Jeff Ireland

[flyingjolly]

Sorry you have mis-read my post -- I said your shorty headers have the "correct" pairing, but was wondering if why your stage 2 headers have a different pairing.

http://www.iemotorsport.com/bmw/2002-exhaust/02stephead1.html

Thx!

Byas

i think you're mixing two different designs up:

4-2-1 need the 1/4-2/3 pairing

while 4into1 headers can be paired as space allows whereas it's important all pipes are the same lenght

[Guest Anonymous]

Sorry my error. I looked at our website. I guess my guys have decided to call the 4 into 1 long header stage 2. The fact that the tubes end up beside each other at the collector does not mean they are arranged 1-2 and 3-4 . It is not significant. The tubes are in a bundle so each tube touches all the other tubes.

Jeff Ireland

[bnam]

Ahh -- got it -- they all end up together. 4-1 not 4-2-1.

Did you by any chance offer a 4-2-1 with the 1&2 and 4&2 pairing? My car's PO attributed the header to you.

B

[Guest Anonymous]

No we never made one like that.

[bnam]

Found this in another thread today. Original source was CD

The top header has 4&2 paired -- I think I may have found the origin of my header.

Anyone have anything good to say about this Ansa header?

I had installed Ansa on a Fiat spider many years ago and I remember it went together very easily and hung/fit well.

Thx,

B

[roadhog0]

Found this in another thread today. Original source was CD

The top header has 4&2 paired -- I think I may have found the origin of my header.

Anyone have anything good to say about this Ansa header?

I had installed Ansa on a Fiat spider many years ago and I remember it went together very easily and hung/fit well.

Thx,

B

I believe is is a copy of an Alipna initially. The reason for the funky look if I remember correctly is to have all the tubes the same length, I believe it is for better torque.