hernanca

I definitely missed it - I would like to know as well.

Very cool, Hans - helpful, even if just for knowing they are out there! Keep us posted on your impressions of them. Interesting on the pairings it looks like they have: 1/4, 2/3 and 5/7, 6/8. Granted, it is a strictly Tri-Y system, so each side stays together, but would be interesting to know whether it was driven by packaging constraints or something else.

ptuomov

Those tri-y headers have the normal pairing (for 928, most Fords, etc.) of 1+2, 3+4, 5+7, 6+8. That's the pairing that gives a minimum three beat spacing for every pair.

hernanca

ptuomov, it was difficult to tell, but I believe the 1-4 side has the 1+4 and 2+3 pairing, while the 5-8 side is as you say. That makes it even more interesting!

I have not looked at other Tri-Y's in a while (Ford, etc.), so I can't speak to those.

Mongo

The design would be a terrific candidate to create a down pipe to merge the necessary banks in order to create 180 degree headers though.

ptuomov

Maybe my eyes are doing tricks with me. Cognitive dissonance.

hernanca

Understand that!

hernanca

Agree, especially since Hans indicated it is very compact - perhaps it will avoid the steering linkage difficulties. But I still like that idea of making the whole shebang easily install-able.

hernanca

Rob, I just noticed how long those Secondaries look - very interesting!

Lizard928

Those headers were made by Phil Threshie.

Lets just say lets not go there........

hernanca

The ones that were on the White Zombie, that Rob showed, or the ones that Hans showed? Or both?!

Lizard928

Both.
The ones Hans shows are either the same, or another stage of the same headers.

danglerb

Nah, lets go there.

Threshie was bad news for many customers, but seems to me it wasn't ALL bad ideas, but poor execution of those ideas.

The pictures that Han's posted show ERT on the last one, and if you look carefully, at least to my eye ALL the pictures use different designs.

Matte finish is 4:1 merge, not tri Y on the 1/4 bank, and 5/6 7/8 tri Y on the 5/8 bank.

Shiny finish is 1/3 2/4 tri y, can't see the other side, but its tri Y.

Third image both are 4:1 merge.

Gold finish with ERT 1/4 2/3 tri Y, can't see other side, but its tri Y

Seems to me all were shooting in the dark prototypes, but I see that as no bad reflection on the concept of a tri Y, just bad execution.

76FJ55

I'm seeing slightly different pairing on the "Shiny" set. for 1-4 it looks to me like it is paired 1/4 and 2/3.

Third image looks to be Tri-Y on both sides.

Also if you look at the two runner design on the matte 1-4 it appears to be identical to the shiny 1-4, but merging in different collectors. The Matte set having a 4-1 collector and the shiny set being Tri-Y with the first meging the outer two tubes 2/3 and the inner two tubes 1/4. Then the third mergine the two initial collectors.

hans14914

Those headers are indeed 928 Developments (Phil's) design.

I found them a couple years ago, and so snapped them up just to take a look. I was able to get the headers, X, and exhaust as pictured in the installed image.

All the images are of the same headers. It looks like the hanger/tab/bracket was cut-off at some point in time, which may explain why it looks different. Also, it was just rattle can black paint, so think it just faded over the years from handling. Close observations show the welds and bends to be the same in all pictures.

When I recieved the headers, there were several gaps in the welds, especially on the X, so I dont think these were ever run or tested... if they were, it would have had a terrible exhaust leak and the O2 would have measured very wonky.

I was going to have a friend bake off the old paint, then finish weld everything and see if they fit. There is certainly some room for improvement, but may not be a bad starting point for a more polished concept.

Thanks
Hans

danglerb

Note to all designers of headers who want to keep the configuration secret, paint them shiny black. I plead late night and sore foot, for failing to blow up the image on the 3rd pict which is indeed tri y. Angle and light makes it very hard to see where one black pipe is relative to another.

1/4 bank in the first picture is a 4:1 merge, not a tri Y. Primary layout does look the same, but the type of merge is the tuning element. Seems too short to me for it to be tri Y instead of 4:1.

Second pict, blow it up 400% and I can see 2 goes over 3, and 1 goes under 3, same as first pict, but tri Y with you are right 1/4 and 2/3

I take back what I said about prototypes, these look more like a test fit mock up. Without the tuning distances correct, a fairly pointless exercise.