EvanSG

Beautiful! The tips look great. Too bad I can't park it up on a rack every evening to admire it.

victor25

B E A utiful

FIRE THAT DAMN THING UP WITH A VIDEO OR SOUND BITE SO WE CAN HEAR IT!!

.

GregBBRD

I try to learn something new, every time I do something.

I'm playing with some exhaust pulse theory.

Got a couple of things to try....just not ready for "prime time".

Rob Edwards

GB, holler if you need the digital audio recorder. Would be fun to have a good .wav file of the sound.

Ducman82

and let me know if you need to me come by and hold the mic

SMTCapeCod

Your pride is well-justified.

Given the engineering put into primary length and collectors, is the expectation that the balancing of pulses won't be as necessary up front? But further back it can attenuate differences arise from the need to have asymmetric tailpipes?

I think the images would be an outstanding icon for Frenzy 2014....or an O/C poster....or something I might get my hands on one day!

Looking forward to dyno results, hoping for vid!

ptuomov

My expectation is that it's going to make more power with a balance pipe right before the cats. No prediction on the sound quality, as that's subjective. It'll be interesting to see what actually happens.

The reasons why I think it's going to make more power with a balance pipe right before the cats are the following. First, I suspect (but don't know) that the cat is a big enough restriction on flow that smoothing the flow rate in any way will improve flow / reduce back pressure. Second, I suspect (and again don't know) that the converter case that feeds the gas to the element has a large expansion in cross-sectional area right before the element starts. If so, it may terminate the pulses, rendering the downstream x-pipe largely ineffective from the pulse tuning perspective. Wild speculation as always.

H-pipe at about 9 inches from the primary pipe ends or alternatively 18 inches from the primary pipe end might work well. Or might not. I don't know how much room there is between the primary pipe ends and the cats. If the cats would not be there, an X-pipe somewhere around 70-75" from the primary pipe ends might also work well. That based on some simple back of the envelope formulas and assumption that you guys are shooting for 3500-6000 rpm power band.

blazing928

From my point of view I'm just stoked the 928 community has several totally brilliant people working and helping to keep our cars going.
The healthy debate can only be good for outcome.
The depth of knowledge mostly goes way over my head, but read on I do.
A big thanks!!

Strosek Ultra

To cross-over, or not cross-over, that is the question.

FBIII

It seems we are going full circle. Last 20 to 5 years ago crossover pipe, last 5 years x pipe and currently crossover pipe revisited.

RKD in OKC

It's x-pipe and h-pipe, both are crossovers.

FBIII

Your getting trivial on definitions misses my point. X pipes were meant to be a huge improvement/gain over the H pipe. Now we could to be going back to the former.

ptuomov

NASCAR uses both. There's variation, but it seems to me that as general pattern they use H-pipe on tracks on which a short collector length is optimal and X-pipe where a long collector length is optimal. The location of the cross-over is more important than the type of the cross-over and there's no room to package an X with straight enough flow paths with a short collector. This all based on hearsay.

hopwood

Let me know if you need me to come and hold the door open with my ***. Or just drool on the floor

Mike Frye

Greg,

Can I make a request?
Maybe update the first post so people can skip to the good parts?

Here's what I have so far:
post #34- dyno base line with Porken chips, intake spacers
post #58- pic of headers test fit on engine block (the centerfold!)
post #134- pic of them installed on the car
post #147- more pics of them installed on car