ayousef

Well, Ive been thinking of a 180degree header for quite a while now and I know of a fabricator who can make it happen, yes it will be VERY expensive, but lets forget about that for a second and ask how will this sound on a 1000rwhp 427ci motor with a big whipple 4.0 and a full 3" exhaust.

Basically I call it the 180degree tri-y header, I came up with this crap sounds insane on paper

Will this loose/gain horsepower over a traditional 2" 4-1 header design, and how will it sound, thats the main reason behind this, sound.

oldngray

iTrader: (9)

Every 180 degree header I have heard sounds like a v-6 to me.. my .02

409CISecondGen

iTrader: (2)

That doesn't sound like a V6....

OP, you would have to R&D the **** out of the optimum lengths to get the most out of that header. Too many variables to just use a calculator and build it.

Ellsworth

I'd say if it did preform well, and sounded good. Big companys like Kooks and Pacesetter would of already have done it.

Just no

my .02

ayousef

not true,

its really expensive and complex to build on a front engine car. Ground clearance suffers, and power will also be all over the place because the pipes would have to be very long to cross over to both collectors. You WILL need to retune because the left oxygen sensor now reads fueling output from a mixture of two left cylinders and two right cylinders, know how to get around that? I do but I dont think it makes sense for the exhaust manufacturers to have such a product.

On the other hand I wanted it for a sound purpose only, and I also incorporated a tri-y design into the 180-degree header, not giving a **** about performance since blower cars are not TOO dependent on exhaust scavenging.

Since that time I decided to scratch off the idea and focus on a performance-only oriented exhaust. I contacted an exhaust genius whos now speccing me an exhaust for my specific configuration. It will be a 4-1 custom header, might be stepped (not sure yet), with custom everything. I will fabricate it from Inconel 625, and possibly complete the exhaust in titanium and have custom butterfly valves.

Im taking this to the next step.

DietCoke

iTrader: (18)

http://kalecoauto.com/index.php?main...products_id=41

MasterTomos

iTrader: (15)

In my head it sounds like wahwahwahwahwahwahawah at idle, and when you rev it it'd sound more like wraaaaaAAHHHHHM!!!! Depends on the cam as well though.

Just my .02

MIKE1444

What you've done is made a completely separated set of 180 degree headers. It'll sound like any other set of 180 headers, basically like a ferrari maybe more "crackle" like a TVR v8.

You only get a growl when your cylinders fire over inequal lengths of time on the same header.

Harley davidson for example. 405-315-405-315-405-315.

Engines that buzz would be
singles (720-720-720-720 blah)
straight six 120-120-120-120-120-120
180 headers v8, flat plane v8. 90-90-90-90-90-90-90-90
4-banger - 180-180-180-180
2-stroke twin - 180-180-180 (nobody pairs the pipes, so they don't sound like 4-cylinders)
V6's are always screwed up. Vq's are 120 style, But GM V6's seem to be 180-60 patterns that growl at idle, but sound like a Cow mooing, and an elephant farting, all in an airport hangar.


Crossplane V8's are unique. 180-270-180-90-180-270-180-90
That 90 degree turns those cylinders into one big cylinder, so our crossplane v8's are really sounding like some Gnarly V6's. The sound is more like 225-225-135-135. When you compare the centerlines of those sounds, you get 450-270.

My pet project is to take my 4.3 and pair cylinder 1,6,&3, and then 5-4-2 in the other pipe. No-Xpipe. I get 180-300-240, with continuously messed up centerlines. 240-210-210, then 225-255-240, then 240-247.5-232.5. My theory is that since these are all over 180 degrees apart, my scavenging will be ruined. but I'm afraid to X-pipe it since the v6 sound might come back.

ayousef

Thanks for the elaborate explanation Mike, I didnt understand how our crossplane V8s would end up sounding like the 225-225-135-135 however that got me puzzled.

But let me ask you, do you think the change I incorporated into the 180 degree header design would have any advantage or disadvantage? I know tri-y (which isnt the best name for what is essentially the joining of two pipes on a V8) headers have a slightly different tone than the 4 into 1 headers, but im wondering how would this sound.

I also dont know if I want to experiment with this header on my 1000rwhp Camaro ZL1 for fear of it sounding raspy or like a v4. Any ideas perhaps?

MIKE1444

Your 180 headers are going to make it sound like a Ferrari, aka 4-cylinder flat plane sound.

What kind of sound are you looking for? Growl? BMW E92 M3? Mercedes E63 AMG 6.3? Alfa romeo 8C 4.7? 60's Shelby? C6.R GT2?

Now for the 225-225-135-135. There's an error for the 235 pieces, so I'll re-correct it below.

Let's use 18436572. The LS order is the same thing rotated 180 degrees.
Make 8 dots and follow the firing path. You'll see what I'm talking about.

8-4 generates 270 degrees of sound wave.
No. 6 makes 180 degrees, as does no.2

The angular distance between the center of 8-4 and the center of 6 is 225 degrees.
The angular distance between the center of no.2 and the center of 8-4 is 225 degrees.
The angular distance between the center of no.6 and the center of 2-8 is 270 degrees.

Take a lego tire, and space push pins at half intervals of those angles and tell me if it sounds familiar.

MIKE1444

You get a growl whenever you have any uneven centerlines.

Raspy sounds are a muffler thing. I believe big cased lightly fiber packed mufflers solve that.
Flow speed has a big effect too, but I'm trying to quantify it. I believe breaking the speed of sound should make a cracking (raspy) sound, but all of my data from some studies has too many other variables. Distortion is a clipped sound wave, and makes a raspy sound. under some conditions. If Exhaust port flow has chop-top flow, it might be the cause of that pinging sound in longtubes. 4.8's sound super smooth all the time, but 6.2's have some crunchyness.

ayousef

Well what im going after is a smooth exhaust note, high pitched something exotic like, say Ferrari, Lambo etc.. im not sure there is a way to make a V10 or V12 sound, but mimicking a flatplane Ferrari V8 like the 458 "should" be possible. Mufflers HAVE to be a Corsa because of how good they are at killing low frequency sound waves and leaving out the high frequency waves un touched.

Now while im after a high-pitched sound I definitely do not want to run into a raspy exhaust note (note old M3), or how some cars end up sounding like when you take the cats off. I obviously don't have this down to a science, but although I never had any problem with 427's rasping except that it DID happen on my truck when I opened up the exhaust too much. I installed 1 7/8 headers, offroad xpipe, and a true dual 3" exhaust with straight through mufflers. The exhaust rasped under light load when the converter was slipping, however completely went away at WOT.

Im thinking maybe I shouldn't go above 1 7/8 primaries, 3 inch collectors and 3 inch dual exhausts if I do my tri-y 180 degree header. I think it should also have a smooth cam to maintain a smooth exhaust note and im not sure about using an x-pipe except I know that deceleration popping sucks when you don't have x-pipes and x-pipes smooth out the exhaust note coming out of the tips.

So in one sentence, how to build a non raspy yet high-pitched exhaust for an LS crossplane v8 motor using 180 degree headers.

MIKE1444

Ferrari 458's have a 4 into 1 header and then they go to an xpipe.

You'll have the euro sound with your layout. Good luck.

MIKE1444

So, I took a look at a 4.3 crankshaft. 30 degree splay on a 90 degree block. It's an even-fire engine.

The "180 style" setup on a 4.3 gives me a 240-120-360 exhaust note without an x or y pipe. It just might work.