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67LS1
67LS1 New Reader
5/11/21 10:06 a.m.

In reply to Curtis : Reviving this old post (again)...do all V6 engines fire at 120 degrees? 

 

Driven5
Driven5 UltraDork
5/11/21 10:57 a.m.

In reply to 67LS1 :

Not all, but almost all. Yours does.

Paul_VR6 (Forum Supporter)
Paul_VR6 (Forum Supporter) SuperDork
5/11/21 1:00 p.m.

Unless you start with a straight 6 or V12 it will sound like trash. Sorry*

*maybe flat plane V8 would be ok sometimes

67LS1
67LS1 New Reader
5/11/21 1:40 p.m.

Then am I correct in assuming V12s fire at 60 degrees? 
BTW, I agree that V6 engines don't (can't'?) sound as good as a V8. It's in the cadence. 
 

frenchyd
frenchyd UltimaDork
5/11/21 3:28 p.m.

In reply to curtis73 :

It really depends on the firing order of the engine.  90 degree V8's will have adjacent cylinders firing between 90 /180 degrees and 270 degrees.  To get equal pulses exhaust tubes must cross over/under other wise you basically hear 3 cylinders and a pause.  Most notable at a slow idle. 

pres589 (djronnebaum)
pres589 (djronnebaum) UltimaDork
5/11/21 9:35 p.m.

Oh I don't know, I can think of a V6 or two that sounds nice...

https://www.youtube.com/watch?v=52K5rxw6o0c

SVreX (Forum Supporter)
SVreX (Forum Supporter) MegaDork
5/21/21 4:58 p.m.

How about the LSX?

I love the performance of these monsters, but honestly I've never heard one I thought sounded good. 
 

Now I have a car with an LSX, and I need some help.  What are some of the best solutions for exhaust tone on the LS?

Driven5
Driven5 UltraDork
5/21/21 5:12 p.m.

In reply to SVreX (Forum Supporter) :

1) 180 Degree Headers.

2) 8-1 Collector.

SVreX (Forum Supporter)
SVreX (Forum Supporter) MegaDork
5/21/21 6:54 p.m.

In reply to Driven5 :

Definitely not enough space for 180 degree headers. 

67LS1
67LS1 New Reader
5/22/21 8:46 a.m.

In reply to pres589 (djronnebaum) : That sounds pretty good all wound up for racing but street driven, idling at stop lights, etc, V6 engines just don't sound as good as V8s. I've got a V6 in my 66 Chevelle and I'm going for quiet, no, silence, because I can't make it sound good.

 

Pete. (l33t FS)
Pete. (l33t FS) MegaDork
5/22/21 10:03 a.m.

In reply to 67LS1 :

Like anything purely subjective, it's all down to personal taste.  I personally think the blop-blop-blop warble of a crossplane V8 sounds embarassingly cheap.  Other people like it so much that they run completely separated dual exhausts, no crossover, to amplify it.  Everybody's got their own tastes.

One of the best sounding new cars I've heard on the road was a V6 Challenger with some sort of exhaust.  Definitely a six.  It had a wail like a water cooled 911 but more liquidy-smooth, without the harsh back of the throat kind of rasp that 911s tend to get.  (THAT may be the result of the airbox and exhaust being so close together, normally there is more separation between intake and exhause noise)

rslifkin
rslifkin UberDork
5/23/21 8:27 a.m.

On the crossplane V8 thing, some sound decent, others sound like crap.  It depends on the firing order as well as the exhaust setup.  I general, I think they often sound better with unequal length stuff in the exhaust and a Y into a single usually helps too.  Cam selection matters a lot as well. 

The 360 in my Jeep sounds decent at idle with 4-2-1 headers and an unequal length y-pipe.  The 454s in the boat do as well with manifolds and an enqual length y-pipe on each engine.  Although those have a bit of a gurgling waterfall noise added to the sound at idle from the water lift mufflers (and they're pretty quiet as well).  The 360 is moderate compression (9.7:1) with a fairly short duration, but high lift (so fast lift rates) roller cam.  The 454s are low compression (8.5:1) with moderate duration, low lift, generally mild flat tappet cams.  Interestingly, they share the 1-8-4-3-6-5-7-2 firing order (ignoring the fact that one of the 454s spins backwards, so has the firing order reversed). 

I have very little idea what the BMW V8 in my E38 sounds like at idle, as I've only heard ones with a louder exhaust in a video, not in person.  And the stock exhaust on mine (duals with an X pipe in the center resonator) is so quiet that if you stand behind the car at idle, you just hear a faint bassy hum. 

LS motors tend to sound like crap with a loud exhaust IMO.  And the 5.0 (old and new) Fords tend to gurgle like they're underwater.  I'm not sure what it is, but something about those engines just produces less than desireable sounds. 

67LS1
67LS1 New Reader
5/23/21 11:32 a.m.

I agree that exhaust notes are subjective. To me it's a fascinating subject. I actually had another post on here ( https://grassrootsmotorsports.com/forum/grm/exhaust-system-thoughts/183406/page1/ ) about the science of tuning an exhaust note. I got a lot of good info and will be putting my third set of mufflers on my car soon ( as soon as I can finish a 2 day Mustang project for my brother that's in its 5th week ), probably with resonators. I'm looking for really, really quiet. Like silence.

preach (fs)
preach (fs) HalfDork
5/23/21 1:59 p.m.
67LS1
67LS1 New Reader
5/23/21 4:53 p.m.

In reply to preach (fs) : that does sound good. My Chevelle would really make some people double take if it sounded like that.

 

67LS1
67LS1 New Reader
5/23/21 5:00 p.m.

In reply to Pete. (l33t FS) : Interesting. So the compact length of the 911 exhaust must contribute to its exhaust note. I wonder what the affect would be on a modern V6 if the exhaust, cat, muffler, resonator were reduced to a super-compact system that terminated say right behind the front wheel.

 

Pete. (l33t FS)
Pete. (l33t FS) MegaDork
5/23/21 5:15 p.m.

In reply to 67LS1 :

I couldn't really explain it.  I wish I had the vocabulary (if it exists) to describe exhaust characteristics.

 

A certain GRM'er did a DOHC six swap in his E30 BMW, and with 6-into-2 long tube headers, it sounds remarkably 911-like.  Paul is off the line in his 911 at the extreme beginning, followed by Artur in his BMW.  I deliberately retained all that in the video because it just sounded so good smiley

 

I'm not all that certain that exhaust PIPE length matters that much.  911s do have fairly substantially sized mufflers, the main difference is they don't have to add eight feet of pipe to get it to the back of the car.

Driven5
Driven5 UltraDork
5/24/21 10:01 a.m.
67LS1 said:

I've got a V6 in my 66 Chevelle and I'm going for quiet, no, silence, because I can't make it sound good.

Just an opinion, but I don't know that "can't" is the word I'd use there:

 

67LS1
67LS1 New Reader
5/24/21 3:52 p.m.

In reply to Driven5 : To me, those aren't bad but they're still quite raspy. I thought my Flowmaster 50 Series sounded better. And I could not duplicate that Borla package in my Chevelle.

But this does kinda show why there are so many  aftermarket muffler manufactures. Everyone likes something a little different.

 

snailmont5oh
snailmont5oh Dork
1/13/22 2:07 a.m.

In reply to rslifkin :

More for packaging than anything, I went with long-tube headers, a slightly unequal-length intermediate pipes, a Flowmaster merge collector, a 3" straight-through muffler, and a tailpipe made of mandrel bends welded together.

Here's what it sounds like without the muffler:

And here's what it sounds like at full-boogie:

 

67LS1
67LS1 Reader
1/13/22 4:53 a.m.

Ha. If my tiny V6 sounded like that I'd leave it. Alas, mine sounds like a blender on Frappe.

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) MegaDork
1/15/22 6:08 p.m.
67LS1 said:

In reply to Curtis : Reviving this old post (again)...do all V6 engines fire at 120 degrees? 

 

I can't think of any V6s that don't

Pete. (l33t FS)
Pete. (l33t FS) MegaDork
1/15/22 6:18 p.m.

In reply to Curtis73 (Forum Supporter) :

I can think of three.  Odd fire Chevy and Buick V6s (I know the Buicks were a V8 firing order with two cylinders missing) were very odd fire.  The 4.3 Chevys up to the end (before the LT1 based) had a 108/132 degree firing interval because they didn't do a full split on the pin like even fire Buicks.

 

I think all purpose built Busch Grand National engines were odd fire with 120 degree spaced straight pins.  This makes one bank 30 degrees off, since an even fire straight pin V6 would have a 120 degree bank angle.  I think Lancia actually made one of those, or maybe Alfa Romeo.

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) MegaDork
1/15/22 6:22 p.m.
SVreX (Forum Supporter) said:

How about the LSX?

I love the performance of these monsters, but honestly I've never heard one I thought sounded good. 
 

Now I have a car with an LSX, and I need some help.  What are some of the best solutions for exhaust tone on the LS?

Short of a flat-plane crank, a custom cam for a new firing order might help.  The thing that makes a flat plane crank sound good is the even-er firing order.  You always get a left-right-left-right firing order to help the pulses get to the collector at different times.

The common cam order swap is to exchange 4 and 7 (commonly called a 4-7 cam)  You can also get a 4-7/3-2 swap cam.  That makes the new firing order 1-8-7-2-6-5-4-3, or a left-right-left-right pattern.  The 4-7 swap is mostly done to make things a bit lower on the NVH and can make a little power on the intake side since there aren't as many cylinders fighting for the same air at the same time.  The 4-7/3-2 swap can make things buzz like crazy.

I personally don't mind the sound of an LS.  I think with the right muffler they sound super sweet.  I am, admittedly, an old-school car crafter, so V8 noises are a happy place for me.

Like this:  This is my happy place.

 

frenchyd
frenchyd UltimaDork
1/15/22 6:29 p.m.

I wonder what a set of brass megaphones would do for the sound. I suppose the diameter and length would really effect the sound. 

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