LSA or Duration to fine tune glasspacks??

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318willrun

318willrun

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If a person wants to fine tune the sound of glasspacks, would LSA or duration have the greatest effect on fine tuning the sound of the glass pack to make it sound more like a glass pack should sound?
We all know on a 4 cylinder sounds like a terrible weed eater because of the order of the exhaust pulses. We know we can delay or speed up the order of exhaust pulses with the cam. So which would be the best way to accomplish this, LSA or duration?
 
what's a good glasspack sound like when a glasspack sounds like a good glasspack should sound?
 
If I wanted to fine tune glasspacks, I'd probably throw them away :lol:

...only kidding...a little.

I'd probably change the piping (distance from engine) before the cam...just me though.
 
The duration that this is used will change the sound of your glasspacks dramatically.

hammer.jpg
 
GeorgeH said:
what's a good glasspack sound like when a glasspack sounds like a good glasspack should sound?
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when it goes "thip thip thip thip thip", it sounds like a burnt valve 273 2bbl.
when it goes "thap thap thap thap" , it sounds like a 10.1 340 up to snuff.
 
How much duration and lsa does it take to blow the packing? they always sound better after.
 
txstang84 said:
If I wanted to fine tune glasspacks, I'd probably throw them away :lol:

...only kidding...a little.

I'd probably change the piping (distance from engine) before the cam...just me though.
Click to expand...
Placement of the glasspacks..... closer to the engine or closer to the rear end, interesting thought :realcrazy:
 
Case in point: Go listen to the exhaust note of an SN95 Mustang with a 4.6 with mufflers before the axle, then listen to an S197 or S550 ('05-up) with a 4.6 or 5.0 and the mufflers at the bumper.

Hint: They do NOT sound the same despite all else being equal (type of muffler, whether or not the cats are there, etc)
 
I would say the same thing goes for the F bodies, but they used the single in dual out mufflers near the bumper from 82-02, then swapped to dual mufflers near the bumper in '10 when they came back on the market...
 
txstang84 said:
Case in point: Go listen to the exhaust note of an SN95 Mustang with a 4.6 with mufflers before the axle, then listen to an S197 or S550 ('05-up) with a 4.6 or 5.0 and the mufflers at the bumper.

Hint: They do NOT sound the same despite all else being equal (type of muffler, whether or not the cats are there, etc)
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txstang84, did you talk to this guy also? Seems he moved his back...
 
Ah, but now you're muddying the waters--that's a boxer 4, not a 90* V8

Your post is invalid and irrelevant
 
the sickened weed eater noise I was talk'n about...
 
...Besides, if you're going to actually use glasspacks, just spring for a real set and buy the dynomax race bullets or something similar...the dime store thrush or cherry bombs are downright awful and remind me of far too many mid 70s chevy pickups with wagon wheels and mud tires only on the back, megaphone tips (insert pukey face)
 
txstang84 said:
Ah, but now you're muddying the waters--that's a boxer 4, not a 90* V8

Your post is invalid and irrelevant
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which brings the next point. If you put a glasspack on an old straight 8 instead of the V8....

Wait... back to point. LSA or duration to get the Thap Thap Thap instead of the thip thip thip
 
But you're still using 4 cylinders as an example when you introduced the topic as how to tune the sound of shitpacks, I mean glasspacks, on a V8 by changing your cam timing or attributes.

Your post is again invalid.

Try again
 
The thip thip thip vs thap thap thap is more about pipe diameter, although a shallower sound would indicate a relatively quick exhaust closing event to me...
 
318willrun said:
...If you put a glasspack on an old straight 8 instead of the V8....
Click to expand...

Good luck finding one still running--but I would like to hear it. 8 cylinders still, by definition, fire every 90* of crank rotation, but will probably sound somewhat different due to the way the exhaust would be scavenged...would it be a solid log manifold, or a tuned header? Or a Dual collector type arrangement like the split headers on a /6?
 
Immediate answer is shorter seat to seat (duration), but if you advanced a longer duration cam to the point where it did that, you might be kissing pistons or at least have something that doesn't run right...
 
txstang84 said:
Immediate answer is shorter seat to seat (duration), but if you advanced a longer duration cam to the point where it did that, you might be kissing pistons or at least have something that doesn't run right...
Click to expand...
true.... true
 
Well, back in the day, I had a set of glasspaks on my stock 361 big block. They sounded like mmmmm mmmmm mmmmm.
I rebuilt the engine and changed to a DP4B aluminum intake, AVS carb, and a 484 Purple cam. I did switch the exhaust manifolds to headers and kept the glasspaks. The sound was now buhwumpa buhwumpa buwumpa and when I went through the gears the sound was a deafening deep WAAAAAAAA!
So my guess is that it was the duration.
 
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