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Just replaced stock exhaust with 3/3 cat and magnaflow 15620 LT1 (1993-97 v8) full 3" cat back. Added 18" dnynomax bullit in mid pipe. (it pretty much IS the mid pipe)
Ordered CAT with rear O2 boss, works great, no codes.
System is already breaking in at about 100 miles so far.
Very deep, sounds very tough, very little rasp if any at top end...it just gets LOUD at WOT. The 1.9 rockers and air intake like the new fat exhaust... so does my foot...my seat doesn't, however. [img]smile.gif[/img]
I knew the exhaust would be much louder than stock. (been around awhile...this bird is not my loudest car...383 formula s gets that title) But, it is louder than I would like. I know what you are thinking..."dude, dah..." Now, before ya'll get going on me I will get to the point, hold on...I like driving like Steve McQueen. I love a good muscle car, tough sound, hi performance, etc. Yo, you know it.
It is loud to say the least when you get on it. It could be much louder. It is not dual exhaust big block with headers loud, but loud none the less. I prefer a bit more, um, stealthiness if possible. So, here is an idea...
The standard magnaflow dual out muffler...this one is 3in with dual 2.5 out. Muffler is fiber packed oval with the incoming exhaust entering through passenger side. There is a staight through perf tube that exits to the drivers side. The drivers side tail pipe is thereby 'muffled' by the perf tube packed with fiber glass. That in and of itself is not much muffling as it is straight through rather than encountering 2 x 180 degree bends to slow everything down. The passenger side tail pipe is fed 'directly' off of the 3" incoming by a curved baffle that covers about half of the main muffler entrance...directing 'unmuffled' exhaust right back out and into the passenger side tail pipe. magnaflow is relying on audio phaseing to negate the sound volume of similar but out of phase wave forms to reduce the overall sound level. This is not perfect but it will work to some extent. The muffler is about 20 inches long so the wave forms we are talking about are in the bass range...about 40 - 300 hz or less if I remember correctly. (60 hz = about 12 inches I think) Only those wave forms that happen to be in the size range or so as the muffler are canceled out...if at all. Anyway... this is where much of the low level drone comes from when combining/spliting a mono signal such as a single exhaust source into two seperate but opposing length ouputs.
I think I might drill some holes (1/4d) in the incoming side of the front directional baffle so that more main exhaust gets directed down the primary perf tube and into the drivers side tail pipe. This would...possibly...yield less drone in the low range as less exhaust is being 'phased' and possibly muffle the output a bit more as more of the exhaust is traveling down the 'sorta a muffler' fiber packed perf tube. Overall performance should not be hindederd too much...any back pressure that develops should be minimal as the system is still no less than 2.5 id at any giving port of exit as well as there is still a fuctional 'quick out' to the passenger side tail pipe. If I screw it up with the drilling idea...jbweld can work wonders.
Has anyone ever tried anything like this?
Thanks to everyone who has given great and helpful input into my 'exhaust overhaul' portion of this project. (ellick, blldog, to name just a few) That "LT1 v8 catbiak comes with the S pipe, just cut off the flange and the cat slips right on" is realy a HUGE tip. Thanks all.
Oh, yea, no codes. I thought people got ses codes when going to extreme exhaust like a full 3 inch system? Is that just with headers? Have the cat with rear O2 boss...is that maybe yielding higher temps than if it was back in the S pipe thereby not so quick to set off code? Or is it just a sometimes you get codes sometimes you don't sort of think? knock on wood. I gotta go drive that sucker. catch ya'll later. [img]graemlins/rock.gif[/img]
Ordered CAT with rear O2 boss, works great, no codes.
System is already breaking in at about 100 miles so far.
Very deep, sounds very tough, very little rasp if any at top end...it just gets LOUD at WOT. The 1.9 rockers and air intake like the new fat exhaust... so does my foot...my seat doesn't, however. [img]smile.gif[/img]
I knew the exhaust would be much louder than stock. (been around awhile...this bird is not my loudest car...383 formula s gets that title) But, it is louder than I would like. I know what you are thinking..."dude, dah..." Now, before ya'll get going on me I will get to the point, hold on...I like driving like Steve McQueen. I love a good muscle car, tough sound, hi performance, etc. Yo, you know it.
It is loud to say the least when you get on it. It could be much louder. It is not dual exhaust big block with headers loud, but loud none the less. I prefer a bit more, um, stealthiness if possible. So, here is an idea...
The standard magnaflow dual out muffler...this one is 3in with dual 2.5 out. Muffler is fiber packed oval with the incoming exhaust entering through passenger side. There is a staight through perf tube that exits to the drivers side. The drivers side tail pipe is thereby 'muffled' by the perf tube packed with fiber glass. That in and of itself is not much muffling as it is straight through rather than encountering 2 x 180 degree bends to slow everything down. The passenger side tail pipe is fed 'directly' off of the 3" incoming by a curved baffle that covers about half of the main muffler entrance...directing 'unmuffled' exhaust right back out and into the passenger side tail pipe. magnaflow is relying on audio phaseing to negate the sound volume of similar but out of phase wave forms to reduce the overall sound level. This is not perfect but it will work to some extent. The muffler is about 20 inches long so the wave forms we are talking about are in the bass range...about 40 - 300 hz or less if I remember correctly. (60 hz = about 12 inches I think) Only those wave forms that happen to be in the size range or so as the muffler are canceled out...if at all. Anyway... this is where much of the low level drone comes from when combining/spliting a mono signal such as a single exhaust source into two seperate but opposing length ouputs.
I think I might drill some holes (1/4d) in the incoming side of the front directional baffle so that more main exhaust gets directed down the primary perf tube and into the drivers side tail pipe. This would...possibly...yield less drone in the low range as less exhaust is being 'phased' and possibly muffle the output a bit more as more of the exhaust is traveling down the 'sorta a muffler' fiber packed perf tube. Overall performance should not be hindederd too much...any back pressure that develops should be minimal as the system is still no less than 2.5 id at any giving port of exit as well as there is still a fuctional 'quick out' to the passenger side tail pipe. If I screw it up with the drilling idea...jbweld can work wonders.
Has anyone ever tried anything like this?
Thanks to everyone who has given great and helpful input into my 'exhaust overhaul' portion of this project. (ellick, blldog, to name just a few) That "LT1 v8 catbiak comes with the S pipe, just cut off the flange and the cat slips right on" is realy a HUGE tip. Thanks all.
Oh, yea, no codes. I thought people got ses codes when going to extreme exhaust like a full 3 inch system? Is that just with headers? Have the cat with rear O2 boss...is that maybe yielding higher temps than if it was back in the S pipe thereby not so quick to set off code? Or is it just a sometimes you get codes sometimes you don't sort of think? knock on wood. I gotta go drive that sucker. catch ya'll later. [img]graemlins/rock.gif[/img]
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