Cutting off muffler...?
- Thread starter rockymt21
- Start date
Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.
shsportsfan12
Full Access Member
- Joined
- Apr 29, 2009
- Posts
- 418
- Reaction score
- 5
but it's extremely hurting your performance....
nah not bad. reprogrammed computer. runs smooth as ever and got +1.2 mpg. Don't race it either lol
shsportsfan12
Full Access Member
- Joined
- Apr 29, 2009
- Posts
- 418
- Reaction score
- 5
You have absolutely no backpressure.... I could go on, but you're happy with it so, so be it.
tybardy
everyone needs a Hoe
to say a vehicle with no muffler has NO back pressure would be an under educated assessment... Not completely untrue but lets recap
The first bit of back pressure comes right as the exhaust is leaving the block through the exhaust manifold, this is why many people not only go with long tube headers but also go with a larger dia primary tube (1 3/4" v 1 5/8). The manifold primarys condensing your exhaust into its "collector" creates back pressure. Next your exhaust meets the catalytic converter; this is probably the most obstructive link in the exhaust chain. This thing is jam packed with media meant to filter out carbon deposits, and it works; in doing so it creates a great deal of back pressure....
Finally bringing you to your "stock" muffler, yes now this DOES provide back pressure, but can you say that this particular back pressure is NEEDED? Honestly, i am not 100% on that; however i went with a magnaflow muffler because of its straight through design to hopefully allow for better air flow. My magna provides the exact same amount of back pressure as simply lopping off the muffler.
so please do go on, for my sake, because i am curious to learn
The first bit of back pressure comes right as the exhaust is leaving the block through the exhaust manifold, this is why many people not only go with long tube headers but also go with a larger dia primary tube (1 3/4" v 1 5/8). The manifold primarys condensing your exhaust into its "collector" creates back pressure. Next your exhaust meets the catalytic converter; this is probably the most obstructive link in the exhaust chain. This thing is jam packed with media meant to filter out carbon deposits, and it works; in doing so it creates a great deal of back pressure....
Finally bringing you to your "stock" muffler, yes now this DOES provide back pressure, but can you say that this particular back pressure is NEEDED? Honestly, i am not 100% on that; however i went with a magnaflow muffler because of its straight through design to hopefully allow for better air flow. My magna provides the exact same amount of back pressure as simply lopping off the muffler.
so please do go on, for my sake, because i am curious to learn
shsportsfan12
Full Access Member
- Joined
- Apr 29, 2009
- Posts
- 418
- Reaction score
- 5
It's not a matter of having no muffler.... ****, I don't run a muffler.... True duals do hurt performance. First let me point out I read his post with the " W/" to be "without cats", instead of "With cats". Now if you take off cats, muffler, and run true duals, what are the benefits of that? There are numerous threads, including with dyno charts, over on GMFS that supports the idea, that true duals, no cats, no muffler, no nothing, hurts performance. Granted I did read his post wrong as stated above, with cats it provides substantial backpressure. When you eliminate all components of an exhaust, how is there any benefit?
tybardy
everyone needs a Hoe
the idea is always that better air flow provides more power... on paper this looks great but like you pointed out, the dyno tells a different story.
so of course the million dollar question is, when does air flow become "too much?" I am actually curious about this because in about 8-9 months i plan on doing LT headers and a high flow cat. I want to make sure i maintain proper back pressure while still allowing MAX air flow. This leads me to believe that if i go with 1 5/8 Long Tube headers i might actually be better off then the standard 1 3/4" that everyone goes with... but again, i dont really know what the **** i am talking about and i would love to see some tested data to show the difference
so of course the million dollar question is, when does air flow become "too much?" I am actually curious about this because in about 8-9 months i plan on doing LT headers and a high flow cat. I want to make sure i maintain proper back pressure while still allowing MAX air flow. This leads me to believe that if i go with 1 5/8 Long Tube headers i might actually be better off then the standard 1 3/4" that everyone goes with... but again, i dont really know what the **** i am talking about and i would love to see some tested data to show the difference
DESIGN
Member
It is less a matter of back-pressure as it is thermal and fluid dynamics. A proper exhaust aimed at performance will keep the exhaust from cooling too early. Keeping the heat in the tubes doesn’t just keep the engine bay and cabin cooler it actually helps with air flow.
Well designed muffler actually causes a low pressure area (usually obtained by crossing the paths of the two exhaust tubes) therefore “pulling” the exhaust gases through the system. This is why a “true dual’ type exhaust system will almost always utilize a x-pipe somewhere between the headers and the mufflers. This is commonly referred to exhaust scavenging.
Headers will both smooth the air flow and decrease back pressure through larger primaries. Do some reading on the styles of headers and you will discover that they make power at varied RPMs. That is why that people will say that the feel they have lost power with long tube headers during daily driving. Once you spin the motor up they become monsters.
Well designed muffler actually causes a low pressure area (usually obtained by crossing the paths of the two exhaust tubes) therefore “pulling” the exhaust gases through the system. This is why a “true dual’ type exhaust system will almost always utilize a x-pipe somewhere between the headers and the mufflers. This is commonly referred to exhaust scavenging.
Headers will both smooth the air flow and decrease back pressure through larger primaries. Do some reading on the styles of headers and you will discover that they make power at varied RPMs. That is why that people will say that the feel they have lost power with long tube headers during daily driving. Once you spin the motor up they become monsters.
Yeah you must have read it wrong. It's cool though. But yeah, that's why I left the cats. A buddy of mine is running true straight pipes & his truck sounds like shit and doesn't run near as good as before he removed the cats. I realize I lost a tad of back pressure but with the cats I'm at the low end of the spectrum but still in the clear. I would not, however, recommend doing it if the OP is thinking about racing etc...
Also, i read earlier in the thread that someone mentioned the summit mufflers. Another buddy of mine used summit mufflers when he built his dirt track car and I can personally vouch for them.
shsportsfan12
Full Access Member
- Joined
- Apr 29, 2009
- Posts
- 418
- Reaction score
- 5
Occassionally I'll throw my muffler back on (I have a flange on it so I can do with it as I please) and it's a Summit Glass Pack. Picked it up for $20. That and a turn down cost me $25. I had an old tip around and welded that onto the turn down. Came out alright.
You can see it in the second video here:
http://www.tahoeyukonforum.com/forum/showthread.php?t=133
You can see it in the second video here:
http://www.tahoeyukonforum.com/forum/showthread.php?t=133
