muffler or no muffler - Page 4

**Zach** · 7-15-07, 19:41

Quote:

Originally Posted by TR-mx6

at 3000rpm

you know that doesn't tell us anything. I can hold my engine at 3k rpm's and be at 15 in/Hg. Try driving around with the gauge hooked up, under full load, then let us know what it the gauge reads. a video of it would be cool too...since most cell phones now a days have video capability.

**TR-mx6** · 7-15-07, 19:59

I did the tests while being in school, if I get my hand on an o2 adapter plug and vaccum\pressure gauge ill take a vid, but I don't own any of those 2 things.

The point being that despite the ugliness of the downpipe it is well sized for minimum backpressure with the stock turbo and well designed for the fittement of the a\c compressor.

**SixSick6** · 7-16-07, 1:40

http://www.mx6.com/forums/1g-faq-eng...re-tester.html (DIY backpressure tester)

RedRocket90'626 · 7-17-07, 1:20

one thing to keep in mind:

less backpressure = more top end hp

more back pressure= more low end torque

On my 626 DX 1st gen, im running the stock 2" exhaust, no cat or resinator, and a APC mini race muffler out back, straight through, just like a fartcan only w/o the horid buzz. It makes a nice deep tone. its 2.5" inlet, 5" canaster, and 3" outlet. Im going to make it 2.5" straight pipe to the muffler for more power.

**TR-mx6** · 7-17-07, 16:57

Quote:

one thing to keep in mind:

less backpressure = more top end hp

more back pressure= more low end torque

There are certain limitations to that theory\fact. Diminishing returns.

**TR-mx6** · 7-17-07, 17:02

Quote:

On my 626 DX 1st gen, im running the stock 2" exhaust, no cat or resinator, and a APC mini race muffler out back, straight through, just like a fartcan only w/o the horid buzz. It makes a nice deep tone. its 2.5" inlet, 5" canaster, and 3" outlet. Im going to make it 2.5" straight pipe to the muffler for more power.

I highly doubt you'll make more power, I'm going to say you will make less. If the power potential is greater than it was before it will be at a level out of your rev range as you will not push enough exhaust form this engine to justify the need for and exhaust system that large. Increasing the exhaust size\decreasing length\increasing length, changes the characteristics of the engines maximum power, as in where and when but does not directly change the amount available. Gain more up very high where you don't make any and lose a bit down low where you used to.

plz think twice about your future exhaust system modification.

RedRocket90'626 · 7-18-07, 1:19

well in time im also going to turbo my DX with a T28 or T25 Garret, so im plainning on running that exhaust system with the turbo, and im doing it all at once, turbo, exhaust, all my internal and tranny upgrades, etc.

edit: I should of said that i was goin to turbo it w/ the new system, sorry.

**SixSick6** · 7-18-07, 1:57

Sure you are/will.

**pHeLiOs27** · 7-18-07, 10:02

I have a 3" turbo back with magnaflow cat/muffler and is serving me well. HOWEVER i'm getting some pinhole leaks and I haven't the time to fix them right now. I'll prolly go with a VRS next time around as well.

**TR-mx6** · 7-19-07, 18:09

I juste learned something quite interesting today, the turbo is spun because of the differential in pressure(back pressure if youd like) between the manifold and the pipes. Therefore, a small exhaust manifold creates a large amount of backpressure because of the the size and restriction of the turbo and a huge pipe after the turbo enables it to spin better. Lesson, thats the reason small diamter manifolds are better.

7-15-07, 19:59	#47 (permalink)
TR-mx6 Rock n' Roll \m/ Join Date: May 2005 Location: , Canada Age: 23 iTrader: (0)	I did the tests while being in school, if I get my hand on an o2 adapter plug and vaccum\pressure gauge ill take a vid, but I don't own any of those 2 things. The point being that despite the ugliness of the downpipe it is well sized for minimum backpressure with the stock turbo and well designed for the fittement of the a\c compressor.
	Keepin' it Heavy www.myspace.com/trrock Check us out!

7-18-07, 10:02	#54 (permalink)
pHeLiOs27 Join Date: Oct 2002 Location: Albuquerque, Nm, NM, USA Age: 33 iTrader: (0)	I have a 3" turbo back with magnaflow cat/muffler and is serving me well. HOWEVER i'm getting some pinhole leaks and I haven't the time to fix them right now. I'll prolly go with a VRS next time around as well.
	91Mx6GT,MTX, Kia fuel filter, Conefilter, NGK plugs/wires,Autometer Boost Gauge, PRD mbc @11psi. Dyno: http://img75.imageshack.us/img75/6387/mx6gtdyno9bx.jpg Dyno2 12psi/3"dp and exhuast: http://www.njsr.org/pics/albums/user...yno%20copy.jpg

7-19-07, 18:09	#55 (permalink)
TR-mx6 Rock n' Roll \m/ Join Date: May 2005 Location: , Canada Age: 23 iTrader: (0)	I juste learned something quite interesting today, the turbo is spun because of the differential in pressure(back pressure if youd like) between the manifold and the pipes. Therefore, a small exhaust manifold creates a large amount of backpressure because of the the size and restriction of the turbo and a huge pipe after the turbo enables it to spin better. Lesson, thats the reason small diamter manifolds are better.
	Keepin' it Heavy www.myspace.com/trrock Check us out!

7-17-07, 1:20	#49 (permalink)
RedRocket90'626 New Member Join Date: Jul 2007 Location: Butte, MT, USA Age: 17 iTrader: (0)	one thing to keep in mind: less backpressure = more top end hp more back pressure= more low end torque On my 626 DX 1st gen, im running the stock 2" exhaust, no cat or resinator, and a APC mini race muffler out back, straight through, just like a fartcan only w/o the horid buzz. It makes a nice deep tone. its 2.5" inlet, 5" canaster, and 3" outlet. Im going to make it 2.5" straight pipe to the muffler for more power.

7-18-07, 1:19	#52 (permalink)
RedRocket90'626 New Member Join Date: Jul 2007 Location: Butte, MT, USA Age: 17 iTrader: (0)	well in time im also going to turbo my DX with a T28 or T25 Garret, so im plainning on running that exhaust system with the turbo, and im doing it all at once, turbo, exhaust, all my internal and tranny upgrades, etc. edit: I should of said that i was goin to turbo it w/ the new system, sorry.