yeah! but even with nitrous the better header design still tends to pull that extra torque over and above what you get with a dual exhaust, in fact its generally even more effective due to the larger gas volumes and higher pressure exhaust flow rates
cylinder fill efficiency is a compromise, your engine design is forced to make selecting the way components are matched, the factors of cam timing compression and exhaust header tuning all must fall in the same 3000 rpm power band and ideally in the same 1500 rpm range to maximize power.
the choices between cam timing and compression ratio, and head and intake flow rates, valve size and valve lift and duration,
has a huge effect on,exhaust scavenging and
while most people think the port flow rate is mostly the result of the piston dropping away from TDC,
lowering the cylinder pressure , thus drawing in the intake runner charge, this is not the major factor once the engine rpms increase significantly.
its exhaust scavenging during the valve over lap , being well matched to the engine displacement and cam timing, header diameter, and length, and collector design,
and intake ram tuning that can significantly boost cylinder fill and cylinder scavenging efficiency rates.
OK, first fact! the piston can,t compress anything being trapped in the cylinder by the piston compressing it as it raises,until both valves seat & seal
http://garage.grumpysperformance.com/index.php?threads/calculate-compression.9162/#post-32706
http://garage.grumpysperformance.co...lsa-effects-your-compression-torque-dcr.1070/
If your looking to reduce noise installing several x-pipes in series, blends and reduces the exhaust pulse strength,yes Im sure it could, if theres enough physical real estate under the car, or truck ,available to allow it to be installed,
but I found a full length 3" exhaust with just two 3" X-pipes mounted as close as you can get them too the header collectors
x-pipes like this in series and, two 3" inlet and dual outlet ,
mount the mufflers as far back as you can and be sure to have the tail pipes exit past the cars bumper and point back and downward at about a 45 degree exit,
what your trying to accomplish, is basically two goals,
(1) you want to keep the exhaust gas velocity fairly high so its exiting inertia will help scavenge the engines cylinders, on most mild street engines a 2.5" full length exhaust with an (X-PIPE) will be ok, but
once you exceed about 370 cubic inches of displacement AND/OR 6000 rpm,
you can usually benefit from the larger and lower restriction of a full 3" exhaust system.
(2) obviously youll want significant noise reduction , below about 4000 rpm where youll spend more than 90% of the time driving on the street.
low flow restriction mufflers does a reasonably good job at reducing the sound levels, a 3" inlet and dual 2.25" outlet exhaust muffler design works reasonably well, but do your research as different brands have wildly different flow characteristics. and yes dual 2.25" outlets can flow equally to a single 3" inlet, and remember as the exhaust gases cool volume is reduced
3" o.d = 2.87" diam. inside--approximately 6.5 sq inches of area
2.75 o.d = 2.62"diam. inside--approximately 5.4 sq inches of area
2.5 o.d = 2.37" diam. inside--approximately 4.4 sq inches of area
2.25 o.d = 2.12" diam. inside--approximately 3.5 sq inches of area
that adding just two, 3" x-pipes in close series does make a significant difference in noise levels , is well proven, if you could fit 3 that would certainly not hurt.
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GrumpyThe Grumpy Grease Monkey mechanical engineer.Staff Member
more numbers for ya'll who like numbers.
All tests via an independent lab
All tests @ 15” wc
2 “ Straight Pipe 283 CFM
2 ¼ “ Straight Pipe 365 CFM
2 ½ “ Straight Pipe 521 CFM
2 ¼” Typical Bent tailpipe 268 CFM
2 ½” Typical Bent Tailpipe 417 CFM
2 ¼” Inlet/Outlet_ Glass Pack Tips- No Louvers- Smooth 274 CFM
2 ¼” Inlet/Outlet- Glass Pack Tips-Louvered 133 CFM
Same as above set for reverse flow 141 CFM
2 ¼” Cherry Bomb 239 CFM
2 ½” Cherry Bomb 294 CFM
2 ½” Inlet/Outlet Dynomax Super Turbo 278 CFM
2 ½” Inlet/Outlet Ultraflow Bullet 512 CFM
2 ½” Inlet/Outlet Gibson Superflow 267 CFM
2 ½” Inlet/Outlet Flowmaster ( 2 Chamber) 249 CFM
2 ½” Inlet Outlet Flowmaster ( 3 Chamber) 229 CFM
2 ¼” Inlet/Outlet Thrush CVX 260 CFM
2 ½” Inlet/Outlet Maremount Cherry Bomb 298 CFM
2 ½” Inlet/Outlet Hooker Aero Chamber 324 CFM
2 ½” Inlet/Outlet Hooker Max Flow 521 CFM
2 ½” Inlet/Outlet Borla Turbo 373 CFM
2 1/2" Inlet/Outlet Magnaflow 284 CFM
in the ideal exhaust system youll want to have less than .5
(thats 1/2 a PSI of back pressure) at the engines peak rpm
http://www.exhaustvideos.com/faq/how-to-calculate-muffler-size-pipe-diameter/
http://www.pontiacstreetperformance.com/psp/exhaust.html
http://www.mk5cortinaestate.co.uk/calculator5.php
http://forums.superchevy.com/super-...-calculate-muffler-size-and-exhaust-pipe-dia/
http://garage.grumpysperformance.com/index.php?threads/is-backpressure-hurting-your-combo.495/
http://garage.grumpysperformance.com/index.php?threads/x-or-h-pipe.1503/
http://garage.grumpysperformance.com/index.php?threads/calculating-required-exhaust-pipe-size.11552/