Roush Exhaust difference: Legal vs. Off-Road
#1
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Roush Exhaust difference: Legal vs. Off-Road
I am buying a Roush body kit and exhaust for my 2008 Mustang GT, but there are two choices for the exhaust: Legal (401338) and Off-Road (401339). The pictures look alike and both are cat-backs only. So, how are they different? What makes the off-road not legal? Has anyone had experiece with the sound difference? Thanks much for the help!
#2
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If it's a cat-back system only, then likely the one version is louder and therefore not legal in (probably) California and maybe a handfull of other states, but Cali I believe is the only one that is significantly different from the rests in terms of sound limitations. Anyone here from the left coast, jump in here........
Otherwise, you'll be fine anywhere else for the most part.
Otherwise, you'll be fine anywhere else for the most part.
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you will be fine as long as your state doesn't have a decibel law. my friend has these mufflers on his roush and they sound great and have a nice deep growl to them.
#6
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i have a 428R with the "legal" Roush axlebacks and wanted more sound but instead of investing in the "illegal" off road roush i bought and installed a magnaflow catted x-pipe. more growl when you step on the gas pedal and less drone @ cruising/highway speed (75-80 mph). my old ears are happy!!!
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Ahh.. maybe I am only half correct. And what is the actual differences between a Roush 427 and 428R anyway. I have seen both at a local dealer and I can't see any difference except in the badging and decals.
#12
Ive got the Roush exhaust that looks identical to the Borla and FRPP stingers. This exhaust paired with my Kooks lt headers with hi flow cats sounds very good (to me anyway) but it is on the loud side, but I like that.
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427R vs 428R
Only 200 428R total conversions. 435hp, polished supercharger (vs black for the 427R), slightly smaller pulley for a little more HP, some billet engine dress up items under the hood. i think 429R's are now available or can be ordered from roush dealerships. btw, the square exhaust tips were used on the Roush Stage 3's, 427/428 use the rebadged Borlas. hope this helps
#15
In California, the highest dB level you can be at for exhaust on a passenger car is 95 dB +/- 1 dB. Stock Mustang GT exhaust (1999 to 2004 models) is 92 dB. My Bassani cat back measured 99 dB. Bassani cat back with catted X pipe measured 118 dB. This was done using California's Standard test procedures at a smog ref station. Assuming an '05 and up GT is around the same level as a '99-'04 GT, Ford doesn't give you much room to go any louder legally. I bet the Roush street legal exhaust is not even street legal at all.
And yes it was because of a ticket.
And yes it was because of a ticket.
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Here is link to an article about a few different axleback setups. I do question the article however. According to the article. The JBAs were the loadest among the axlebacks tested. This includes borla stingers. I have JBAs, while the tone is excellent, I wouldn't call them loud.
http://mustanglife.tenmagazines.com/...ticle&aid=3827
http://mustanglife.tenmagazines.com/...ticle&aid=3827
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