Well then how do you explain this report:
"This is Joe at Fabspeed motorsport. I own a 6 speed 360 spider and tried 4 different exhaust systems on my car in order to experience all the sound varieties and for empiracle and testing data. I do a lot of research design and development on exhaust systems and intake
A couple of things to consider.
Yes the Ferrari oem challenge straddle muffler and the oem 430 muffler have the exact external size and shape. Therefore the mufflers are interchangeable. However Ferrari has different part numbers for these mufflers and Xray inspection shows the internal designs are quite different and the sound was different ......the 430 muffler is more restrictive internally and attenuates controls the sound more versus the straddle coupes muffler.
I actually installed both of these mufflers on my 360 as I wanted to recreate for sale a challenge straddle muffler for 360 cars based on what I believed Might be the best possible choice of sportscar sound and power. I actually bought at great expense a complete challenge straddle rear muffler with straddle tips and I had a factory f430 muffler with tips laying around too.
I waterjet cut tig welded the correct brackets in order to correctly mount the oem straddle system on my car. I installed everything and hooked up the vacuum valves. So I had everything installed and made solid works files of all the brackets and was ready to duplicate the entire oem ferrari challenge straddle system for regular 360 cars.
I was greatly disappointed with the retrofitted 360 challenge straddle muffler on my USA
360 spider. The problem was That the car was down on power and the sound was not as aggressive as I assumed it would be. In analysis I attributed this to 2 factors. One of these factors I could not remedy so I ditched the project.
On the straddle the oem factory headers do not have pre cats so the sound level is more sporty f1 like right from the factory. I can address that with race quality headers.
The real issue was that the 360s vacuum operated exhaust valves did not open up very often despite aggressive driving as my cars ECU was tuned for the cars original boat anchor coffin style muffler and the cars ECU opened the exhaust actuated bypass valves just as Ferrari programmed them to open for the big boxy muffler. So there I am driving and road testing with a complete expensive Challenge Stradale factory OEM rear muffler system with factory tips and the car sounds weak and is Down on power. Exhaust flapper valves only open at certain rpm points. I am frustrated and realize the difference must be locked in the Challenge straddle OEM ecu brain programming.
Anyway I swap out topside the challenge muffler to the 430 muffler . Car is even more muted and my exhaust valves open at the same rpm points ranges dictated by my ecu.
Pm me for more info I do have extra brackets mounting hardware laying around from this endeavor.
You will have to fabricate exhaust brackets in order to install the 430 muffler "
Check the link if you dont believe me 430 exhaust in a 360 Need Help - FerrariChat.com