Hi, Does anyone have an OEM F430 exhaust for sale for cheap? I want to have a muffler shop cut one open and see if anything can be done - taken out or changed - to make it sound more like a Tubi. Since this is an experiment of sorts that could take time I don't want to use mine. Thanks, Oliver
On the stock exhaust, when the valves open up, the exhaust gas almost completely bypasses the muffler, so it is already pretty much as loud as it will get.
I have on multiple occasions looked at Ferrari's drawings for the 430, and I do not see any by-pass valves. As to the 360, the only functional purpose I see of the by-pass valves is to block one outlet tube on each side to force the exhaust gasses to pass less efficiently and thus quieter through the muffler. When these are opened or removed, naturally the exhaust note would be louder. This is part of the Tubi "trick". The statement of the exhaust gasses by-passing the muffler on the 430's I do not believe to be accurate. I see no evidence of this, and the noise would be unbearable. I do see that the OEM 430 muffler is about 1/2 the size of the 360, and that I believe is due to different valve timing as well as a change in the intakes. The 430 uses the same flow meters as the 360 CS according to Ferrari's part numbers. Loud does not equate to power gains. Something is not right here in the equation.
"You can hear valves open and the car gets considerably louder after a certain RPM.." I am well aware of this. The valves open to allow the exhaust gasses to flow out of the 4 tubes rather than 2. My statement goes to the "alleged" valves on the 430 and the fact that pictorally I don't find them on that car.
Your in luck... st2ferrari is selling his and he just posted today. http://www.ferrarichat.com/forum/showthread.php?t=114763 Hammer
When the valves are closed, exhaust gases flow through the muffler. When the valves are open, some of the gases still go through the muffler, but most of the gases go straight out without going through the muffler.
Quote: My statement goes to the "alleged" valves on the 430 and the fact that pictorally I don't find them on that car.Unquote Look closer -- valves are apparent in photo below -- vaccuum actuated. Image Unavailable, Please Login
Jack, Thanks for the photo. My OEM drawings are, for some strange reason, not showing these valves. Their function is solely to meet noise limits in most jurisdictions up to about 1,500 RPM. In 1975, I established the noise standards with the CHP for aftermarket exhaust in the State of California. The CHP test required an SPL meter on a 12"-14" stand positioned behind the exhaust a stated distance and at a 45 degree angle to the exhaust. Few cars at that time had more than two pipes on one side. i believe the E Type Jag was the only one that had four spaced apart. The test was to have been done at idle and at, I believe, 1,500 RPM. I cannot now remember the max SPL limit, but it was quite tough at the time and became a standard in CA which other states later adopted. Ferrari uses these by-pass valves to stay within this limit. My 360 TUBI does not have them, and, therefore, it can be quite loud at idle but does growl nicely at higher RPM's.
