usurbrain
Viper Owner
I have a Corsa track exhaust with RT High flow cats. Stock headers. The UPS truck sound drives me nuts....
I have a Corsa track exhaust with RT High flow cats. Stock headers. The UPS truck sound drives me nuts....
I have a Corsa track exhaust with RT High flow cats. Stock headers. The UPS truck sound drives me nuts....
I have a Corsa track exhaust with RT High flow cats. Stock headers. The UPS truck sound drives me nuts....
mine has same set-up and it sounds much better than stock.
Every one has a small piece of the answer but let me try to help answer the question "Why does the Viper engine sound the way it does"..well to start with..there is a pulse (tone) ring on the crankshaft that has five groups of two notches equally spaced apart at the outer edge. Each group of notches will represent a signal for a specific set of pistons. The PCM will determine the basic timing by looking at the falling edge of the slots. Each corresponding slot is 72 degrees apart and 3 degrees wide and there is 15 degrees between each slot in the pair.
The falling edge of the first slot, of each pair of slots is used for cylinders 10,4,6,8,2. The second falling edge is used for cylinders 1,9,3,5,7. There are five sets of paired cylinders: #10 and #5,#9 and #8, #4 and #7, #3 and #2, #1 and #6. It could take the PCM one full engine revolution to determine the crankshaft position when it is cranking.
Since the V10 is a 90 degree block, the combined angle of the bore center lines of the opposing banks will be 90 degrees, which means that a piston will at TDC every 90 degrees. Sooooo for each cylinder to fire, it would take 900 degrees of crankshaft rotation and no matter how you do the math....that won't work. So to match the crankshaft rotation, it was necessary to make it an "odd fire" engine. That means that the cylinders are not fired at the same crankshaft angle. Five of the cylinders are fired at 54 degrees and the other five are fired at 90 degrees which adds up to 720 degrees or two complete crank revolutions. This is why the notch edges are at different degrees since the spark will be staggered. Ok, so I have expanded on Marv S's answer... now lets expand on Doug's answer.
A DIS coil can be arranged in various alterations of polarity. This means it does not matter if the spark fires positive or negitive as long as there is enough voltage to jump the spark plug gap. As the primary flux collapses through the secondary coil windings when the primary coil is interruped, a high voltage potental is created. A quick interruption causes the flux to cut through the secondary windings faster which means a quicker interruption results in more secondary voltage than a slow interruption. Dwell (spark timing) is constant, at low RPM based on battery voltage. A constant dwell allows constant voltage at the coil for a constant spark. But at high RPM, there isn't time for full saturation of the coil. So the PCM will change the primary duty cycle from 100% to 80% to speed things up.
The voltage will leave the coil tower for example, #1 and travel through the wire to the #1 plug, through the center electrode, jump the gap to ground. This would be the cylinder that is on the compression stroke. This will require about 10-15k volts of the 40k potential from the coil. The companion cylinder, #6 will be the wasted spark cylinder. To complete the series circuit back to the coil, the remaining 25k volts travels through the block to
the #6 plugs ground, and jumps the gap. This will take about 1-3k volts. The circuit is then completed through the spark plug wire back to the coil pack.
When cylinder #6 goes to the compression stroke, cylinder #1 is on the wasted spark stroke. But the voltage from the coil takes the exact same path due the polarity of the coil. There is more than enough voltage to fire the plugs at any RPM.
Hope this helps.
Hey Glen 97, No problems with California emissions? I'm just outside of Sacramento. I don't want to spend the coin only to find out my ride won't pass the pollution police.. Thanks Jeff
While my Gen III new and out of the box sounded "different", it was still a little UPS/Tractor/GEN I sounding from new.
The moment, I bolted on the full Bellanger set up of Headers, Hi-Flo Cats and Cat-Back, it woke it up to a a real muscle car sounding machine. Rich and deep! That is from 0-3000 rpm. Then above 3000 rpm, it changes and starts sounds like an exotic car, as it should have come from the factory. A very rich and perfect blend of low to high, deep to wail as it goes through the rpm band. It also gets louder, the hotter it gets. It is pretty loud but NOT abnoxious.
I will admit that now the car does get a little drone from 2000 rpm to about 3000 rpm at higher speeds, but in the first four gears around town, it is not a problem, as it actually makes the car sound like a real mean muscle exotic car. At highway speeds of 60 mph to 75 mph in 5th or 6th, and extended long trips, it can wear on you as the sounds are there. Then again with the lightweight Fidanza flywheel and 3.55 rear gears, it is easier to get out of that range and be comfortable. With our car, we went a step further and Dynamatted the entire interior of our coupe, every panel inside. Huge difference as now the louder exhaust is just there when you roll the windows down. When it is just myself, all windows are down. When my wife is with me, the windows are up.
Regardless, I have yet to have a Viper member or a member of any other muscle car or exotic car from the Cars and Coffee events or canyon cruises, not come up to me to express how perfect the car sounds now. How mean, muscular and exotic it sounds, yet not abnoxious sounding in any way.
I assume you are looking for this type of sound and experience. I only have experience with the full Bellanger set-up and I bought that from Parts Rack. Jon and Lou even helped me achieve a "factory" type of look by jet-hotting the exhaust tips in Black before I put the exhaust on. It really does look factory and not added on. It sounds like the way the car should have come from the factory.
Some people Cat, some don't. In the end, Colorado has very strict emissions testing and I experienced a big gain in HP with this set up, so my recommendation would be to still Cat. It also cleans up on the smells of the exhaust. Pull the Cats off and it takes that sound to another level, no doubt. Me, I experienced the gains I wanted, the sound I wanted, no issues (no CELs or problems of any kind) and it was good enough for me. Only advice would be to realy concentrate on how you run the wires to the O2 sensors as that wiring needs to be as far away form the exhaust headers as you can and routed to not come in contact.
Hope that helps you in deciding what to do.
Rick
While my Gen III new and out of the box sounded "different", it was still a little UPS/Tractor/GEN I sounding from new.
The moment, I bolted on the full Bellanger set up of Headers, Hi-Flo Cats and Cat-Back, it woke it up to a a real muscle car sounding machine. Rich and deep! That is from 0-3000 rpm. Then above 3000 rpm, it changes and starts sounds like an exotic car, as it should have come from the factory. A very rich and perfect blend of low to high, deep to wail as it goes through the rpm band. It also gets louder, the hotter it gets. It is pretty loud but NOT abnoxious.
I will admit that now the car does get a little drone from 2000 rpm to about 3000 rpm at higher speeds, but in the first four gears around town, it is not a problem, as it actually makes the car sound like a real mean muscle exotic car. At highway speeds of 60 mph to 75 mph in 5th or 6th, and extended long trips, it can wear on you as the sounds are there. Then again with the lightweight Fidanza flywheel and 3.55 rear gears, it is easier to get out of that range and be comfortable. With our car, we went a step further and Dynamatted the entire interior of our coupe, every panel inside. Huge difference as now the louder exhaust is just there when you roll the windows down. When it is just myself, all windows are down. When my wife is with me, the windows are up.
Regardless, I have yet to have a Viper member or a member of any other muscle car or exotic car from the Cars and Coffee events or canyon cruises, not come up to me to express how perfect the car sounds now. How mean, muscular and exotic it sounds, yet not abnoxious sounding in any way.
I assume you are looking for this type of sound and experience. I only have experience with the full Bellanger set-up and I bought that from Parts Rack. Jon and Lou even helped me achieve a "factory" type of look by jet-hotting the exhaust tips in Black before I put the exhaust on. It really does look factory and not added on. It sounds like the way the car should have come from the factory.
Some people Cat, some don't. In the end, Colorado has very strict emissions testing and I experienced a big gain in HP with this set up, so my recommendation would be to still Cat. It also cleans up on the smells of the exhaust. Pull the Cats off and it takes that sound to another level, no doubt. Me, I experienced the gains I wanted, the sound I wanted, no issues (no CELs or problems of any kind) and it was good enough for me. Only advice would be to realy concentrate on how you run the wires to the O2 sensors as that wiring needs to be as far away form the exhaust headers as you can and routed to not come in contact.
Hope that helps you in deciding what to do.
Rick