rcl4668
Enthusiast
This thread is a placeholder for a comparison of dyno runs before and after installation of the Belanger headers, high flow cats, magnaflow muffler and sidepipe exhaust kit (referred to collectively as the "Belanger Exhaust system").
Today I brought my 2008 convertible to Wong’s Performance Engineering in Vancouver, WA for a baseline dyno with the stock header and exhaust system. (The entire drivetrain is completely stock.) The dyno used is a Mustang dynamometer. Mileage on the car was 1617 miles. Ambient Temp was 70 degrees F, air pressure was 29.9 inches of mercury and humidity was 34.27%. Car had half a tank of Chevron E10 blend premium fuel rated at 92 octane. Tire pressures were set to 29 psi cold as recommended by Chrysler.
Three dyno runs were taken with cool down periods of several minutes between runs. A graph of the average dyno data is as follows (sorry for the huge picture but it is the only way the numbers are legible):
The average of the three runs showed a maximum wheel horsepower of 529 and maximum wheel torque of 505 ft lbs. Could someone please check my math (am I doing this right?): Using a correction factor of 12% this would yield 601 flywheel hp and 574 ft lbs of flywheel torque. Using a 15% correction factor would yield 622 flywheel horsepower and 594 ft lbs of torque. I am still not clear on which correction factor to use (Tom recommended 12-15% based on previous Vipers he has dynoed) but I am assuming that because the 12% correction factor got me closer to what Chrysler rates the engine (600-602 flywheel hp), that this is the more accurate correction factor.
For others that have dynoed their 2008s, does the graph look normal to you? Specifically, Tom was curious about the weird "double bump" in the torque curve. I mentioned that the 2008 Vipers had gone to a drive by wire throttle system and he wondered whether the programming in the drive by wire incorporated some form of torque management whereby torque was reduced at certain throttle positions to address potential traction issues.
At any rate, I will bring the car into my dealer for install of the Belanger system in the next few days, drive the car with the system for about 500-1,000 miles and take another dyno at Wong's and report the results back on this thread.
/Rich
Today I brought my 2008 convertible to Wong’s Performance Engineering in Vancouver, WA for a baseline dyno with the stock header and exhaust system. (The entire drivetrain is completely stock.) The dyno used is a Mustang dynamometer. Mileage on the car was 1617 miles. Ambient Temp was 70 degrees F, air pressure was 29.9 inches of mercury and humidity was 34.27%. Car had half a tank of Chevron E10 blend premium fuel rated at 92 octane. Tire pressures were set to 29 psi cold as recommended by Chrysler.
Three dyno runs were taken with cool down periods of several minutes between runs. A graph of the average dyno data is as follows (sorry for the huge picture but it is the only way the numbers are legible):
The average of the three runs showed a maximum wheel horsepower of 529 and maximum wheel torque of 505 ft lbs. Could someone please check my math (am I doing this right?): Using a correction factor of 12% this would yield 601 flywheel hp and 574 ft lbs of flywheel torque. Using a 15% correction factor would yield 622 flywheel horsepower and 594 ft lbs of torque. I am still not clear on which correction factor to use (Tom recommended 12-15% based on previous Vipers he has dynoed) but I am assuming that because the 12% correction factor got me closer to what Chrysler rates the engine (600-602 flywheel hp), that this is the more accurate correction factor.
For others that have dynoed their 2008s, does the graph look normal to you? Specifically, Tom was curious about the weird "double bump" in the torque curve. I mentioned that the 2008 Vipers had gone to a drive by wire throttle system and he wondered whether the programming in the drive by wire incorporated some form of torque management whereby torque was reduced at certain throttle positions to address potential traction issues.
At any rate, I will bring the car into my dealer for install of the Belanger system in the next few days, drive the car with the system for about 500-1,000 miles and take another dyno at Wong's and report the results back on this thread.
/Rich
By my calculations, if I applied a 25% correction factor to my Mustang dyno numbers, I would get 529 rwhp x 100 / 75 = 705 flywheel hp which can't be right. Is your 25% correction factor unique to your Mustang dyno? Since my dyno guy could not give me a definitive correction factor, is there a way I can figure out what my flywheel hp is? Thanks for any insights you can provide.
