Need dyno access
Cargo Master
Joined: Jun 2003
Posts: 2,203
Likes: 0
From: Carlsbad, California
The Torqshift will hold the gear in either 3rd, 2nd, and presumable 1st gear.
Third would be the best to use because it is closest to 5th gear which is 1:1.
The problem is that as you go to the lower gears the torque multiplication is even higher and the intertia dynos spin up too fast to allow the motor to really build some boost.
The SAE paper (SAE 2002-01-0887) I mentioned earlier is titled:
"Listening to the Voice of the Customer: Inertia Dyno Horsepower Versus OEM Rated Net Horsepower"
It is quite an interesting read for those really interesting in dyno testing and I'd advise those folks to get a copy. There are a number of areas and concerns when using an intertia chassis dyno. In particular is the mass equivalent (ME) of the dynos roller.
The paper states: "Ideally, for measurement on an inertial dyno, the ME value should be as close as possible to the curb weight of the vehicle. If they are not close, then the rotating elements of the vehicle’s drivetrain will accelerate faster (or slower, depending on the roller ME versus the vehicle weight) than they would in a WOT road test. This would result in a correspondingly larger (smaller) power loss due to inertial losses. Additionally, the variation in roller equivalent mass from one dyno to another is the reason why the same vehicle will deliver different power ratings on different inertia dynos. Each of the three major inertia dyno manufacturers uses a different mass equivalent for its rollers. Representative ME’s for the three largest inertia dyno vendors are approximately 862 kg (SuperFlow), 1,088 kg (Mustang Dynamometer), and 1,633 kg (Dynojet). Before entering into detailed discussion of losses due to different dyno ME’s, it is first necessary to address the difference in losses due to the lack of road loads on the inertial dyno. . . ."
There's lots more good stuff in there.
The bottom line is that intertia dynos while fast and easy to operate don't always give the true results.
Third would be the best to use because it is closest to 5th gear which is 1:1.
The problem is that as you go to the lower gears the torque multiplication is even higher and the intertia dynos spin up too fast to allow the motor to really build some boost.
The SAE paper (SAE 2002-01-0887) I mentioned earlier is titled:
"Listening to the Voice of the Customer: Inertia Dyno Horsepower Versus OEM Rated Net Horsepower"
It is quite an interesting read for those really interesting in dyno testing and I'd advise those folks to get a copy. There are a number of areas and concerns when using an intertia chassis dyno. In particular is the mass equivalent (ME) of the dynos roller.
The paper states: "Ideally, for measurement on an inertial dyno, the ME value should be as close as possible to the curb weight of the vehicle. If they are not close, then the rotating elements of the vehicle’s drivetrain will accelerate faster (or slower, depending on the roller ME versus the vehicle weight) than they would in a WOT road test. This would result in a correspondingly larger (smaller) power loss due to inertial losses. Additionally, the variation in roller equivalent mass from one dyno to another is the reason why the same vehicle will deliver different power ratings on different inertia dynos. Each of the three major inertia dyno manufacturers uses a different mass equivalent for its rollers. Representative ME’s for the three largest inertia dyno vendors are approximately 862 kg (SuperFlow), 1,088 kg (Mustang Dynamometer), and 1,633 kg (Dynojet). Before entering into detailed discussion of losses due to different dyno ME’s, it is first necessary to address the difference in losses due to the lack of road loads on the inertial dyno. . . ."
There's lots more good stuff in there.
The bottom line is that intertia dynos while fast and easy to operate don't always give the true results.
Postmaster
Joined: Apr 2004
Posts: 2,654
Likes: 0
From: Bossier City, LA
Originally Posted by darylhunter
The Torqshift will hold the gear in either 3rd, 2nd, and presumable 1st gear.
Third would be the best to use because it is closest to 5th gear which is 1:1.
The problem is that as you go to the lower gears the torque multiplication is even higher and the intertia dynos spin up too fast to allow the motor to really build some boost.
Third would be the best to use because it is closest to 5th gear which is 1:1.
The problem is that as you go to the lower gears the torque multiplication is even higher and the intertia dynos spin up too fast to allow the motor to really build some boost.
Originally Posted by darylhunter
It is quite an interesting read for those really interesting in dyno testing and I'd advise those folks to get a copy. There are a number of areas and concerns when using an intertia chassis dyno. In particular is the mass equivalent (ME) of the dynos roller.
Ryan
Last edited by mrxlh; Dec 3, 2004 at 12:45 PM.
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