Remap today
- Thread starter BenW
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This is one of the most accurate ways of testing,it helps that we also have a ex Ford Motor Compay test and development Dyno guy on the staff.
The first and most obvious difference is the elimination of the tire to roller interface on a conventional roller dyno. The Dynapack eliminates this variable by using a hub adapter that provides a direct coupling to our Power Absorption Units. There can be no tire slip, no rolling resistance, and no chance of the vehicle coming off of the dyno at high speeds. Notice that we call this a variable. Sometimes it may be a problem area, other times it may not. Tire temperature, pressure, traction, etc, are all variables that can change - not only from run to run, but during the run as well. Throw an unknown variable like this into the equation and your data has now become subject to a potentially high margin of error. It is obviously better if these variables could be eliminated - which is exactly what we have done. There are other associated problems with the roller method as well. Take tie-down straps for example. Most roller dynos use ratcheting tie-down straps to attempt to hold the vehicle in position while being tested. If the straps are cinched down tightly, the tire has become loaded even further, in an unpredictable manner. While this may be good for enhancing traction, it changes the rolling resistance of the tire - skewing the data further. Since these tie-down straps aren’t perfect, the vehicle squirms around on the rollers - dramatically changing the tire drag during the run. If the vehicle is tested in two different sessions, the straps can’t be set exactly the same way twice in a row. Again, the data will be inconsistent. We have heard of cases where the ratcheting tie-down straps were loosened by two clicks and the measured power increased by ten horsepower. What if the straps stretch - either from run to run, or during the run itself? Wouldn’t it be great if all of these problems could disappear? With a Dynapack, they were never there in the first place.
Another major difference is the effect of inertia. Street wheels and tires spinning at high RPM have a large amount of inertia. A large steel drum spinning at the same ground speed has much more inertia. What you end up with is a giant, heavy flywheel attached to your engine. The inertia is such, that just trying to accelerate the mass of the roller is a substantial load for the engine. That is the principle that some roller dynos (or “inertia dynos” as they are also called) operate on. Accelerate a known mass to a measured speed over a given time and it can be calculated to equal a certain amount of power. There is nothing wrong with this theory, but like many theories, its application in the real world can be troublesome. How do you think your measurements will be effected by being subjected to this large heavy flywheel phenomenon? Will small fluctuations be noticeable? In a word, no. The flywheel effect tends to take small rapid variations and smooth them right out - as energy that should be going into the dyno is being wasted trying to accelerate a large lump of steel. This is great if you want your power curve to look like a smooth pretty line, but it doesn’t give you much insight into what is really occurring. What if you eliminated the flywheel effect? While nothing that has a spinning mass has “no” inertia, when compared the total mass of the wheels, tires, rollers, and other associated hardware of a roller dyno, the inertia of a Dynapack is practically zero. This allows us to precisely measure and display tiny rapid pulses and oddities that you may not have seen before. Now you have a window into areas that no roller dyno will allow you to see. Another benefit of having virtually zero inertia is the ability to change the rate of acceleration at will. In many situations, you may want to accelerate the vehicle at a different rate to simulate a specific condition. With a few simple keystrokes, we allow you to make the vehicle accelerate very quickly, slowly, or anywhere in between. Because of our lack of inertia and total control of the engine speed, we give you choices that none of our competitors can even dream of - and as you know, choices are good!
"For R&D purposes, the Dynapack has proven to be an invaluable asset to our business. The dyno allows our engineers to create precise fuel injection programs by simulating various load situations. The hub mounted design prevents any data loss that might occur from wheel spin on higher horsepower applications. Excellent technical service, constantly improving software, and a wide array of accessories make the Dynapack dynamometer our number one choice for tuning.”
-Toshi Hayama, Apex Integration Inc.
“I would like to compliment Dynapack on their new chassis dyno design. Our unit has performed flawlessly. The repeatability is excellent. Dynapack has re-invented the chassis dyno. If you’re not using a Dynapack, you’re using yesterday’s technology.”
-Bob Giese, Toyota Racing Development
"DC Sports built and continues to maintain its reputation by producing high quality components that maximize performance. The Dynapack 3000 plays an important role in this process because of its portability and ease of use. With its ability to perform fixed-speed and fixed-load tests, we are able to test multiple design iterations accurately without the inconsistencies found in inertia- or drum-type dynos."
- Steve Schmidt, DC Sports
I love my Dynapack dyno!!! It has become the central part of our engine development program. I consider it to be a true engine dyno even though it's driven at the wheels. It gives me 100% repeatability and the actual usable HP/TQ figures, right where it counts....at the wheel!! I have a relatively small shop and the Dynapack is so compact and portable it fits any where....and totally out of the way when not in use.
Hands down the best Dyno for the $$$$.
- Rick DeMan, DeMan Motorsport
“I can honestly say that every car has been improved, in some cases dramatically. Try as I may, I can not find any application that this dyno falls short of in our expectations... (It) has proven to be very easy to use... This is truly the most accurate dyno I have ever used.”
-Tony Devos, BMW Master Technician
(Tony liked the dyno so much, he joined the company soon afterward!)
“We’ve never been able to see the difference between our qualifying and our race setups on a dyno before - now we KNOW what makes a difference!”
-David Ridling, YELLOW Racing (NASCAR Busch Grand National team)
The first and most obvious difference is the elimination of the tire to roller interface on a conventional roller dyno. The Dynapack eliminates this variable by using a hub adapter that provides a direct coupling to our Power Absorption Units. There can be no tire slip, no rolling resistance, and no chance of the vehicle coming off of the dyno at high speeds. Notice that we call this a variable. Sometimes it may be a problem area, other times it may not. Tire temperature, pressure, traction, etc, are all variables that can change - not only from run to run, but during the run as well. Throw an unknown variable like this into the equation and your data has now become subject to a potentially high margin of error. It is obviously better if these variables could be eliminated - which is exactly what we have done. There are other associated problems with the roller method as well. Take tie-down straps for example. Most roller dynos use ratcheting tie-down straps to attempt to hold the vehicle in position while being tested. If the straps are cinched down tightly, the tire has become loaded even further, in an unpredictable manner. While this may be good for enhancing traction, it changes the rolling resistance of the tire - skewing the data further. Since these tie-down straps aren’t perfect, the vehicle squirms around on the rollers - dramatically changing the tire drag during the run. If the vehicle is tested in two different sessions, the straps can’t be set exactly the same way twice in a row. Again, the data will be inconsistent. We have heard of cases where the ratcheting tie-down straps were loosened by two clicks and the measured power increased by ten horsepower. What if the straps stretch - either from run to run, or during the run itself? Wouldn’t it be great if all of these problems could disappear? With a Dynapack, they were never there in the first place.
Another major difference is the effect of inertia. Street wheels and tires spinning at high RPM have a large amount of inertia. A large steel drum spinning at the same ground speed has much more inertia. What you end up with is a giant, heavy flywheel attached to your engine. The inertia is such, that just trying to accelerate the mass of the roller is a substantial load for the engine. That is the principle that some roller dynos (or “inertia dynos” as they are also called) operate on. Accelerate a known mass to a measured speed over a given time and it can be calculated to equal a certain amount of power. There is nothing wrong with this theory, but like many theories, its application in the real world can be troublesome. How do you think your measurements will be effected by being subjected to this large heavy flywheel phenomenon? Will small fluctuations be noticeable? In a word, no. The flywheel effect tends to take small rapid variations and smooth them right out - as energy that should be going into the dyno is being wasted trying to accelerate a large lump of steel. This is great if you want your power curve to look like a smooth pretty line, but it doesn’t give you much insight into what is really occurring. What if you eliminated the flywheel effect? While nothing that has a spinning mass has “no” inertia, when compared the total mass of the wheels, tires, rollers, and other associated hardware of a roller dyno, the inertia of a Dynapack is practically zero. This allows us to precisely measure and display tiny rapid pulses and oddities that you may not have seen before. Now you have a window into areas that no roller dyno will allow you to see. Another benefit of having virtually zero inertia is the ability to change the rate of acceleration at will. In many situations, you may want to accelerate the vehicle at a different rate to simulate a specific condition. With a few simple keystrokes, we allow you to make the vehicle accelerate very quickly, slowly, or anywhere in between. Because of our lack of inertia and total control of the engine speed, we give you choices that none of our competitors can even dream of - and as you know, choices are good!
"For R&D purposes, the Dynapack has proven to be an invaluable asset to our business. The dyno allows our engineers to create precise fuel injection programs by simulating various load situations. The hub mounted design prevents any data loss that might occur from wheel spin on higher horsepower applications. Excellent technical service, constantly improving software, and a wide array of accessories make the Dynapack dynamometer our number one choice for tuning.”
-Toshi Hayama, Apex Integration Inc.
“I would like to compliment Dynapack on their new chassis dyno design. Our unit has performed flawlessly. The repeatability is excellent. Dynapack has re-invented the chassis dyno. If you’re not using a Dynapack, you’re using yesterday’s technology.”
-Bob Giese, Toyota Racing Development
"DC Sports built and continues to maintain its reputation by producing high quality components that maximize performance. The Dynapack 3000 plays an important role in this process because of its portability and ease of use. With its ability to perform fixed-speed and fixed-load tests, we are able to test multiple design iterations accurately without the inconsistencies found in inertia- or drum-type dynos."
- Steve Schmidt, DC Sports
I love my Dynapack dyno!!! It has become the central part of our engine development program. I consider it to be a true engine dyno even though it's driven at the wheels. It gives me 100% repeatability and the actual usable HP/TQ figures, right where it counts....at the wheel!! I have a relatively small shop and the Dynapack is so compact and portable it fits any where....and totally out of the way when not in use.
Hands down the best Dyno for the $$$$.
- Rick DeMan, DeMan Motorsport
“I can honestly say that every car has been improved, in some cases dramatically. Try as I may, I can not find any application that this dyno falls short of in our expectations... (It) has proven to be very easy to use... This is truly the most accurate dyno I have ever used.”
-Tony Devos, BMW Master Technician
(Tony liked the dyno so much, he joined the company soon afterward!)
“We’ve never been able to see the difference between our qualifying and our race setups on a dyno before - now we KNOW what makes a difference!”
-David Ridling, YELLOW Racing (NASCAR Busch Grand National team)
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They are quite easy to move around (but very heavy) and for all but very short runs have to be water cooled ,and fans for the cars .But overall as quick if not quicker to set up than a roller type.
We hve made lifting bars for them .They come on there own wheels for moving in the workshop.
I'm the Motorcycle Technician ,and I cover on the lecturering (Cars and Bikes).
Toolmaker by trade.cheers
John
We hve made lifting bars for them .They come on there own wheels for moving in the workshop.
I'm the Motorcycle Technician ,and I cover on the lecturering (Cars and Bikes).
Toolmaker by trade.cheers
John
Last edited:
richandgem
Platinum Member
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