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someguy · 02-11-2010, 11:16 AM

That information on the Dynojet brand is SO OLD AND INCORRECT that it's not even worth posting. Circa 1996 or 1997? Dynojet has offered load controlled dyno runs on the 224 series automotive chassis dynos for over 10 years!

Wow, where to begin? So much bad info...I'll do my best to give the actual, correct information to refute the outdated, bad or erroneous things here.
Quote:
Originally Posted by renzo088

Come to find out..
A mustang dyno & dyno dynamics are much much better for tuning

False. Load style dynos do things differently than inertia style dynos, but once you add a PAU (power absorption unit) to an inertia style dyno, it can then do BOTH. Quote:
Originally Posted by renzo088

here is an excerpt ive taken from another website that really talks about the difference.
Quote:
DynoJets are inertia dynos, and have been around for years, much longer than any type of load cell dyno.

Incorrect. Load style dynos have been around much longer that Dynojet has. Inertia as a design principle has been around for longer than Dynojet too...we didn't invent the idea - just did a good job of offering it to the public at an affordable cost. Quote:
Originally Posted by renzo088

Quote:
Inertia dyno's work on the principle of the acceleration of a known mass over time. Their rollers are the known mass. Weighing in at over 2500lbs or so. Your car gets strapped down to the machine, and the dyno collects it's data. It is able to calculate horsepower by measuring the acceleration in rpm of the rollers in regards to RPM.

Most of this is correct, but the acceleration of the drum is measured by TIME, not RPM. The Dynojet inertia dyno will accurately collect data and display HP vs. speed with no RPM input at all. This is the most basic dyno run it can do. Add RPM information from the engine and then it can calculate torque off the well known forumla that TQ = (HP * 5252) / RPM. Quote:
Originally Posted by renzo088

Quote:
This is why gearing can affect the dyno results, more on that in a bit. Now that the dyno has recorded the horsepower curve, it can take the integral of that curve and get the torque curve. Since the dyno’s power calculations are based on the acceleration of mass over time in regards to RPM, gearing is very important. Since a vehicle with a lower gear ratio can accelerate the mass to a higher speed using less engine RPM, it will show a higher horsepower number than a car with a higher gear ratio. If a car is able to accelerate the dyno’s rollers from 200rpm (roller) to 300rpm (roller)in 1500rpm (engine), then the dyno is going to record more power than a car that did that in 2000rpm (engine).

Also incorrect. Gearing has no bearing in the horsepower/torque figures displayed. Gearing does have a bearing on the FORCE put to the dyno drum, but this is all relative per gear. 2nd gear will have more mechanical advantage and accelerate the drum quicker than 4th gear, but the delta (change in) speed is not as great. If you look at a given RPM range (let's use 2000rpm to 6000rpm for ease), then in 2nd gear that may translate to a dyno run that goes from 20mph to 60mph, where in 4th that may be from 35mph to 100mph. While it takes longer to make the run in 4th, it also has a greater delta speed.

Also to note here is that in our example above, in 2nd gear, more of the HP the engine produces is going to be used to accelerate the inertia of the drivetrain, engine internals, etc. over that shorter timeframe. In doing so, less HP actually gets to the wheels. This is why you will typically see less HP in gears that are not a 1:1 ratio, and the further you get from 1:1, then less power the vehicle will put to the wheels.

The exception to this is large turbo applications with big torque - like turbo diesels - that have far more torque than HP. They need the extra run time of the taller gears to build boost and load the engine over a very short RPM range. Quote:
Originally Posted by renzo088

Quote:
Now we go to Mustang dyno’s and other loaded dyno’s. Our Mustang MD-1100SE dyno’s rollers weigh 2560lbs. That is the actual mass of the rollers, much like the DynoJet. That’s about where all the similarities end. When we get a car on our dyno, we enter two constants for the dyno’s algorithms. One being the vehicle weight, the other being what’s called “Horsepower At 50mph”. This is a number that represents how much horsepower it takes for the vehicle to push the air to maintain 50mph. This is used as the aerodynamic force. Mustang dyno’s are also equipped with a eddy currant load cell. Think of a magnetic brake from a freight train. This magnetic brake can apply enough resistance to stall a big rig. Off one side of the eddy currant load cell, there is a cantilever with a 5volt reference load sensor (strain gage).

The setup referenced here using a PAU and a strain gauge is exactly the same setup used on the Dynojet 224xLC and 424xLC2 dynos. One MAJOR difference though, is that there are no "constants" that need to be added to the Dynojet software. Giving the operator this control gives them the ability to fudge the numbers. Think I'm full of it? Next time you're on that Mustang dyno, enter a vehicle weight of 3000#, make some dyno runs and then change the weight to 4000#. What happened? The HP went up? Why would it do that? Are you telling me that if I put friends in my car on the way to lunch and the car is heavier, that now my engine makes more HP? How can that be? LOL
Quote:
Originally Posted by renzo088

Quote:
I like to state it like this. . . I start by asking how much your car weighs, lets say 3500lbs. Now you take your car and you make a make a WOT rip in your tallest non overdrive gear, how much mass is your engine working against? 3500lbs right? Now you strap your car on a DynoJet and you make a WOT in the same gear, how much mass is your engine working against? 2500lbs right?

Yes, OR NO. With the load controlled Dynojet dynos, you can setup sweep tests, step tests or custom load test using the PAU in the same method as the other load style dynos. We actually have one routine that allows the user to input how much load to add versus either engine speed, time or road speed. For instance, we can have the load increase as vehicle speed increases, to simulate wind drag and aerodynamic loads. We even provide our dyno centers a spreadsheet they can use to input the vehicle weight and aerodynamic values (coefficient of drag and frontal area) which calculates the custom load profile for them.

The load is then added during the run. This slows the acceleration of the drums, which means we measure less HP to the drum, but then we record the strain gauge data as to how much torque is being absorbed by the PAU during the run, and do the math to calculate the total HP as if the load had not been applied. Quote:
Originally Posted by renzo088

Quote:
Now you strap your car on a Mustang dyno, how much mass is your engine working against? 2500lbs. Plus the resistance being applied by the eddy current generator. We’ve seen anywhere for 470lbs of resistance to over 700lbs of resistance as measured in PAU force in the data logs. So which one is more accurate? Well they their both accurate. If a DynoJet dyno says you made 460rwhp, then you made 460rwhp. If a Mustang dyno says you made 460rwhp, you also made 460rwhp. Now which one of those numbers best represents what your car is doing when its on the street. That’s a different question.

See, same result - the information quoted here is SO OLD that it doesn't take into account that Dynojet has offered this same technology for over 10 years! Quote:
Originally Posted by renzo088

Quote:
For instance, my 2002 Z28 with a forged internal LS6 Heads/Cam/Intake, makes 460rwhp on our dyno. I thought that was a little low, since I’ve had cam only LS6 Z06 vettes make 450rwhp. So I overlaid the dyno graphs. Guess what, the PAU force for my car was almost 200lbs more than the C5Z06 that made 450rwhp with cam only. So I entered the weight and horsepower at 50 number for a C5Z06 and did another horsepower rip with my car. The only reason I did that was to compare Apples to Apples. This time my car made 490rwhp, no other changes. Now I don’t go around saying my car made 490rwhp, I say what it actually did with the correct information entered into the computer. It made 460rwhp.

So, the operator changed a number typed into the software and the HP changed? (I think I mentioned that above). So what good is a dyno that the operator has the control over to make it read whatever he wants? The whole point behind the dyno is to have a CONSISTENT and REPEATABLE testing tool that cannot be manipulated to show different power figures. If this rule is not followed, what guarantee does the vehicle owner have that gains shown on the dyno printout were truely made? On a Dynojet dyno, there is no value that can be entered to change the HP displayed. Quote:
Originally Posted by renzo088

Quote:
Now which one is more "real world" is a totally different question. I like to explain it like this..... If you drive your car in a situation in which you have no mass and you're in a vacuum, so basically if you do intergalactic racing in space, use a DynoJet. If your car sees gravity, and has an aerodynamic coefficient, and you race on a planet called Earth, then use a Mustang Dyno.

I think we've now illustrated the point that this is completely false. Don't let the sales mumbo jumbo and 10 year old quoted speeches give you bad information.
__________________

Whew, almost done...

Quote:
Originally Posted by renzo088

whats the difference between:
dynojet Giant Drum at a given weight, Dyno reads how much energy the car has to use to push against the given weight. Often reads the highest of any dyno due to the fact you cannot apply additional load. The weight is the only resistance on every car for every run/chassis/weight etc of the car- You cannot tune the low end or mid range cells on a dynojet, You can only tune based on straight power pulls or on-off attempts to simulate load.

This has now been proven false as well. Anything you can do with a load style dyno you can do with the Dynojet (properly optioned) as far as loading the car for simulated dyno runs. Quote:
Originally Posted by renzo088

dyno dynamics
Dyno Dynamics is the best dyno for the money imo. It reads lower than all other mainstream dynos on the market because it uses an Electromagnetic Brake that is slowed by the magnets applying a force to slow the rollers the HARDER the car trys to push against the applied force. This dyno also allows the operator to apply various amounts of load conditions, simulate highway speeds, acceleration and other driving conditions that cannot be simulated with any other dyno.

I think I've also discussed how everything this dyno can do, can be done with the Dynojet dyno as well. Not to mention, Dyno Dynamics is now out of business. Support and repair parts for these dynos are now non-existent.
Quote:
Originally Posted by renzo088

If you want your car tuned properly take it to a Mustang or DynoDynamics dyno

Links
Dyno faq - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

In conclusion, that last statement is completely FALSE. I believe that I've stated all the pertinent facts to show that the Dynojet dyno has all the benefits of a load bearing dyno (as it can be one when optioned with the PAU), and all the benefits of the repeatability and consistency of an inertia dyno. There is a reason why nearly every NASCAR team in the country has a Dynojet inertia dyno. This is why discerning performance shops like Beyond Redline, AMS Performance, Hennessey Performance, Borla, K&N and many others choose a Dynojet dyno. When it comes to testing and getting repeatable and consistent results, you can't beat a Dynojet.

or a link if that is unclear http://www.gencoupe.com/engine/28966...no-tuning.html

02-11-2010, 11:16 AM	#53
someguy Join Date: Feb 2010 Location: not here Age: 44 Posts: 1 Trader Rating: (0)	That information on the Dynojet brand is SO OLD AND INCORRECT that it's not even worth posting. Circa 1996 or 1997? Dynojet has offered load controlled dyno runs on the 224 series automotive chassis dynos for over 10 years! Wow, where to begin? So much bad info...I'll do my best to give the actual, correct information to refute the outdated, bad or erroneous things here. Quote: Originally Posted by renzo088 Come to find out.. A mustang dyno & dyno dynamics are much much better for tuning False. Load style dynos do things differently than inertia style dynos, but once you add a PAU (power absorption unit) to an inertia style dyno, it can then do BOTH. Quote: Originally Posted by renzo088 here is an excerpt ive taken from another website that really talks about the difference. Quote: DynoJets are inertia dynos, and have been around for years, much longer than any type of load cell dyno. Incorrect. Load style dynos have been around much longer that Dynojet has. Inertia as a design principle has been around for longer than Dynojet too...we didn't invent the idea - just did a good job of offering it to the public at an affordable cost. Quote: Originally Posted by renzo088 Quote: Inertia dyno's work on the principle of the acceleration of a known mass over time. Their rollers are the known mass. Weighing in at over 2500lbs or so. Your car gets strapped down to the machine, and the dyno collects it's data. It is able to calculate horsepower by measuring the acceleration in rpm of the rollers in regards to RPM. Most of this is correct, but the acceleration of the drum is measured by TIME, not RPM. The Dynojet inertia dyno will accurately collect data and display HP vs. speed with no RPM input at all. This is the most basic dyno run it can do. Add RPM information from the engine and then it can calculate torque off the well known forumla that TQ = (HP * 5252) / RPM. Quote: Originally Posted by renzo088 Quote: This is why gearing can affect the dyno results, more on that in a bit. Now that the dyno has recorded the horsepower curve, it can take the integral of that curve and get the torque curve. Since the dyno’s power calculations are based on the acceleration of mass over time in regards to RPM, gearing is very important. Since a vehicle with a lower gear ratio can accelerate the mass to a higher speed using less engine RPM, it will show a higher horsepower number than a car with a higher gear ratio. If a car is able to accelerate the dyno’s rollers from 200rpm (roller) to 300rpm (roller)in 1500rpm (engine), then the dyno is going to record more power than a car that did that in 2000rpm (engine). Also incorrect. Gearing has no bearing in the horsepower/torque figures displayed. Gearing does have a bearing on the FORCE put to the dyno drum, but this is all relative per gear. 2nd gear will have more mechanical advantage and accelerate the drum quicker than 4th gear, but the delta (change in) speed is not as great. If you look at a given RPM range (let's use 2000rpm to 6000rpm for ease), then in 2nd gear that may translate to a dyno run that goes from 20mph to 60mph, where in 4th that may be from 35mph to 100mph. While it takes longer to make the run in 4th, it also has a greater delta speed. Also to note here is that in our example above, in 2nd gear, more of the HP the engine produces is going to be used to accelerate the inertia of the drivetrain, engine internals, etc. over that shorter timeframe. In doing so, less HP actually gets to the wheels. This is why you will typically see less HP in gears that are not a 1:1 ratio, and the further you get from 1:1, then less power the vehicle will put to the wheels. The exception to this is large turbo applications with big torque - like turbo diesels - that have far more torque than HP. They need the extra run time of the taller gears to build boost and load the engine over a very short RPM range. Quote: Originally Posted by renzo088 Quote: Now we go to Mustang dyno’s and other loaded dyno’s. Our Mustang MD-1100SE dyno’s rollers weigh 2560lbs. That is the actual mass of the rollers, much like the DynoJet. That’s about where all the similarities end. When we get a car on our dyno, we enter two constants for the dyno’s algorithms. One being the vehicle weight, the other being what’s called “Horsepower At 50mph”. This is a number that represents how much horsepower it takes for the vehicle to push the air to maintain 50mph. This is used as the aerodynamic force. Mustang dyno’s are also equipped with a eddy currant load cell. Think of a magnetic brake from a freight train. This magnetic brake can apply enough resistance to stall a big rig. Off one side of the eddy currant load cell, there is a cantilever with a 5volt reference load sensor (strain gage). The setup referenced here using a PAU and a strain gauge is exactly the same setup used on the Dynojet 224xLC and 424xLC2 dynos. One MAJOR difference though, is that there are no "constants" that need to be added to the Dynojet software. Giving the operator this control gives them the ability to fudge the numbers. Think I'm full of it? Next time you're on that Mustang dyno, enter a vehicle weight of 3000#, make some dyno runs and then change the weight to 4000#. What happened? The HP went up? Why would it do that? Are you telling me that if I put friends in my car on the way to lunch and the car is heavier, that now my engine makes more HP? How can that be? LOL Quote: Originally Posted by renzo088 Quote: I like to state it like this. . . I start by asking how much your car weighs, lets say 3500lbs. Now you take your car and you make a make a WOT rip in your tallest non overdrive gear, how much mass is your engine working against? 3500lbs right? Now you strap your car on a DynoJet and you make a WOT in the same gear, how much mass is your engine working against? 2500lbs right? Yes, OR NO. With the load controlled Dynojet dynos, you can setup sweep tests, step tests or custom load test using the PAU in the same method as the other load style dynos. We actually have one routine that allows the user to input how much load to add versus either engine speed, time or road speed. For instance, we can have the load increase as vehicle speed increases, to simulate wind drag and aerodynamic loads. We even provide our dyno centers a spreadsheet they can use to input the vehicle weight and aerodynamic values (coefficient of drag and frontal area) which calculates the custom load profile for them. The load is then added during the run. This slows the acceleration of the drums, which means we measure less HP to the drum, but then we record the strain gauge data as to how much torque is being absorbed by the PAU during the run, and do the math to calculate the total HP as if the load had not been applied. Quote: Originally Posted by renzo088 Quote: Now you strap your car on a Mustang dyno, how much mass is your engine working against? 2500lbs. Plus the resistance being applied by the eddy current generator. We’ve seen anywhere for 470lbs of resistance to over 700lbs of resistance as measured in PAU force in the data logs. So which one is more accurate? Well they their both accurate. If a DynoJet dyno says you made 460rwhp, then you made 460rwhp. If a Mustang dyno says you made 460rwhp, you also made 460rwhp. Now which one of those numbers best represents what your car is doing when its on the street. That’s a different question. See, same result - the information quoted here is SO OLD that it doesn't take into account that Dynojet has offered this same technology for over 10 years! Quote: Originally Posted by renzo088 Quote: For instance, my 2002 Z28 with a forged internal LS6 Heads/Cam/Intake, makes 460rwhp on our dyno. I thought that was a little low, since I’ve had cam only LS6 Z06 vettes make 450rwhp. So I overlaid the dyno graphs. Guess what, the PAU force for my car was almost 200lbs more than the C5Z06 that made 450rwhp with cam only. So I entered the weight and horsepower at 50 number for a C5Z06 and did another horsepower rip with my car. The only reason I did that was to compare Apples to Apples. This time my car made 490rwhp, no other changes. Now I don’t go around saying my car made 490rwhp, I say what it actually did with the correct information entered into the computer. It made 460rwhp. So, the operator changed a number typed into the software and the HP changed? (I think I mentioned that above). So what good is a dyno that the operator has the control over to make it read whatever he wants? The whole point behind the dyno is to have a CONSISTENT and REPEATABLE testing tool that cannot be manipulated to show different power figures. If this rule is not followed, what guarantee does the vehicle owner have that gains shown on the dyno printout were truely made? On a Dynojet dyno, there is no value that can be entered to change the HP displayed. Quote: Originally Posted by renzo088 Quote: Now which one is more "real world" is a totally different question. I like to explain it like this..... If you drive your car in a situation in which you have no mass and you're in a vacuum, so basically if you do intergalactic racing in space, use a DynoJet. If your car sees gravity, and has an aerodynamic coefficient, and you race on a planet called Earth, then use a Mustang Dyno. I think we've now illustrated the point that this is completely false. Don't let the sales mumbo jumbo and 10 year old quoted speeches give you bad information. __________________ Whew, almost done... Quote: Originally Posted by renzo088 whats the difference between: dynojet Giant Drum at a given weight, Dyno reads how much energy the car has to use to push against the given weight. Often reads the highest of any dyno due to the fact you cannot apply additional load. The weight is the only resistance on every car for every run/chassis/weight etc of the car- You cannot tune the low end or mid range cells on a dynojet, You can only tune based on straight power pulls or on-off attempts to simulate load. This has now been proven false as well. Anything you can do with a load style dyno you can do with the Dynojet (properly optioned) as far as loading the car for simulated dyno runs. Quote: Originally Posted by renzo088 dyno dynamics Dyno Dynamics is the best dyno for the money imo. It reads lower than all other mainstream dynos on the market because it uses an Electromagnetic Brake that is slowed by the magnets applying a force to slow the rollers the HARDER the car trys to push against the applied force. This dyno also allows the operator to apply various amounts of load conditions, simulate highway speeds, acceleration and other driving conditions that cannot be simulated with any other dyno. I think I've also discussed how everything this dyno can do, can be done with the Dynojet dyno as well. Not to mention, Dyno Dynamics is now out of business. Support and repair parts for these dynos are now non-existent. Quote: Originally Posted by renzo088 If you want your car tuned properly take it to a Mustang or DynoDynamics dyno Links Dyno faq - Zilvia.net Forums \| Nissan 240SX (Silvia) and Z (Fairlady) Car Forum In conclusion, that last statement is completely FALSE. I believe that I've stated all the pertinent facts to show that the Dynojet dyno has all the benefits of a load bearing dyno (as it can be one when optioned with the PAU), and all the benefits of the repeatability and consistency of an inertia dyno. There is a reason why nearly every NASCAR team in the country has a Dynojet inertia dyno. This is why discerning performance shops like Beyond Redline, AMS Performance, Hennessey Performance, Borla, K&N and many others choose a Dynojet dyno. When it comes to testing and getting repeatable and consistent results, you can't beat a Dynojet. or a link if that is unclear http://www.gencoupe.com/engine/28966...no-tuning.html Last edited by someguy; 02-12-2010 at 12:56 PM..