Just an observation.
03-29-2008, 07:45 AM
#21
Bullshit?.... You dont understand much about dynamometers then.
If you change the acceleration rate of a engine it will change the measured tq reading. This is done on an engine dyno by changing the rpm/sec acceleration rate and is done on a Mustang Dyno the same way when running the dyno in Constant Acceleration Mode.
The other way the acceleration rate is increased or decreased is by changing the vehicle weight input if using the dyno in Vehicle Simulation Mode.
When using a loadcell dyno in vehicle simulation the dyno uses the input for vehicle weight and hp at 50mph to create a load curve to simulated highway conditions on the vehicle. You can also enter grade % but we will take one thing at a time.
The amount of load determines the acceleration rate of the engine. So naturally changing vehicle weight will allow the engine to accelerate faster or slower. That is WHY you get a different measured tq reading if you change the weight input.
Again the same is true with a engine dyno. Go back even 30 years ago and nothing is different now. Alot of people looking for higher numbers to brag about or sell parts did their engine dyno testing at 100 rpm/sec or step testing to show a higher number than the people that were testing at 300 rpm/sec. Did the engine MAKE more power on the engine dyno...? No. But did it MEASURE more ..? YES!
Bullshit? I dont think so.
The other way the acceleration rate is increased or decreased is by changing the vehicle weight input if using the dyno in Vehicle Simulation Mode.
When using a loadcell dyno in vehicle simulation the dyno uses the input for vehicle weight and hp at 50mph to create a load curve to simulated highway conditions on the vehicle. You can also enter grade % but we will take one thing at a time.
The amount of load determines the acceleration rate of the engine. So naturally changing vehicle weight will allow the engine to accelerate faster or slower. That is WHY you get a different measured tq reading if you change the weight input.
Again the same is true with a engine dyno. Go back even 30 years ago and nothing is different now. Alot of people looking for higher numbers to brag about or sell parts did their engine dyno testing at 100 rpm/sec or step testing to show a higher number than the people that were testing at 300 rpm/sec. Did the engine MAKE more power on the engine dyno...? No. But did it MEASURE more ..? YES!
Bullshit? I dont think so.
I have noticed several people here lately say that a Mustang Dyno is a more "true" reading because it loads the wheels relative to the cars weight.
Bullshit.
How much a car weighs has absolutely nothing to do with how much HP the engine makes. Nothing, nada, zilch.
An engine makes the same hp whether it is in a tonka truck or a peterbuilt.
I won't argue that it may be a better tuning tool and whatever else but being a more accurate reprensentation of hp because of it loading the wheels to account for weight is just completely wrong.
Bullshit.
How much a car weighs has absolutely nothing to do with how much HP the engine makes. Nothing, nada, zilch.
An engine makes the same hp whether it is in a tonka truck or a peterbuilt.
I won't argue that it may be a better tuning tool and whatever else but being a more accurate reprensentation of hp because of it loading the wheels to account for weight is just completely wrong.
03-29-2008, 07:57 AM
#22
Rule #1... A loadcell engine or chassis dyno like a Mustang, Superflow MEASURES tq and calculates hp from that by referencing engine RPM. This is measured by a load cell and has nothing to do with calculating the acceleration rate of the drum vs. time like a inertia dyno does.
Rule #2... Generally on a loaded dyno, if you are using Vehicle Simulation Mode like you are refering to, increasing the vehicle weight will increase measured tq and hp also. This is just generally and not always true but I only point that out because everyone is always saying how you "input a lower vehicle weight on a Mustang Dyno to get a higher HP number". Most of the time the opposite is true.
The power numbers that you see on a dyno computer screen are calculated. They are calculated with the acceleration of the dyno drum vs time. A lighter drum spins faster and the dyno calculates more power. Most DynoJets use a 2500lb drum, while Mustang dynos give you the ability to tailor the drums resistance to the weight of the car. A 2500lb drum will accelerate quicker than a simulated 3600lb drum will. That's the difference in power numbers. Finally, from someone who has actually had their car on both dynos nearly back to back, DynoJets read higher, the pulls are much quicker, and the engine note sounds very different.
You're right, an engine makes the same power whether its in a Tonka or a Peterbuilt. Too bad you don't measure engine HP with a CHASSIS DYNO!!!!!!!!!!!
Rule #2... Generally on a loaded dyno, if you are using Vehicle Simulation Mode like you are refering to, increasing the vehicle weight will increase measured tq and hp also. This is just generally and not always true but I only point that out because everyone is always saying how you "input a lower vehicle weight on a Mustang Dyno to get a higher HP number". Most of the time the opposite is true.
The power numbers that you see on a dyno computer screen are calculated. They are calculated with the acceleration of the dyno drum vs time. A lighter drum spins faster and the dyno calculates more power. Most DynoJets use a 2500lb drum, while Mustang dynos give you the ability to tailor the drums resistance to the weight of the car. A 2500lb drum will accelerate quicker than a simulated 3600lb drum will. That's the difference in power numbers. Finally, from someone who has actually had their car on both dynos nearly back to back, DynoJets read higher, the pulls are much quicker, and the engine note sounds very different.You're right, an engine makes the same power whether its in a Tonka or a Peterbuilt. Too bad you don't measure engine HP with a CHASSIS DYNO!!!!!!!!!!!
03-30-2008, 01:57 AM
#23
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Sorry guys not trying to hijack here. I was searching looking for just one of these discussions you guys are having. I just got a dyno tune on a mustang dyno. The #'s the car made seemed a high to me. So i posted them and everyone basically just jumped my *** for them. Sheet reads 427rwhp@5792 & 436rwtq@4039rpm. All mods are in sig. Does this have to do with the operator/owner of the dyno? I noticed yall talking about weight. He entered my weight at 3875lbs. Which is probably bout right for me. Why are my #'s so high? I dont have a dynojet anywhere around where i live unless i drive way down south.
03-31-2008, 05:31 AM
#24
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yep..... the funny thing is only about 10% of the people on here or anywhere for that matter know what the hell is going on with cars and mechanical things...... people are so fast to say that something cant happen, or they read something somewhere that says that is impossible..... those people never have even touched the product they are talking about but just troll websites reading info...... a dyno is a dyno IMO and they are all gonna read a little different from each other but saying that one dyno is not as good as another is BS cause they are all made to do different things to a car as you listed earlier! jake
notice my post count? i dont bother with the idiots
03-31-2008, 06:25 AM
#25
Bullshit?.... You dont understand much about dynamometers then.
If you change the acceleration rate of a engine it will change the measured tq reading. This is done on an engine dyno by changing the rpm/sec acceleration rate and is done on a Mustang Dyno the same way when running the dyno in Constant Acceleration Mode.
The other way the acceleration rate is increased or decreased is by changing the vehicle weight input if using the dyno in Vehicle Simulation Mode.
When using a loadcell dyno in vehicle simulation the dyno uses the input for vehicle weight and hp at 50mph to create a load curve to simulated highway conditions on the vehicle. You can also enter grade % but we will take one thing at a time.
The amount of load determines the acceleration rate of the engine. So naturally changing vehicle weight will allow the engine to accelerate faster or slower. That is WHY you get a different measured tq reading if you change the weight input.
Again the same is true with a engine dyno. Go back even 30 years ago and nothing is different now. Alot of people looking for higher numbers to brag about or sell parts did their engine dyno testing at 100 rpm/sec or step testing to show a higher number than the people that were testing at 300 rpm/sec. Did the engine MAKE more power on the engine dyno...? No. But did it MEASURE more ..? YES!
Bullshit? I dont think so.
If you change the acceleration rate of a engine it will change the measured tq reading. This is done on an engine dyno by changing the rpm/sec acceleration rate and is done on a Mustang Dyno the same way when running the dyno in Constant Acceleration Mode.
The other way the acceleration rate is increased or decreased is by changing the vehicle weight input if using the dyno in Vehicle Simulation Mode.
When using a loadcell dyno in vehicle simulation the dyno uses the input for vehicle weight and hp at 50mph to create a load curve to simulated highway conditions on the vehicle. You can also enter grade % but we will take one thing at a time.
The amount of load determines the acceleration rate of the engine. So naturally changing vehicle weight will allow the engine to accelerate faster or slower. That is WHY you get a different measured tq reading if you change the weight input.
Again the same is true with a engine dyno. Go back even 30 years ago and nothing is different now. Alot of people looking for higher numbers to brag about or sell parts did their engine dyno testing at 100 rpm/sec or step testing to show a higher number than the people that were testing at 300 rpm/sec. Did the engine MAKE more power on the engine dyno...? No. But did it MEASURE more ..? YES!
Bullshit? I dont think so.
My point was that 1 hp is a FIXED measure of work. The weight of the object doing the work should not have any effect on the work being accomplished.
1 hp is a known quantity. Does the size of the horse have anything to do with it.?? NO. The exact definition of one horsepower is 33,000 lb.ft./minute.
Doesn't matter if the horse is a shetland pony or a clydesdale, it still has to move the object the same distance in the same amount of time.
Doesn't matter if the horse is a shetland pony or a clydesdale, it still has to move the object the same distance in the same amount of time.
03-31-2008, 06:30 AM
#26
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Are you trying to tell me that your car will make less Hp when you leave the club at 2 am with the 250 lb drunk chick than it does when you pick up a really hot 115 lber?? I don't think so, it will accelerate slower die to having a higher weight to move, but the power the car actually puts to the wheels is constant.
