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| FPV_GTp |
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why ? how ? when ?
wonder where newtons laws of physics fit into chassis dynos ?
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| FPV_GTp |
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a strain gauge or load cell and a rpm or speed input and with today's technology im sure we can accurately measure horse power and frictional losses or losses associated with driving a piece of equipment
so Mr Newton must of got it right back over three hundred years ago "Sir Isaac Newton, in his Principia of 1687, stated three laws of motion that are the foundation of our analysis of forces and motion today. Those three laws are: 1. Law of Inertia: Every body maintains a state of rest or of constant speed in a straight line unless acted upon by a nonzero net force. 2. When a body of mass m is acted upon by a net force, Fnet = SF, its acceleration, a, is given by a = Fnet/m (The direction of the net force is the same as the direction of the acceleration.) 3. When one thing exerts a force on a second thing, then that second thing exerts an equal and opposite force on the first thing. just some trivia thrown in for entertainment cheers
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| tickford_6 |
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Posts: 6449 Joined: 11th Nov 2004 |
if they are so good, why is it that a car can, in the space 20mins make 3 runs and get three different read outs, with no changes made the car or dyno.
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| FPV_GTp |
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tickford_6 wrote: if they are so good, why is it that a car can, in the space 20mins make 3 runs and get three different read outs, with no changes made the car or dyno.
give me a example ????? how big is the dyno differance reading ?? 5% , 10% ,15%,20% or more ? how different are the results if all is the same remember heat soke in car ?? do 3 runs after one another in less than 3 minutes i will put my money where my mouth is and lets see a difference of a few kwatts thats all thats 1 run in less than 1 minute intervals or in some cases i can perfer these three runs even quicker to provide a graph for the same car Maybe look at what ur testing , the dyno is giving u a reading of what it is measuring , so if the power is down, like i said look, at ur test vehicle ( Heat soke into components ie inlet manifold engine block head(s) and so on ,not the dyno When u run a dyno im sure u will understand more. cheers
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| tickford_6 |
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Posts: 6449 Joined: 11th Nov 2004 |
from the highest to lowest reading it was about 10kw difference.
heat soak not an issue, the car had been driven around all day sat for ten mins in the car park then straigh on the dyno. and i've had more time around dynos then you seem to think i have. it' that time that has given me my opinions about them |
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| FPV_GTp |
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tickford_6 wrote: from the highest to lowest reading it was about 10kw difference.
heat soak not an issue ?????, the car had been driven around all day sat for ten mins in the car park then straight on the dyno. and i've had more time around dynos then you seem to think i have. it' that time that has given me my opinions about them I think u better have a think again on some of ur opinions about heat soak 10 minutes in the car park doesn't mean the car has normalized temperature wise do 10 power pulls on a dyno wide open throttle on max rpm the engine will do and hold it there for 1 minute each time and then u tell me heat soak is not a issue and if ur to scared to do 10 power pulls , just do one and hold the engine for a length of time on txt screen mode not graph mode and lets see what the kwatts do I love discussions on forums , im not undermining ur intelligence on dynos but be open minded
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| tickford_6 |
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Posts: 6449 Joined: 11th Nov 2004 |
FPV_GTp wrote: tickford_6 wrote: from the highest to lowest reading it was about 10kw difference. heat soak not an issue ?????, the car had been driven around all day sat for ten mins in the car park then straight on the dyno. and i've had more time around dynos then you seem to think i have. it' that time that has given me my opinions about them I think u better have a think again on some of ur opinions about heat soak 10 minutes in the car park doesn't mean the car has normalized temperature wise do 10 power pulls on a dyno wide open throttle on max rpm the engine will do and hold it there for 1 minute each time and then u tell me heat soak is not a issue and if ur to scared to do 10 power pulls , just do one and hold the engine for a length of time on txt screen mode not graph mode and lets see what the kwatts do I love discussions on forums , im not undermining ur intelligence on dynos but be open minded i never said the temp had normalised. but would you like to let me know how heat soak is an issue if every thing is already hot. perhaps you should take some of you own advice and be open minded i can see thread going the same way as you previous dyno realated thread about % power losses. of coures you can prove anything if your the guy operating the dyno 
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| arm79 |
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tickford_6 wrote: i can see thread going the same way as you previous dyno realated thread about % power losses. of coures you can prove anything if your the guy operating the dyno
And me thinks you should stop insinuating that you are being setup or lied to everytime you cant get your own way.
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| stockstandard |
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THE PROBLEM IS NOT DYNOS - ITS THE GUYS WORKING THEM!
The dyno will accurately measure the force on the rollers. This then gets pushed through the correction factors to come up with what you see on the graph. Ive spent quite a bit of time around dynos and talking to operators and they all say there is no reason at all why two dyno's should not read the same number. I believe them as well because Ive run on 5 dyno's in the last year or so in adelaide (Tilbrook, Morpowa, BDT, Road and Track, and BoostinOz) and got 1.2rwkw variation between the highest and lowest numbers. Ive also played around with measuring power myself. I made an adaptor so I could datalog through the diagnostic port. I wrote some software that would look at the engine rpm and convert it to speed. From speed and time it works out acceleration. From acceleration and an estimate of my cars weight (1550kg) I can work out how much force the engine is applying to the road (in Newtons). From newtons and distance I can work out torque, and from torque and the origional rpm values it works out power. Comparing the graph of the output it shows that amazingly the power numbers it comes up with are respectable. If I can get something that is pretty close with 50c worth of electronics, a laptop, and a bit of software surely a real dyno can get it right.
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| stockstandard |
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and by pretty close i mean -
against 
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| FPV_GTp |
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ok ok i must have a huge chip on my shoulder
cause what i read tickford is what u wrote hahahha ok u do ur testing like u siad take ur own advice and i will do my testing seems heat is not a issue cheers
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| 4.9 EF Futura |
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Very impressive little device you've crafted there mark. I assume the calculation is the same as a gtech but measures distance based on engine revs/drivetrain as opposed to using an accelerometer.
You know - people pay $50 for a gtech...
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| FPV_GTp |
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tickford_6 wrote: FPV_GTp wrote: tickford_6 wrote: from the highest to lowest reading it was about 10kw difference. heat soak not an issue ?????, the car had been driven around all day sat for ten mins in the car park then straight on the dyno. and i've had more time around dynos then you seem to think i have. it' that time that has given me my opinions about them I think u better have a think again on some of ur opinions about heat soak 10 minutes in the car park doesn't mean the car has normalized temperature wise do 10 power pulls on a dyno wide open throttle on max rpm the engine will do and hold it there for 1 minute each time and then u tell me heat soak is not a issue and if ur to scared to do 10 power pulls , just do one and hold the engine for a length of time on txt screen mode not graph mode and lets see what the kwatts do I love discussions on forums , im not undermining ur intelligence on dynos but be open minded i never said the temp had normalised. but would you like to let me know how heat soak is an issue if every thing is already hot. perhaps you should take some of you own advice and be open minded i can see thread going the same way as you previous dyno realated thread about % power losses. of coures you can prove anything if your the guy operating the dyno "i never said the temp had normalised. but would you like to let me know how heat soak is an issue if every thing is already hot. " read ur previous post car was drive all day and parked for 10 minutes If u claim the way u putting u opinion accross in here u have a large amount of dyno experience the why do i ahve to give any explaination about heat soak ???? Im sure u understand the principle HEAT SOAK ? look its always a heated debate as far as setups its a no go zone tickford u come into this thread on ur own free will cheers
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| stockstandard |
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4.9 EF Futura wrote: Very impressive little device you've crafted there mark. I assume the calculation is the same as a gtech but measures distance based on engine revs/drivetrain as opposed to using an accelerometer.
You know - people pay $50 for a gtech... Yeah, it works exactly the same as a gtech except it uses engine rpm instead of the accelerometer. I was using it to play around with different things - got some interesting results I played around with locking the BBM on long/short runners and running those logs through 
It was working well so I put a bit more work into the software to store different car profiles, automatically scale the x/y axis values and allow comparison between plots. I used it when I started tuning with the ms2 but that is when I ran into problems. For some reason there was a lot of electrical noise comming through the diag port after the MS2 install so I had to do a lot of filtering in software before I could make sense of the info. Ended up being too much hard work for each graph so I havent touched it in about 6 months. This is the last version of the software I did comapring one of my early MS2 tunes to the old chiptorque 
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| tickford_6 |
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Posts: 6449 Joined: 11th Nov 2004 |
i just find it interesting to see that you need to try and justify all this crap.
first it percent losses now it what gear. at the end of the day does it even mater? we see all these peak power numbers being posted all the time, then we see the same people posting 1/4 mile times and trap speed and the numbers just don't add up. i like i said befor if dynos were so good and accurate the debate would have never stared in the first place. |
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