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| FPV_GTp |
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{USERNAME} wrote: {USERNAME} wrote: {USERNAME} wrote: Its not definative but my car made 260 on the dyno used by gas research when it was owned by the previous owner and it made 261 on the hallam dyno with no further mods. I dynoed it "stock" so I had a baseline. Dyno figures prove nothing. The track is where it should be measured. PMSFL its amazing how race teams spend hours and hours RD ing on engine dynos and chassis dynos and u tell me dyno figures prove nothing hahahahahahahah   people must understand never mind cya Yes but do they go comparing their own cars to others that have run on different dynos? How many race teams would run there cars on one dyno one day then a different dyno the next? They are a great tuning tool, noone is arguing that fact. The problem is people run their 130rwkw then cry when a similar car ran quicker on the track but less rwkw on a dyno run. Dyno figures are not a 100% accurate and comparable to each other, everyone knows yet they still complain. I dont get it. Quarter mile times dont lie. have u read it from start to finish the person is not p****d off why his car has less power but curious why his car has different power readings to another dyno and his car runs quicker than the supposed car with more power down the quarter mile i would wanna know why cya
_________________ WANTED - Complete BTr4 and zf 6hp26 automatic transmission 6 cylinder and V8 transmission(s) suit rebuild? Drop me a PM if you can help would be greatly appreciated - thanks |
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| EFFalcon |
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heres what ya do.
take ya engine out and put it on an engine dyno.
_________________ FALCN6 - EF GLi Turbo, 20" Rims, Air Bag Suspension, Straight LPG, 225rwkw |
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| MikGan |
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And the quality of the curve would mean alot also, what if theres a dive at say 60k's but picks up well above 120 and ends up with a bigger final power figure. Set this car up against a car with a perfect smooth curve all the way up to say 17% lower final power figure, Id say it would be close, put driver error and small differecents in setup into the equation and theres a good chance the lower figured car will beat the highter rwkw car down the line...... doesnt seem too far fetched does it?
Theres a good chance Ive missed the point completly here so lets keep this clean  no flamming.... plz 
_________________ I couldnt fix your brakes so I made your horn louder
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| v8capri |
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would diff ratios play a part in it.
if an engine had a great top end it would dyno well, yet another engine 20% less but more torque low down would probably 1/4 mile faster. peak power is only 1 part of the many things that are needed in the 1/4 mile equation. What a sh*tfight this has become 
_________________ BA Ghia 320 rwkw @ FordMods dyno day
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| Nicko |
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{USERNAME} wrote: would diff ratios play a part in it.
if an engine had a great top end it would dyno well, yet another engine 20% less but more torque low down would probably 1/4 mile faster. peak power is only 1 part of the many things that are needed in the 1/4 mile equation. What a sh*tfight this has become i dont think its become a s**t fight - i think its a great discussion and has lots of information. Some people are taking this persobally and turning it into a s**t fight. Its a fair question thats being asked and as said it isnt a witch hunt but a experiment
_________________ Nicko |
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| CHEF |
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Ive been waiting for someone to bring up torque as it makes a huge difference in 1/4 times, even on cars with the same wkws
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| Steady ED |
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I agree completely with your previous point FPV-GTp...
Here we have dynos made by the same company, Dyno Dynamics, all presumedly manufactured to the same standards, and all supposedly running the same software. Forgetting differences caused by intake air temp, altitude, air density blah blah etc. these dynos should read the same. When people are dynoing cars and getting ridiculously varied readings that cannot all be attributed to varying conditions, you have to ask "why?"
_________________ ED XR8 Sprint - S-Trim, V500, 249rwkw |
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| data_mine |
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But you can't forget the differences, they play major parts in the calculations made.
Here's some math for ya... (figure are in HP, Foot Lbs unless otherwise stated) HP = (Torque X RPM) / 5252 Torque = (5252 X HP) / RPM RPM = (5252 X HP) / Torque (simple they're all mutations of each other) Now here's what a dyno does: Cf = 1.180 X [ (990 / Pd) X Root((Tc + 273) / 298) ] - 0.18 Pd = Dir ary pressure (pascals) Tc = Ambient temp (celcius) Displayed HP = DynoHP X Cf So at SI standard conditions (1 Atmosphere pressure, 20C ambient) the Correction Factor is about 0.9632. So the displayed figure will be slightly less than teh measured figure. Change the pressure or ambient (very possible on a busy dyno as they have alot of heat to get rid of), the the results will be different. Plus you still have the human factor in there too. Did the operator press the accelerator in the SAME way each time. Was the car cold on one run, but warmed up on another. As I've said before there are far to many variables that make affect, but the dyno software can only account for so many. And Engine dyno however, take control of pressure and ambient temp, it takes control of the throttle, so has less room for differences.
_________________ 1998 DL LTD in Sparkling Burgundy, daily, 302W, stereo, slow |
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| FPV_GTp |
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my two bobs worth
http://www.fordmods.com/forums/viewtopi ... sc&start=0
_________________ WANTED - Complete BTr4 and zf 6hp26 automatic transmission 6 cylinder and V8 transmission(s) suit rebuild? Drop me a PM if you can help would be greatly appreciated - thanks |
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| Steady ED |
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Yeah I see your point data_mine, obviously these factors can't actually be ignored, as they do make a massive difference.
But are they solely responsible for the differences we are seeing? That's the point I'm trying to make. Surely when we see output at the treads of some vehicles vary ENORMOUSLY from dyno to dyno, there has to be something else going on, whether dynos have massive engineering tolerances (which I would think is strange for a measuring instrument), or there is a 'nudge' factor in the software that some operators abuse.
_________________ ED XR8 Sprint - S-Trim, V500, 249rwkw |
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| FPV_GTp |
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hi guys
Some of u guys are missing the piont here Ur introducing all theses constrants and paramaters ARM79 siad a controlled inviroment 1. same cars tested back to back 2. same day testing ( no weather affected test ) 3. we are both at sea level ( again no barometric pressure affects ) 4. same dynos ( made by the same manufacturers ) 5. if need be i control the other persons dyno and he controls my dyno 6. same ramp rates ( all dyno settings the same ) 7. so forget about all the variables you guys are throwing in now in my books if i went to K-mart or Bunnyings to buy a weight scale to wiegh myself and jumped on 12 scales at the shop made by the same manufacture i would expect to see the same wieght YES or NO simple no physics maths required here hangon FONE A FRIEND pmsfl 
_________________ WANTED - Complete BTr4 and zf 6hp26 automatic transmission 6 cylinder and V8 transmission(s) suit rebuild? Drop me a PM if you can help would be greatly appreciated - thanks |
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| data_mine |
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Well if EVERY external factor that can be controlled is, then it comes down to dodgy manufacturing on the dynos, or they're poorly calibrated.
HUMAN ERROR. (but I still can't understand how you can say forget the variables, and still expect an answer on why they're different - there's always variables you can't get rid of all of them). The test you need to do is. Run the SAME car on the SAME dyno (same location, parameters, operator) 5 times one day, 5 times the next day - repeat ad infinitum, and see how different the results are (how repaetable is the result?). I'd persoanlly like to see these results.
_________________ 1998 DL LTD in Sparkling Burgundy, daily, 302W, stereo, slow |
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| MikGan |
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Ive had my car dynoed a number of times at a few places now on the same day and even in some cases a few days apart and got almost the exact same result each time
_________________ I couldnt fix your brakes so I made your horn louder
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| data_mine |
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{USERNAME} wrote: now in my books if i went to K-mart or Bunnyings to buy a weight scale to wiegh myself and jumped on 12 scales at the shop made by the same manufacture i would expect to see the same wieght YES or NO
Within tolerances, bathroom scales are not scientific instruments, and many have user calibration points. So what if so 5yo went aroudn and fiddled with all the scales? What if one set had a dodgy set of springs in it. What if a WHOLE batch had dodgy springs in them. They all said you weighed 110KG, when another brand (or another batch of the same brand) say you weigh only 75KG. All I'm getting at is as the saying goes - the devil is in the detail. You can't ignore the variables. Now on the other hand, if you went and weighed yourself on a set of scientific calibrated scales (eg. thoses used by greengrocers, scientists etc.) they should all say the same thing, and because they're calibrated in some degree to the SI standard kilogram (a 1KG block of some exotic metal that is kept in a vault in France and is 1KG down to the atomic level) they should be both REPEATABLE and CORRECT.
_________________ 1998 DL LTD in Sparkling Burgundy, daily, 302W, stereo, slow |
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| FPV_GTp |
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{USERNAME} wrote: Well if EVERY external factor that can be controlled is, then it comes down to dodgy manufacturing on the dynos, or they're poorly calibrated.
HUMAN ERROR. (but I still can't understand how you can say forget the variables, and still expect an answer on why they're different - there's always variables you can't get rid of all of them). The test you need to do is. Run the SAME car on the SAME dyno (same location, parameters, operator) 5 times one day, 5 times the next day - repeat ad infinitum, and see how different the results are (how repaetable is the result?). I'd persoanlly like to see these results. lets see what u are going to say now i have a cortina with a 351 cleveland and c10 auto 9 in diff it runs 10.8 at calder race way at 120 miles per hr calder is 5 minutes waya from me now if hallam had a drag strip that the 60ft mark was prepped up with VHT what should my cortina run there after driving straight from calder down to hallam with in a hour i think i know i wpuld expect to see the same times within 10th of a second cya
_________________ WANTED - Complete BTr4 and zf 6hp26 automatic transmission 6 cylinder and V8 transmission(s) suit rebuild? Drop me a PM if you can help would be greatly appreciated - thanks |
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