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WOT is the CORRECT DYNO READING ??????????? 

 

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 Post subject: rear wheel horsepower
Posted: Wed Aug 10, 2005 1:42 am 
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stockstandard wrote:
122mph in 2640 car takes 374 ponies at the wheels, 10.8s in same car takes 414 ponies.

mph is more reliable power indicator so according to forumulas around 280rwkw using

whats the dyno say?


hi

this vehical on my chassis dyno produced 227kwatts and tractive effort is 8900nm

now Dyno Dynamics maths is 227/2 = 113.5 , 227 + 113.5 = 340.5 kwatts at the flywheel if we use what dyno dynamics say the 33% losses rule

flywheel horsepower is 340.5 times 1.34 = 456.2 Bhp :?: :?: :?:
rear wheel horsepower is 227 times 1.34 = 304.18 RWhp :?: :?:


now work out what that equates to flywheel horsepower (Kwatts) :?:

now before you jump the gun this car runs slicks and is a proven super street car 60ft mark is 1.51 seconds and it leaves the line straigh as a arrow and no wheel spin of the mark nor down the track

gear changes happen at 6300rpm and crosses the line at 6500rpm in top gear.

now by ur calculations that horsepower figure is way to Hgh from known vehicals at the race track and knowing there engine dyno and chassis dyno figures it is very spot on as far as the horsepower figure is now what im understanding from ur calaculation ur say it works out to 374 hp at the rear wheels now if i convert that to the flywheel that would be 561 Bhp which from my experience is not the correct horsepower to power the weight of this vehicle down the quarter mile :?: :?: :idea: :idea:

would be interested to hear your thoughts

cya

 

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Posted: Wed Aug 10, 2005 12:32 pm 
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Its probably way off. From what I can tell by playing around with these estimation forumulas is that they seem to qork quite well for street cars, but the faster the car goes the more difficult it becomes because other factors besides the engines power start to play significant roles.

Anyway, the car runs ~10.8 @ 122 which cant be argued. No matter how many dyno's you run this on that number wont change. If however you tune on the dyno and get an increase, all dynos should show a proportional increase. As long as the dynos are consistent in they way they report changes to HP, then they are usefull tuning tools regardless as to if they report the exact same HP figure or not.

 

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 Post subject: quarter mile drags
Posted: Wed Aug 10, 2005 3:07 pm 
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stockstandard wrote:
Its probably way off. From what I can tell by playing around with these estimation forumulas is that they seem to qork quite well for street cars, but the faster the car goes the more difficult it becomes because other factors besides the engines power start to play significant roles.

Anyway, the car runs ~10.8 @ 122 which cant be argued. No matter how many dyno's you run this on that number wont change. If however you tune on the dyno and get an increase, all dynos should show a proportional increase. As long as the dynos are consistent in they way they report changes to HP, then they are usefull tuning tools regardless as to if they report the exact same HP figure or not.




hi

yes there are alot of variations and variables that influence the performance and reflect back to the drag strip like one of my friends says " the s**t stops when the flag drops " OR " the flag crops the s**t stops"

dynos thats another kettle of fish all together like i was saying all along if i run this car on my dyno( dyno dynamics unit ) or another dyno dynamics dyno the kwatts are so close yet the same car on a late model dyno of a different manufacture quotes different horsepower , all the tryed examples i have set in here one would think the two dyno manufactures would read within a bees penis casue the same car is supplying a set force and a equaly oppsoed force is being applyed back the dyno manufactures load cells should be experiencing the same force therefore the we should see the same horsepower reading withing plus or minus 5% error

but a huge whopping 20% error between dynos makes one think :idea: certainly makes me think

I know from my own experience everyone ( or i should say MOST ) people love bigger dyno figures Men are men LOL :wink: mines BIGGER than yours attitude LOL :wink:

its been a great exercise with this posting

If anyone has some interesting story to share dont be shy causre the only way to learn is ask questiosn :wink: :idea: :idea: :?:


have fun all

cya at the RACE track

 

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Posted: Wed Aug 10, 2005 8:41 pm 
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pepsimax wrote:
USELESS wrote:
I must disagree with everyone here. I believe dynos are great sales tools.

If I decide to sell the wagon I will be heading back up to my mates at Croydons because they give great numbers and then I can have that as a selling point.


and how many buyers really give a rats a*** about dyno results,,they just want to know if it runs and how quick it gets to 100k's,,and to most people dyno results can be bodgied to suit the occasion,,,there just a tuning tool and thats it
I agree with pepsi on this one. I know its a different industry but in our workshop a truckie will bring his rig in complaining of low power (normally because he got bagged up by a less powerful truck up a certain hill). We will do f**k all to the engine, throw it on the dyno and tell the driver it pulled 520 hp at the wheels (out of a 600 hp engine). They do the sums in their head (600 - 20%) and realise this is a good reading. Ring the customer 2 days later and they swear blind the things 10 time better than before (even though nothing was done to it). So dont say most people dont give a rats about dyno results, it can influence peoples perceptions or put their minds at ease.

 

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 Post subject: LOL
Posted: Wed Aug 10, 2005 9:11 pm 
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seton005 wrote:
pepsimax wrote:
USELESS wrote:
I must disagree with everyone here. I believe dynos are great sales tools.

If I decide to sell the wagon I will be heading back up to my mates at Croydons because they give great numbers and then I can have that as a selling point.


and how many buyers really give a rats a*** about dyno results,,they just want to know if it runs and how quick it gets to 100k's,,and to most people dyno results can be bodgied to suit the occasion,,,there just a tuning tool and thats it
I agree with pepsi on this one. I know its a different industry but in our workshop a truckie will bring his rig in complaining of low power (normally because he got bagged up by a less powerful truck up a certain hill). We will do f**k all to the engine, throw it on the dyno and tell the driver it pulled 520 hp at the wheels (out of a 600 hp engine). They do the sums in their head (600 - 20%) and realise this is a good reading. Ring the customer 2 days later and they swear blind the things 10 time better than before (even though nothing was done to it). So dont say most people dont give a rats about dyno results, it can influence peoples perceptions or put their minds at ease.


LOL

read what i wrote

LOL

 

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 Post subject: NO STORYS
Posted: Sat Aug 13, 2005 7:56 pm 
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hi

so no one has any intertesting storys to tell about chassis dynos

LOL

cya

 

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