WTF!Rolling Road
Discussion
Posting this on behalf of a mate heres the story:
He took his car (leon cupra r)to a rolling road a few weeks back for a simple power run.
When he turned up the guy asks him what he has done to it and he says a remap and says that it is supposed to give the car 250bhp,but wanted to see what it is actually running.So off they go.
Whilst there he notices the setup at the garage isnt state of the art by any means,old clocks infront of the rollers that were shaking and the needle reading different values due to the shake,also the clocks only go upto 150mph,and 180 bhp. No torque clock?
So after numerous runs he comes out of the car with a bit of paper and some figures on it,types into his phone and shows my mate a figure of guess what....
250 bhp like he said at the start,when he stopped the car was idling lumpy and up and down he doesnt say anyhthing.drives the car off the rollers and thats it,says meet me back in the shop to pay,so in the shop he's playng around on the computer and comes with a supposed to be power graph,bearing in mind this little shed where the rolling road is,is around 200yds away from shop and no visible connection to the shop for computer etc.
My mate asks where is the torque curve my he says there it is a faint line on the same graph that goes off the page,he says because the torque is so high its gone off the graph!
My mate goes home only to find the car cutting out and has a quick look and a vacum hose has blown off.So not their faulkt could happen anytime,but he didnt give a shite,So any way my question is can you work out a cars bhp by putting it in your phone and doing some kind of formula,only info he had is a dodgy bhp clock that only went to 180 bhp,and speed shaking speed clock?
Think this is a little dodgy?
He took his car (leon cupra r)to a rolling road a few weeks back for a simple power run.
When he turned up the guy asks him what he has done to it and he says a remap and says that it is supposed to give the car 250bhp,but wanted to see what it is actually running.So off they go.
Whilst there he notices the setup at the garage isnt state of the art by any means,old clocks infront of the rollers that were shaking and the needle reading different values due to the shake,also the clocks only go upto 150mph,and 180 bhp. No torque clock?
So after numerous runs he comes out of the car with a bit of paper and some figures on it,types into his phone and shows my mate a figure of guess what....
250 bhp like he said at the start,when he stopped the car was idling lumpy and up and down he doesnt say anyhthing.drives the car off the rollers and thats it,says meet me back in the shop to pay,so in the shop he's playng around on the computer and comes with a supposed to be power graph,bearing in mind this little shed where the rolling road is,is around 200yds away from shop and no visible connection to the shop for computer etc.
My mate asks where is the torque curve my he says there it is a faint line on the same graph that goes off the page,he says because the torque is so high its gone off the graph!
My mate goes home only to find the car cutting out and has a quick look and a vacum hose has blown off.So not their faulkt could happen anytime,but he didnt give a shite,So any way my question is can you work out a cars bhp by putting it in your phone and doing some kind of formula,only info he had is a dodgy bhp clock that only went to 180 bhp,and speed shaking speed clock?
Think this is a little dodgy?
Edited by Kinky on Sunday 27th May 20:29
It looks a bit dodgy at first read doesn't it? and to be honest it doesn't sound exactly state of the art, however ..
the 180 bhp the dyno is pegged to will likely be a wheels figure .. so that would be about 220-230 at the flywheelon most cars ...
now what the guy could have been doing is note down the hp at the wheels every 1000 rpm into his fone .. once he knows that and the revs he can work out a hp at the wheels graph. if the graph goes outside his dyno limits he just extrapolates the figures he does have to come up with a likely hp curve. IE he will have a graph which rises towards peak, then no figures, then drop away past peak, he then fills in the small blank bit inbetween in a join the dots type style.
once he has the hp at the flywheel (by using the hp at the wheels plus 18% or whatever correction he's using) he can work out a flywheel torque graph for you aswell ..
so it's entirely possible to create a hp and torque graph from the information available at the time, though it's best used as a very rough guide only methinks.
the 180 bhp the dyno is pegged to will likely be a wheels figure .. so that would be about 220-230 at the flywheelon most cars ...
now what the guy could have been doing is note down the hp at the wheels every 1000 rpm into his fone .. once he knows that and the revs he can work out a hp at the wheels graph. if the graph goes outside his dyno limits he just extrapolates the figures he does have to come up with a likely hp curve. IE he will have a graph which rises towards peak, then no figures, then drop away past peak, he then fills in the small blank bit inbetween in a join the dots type style.
once he has the hp at the flywheel (by using the hp at the wheels plus 18% or whatever correction he's using) he can work out a flywheel torque graph for you aswell ..
so it's entirely possible to create a hp and torque graph from the information available at the time, though it's best used as a very rough guide only methinks.
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