rolling roads do and don't.
04 February 2002, 10:40 PM
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hi there
there has been a lot of debat lately about the rolling road figures. it seem to have confused a lot of people.
on the rollers it measures torue and not bhp then it calculate the BHP fromt the equation BHP=[TORQUE x rpm ]/ 5252
the easiest way to explain things is expalin the main disadvantages of rolling roads, which is measuring the torque at the road wheels (PaW) and not staight of the engine. this means that the final power at the fly wheel ( road wheel)will be affected by transmission system operating conditions, such as clutch slip, oil drag in the box or the asle and the rolling resistance of the tyres. this does not give a direct picture of what is happening at the engine or the road.
on the road the tyre get one compression flat spot when it make contact with tarmac, while of the rollers you have two compression flat spots because you have to rollers pressing against the wheel. this introduce so unrealistic losses as well. because you have an unnatural degree of compression to the tyres. now add to that the straps, which also add the the transmission loses!! now it becomes even more interesting. the more powerful cars like mine and john philips
will need to be strapped down more firmly, to pull the car back on the rollers, these powerful cars usually have bigger wider tyres. all this will lead to more energy is used to compress the side walls and also it is quite obvious that the faster you go the more effort it takes to keep deforming the side wall and hence the total rolling loses increases with speed.
that means cars like mine will have to get increased transmission loses, than a scoob, but it is also will explain why the cars like John banks and Tuk got more power than other scoobs with the same mods. basically they asked the operator to rev the car all the way to the rev limiter, that really means that their result just could not compare with the rest as they added an extra inaccuracy in the equation in more than one way. also if you check the eqation at the top of the page you will see that the higher the rpm the more Paw you will get. sorry guys
another thing that is not ususally taken into account is that power at the engine is always changing as the combustion chambers heat up, power fades. also as oil and coolant temps change power at the fly wheel change. so were all the cars fully warmed up before the power run started?
another thing is acceleration, if the engine accelerates too quickly you get higher readings, and more energy gets transmitted through the rollers and hence more power losses, that is way shorter geared cars will get more power at the wheels. so you can't really compare this either. the way around this is to load the roller differently ( ie more load) for the faster cars. i am not sure of star does that automatically as it is a stat of the art new roller?
what all this means is power figures at the wheels are meaningless!! could be only used maybe between two identical cars and that is about it, and when i mean identical i mean same tyre pressure, wheel size, RPM oil etc....
if that was not complicated enough, power at the wheels also changes with raod speed, as the rolling resistance of the tyres depends to road speed. this goes back again to gear ratios and to RPM REACHED. saying that lower speed at the roller means less transmission loses, so that is who the roller compensates for the speed between cars, different RPMs and so on. if you add a god 10 psi of pressure to your tyres on the rollers you will gain around 5-7 bhp at the wheels!!!!!!
from this you can see also that adding a little % to the power at the wheels for the transmission loses is totally in accurate as there is just far too many parameters.
basically the only accurate measure is the power at the fly wheel and that depends on the way the operator loads the rollers for the most cars. you can't expect the rollers to have the same load for all cars. on the day you get cars varying form 150bhp to 500bhp!!!
so what we probably need to do is
make sure all the cars are measured the same way. and it should be up to the operator and not the individual. basically we can opt for all the cars to be reved to MAX rpm or lets say 7500revs. i think spraying water over the scoob tmic as PE do is also a good idea. but it needs to be done to all the cars with TMIC.
my wrist and head hurt now
i hope this helps
sam
ps could not be bothered reading it again so please no slagging for spelling mistakes
there has been a lot of debat lately about the rolling road figures. it seem to have confused a lot of people.
on the rollers it measures torue and not bhp then it calculate the BHP fromt the equation BHP=[TORQUE x rpm ]/ 5252
the easiest way to explain things is expalin the main disadvantages of rolling roads, which is measuring the torque at the road wheels (PaW) and not staight of the engine. this means that the final power at the fly wheel ( road wheel)will be affected by transmission system operating conditions, such as clutch slip, oil drag in the box or the asle and the rolling resistance of the tyres. this does not give a direct picture of what is happening at the engine or the road.
on the road the tyre get one compression flat spot when it make contact with tarmac, while of the rollers you have two compression flat spots because you have to rollers pressing against the wheel. this introduce so unrealistic losses as well. because you have an unnatural degree of compression to the tyres. now add to that the straps, which also add the the transmission loses!! now it becomes even more interesting. the more powerful cars like mine and john philips
will need to be strapped down more firmly, to pull the car back on the rollers, these powerful cars usually have bigger wider tyres. all this will lead to more energy is used to compress the side walls and also it is quite obvious that the faster you go the more effort it takes to keep deforming the side wall and hence the total rolling loses increases with speed. that means cars like mine will have to get increased transmission loses, than a scoob, but it is also will explain why the cars like John banks and Tuk got more power than other scoobs with the same mods. basically they asked the operator to rev the car all the way to the rev limiter, that really means that their result just could not compare with the rest as they added an extra inaccuracy in the equation in more than one way. also if you check the eqation at the top of the page you will see that the higher the rpm the more Paw you will get. sorry guys
another thing that is not ususally taken into account is that power at the engine is always changing as the combustion chambers heat up, power fades. also as oil and coolant temps change power at the fly wheel change. so were all the cars fully warmed up before the power run started?
another thing is acceleration, if the engine accelerates too quickly you get higher readings, and more energy gets transmitted through the rollers and hence more power losses, that is way shorter geared cars will get more power at the wheels. so you can't really compare this either. the way around this is to load the roller differently ( ie more load) for the faster cars. i am not sure of star does that automatically as it is a stat of the art new roller?
what all this means is power figures at the wheels are meaningless!! could be only used maybe between two identical cars and that is about it, and when i mean identical i mean same tyre pressure, wheel size, RPM oil etc....
if that was not complicated enough, power at the wheels also changes with raod speed, as the rolling resistance of the tyres depends to road speed. this goes back again to gear ratios and to RPM REACHED. saying that lower speed at the roller means less transmission loses, so that is who the roller compensates for the speed between cars, different RPMs and so on. if you add a god 10 psi of pressure to your tyres on the rollers you will gain around 5-7 bhp at the wheels!!!!!!
from this you can see also that adding a little % to the power at the wheels for the transmission loses is totally in accurate as there is just far too many parameters.
basically the only accurate measure is the power at the fly wheel and that depends on the way the operator loads the rollers for the most cars. you can't expect the rollers to have the same load for all cars. on the day you get cars varying form 150bhp to 500bhp!!!
so what we probably need to do is
make sure all the cars are measured the same way. and it should be up to the operator and not the individual. basically we can opt for all the cars to be reved to MAX rpm or lets say 7500revs. i think spraying water over the scoob tmic as PE do is also a good idea. but it needs to be done to all the cars with TMIC.
my wrist and head hurt now
i hope this helps
sam
ps could not be bothered reading it again so please no slagging for spelling mistakes
04 February 2002, 11:17 PM
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so basically forget the rolling roads and get to the track or strip
I only compare PAW with other UK cars,but have to disagree with you on the revving higher,gives you more PAW's bit.it gave me more flywheel power but no more PAW.the first run my car had saw results of 218.5bhp@flywheel and 139bhp@wheels at about 5900rpm,the next run I asked Jim to rev to 6500rpm as that is where I change up,the results were 234.5bhp@flywheel at 6440rpm but still 139bhp@wheels at about 5900rpm.please explain
I only compare PAW with other UK cars,but have to disagree with you on the revving higher,gives you more PAW's bit.it gave me more flywheel power but no more PAW.the first run my car had saw results of 218.5bhp@flywheel and 139bhp@wheels at about 5900rpm,the next run I asked Jim to rev to 6500rpm as that is where I change up,the results were 234.5bhp@flywheel at 6440rpm but still 139bhp@wheels at about 5900rpm.please explain
04 February 2002, 11:33 PM
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basically the only accurate measure is the power at the fly wheel
What I dont get is why so many ppl are interested in the BHP figure when IMHO, its the torque figure that counts in 95% of situations.
Its torque that gives you acceleration and, due to the way rollers measure you know that this will be accurate as they are not corrected values unlike the BHP which can then be affected by ambient temperature inconsistensies etc etc.
The rollers are measuring the power needed to turn them against a load i.e. the TORQUE needed to turn them so its gonna be accurate
BHP sells cars, torque wins races.
Pete, you need to re-sort your RR day results so that its in descending order according to torque
05 February 2002, 12:37 AM
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hi T-uk
the reason you got the same power at the wheels is probably because jim loaded the car up correctly i mean how many scoobs did he dyno over the last year or so ? loads.
but if you read the point about the final speed which you would have achieved due to the higher RPM that means you have got more transimission loses as more energy was needed to increase the rolling resistance of the tyres. does that make sense
?
if both runs where made in different gears and the rollers were calibrated at the bigenning ( remember when jim sets the 2000rpm ) then you should have had less transimission loses in the higher gears and theoritcally they should have cancelled each other out. but both your runs where done on the same gear ?? but one with effectively higher speed. i know you did not mean that way john
that is why it is pointless comparing cars with different gear ratios. you will find stis,P1s, wrxs all produce generally more PaW than a UK car.
Richie
i meant power at the fly wheel, as i mentioned above to john (t-uk) you just can't compare power at the wheels between cars that have different gears ratios, tyre size, etc.. you just need to trust the roller operator to load the roller probably for the various different cars. i think it is something that just comes with time.
sam
the reason you got the same power at the wheels is probably because jim loaded the car up correctly i mean how many scoobs did he dyno over the last year or so ? loads.
but if you read the point about the final speed which you would have achieved due to the higher RPM that means you have got more transimission loses as more energy was needed to increase the rolling resistance of the tyres. does that make sense
?if both runs where made in different gears and the rollers were calibrated at the bigenning ( remember when jim sets the 2000rpm ) then you should have had less transimission loses in the higher gears and theoritcally they should have cancelled each other out. but both your runs where done on the same gear ?? but one with effectively higher speed. i know you did not mean that way john
that is why it is pointless comparing cars with different gear ratios. you will find stis,P1s, wrxs all produce generally more PaW than a UK car.
Richie
i meant power at the fly wheel, as i mentioned above to john (t-uk) you just can't compare power at the wheels between cars that have different gears ratios, tyre size, etc.. you just need to trust the roller operator to load the roller probably for the various different cars. i think it is something that just comes with time.
sam
05 February 2002, 12:53 AM
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one more thing, a good indication if the figures are correct or not is that theoretically the torque and the bhp have to meet at 5252 rpm. i have found that PE graphs clearly meet up at 5252 and so does well lane however powerstation definitely does not do it all the time.
ok boys check your graphs
the plot thickens
you can tell that i am bored today
ok boys check your graphs
the plot thickens
you can tell that i am bored today
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05 February 2002, 12:11 PM
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hi pete
don't shoot the massenger m8. only one of my graphs ( the one taken before the mods) crosses at 5252. my last one crosses well over 6000rpm.
if you go to the dyno site and look at PE graphs they all cross at 5252 on the dot. also same applies to well lane. this is the theory i have learnt over the last couple of days regarding rolling roads.
what does it mean when they don't cross at that level? some say that the graphs are not accurate. maybe it is a feature of the roller? maybe star performance roller is different?
Jim,
i know that you read this, so can you please contribute and clarify things to us all?
sam
don't shoot the massenger m8. only one of my graphs ( the one taken before the mods) crosses at 5252. my last one crosses well over 6000rpm.
if you go to the dyno site and look at PE graphs they all cross at 5252 on the dot. also same applies to well lane. this is the theory i have learnt over the last couple of days regarding rolling roads.
what does it mean when they don't cross at that level? some say that the graphs are not accurate. maybe it is a feature of the roller? maybe star performance roller is different?
Jim,
i know that you read this, so can you please contribute and clarify things to us all?
sam
05 February 2002, 12:51 PM
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Sam,
I agree with your comments on the inconsistent measurement method but I have to admit that I think Star's rollers are way out when they measure or guestimate the power for our EVO's. Most knowledgable EVO folk I have spoken to (mainly from the MLR) say that with my mods and @1.2 bar I should expect 310-315 bhp, not the 333 that I had measured. Same goes for John's E6, you need about 1.4-1.5 bar to get 340 bhp, his measured 1.1 on the day. And as for your E7 measuring 371 bhp, something is way out!
....Brian
I agree with your comments on the inconsistent measurement method but I have to admit that I think Star's rollers are way out when they measure or guestimate the power for our EVO's. Most knowledgable EVO folk I have spoken to (mainly from the MLR) say that with my mods and @1.2 bar I should expect 310-315 bhp, not the 333 that I had measured. Same goes for John's E6, you need about 1.4-1.5 bar to get 340 bhp, his measured 1.1 on the day. And as for your E7 measuring 371 bhp, something is way out!
....Brian
05 February 2002, 01:39 PM
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hi john
it is not really my logic, i did not sit down and try to figure this whole thing out my self. this the view of couple of books that i have read lately about this. forget the rpm and the PaW scenario but do you agree that the higher speed achieved will give you more power at the fly wheel? now add to that all the stuff about the increasing the rolling resistance, adding more tyre pressure forces on the roller and you will get a very inaccurate readings compared to every one else.
what is needed here is either all cars get revved to the same limit as in PE way or all of them only get revved until the power starts dropping.
i am starting to really think it is a loading problem with the rollers, as it can be very high for the scoobs, such as dereks car pinking on the rollers ( mine use to do it as well at times) and very low load for the evos ?
sam
it is not really my logic, i did not sit down and try to figure this whole thing out my self. this the view of couple of books that i have read lately about this. forget the rpm and the PaW scenario but do you agree that the higher speed achieved will give you more power at the fly wheel? now add to that all the stuff about the increasing the rolling resistance, adding more tyre pressure forces on the roller and you will get a very inaccurate readings compared to every one else.
what is needed here is either all cars get revved to the same limit as in PE way or all of them only get revved until the power starts dropping.
i am starting to really think it is a loading problem with the rollers, as it can be very high for the scoobs, such as dereks car pinking on the rollers ( mine use to do it as well at times) and very low load for the evos ?
sam
05 February 2002, 02:14 PM
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Sam, with my limited knowledge and understanding, I agree with your views, it is all in the setup of the rollers...natch!!
When Dave Brown went up for his power run last week, he mentioned that Jim took some time setting the car up, which can only help give more accurate figures.
What was changed from the power runs days we organise??
Obviously wheelbase so that the car sits in the rollerss correctly.
Does the unit get adjusted for the weight of the car, so that the rolling mass of the rollers see what is actually sitting on them?
If so why does some cars start to lift out the rollers. Mines did, so we put a couple of large gentlemen in it. How does that added weight change the readings? Or does it. Surely the rolling resistance set up should compensate for this. Increase the resistance and slow the accelaration down, keeping the car in the rollers.
I've had the Evo with added 'weight' in it and without. Both gave same figures within a couple of BHP and almost identical torque.
One thing for sure this is a bloody minefield of techno-babble. Jim must get a chuckle when he read our posts, trying to justify our BHP readings....or is it Torque that matters
When Dave Brown went up for his power run last week, he mentioned that Jim took some time setting the car up, which can only help give more accurate figures.
What was changed from the power runs days we organise??
Obviously wheelbase so that the car sits in the rollerss correctly.
Does the unit get adjusted for the weight of the car, so that the rolling mass of the rollers see what is actually sitting on them?
If so why does some cars start to lift out the rollers. Mines did, so we put a couple of large gentlemen in it. How does that added weight change the readings? Or does it. Surely the rolling resistance set up should compensate for this. Increase the resistance and slow the accelaration down, keeping the car in the rollers.
I've had the Evo with added 'weight' in it and without. Both gave same figures within a couple of BHP and almost identical torque.
One thing for sure this is a bloody minefield of techno-babble. Jim must get a chuckle when he read our posts, trying to justify our BHP readings....or is it Torque that matters
05 February 2002, 02:22 PM
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The torque vs power debate will go on and on Whatever, I think we are all agreed that a single measurement technique producing a single value will never give you an overall picture of a car. Perhaps area under torque curve between two engine speeds would be interesting?
Whatever, I think we are all agreed that a single measurement technique producing a single value will never give you an overall picture of a car. Perhaps area under torque curve between two engine speeds would be interesting?
05 February 2002, 03:18 PM
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hi JB
i am not sure if the peak torque is strictly related to boost. i am sure the VE and the cams play a part in that as well.
i did say forget the RPM in respect to the Paw because it does not make sense even to me.
But how will the inflated flywheel figures represent anything on the road the only reason the fly wheel figures are higher is due to transmission loses?? due to the higher speed you have achieved on the rollers? on the road your car will feel the same as the PaW has not ( would not change) isn't that what you are trying to say. just admit it you just wanted larger pub figure numbers
hi John EVOJP
i am not trying to justify anything, why should I ? i have got some of the biggest numbers on the rollers ( always managed somehow) and i have got a piece of paper to prove it. but i am not niave enough to believe them!? but what the hell!! if we are going to believe one figure will have to believe them all and vice versa ? is not that fair enough. i am trying to find out why the rollers are not accurate and they seem to be inccurate for most cars and not just mine. why should i not believe that i have 371bhp on the same roller that gave you 340 ? and john banks 260bhp ? pete 300bhp or have i drawn the short straw .
I WANT THE TRUTH
YOU CAN'T HANDLE THE TRUTH [FEW GOOD MEN STYLE ]
sam
i am not sure if the peak torque is strictly related to boost. i am sure the VE and the cams play a part in that as well.
i did say forget the RPM in respect to the Paw because it does not make sense even to me.
But how will the inflated flywheel figures represent anything on the road
the only reason the fly wheel figures are higher is due to transmission loses?? due to the higher speed you have achieved on the rollers? on the road your car will feel the same as the PaW has not ( would not change) isn't that what you are trying to say. just admit it you just wanted larger pub figure numbers hi John EVOJP
i am not trying to justify anything, why should I ? i have got some of the biggest numbers on the rollers ( always managed somehow)
and i have got a piece of paper to prove it. but i am not niave enough to believe them!? but what the hell!! if we are going to believe one figure will have to believe them all and vice versa ? is not that fair enough. i am trying to find out why the rollers are not accurate and they seem to be inccurate for most cars and not just mine. why should i not believe that i have 371bhp on the same roller that gave you 340 ? and john banks 260bhp ? pete 300bhp or have i drawn the short straw . I WANT THE TRUTH
YOU CAN'T HANDLE THE TRUTH [FEW GOOD MEN STYLE
]sam
05 February 2002, 03:24 PM
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You are right Sam pub figures, but then I would have a VF23 wouldn't I? And personally I don't want that on a road car.
When I got the PPP even then I knew I was not going for high power figures but on-road flexibility, which I reckon in the midrange at least with PPP is respectable, smooth and still very reliable, but I would have got a Link doing it again and would learn to map it myself. But we live and learn!
And personally I don't want that on a road car.When I got the PPP even then I knew I was not going for high power figures but on-road flexibility, which I reckon in the midrange at least with PPP is respectable, smooth and still very reliable, but I would have got a Link doing it again and would learn to map it myself. But we live and learn!
05 February 2002, 03:39 PM
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Sam mate, don't take things as a personal POP at you all the time. I only made the general comment about ALL OF US trying to justify our figures.
I know BBS posts can be interpreted so many ways. Maybe the MLR is starting to rub off a bit
Yer brain must be on meltdown by now, time to recharge the di-lithium crystals and re-align the WARP core
[Edited by evojkp - 2/5/2002 3:59:35 PM]
I know BBS posts can be interpreted so many ways. Maybe the MLR is starting to rub off a bit
Yer brain must be on meltdown by now, time to recharge the di-lithium crystals and re-align the WARP core
[Edited by evojkp - 2/5/2002 3:59:35 PM]
05 February 2002, 05:02 PM
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evo john
i know you are not having a pop at me, obviously you miss understood my post. but again things can get understood differently when written and read.
i am not having a pop at anyone or thinking anyone is trying to with me. no reason for this.
i was just trying to hopefully get a depate that will make us understand things better, and maybe we can come up with something that will uniform the results so that they can be of benefit to every one. i have an evo but i am generally interested in all cars and that is why i have posted this in here and not on the MLR, DRIVETRAIN or something like that.
john banks how can you say that the VF23 is not good for a road car and you have never tried it? surely people that have tried are more qualified to give advise and views about it. ( again not having a pop at you) but i am sure you had strong view when you have bought your PPP, now you say you should have gone for link. and when you get a vf23 you will say oh well i was wrong and you will have a strong view about it as well.
ask the poeple who have tried an upgraded turbo, me, alan G, Dave brown, and ask any off them will they ever go back to a standard turbo? the answer will be NO. the VF23 is not really that big, if you think your car spools up quick and fast that is because you have never been in a car with a VF23, OR VF28. have you actually driven a P1?
sam
i know you are not having a pop at me, obviously you miss understood my post. but again things can get understood differently when written and read.
i am not having a pop at anyone or thinking anyone is trying to with me. no reason for this.
i was just trying to hopefully get a depate that will make us understand things better, and maybe we can come up with something that will uniform the results so that they can be of benefit to every one. i have an evo but i am generally interested in all cars and that is why i have posted this in here and not on the MLR, DRIVETRAIN or something like that.
john banks how can you say that the VF23 is not good for a road car and you have never tried it? surely people that have tried are more qualified to give advise and views about it. ( again not having a pop at you) but i am sure you had strong view when you have bought your PPP, now you say you should have gone for link. and when you get a vf23 you will say oh well i was wrong and you will have a strong view about it as well.
ask the poeple who have tried an upgraded turbo, me, alan G, Dave brown, and ask any off them will they ever go back to a standard turbo? the answer will be NO. the VF23 is not really that big, if you think your car spools up quick and fast that is because you have never been in a car with a VF23, OR VF28. have you actually driven a P1?
sam
05 February 2002, 06:08 PM
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"I expect you are right Sam, but from what you said about your VF23 it sounded a bit laggy on the road? On the track that clearly was not an issue"
actually on paper it may have been a little more laggy than standard, ie when you look at the speedo but that was about it. it was still flowing alot more air even at lower boost pressure that the standard. when it came off the car i was depressed as the car really felt like ****. only alan and pete can tell you how much i have moaned about the car with the vf23 off. it was flat at the bottom and the top end!! by the end of the days the car was mapped perfectly to my driving style and had no noticable lag at all. and BTW on the track it was not big enough . i think that TD04L is probably the worst thing about the scoob.
"I have not driven a MY99/00 UK with a big turbo. Maybe I should But it's not like they are common enough to go and go to a dealer for a test drive like a P1 or STi-UK."
if you are nice to dave or alan G they may give you ride and i will be surprised if you are against any of these cars in a straight line at any speed you will have a chance i mean at the end of the day what is 500rpm earlier between friends
"Maybe there is something about the Evo engine which makes it better off boost, but Subarus feel horrid off boost."
you will find that the subaru engine is probably better on paper than an evo engine. you can certainly run more advance on a UK scoob than an evo!!! but the layout of the subaru have mad the distances between the turbo, intercooler, exhaust manifold etc very big compared to the evo where they have every thing compacted together. i am sure T-uk's knockles will support my theory on that one
sam
actually on paper it may have been a little more laggy than standard, ie when you look at the speedo but that was about it. it was still flowing alot more air even at lower boost pressure that the standard. when it came off the car i was depressed as the car really felt like ****. only alan and pete can tell you how much i have moaned about the car with the vf23 off. it was flat at the bottom and the top end!! by the end of the days the car was mapped perfectly to my driving style and had no noticable lag at all. and BTW on the track it was not big enough
. i think that TD04L is probably the worst thing about the scoob. "I have not driven a MY99/00 UK with a big turbo. Maybe I should But it's not like they are common enough to go and go to a dealer for a test drive like a P1 or STi-UK."
if you are nice to dave or alan G they may give you ride and i will be surprised if you are against any of these cars in a straight line at any speed you will have a chance
i mean at the end of the day what is 500rpm earlier between friends "Maybe there is something about the Evo engine which makes it better off boost, but Subarus feel horrid off boost."
you will find that the subaru engine is probably better on paper than an evo engine. you can certainly run more advance on a UK scoob than an evo!!! but the layout of the subaru have mad the distances between the turbo, intercooler, exhaust manifold etc very big compared to the evo where they have every thing compacted together. i am sure T-uk's knockles will support my theory on that one
sam
05 February 2002, 06:16 PM
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john,
I do not think there is anything wrong with the way Jim loads up the rollers up at Star,only,that I feel he shuts the cars down too quick by watching the PAW graph during the run.
to me,the operator is the most important factor in a rolling road day and the fact that Jim's figures are always so consistent speak for themselves.we should never,as pointed out compare a UK car with a P1/EVO etc,but I do not see any reason why we cannot compare UK cars PAW and torque,to gauge mods and leave the flywheel for the pub .if you ask Jim to load up the rollers differently at the next day,you may as well throw your last days results away and start again as they become useless.I would prefer Jim to rev all UK cars to 6500rpm providing no det is detected,but would never ask him to change his loading technique as his results are far too consistent to question.
to be honest I do not care were your car peaks on the road,I want all UK cars to be run and be loaded the same,as if Jim loads the rollers at different points for different cars these days become useless.
I do not think there is anything wrong with the way Jim loads up the rollers up at Star,only,that I feel he shuts the cars down too quick by watching the PAW graph during the run.
to me,the operator is the most important factor in a rolling road day and the fact that Jim's figures are always so consistent speak for themselves.we should never,as pointed out compare a UK car with a P1/EVO etc,but I do not see any reason why we cannot compare UK cars PAW and torque,to gauge mods and leave the flywheel for the pub
.if you ask Jim to load up the rollers differently at the next day,you may as well throw your last days results away and start again as they become useless.I would prefer Jim to rev all UK cars to 6500rpm providing no det is detected,but would never ask him to change his loading technique as his results are far too consistent to question.to be honest I do not care were your car peaks on the road,I want all UK cars to be run and be loaded the same,as if Jim loads the rollers at different points for different cars these days become useless.
05 February 2002, 06:22 PM
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Perhaps when the load is turned on makes little difference to power figures, but if you want to see the effect on low down torque (which is where I thought most of my improvements would be) you don't want to see peak boost 700RPM too late?
I was quite interested to get from the rolling road a plot of how the torque goes up compared with the boost between 1700 and 3000 RPM - unfortunately my plot is a bit useless for that. It is the only thing my puny TD04L does well let me at least see it plotted accurately! Go on humour me
The torque you get and at what point is quite important? Cars at Powerstation seem to have more representative boost curves..
The following is just something I found knocking around which makes an interesting OPINION - (and only an opinion)
"No ram air - the car is stationary and the only air blowing is the huge industrial fan in front of the car. Ram air is essential for the turbo, the air intake and also the intercooler. Worst of all your engine is not getting the cooling that it requires. Redlining on the road will surely mean your car is already at speed and there will be sufficient air cooling parts of the car. Not so in a dyno facility.
So what happens?
For some - nothing. But for others there have been cases where the stress of a dyno test takes its toll about a week or two later - conrods being the most likely candidate for breaking down. Some have even ventured to say that a dyno test takes out months of a car's lifespan."
[Edited by john banks - 2/5/2002 6:32:27 PM]
I was quite interested to get from the rolling road a plot of how the torque goes up compared with the boost between 1700 and 3000 RPM - unfortunately my plot is a bit useless for that. It is the only thing my puny TD04L does well let me at least see it plotted accurately! Go on humour me
The torque you get and at what point is quite important? Cars at Powerstation seem to have more representative boost curves..
The following is just something I found knocking around which makes an interesting OPINION - (and only an opinion)
"No ram air - the car is stationary and the only air blowing is the huge industrial fan in front of the car. Ram air is essential for the turbo, the air intake and also the intercooler. Worst of all your engine is not getting the cooling that it requires. Redlining on the road will surely mean your car is already at speed and there will be sufficient air cooling parts of the car. Not so in a dyno facility.
So what happens?
For some - nothing. But for others there have been cases where the stress of a dyno test takes its toll about a week or two later - conrods being the most likely candidate for breaking down. Some have even ventured to say that a dyno test takes out months of a car's lifespan."
[Edited by john banks - 2/5/2002 6:32:27 PM]
05 February 2002, 06:32 PM
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it may not alter the figures but I would say that if you are going to get runs tailored to your car,you should do what Dave Brown has done and book the rolling road outwith a r/r day.I only like these days to be able to compare the results from one car to the next,so believe all UK cars need to be run the same.
05 February 2002, 06:36 PM
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that is what i am aiming at T-UK all the cars should be loaded the same and taken to the same rev limit. i think it will be fair to maybe take all the cars to 6500rpm at least the drag loses will be close.
john b
rolling roads have never been good for the car, some cars can even blow up on the rollers. it is just a risk that we have to take again how long are going to keep the car for? few months won't matter
sam
john b
rolling roads have never been good for the car, some cars can even blow up on the rollers. it is just a risk that we have to take
again how long are going to keep the car for? few months won't matter sam
05 February 2002, 06:46 PM
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It is not a competition No really it is not What is fair John K/hill won't be fair as you can drive (quite well IMHO) and I patently can't, but I'll try to improve
No really it is not What is fair John K/hill won't be fair as you can drive (quite well IMHO) and I patently can't, but I'll try to improve
05 February 2002, 06:56 PM
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Theo and Mark V (EMS) mapped his Unichip on the road with rather nice results.
If you mapped on the RR with a TMIC would you be running suboptimal ignition timing because of intake temps?
I suppose it might be tricky to reach all speeds in all gears on the road though "Sorry officer just mapping 6000 RPM in top gear."
If you mapped on the RR with a TMIC would you be running suboptimal ignition timing because of intake temps?
I suppose it might be tricky to reach all speeds in all gears on the road though
"Sorry officer just mapping 6000 RPM in top gear."
05 February 2002, 07:01 PM
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John
I think the bottom end torque on your car probably caught Jim out on the dyno. Having Dyno'd so many scoobs he will be used to a sluggish response at 2000rpm therefore would not have applied much load. As soon as your turbo spooled up the rollers would probably be up to 3000rpm before he had time to load them !
cc
I think the bottom end torque on your car probably caught Jim out on the dyno. Having Dyno'd so many scoobs he will be used to a sluggish response at 2000rpm therefore would not have applied much load. As soon as your turbo spooled up the rollers would probably be up to 3000rpm before he had time to load them !
cc
05 February 2002, 07:06 PM
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sam if you go to www.tuningjapanese.co.uk
there dyno is the same as stars one maha
go and look at the dyno results there you will see that the
air temp is only 12 degrees on some cars
so our runs have been recorded at sometimes over 50 degrees
so this is putting extra power on our dyno results
showing more than they are.
but at tuning japanese there dyno runs only take 30 sec
from start to finish so there cars dont get as hot.
at star my run took about 45 sec
just something for you to think about sam
ps if torque is the main thing to look for my car is good then
434 lbs 4800 revs 483 bhp
keith
there dyno is the same as stars one maha
go and look at the dyno results there you will see that the
air temp is only 12 degrees on some cars
so our runs have been recorded at sometimes over 50 degrees
so this is putting extra power on our dyno results
showing more than they are.
but at tuning japanese there dyno runs only take 30 sec
from start to finish so there cars dont get as hot.
at star my run took about 45 sec
just something for you to think about sam
ps if torque is the main thing to look for my car is good then
434 lbs 4800 revs 483 bhp
keith
05 February 2002, 07:22 PM
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Sam what next a VW & Audi specialist on the scooby net I love it.
The 2 rolling roads you have mentioned are nearly 15 years old as was my old rolling road which is back down south. We are now running a digital rolling road with the most upto date software & it is calibrated 2 times a year. You have mentioned the crossover point at 5250rpm not always the case. When I have to run say 20+ cars in 5 hours that hard work, so what I do is calibrate rpm v speed at 2000rpm because finding a plug lead on a scooby is ****. Now when one car is running say 16" wheels and the next car is running 18" wheels the crossover may vary. The torque on our dyno is measured from the cars rpm. Now if I was to measure rpm from a plug lead the crossover would be more consistent with each car last but not least if the intake temp rises sharply the boost will not hold which leads to the torque dropping which will effect the cross over point. Hope this helps.
The 2 rolling roads you have mentioned are nearly 15 years old as was my old rolling road which is back down south. We are now running a digital rolling road with the most upto date software & it is calibrated 2 times a year. You have mentioned the crossover point at 5250rpm not always the case. When I have to run say 20+ cars in 5 hours that hard work, so what I do is calibrate rpm v speed at 2000rpm because finding a plug lead on a scooby is ****. Now when one car is running say 16" wheels and the next car is running 18" wheels the crossover may vary. The torque on our dyno is measured from the cars rpm. Now if I was to measure rpm from a plug lead the crossover would be more consistent with each car last but not least if the intake temp rises sharply the boost will not hold which leads to the torque dropping which will effect the cross over point. Hope this helps.
05 February 2002, 07:31 PM
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Agree with Keith that the duration of the run can make a big difference. As Sam also commented, heat soak etc.
Why o why does the run not just last as long as 4th (or 5th gear) would on the road
The Dyno is intelligent enough to work out it's own inertia, that's how you can do a 0 - 60 time on it. Just dial in the weight of the car, then let it run from 2000 - max revs. The run would take probably 10 - 20 seconds (5 on Keiths )
That's how modern bike Dynos work. It's so much easier on the engine and is a better representation of how it reacts under acceleration, which is after all what we want to improve
W
Why o why does the run not just last as long as 4th (or 5th gear) would on the road
The Dyno is intelligent enough to work out it's own inertia, that's how you can do a 0 - 60 time on it. Just dial in the weight of the car, then let it run from 2000 - max revs. The run would take probably 10 - 20 seconds (5 on Keiths
)That's how modern bike Dynos work. It's so much easier on the engine and is a better representation of how it reacts under acceleration, which is after all what we want to improve
W