MLR Rolling road today......477 bhp...Graph added.
#201
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Originally Posted by Nash
Originally Posted by dave cos4x4
So where i did mine,they would have been better not putting the temp sensor in the air filter....where would they have put it then that would make the rolling road safe.
they did say that the evos were better suited,as Mark said also.![Wink](https://passionford.com/forum/images/smilies/icon_wink.gif)
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they did say that the evos were better suited,as Mark said also.
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I think APT just have the sensor hanging up in the Booth so it just reads the Air Temp. If its to close to the filter it will pull the heat in from the engine, this will make the computer think the air is hotter than it is. Then it will over correct the readings.
Thats how i understand it anyway mate, might be totally wrong.
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Mark
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I cant believe some of the replies on here by so called knowledgable people.
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IMO, the dyno air sensor SHOULD be in the air filter as this is the air the engine is
consuming to make your horse power and thus is correcting the figure
for the reading obtained (assuming the correction alorithm is actually right)
The air to the filter should be ducted from OUTSIDE the cell
![Wink](https://passionford.com/forum/images/smilies/icon_wink.gif)
This will prevent the engine cell cooling air/exhaust heat from influencing the figures.
Placing the sensor away from the engine air flow supply is measuring the
WRONG air and giving you the wrong correction.
Its a bit like measuring the cars tyre pressure and saying thats the boost
pressure as its close enough to the engine
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Rolling roads calculate power at flywheel by working out losses.
This is done by pushing the clutch in after peak power and letting the
wheels slow down naturally, The time it takes and reverse load measured
on the roller load cells are used to calculate loss which is added to the
measured wheel power to provide a flywheel figure.
If the brakes are dabbed during the run down you get more power
This is done by pushing the clutch in after peak power and letting the
wheels slow down naturally, The time it takes and reverse load measured
on the roller load cells are used to calculate loss which is added to the
measured wheel power to provide a flywheel figure.
If the brakes are dabbed during the run down you get more power
![Wink](https://passionford.com/forum/images/smilies/icon_wink.gif)
#206
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Originally Posted by Flux Capacitor
Rolling roads calculate power at flywheel by working out losses.
This is done by pushing the clutch in after peak power and letting the
wheels slow down naturally, The time it takes and reverse load measured
on the oller load cells are used to calculate loss which is added to the measured wheel power to provide a flywheel figure.
If the brakes are dabbed during the run down you get more power![Wink](https://passionford.com/forum/images/smilies/icon_wink.gif)
This is done by pushing the clutch in after peak power and letting the
wheels slow down naturally, The time it takes and reverse load measured
on the oller load cells are used to calculate loss which is added to the measured wheel power to provide a flywheel figure.
If the brakes are dabbed during the run down you get more power
![Wink](https://passionford.com/forum/images/smilies/icon_wink.gif)
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#207
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Originally Posted by Flux Capacitor
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I cant believe some of the replies on here by so called knowledgable people.
![Rolling Eyes](https://passionford.com/forum/images/smilies/icon_rolleyes.gif)
IMO, the dyno air sensor SHOULD be in the air filter as this is the air the engine is
consuming to make your horse power and thus is correcting the figure
for the reading obtained
The way I'm reading it though Simon is its not the air temp going into the filter thats the problem its the heat from the engine and surrounding parts affecting the sensor, makes sense to me (thats if I've read correctly what Mark is saying)
I suppose if you had a way to protect the sensor from picking up any other heat/temp other than the air going into the filter then there wouldnt be a problem.
Question Simon, if the sensor is hanging in the cell and sensing the temp the engine is pulling in through the filter why is this a problem?
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Originally Posted by Matt J
So if you do as you say and duct in the air from outside why not just hand the sensor outside? ![Surprised](https://passionford.com/forum/images/smilies/bigcry.gif)
![Surprised](https://passionford.com/forum/images/smilies/bigcry.gif)
the line of the actual direct flow to the engine so any other place will
be an average or influenced either way.
If your going to measure it, do it in the right place otherwise any reading
will be wrong wether its too high or low a bhp.
Of course the air should be ducted from OUTSIDE the cell.
#211
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Originally Posted by Flux Capacitor
Rolling roads calculate power at flywheel by working out losses.
This is done by pushing the clutch in after peak power and letting the
wheels slow down naturally, The time it takes and reverse load measured
on the roller load cells are used to calculate loss which is added to the
measured wheel power to provide a flywheel figure.
If the brakes are dabbed during the run down you get more power![Wink](https://passionford.com/forum/images/smilies/icon_wink.gif)
This is done by pushing the clutch in after peak power and letting the
wheels slow down naturally, The time it takes and reverse load measured
on the roller load cells are used to calculate loss which is added to the
measured wheel power to provide a flywheel figure.
If the brakes are dabbed during the run down you get more power
![Wink](https://passionford.com/forum/images/smilies/icon_wink.gif)
Not on a Dyno dynamics RR this does not measure transmission looses so it would add any more power by touching the brakes,
The flywheel fig is a program/guess they worked out at the factory the bases I have been told its based on a Scooby that was tested on a engine dyno then it the car,
So a Ford running on one has a Scooby loss
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Mark
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Originally Posted by rapidcossie
Why are the temps measured before the intercooler at all?
feedback loop. Hope that makes sense.
#215
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Originally Posted by Flux Capacitor
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I cant believe some of the replies on here by so called knowledgable people.
![Rolling Eyes](https://passionford.com/forum/images/smilies/icon_rolleyes.gif)
IMO, the dyno air sensor SHOULD be in the air filter as this is the air the engine is
consuming to make your horse power and thus is correcting the figure
for the reading obtained (assuming the correction alorithm is actually right)
The air to the filter should be ducted from OUTSIDE the cell
![Wink](https://passionford.com/forum/images/smilies/icon_wink.gif)
This will prevent the engine cell cooling air/exhaust heat from influencing the figures.
Placing the sensor away from the engine air flow supply is measuring the
WRONG air and giving you the wrong correction.
Its a bit like measuring the cars tyre pressure and saying thats the boost
pressure as its close enough to the engine
![Surprised](https://passionford.com/forum/images/smilies/bigcry.gif)
![Grin](https://passionford.com/forum/images/smilies/icon_smile.gif)
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The turbo is moving such huge volumetric amounts of air, that it will be pulling in the cooler air from outside the engine bay, with such high flow / speed, that within a few seconds of running, it won't have time to be heated up by the engine bay radiated heat (unless it is a cone filter (without the appropriate heat shielding from the obvious hot spots) which will be sucking a lot of the engine bay air in as well).
Due to where Cossie air filters are located, these are even more susceptible to giving exagerated readings and to prove the point, if Dave was to revisit the exact same rollers and ask them to repeat the run, but to just reposition the sensor to just outside the engine bay, then he would see a more realistic figure of 430-440bhp.
It seems strange in your earlier post that you deride the original figure, yet when this is explained to you how it is arrived at, you suddenly decide that this is the correct way
![Surprised](https://passionford.com/forum/images/smilies/bigcry.gif)
All the DD RR operaters worth their salt have now taken to placing the sensor to measure the dyno cell temps (which is the temp of the air that the turbo will be pulling into it), as to do otherwise gives the grossly exagerated readings that RRs often get berrated for. If you want a figure for the pub, place the sensor as close to the engine as you can (and this goes for both RR and engine dyno
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Also, I forgot mention that given there is a friendly rivalry that exists between Mark and myself - if there was a way we could disagree, we would be doing so
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#216
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Originally Posted by Flux Capacitor
Originally Posted by rapidcossie
Why are the temps measured before the intercooler at all?
feedback loop. Hope that makes sense.
Surely the ONLY air temps that are important are the one that the engine is actually consuming?
#219
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For me a RR is testing the actuall power the car is producing and the only correction that should take place is weather temp and pressure, As this is how the engine is working in its correct enviroment.
Mark
Mark
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Mike, if you dont directly measure the actual thing that affects calculations,
then its wrong simple.... Surely you can see that wether or not it makes
a positive or negative difference to whats expected.
And to clarify, the sensor shoudl be measuring the flow directly into the
air filter with air ducted from OUTSIDE the cell where it cannot be affected
by cell and exhaust heating. This surely is the IDEAL set up.
Only ever seen that at the Honda engine plant where I used to work.!!
then its wrong simple.... Surely you can see that wether or not it makes
a positive or negative difference to whats expected.
And to clarify, the sensor shoudl be measuring the flow directly into the
air filter with air ducted from OUTSIDE the cell where it cannot be affected
by cell and exhaust heating. This surely is the IDEAL set up.
Only ever seen that at the Honda engine plant where I used to work.!!
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You correct for pressure as it does affect turbo efficiency.
The less pressure in the turbo, the harder it has to pump and the more
restriction there is in the exhaust turbine housing..
The less pressure in the turbo, the harder it has to pump and the more
restriction there is in the exhaust turbine housing..
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Originally Posted by rapidcossie
We are measuring the horsepower the engine makes tho, not turbo effciency.
You have to deliver a certain quantity of air to make a certain level of power.
If the air is less dense then it has to pump more to get the same density/pressure to make the same boost etc.....
Density is affected by temperature wether an engine has a turbo or not.
Less oxygen less power !
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Flux Capacitor
I can see you point completly and understand how turbo effciency effects horsepower but I dont believe this needs to be tested for every power run?
Test the turbo during intial set up /development of that turbo but not during a 5 mins power run
I can see you point completly and understand how turbo effciency effects horsepower but I dont believe this needs to be tested for every power run?
Test the turbo during intial set up /development of that turbo but not during a 5 mins power run
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The more factors you measure correctly and take into account
the more accurate measurements will be.
Air temperature has a HUGE affect on power output of any engine.
Even more so on a turbo engine that consumes vast quantities of air
which magnifies the problem.
the more accurate measurements will be.
Air temperature has a HUGE affect on power output of any engine.
Even more so on a turbo engine that consumes vast quantities of air
which magnifies the problem.
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I know that air temp is the most important factor in measurement of power on turbocharged cars thats why I cant understand correcting the figs rather than measuring at the temps you want.
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You correct the figures as you are measuring the engine running in its
natural state (as far as you can).
You dont provide it with perfect conditions as that never occurs on the road.
You measure it as it is......
Corrections are applied to provide a standard for everyone.
natural state (as far as you can).
You dont provide it with perfect conditions as that never occurs on the road.
You measure it as it is......
Corrections are applied to provide a standard for everyone.
#232
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Originally Posted by Matt J
Ah, never thought of that
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So what housing do you use and whats the initial spool up like? I know you do alot of trackdays so lag/boost threshold probably isnt a big issue for you, just wondered what it was like on the road?
Sounds like exactly what I'm after, only the T4 doesnt put me off like it does most folks.
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it is a bit laggy,look at the graph to see the spool up
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on the road it takes a bit to get it going if i'm honest,but when it does kick in you are going too fast for the roads.
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you will have to get in to feel it for yourself Matt.
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#233
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Originally Posted by Flux Capacitor
You correct the figures as you are measuring the engine running in its
natural state (as far as you can).
You dont provide it with perfect conditions as that never occurs on the road.
You measure it as it is......
Corrections are applied to provide a standard for everyone.
natural state (as far as you can).
You dont provide it with perfect conditions as that never occurs on the road.
You measure it as it is......
Corrections are applied to provide a standard for everyone.
![Big Grin](https://passionford.com/forum/images/smilies/icon_biggrin.gif)
Just seems like the DD adds power on in perfectly normal situations, a ACT figure of 50 deg for example.
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If an engines power output doesnt fall for the same steady state conditions
apart from the air temperature then its magically efficient so the power
readings are corrected upwards to show that.
ALso, if the sensor was fooled
you get exagerated readings.
Corrections are used to standardise enviromental condtions so that
setups are easy to compare but obviously if not everyone follows the same
setup and rule, the standards are bollocks .... TUV....
apart from the air temperature then its magically efficient so the power
readings are corrected upwards to show that.
ALso, if the sensor was fooled
![Wink](https://passionford.com/forum/images/smilies/icon_wink.gif)
Corrections are used to standardise enviromental condtions so that
setups are easy to compare but obviously if not everyone follows the same
setup and rule, the standards are bollocks .... TUV....
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#236
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So if you correct for pressure differences on an n/a engine for example they are of the order to deal with very small changes and effect the power in a certain way(whatever the calculation is) fluxuations of millibars etc.
Now you have an engine that is turboed - these fluxuations will change the end power but with what magnitude? I doubt they do it in an exactly related way and effect the end power reading in the same calculable(made up word maybe
) way as N/A due to different turbo operating efficiencies/boost used etc.
Such I believe may be the same problem with intercooling and efficiencies and still using straight temp corrections from n/a aplications.
I am not saying there are not differences as I believe there obviously are from running in different circumstances (temp/pressure) and these need to be considered, I just dont think that n/a corrections which are easier to calculate relates directly to turboed applications or that you get an accurate result.
hope that makes sense lol
Now you have an engine that is turboed - these fluxuations will change the end power but with what magnitude? I doubt they do it in an exactly related way and effect the end power reading in the same calculable(made up word maybe
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Such I believe may be the same problem with intercooling and efficiencies and still using straight temp corrections from n/a aplications.
I am not saying there are not differences as I believe there obviously are from running in different circumstances (temp/pressure) and these need to be considered, I just dont think that n/a corrections which are easier to calculate relates directly to turboed applications or that you get an accurate result.
hope that makes sense lol
#238
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I can see why the pressure correction needs to be done on N/A cars as i suppose a higher barometric pressure is forcing more air into the engine.
On turbo cars its the turbo that does this weather its effcient or not.
On turbo cars its the turbo that does this weather its effcient or not.
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If the air is less dense before the turbo due to the air being at a higher
temperature then the engines efficiency is lower.
Thus the "correction standards" are applied to express power figures of
any engine on any dyno as if they were all operating at the same conditions.
Hope that makes sense
temperature then the engines efficiency is lower.
Thus the "correction standards" are applied to express power figures of
any engine on any dyno as if they were all operating at the same conditions.
Hope that makes sense
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#240
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I "doubt" that the corrections applied are correct. You are saying about working back to an engine in its natural state - to do that you should remove the turbo/intercooler etc - I "doubt" the same correction for n/a works back with turbo due to the different efficiencies of turbo/intercooler systems and the scales they effect at etc, these are not accounted for.