Datalogger and the EERC.
Discussion
As seen on the EERC'S site...
The Powerlogger DL1 and where it fits into the EERC.
2008 will see the Powerlogger DL1 become more of an active participant in the policing of the rules and regulations in Britcar and Britsports.
There have been many comments made both on internet forums and directly to the EERC regarding the Powerlogger and what people’s opinions of it are. There does seem to be a train of thought which is concerned that the results from the Powerlogger will be the be-all-and-end-all of the regs in 2008 and the perceived inaccuracies of the system will cause as many arguments as they resolve.
I would like to take this opportunity to clarify our position and to outline how the Powerlogger will be used in 2008.
On the 28th February 2008 we will gather a collection of cars from Britsports and Britcar at Silverstone on the National straight. A neutral driver will drive each of the cars in a series or acceleration and coasting exercises. This will determine the drag coefficient and the bhp of the car. The dry weights will also be taken and these figures will give us a guide as to the appropriate class for each car. Whilst altering wing settings and gear ratios will effect the figures obtained the live data we see from each car during the season will form a pattern and the overall result will not vary significantly.
If, during the season, a car starts performing significantly faster or is protested by another competitor we have the ability to check the cars dry weight and live power output from qualifying or race situations to determine if either of these figures shows a significant alteration. If these figures are within tolerance then it can be assumed that the increased speed is down to either driver or chassis development, both of which should be actively encouraged in the championships.
During the season we will also randomly check horsepower figures and weights by appropriate means to ensure parity in the classes.
The Powerlogger is an additional tool to help us to keep the cars playing on a relatively level playing field during the season, they are not an absolute we simply see it as easier and cheaper way for all involved to be determining the power outputs from the cars without needing trips to rolling roads or stripping engines.
The Powerlogger DL1 and where it fits into the EERC.
2008 will see the Powerlogger DL1 become more of an active participant in the policing of the rules and regulations in Britcar and Britsports.
There have been many comments made both on internet forums and directly to the EERC regarding the Powerlogger and what people’s opinions of it are. There does seem to be a train of thought which is concerned that the results from the Powerlogger will be the be-all-and-end-all of the regs in 2008 and the perceived inaccuracies of the system will cause as many arguments as they resolve.
I would like to take this opportunity to clarify our position and to outline how the Powerlogger will be used in 2008.
On the 28th February 2008 we will gather a collection of cars from Britsports and Britcar at Silverstone on the National straight. A neutral driver will drive each of the cars in a series or acceleration and coasting exercises. This will determine the drag coefficient and the bhp of the car. The dry weights will also be taken and these figures will give us a guide as to the appropriate class for each car. Whilst altering wing settings and gear ratios will effect the figures obtained the live data we see from each car during the season will form a pattern and the overall result will not vary significantly.
If, during the season, a car starts performing significantly faster or is protested by another competitor we have the ability to check the cars dry weight and live power output from qualifying or race situations to determine if either of these figures shows a significant alteration. If these figures are within tolerance then it can be assumed that the increased speed is down to either driver or chassis development, both of which should be actively encouraged in the championships.
During the season we will also randomly check horsepower figures and weights by appropriate means to ensure parity in the classes.
The Powerlogger is an additional tool to help us to keep the cars playing on a relatively level playing field during the season, they are not an absolute we simply see it as easier and cheaper way for all involved to be determining the power outputs from the cars without needing trips to rolling roads or stripping engines.
I wonder who will be asked to drive the cars? The EERC were so worried about blowing up engines on rolling roads they stopped that one. Surely it is more risky giving your car to an unknown driver and telling him to nail it in a straight line - probably on cold tyres!!!!
Just a thought!! Also, Feb 28th is quite close. As we usually finish our car on the night before the first race we probably won't be ready!
Still, at least they are trying to do something constructive. Lets be thankful for that!
Richard.
Just a thought!! Also, Feb 28th is quite close. As we usually finish our car on the night before the first race we probably won't be ready!
Still, at least they are trying to do something constructive. Lets be thankful for that!
Richard.
935 said:
Surely it is more risky giving your car to an unknown driver and telling him to nail it in a straight line - probably on cold tyres!!!!
no need to nail it at all. You just need to get the car upto about 60 mph and then let it coast down to about 10mph.do this with the data logger running and you can then take the measurements you need from the trace.
So long as cards are checked regularly i'll be happy, never once did i get asked for one last season, knowing the correct variation for each car is the key to ensuring that these work well, personally i'm all for it, anything that makes the racing closer and the playing field more level is a good thing in my book
OK, I stand corrected about the "nailing it" comment. Still, I am not too sure about letting someone else, presumably not insured, drive my car at all.
Frankly I would be suprised if this came about. I can see the EERC may want coast down runs (I have told them of the importance of these over a year ago) but I reckon they will be done by the cars own drivers. I cant see a viable alternative. Tell me, can you see the owners of Astons, Vipers, Moslers etc let some unknown chap drive their cars - even if only at 60 mph? Some may, some may not. Then what happens?
Cheers,
Richard.
Frankly I would be suprised if this came about. I can see the EERC may want coast down runs (I have told them of the importance of these over a year ago) but I reckon they will be done by the cars own drivers. I cant see a viable alternative. Tell me, can you see the owners of Astons, Vipers, Moslers etc let some unknown chap drive their cars - even if only at 60 mph? Some may, some may not. Then what happens?
Cheers,
Richard.
! 
Anybody tried to get a consistent / accurate coastdown figure from a DL1?
Well I have and its friggin impossible
You can get dramatically different results over the same stretch of tarmac doing repeat runs. Depends heavily on wind direction etc. Also the CDa that you input to the DL1 has a huge effect on the resulting power figure. My car could read anything from 200-260 HP just by tweeking the CDa within a realistic range. I'm not convinced it would work as a means to police the reg's in all honesty!
Well I have and its friggin impossible
You can get dramatically different results over the same stretch of tarmac doing repeat runs. Depends heavily on wind direction etc. Also the CDa that you input to the DL1 has a huge effect on the resulting power figure. My car could read anything from 200-260 HP just by tweeking the CDa within a realistic range. I'm not convinced it would work as a means to police the reg's in all honesty!
I am also fully supportive of these tests and have no problem in letting someone drive the car in a straight line at what is in reallity pretty sensible speed. We all gather by Becketts, 4 coast down tests (2 each way) an average reading is taken and there you go.
It`s no worse (and in fact probably a lot better) than having some rolling road unknown blat your car along the rollers.
The one thing I would ask is that results are made public from the test onwards and published after each race. That would do 2 things: It would prove the power logger works & shut people up. It would also make Britcar the most transparent race series in the country.
I will say again though in order to get correct power figures you need to know the weight of the car as it performs the test, not it`s dry weight.
Henry
It`s no worse (and in fact probably a lot better) than having some rolling road unknown blat your car along the rollers.
The one thing I would ask is that results are made public from the test onwards and published after each race. That would do 2 things: It would prove the power logger works & shut people up. It would also make Britcar the most transparent race series in the country.
I will say again though in order to get correct power figures you need to know the weight of the car as it performs the test, not it`s dry weight.
Henry
Henry, tell you what, you drive mine and I will have a go in yours! Actually, I am only half joking!
No one can be more supportive than me of doing things correctly but i am realistic and understand that some people will not want others driving their cars.
Anyway, this discussion shows things are moving along nicely - lets hope we can really enjoy ourselves next year!
Cheers,
Richard.
No one can be more supportive than me of doing things correctly but i am realistic and understand that some people will not want others driving their cars.
Anyway, this discussion shows things are moving along nicely - lets hope we can really enjoy ourselves next year!
Cheers,
Richard.
kinetic said:
Anybody tried to get a consistent / accurate coastdown figure from a DL1?
Well I have and its friggin impossible
You can get dramatically different results over the same stretch of tarmac doing repeat runs. Depends heavily on wind direction etc. Also the CDa that you input to the DL1 has a huge effect on the resulting power figure. My car could read anything from 200-260 HP just by tweeking the CDa within a realistic range. I'm not convinced it would work as a means to police the reg's in all honesty!
I've had some fairly consistent results. how are you getting the figure out. I do it by starting the logger, and then graphing the results. moving the pointer along the graph will then give you the x & y values on the edge of the screen which you can out into the calculator.Well I have and its friggin impossible
You can get dramatically different results over the same stretch of tarmac doing repeat runs. Depends heavily on wind direction etc. Also the CDa that you input to the DL1 has a huge effect on the resulting power figure. My car could read anything from 200-260 HP just by tweeking the CDa within a realistic range. I'm not convinced it would work as a means to police the reg's in all honesty!
You will get a bit of variation, but as Henry says its probably about as acurate as the flywheel guestimate on a rolling road. I can take my car to a couple of local roads and i know the pwer will vary 30-50bhp !!
The big thing the dl's will show up once you start using them is if anyone tweeks anything power wise... a even if the cda is wrong it will show a change...
As I see it everyone wants a visible policing method, one has been proposed, its not perfect but then non of them are, so rather than moan it doesnt work everyone just needs to get on with it and try and make it work....
Unless of course your cheating then bitch like hell about it
935 said:
OK, I stand corrected about the "nailing it" comment. Still, I am not too sure about letting someone else, presumably not insured, drive my car at all.
Frankly I would be suprised if this came about. I can see the EERC may want coast down runs (I have told them of the importance of these over a year ago) but I reckon they will be done by the cars own drivers. I cant see a viable alternative. Tell me, can you see the owners of Astons, Vipers, Moslers etc let some unknown chap drive their cars - even if only at 60 mph? Some may, some may not. Then what happens?
Cheers,
Richard.
I quite agree Richard.Frankly I would be suprised if this came about. I can see the EERC may want coast down runs (I have told them of the importance of these over a year ago) but I reckon they will be done by the cars own drivers. I cant see a viable alternative. Tell me, can you see the owners of Astons, Vipers, Moslers etc let some unknown chap drive their cars - even if only at 60 mph? Some may, some may not. Then what happens?
Cheers,
Richard.
There's a lot of difference between nailing a quick M3 to 60mph than there is nailing a 935 with copious lbft of turbo grunt.
I've seen high powered rwd cars spin on a straight by over-exuberantly applying the right foot in low gears.
And even if it is a few years old, since my car is a one-off, I wouldn't be too pleased if someone bent it.
Rob.
You do not have to nail the car (as Richard says). Drive it up to 100mph (in a reasonable manner) then let the car coast and measure how it slows down.
The alternative is to let someone nail your car on a rolling road.
Either way if you`re not happy then don`t enter the championship.
I am sure that anyone chosing to insure ther car through Davis (the Jemco boys) for the season will find they are equally covered for the test. They would probably even be able to arrange cover for you just for the test.
Keep smiling.
Henry
The alternative is to let someone nail your car on a rolling road.
Either way if you`re not happy then don`t enter the championship.
I am sure that anyone chosing to insure ther car through Davis (the Jemco boys) for the season will find they are equally covered for the test. They would probably even be able to arrange cover for you just for the test.
Keep smiling.
Henry
Great way forward to help maintain a level playing field. Fearnsport (based at Silverstone Circuit) I am sure would be happy to lend the weighing equipment if required. Surely Richard there's far greater chance of terminal engine failure on a muppet rolling road with poor air flow than the risk of an accident on a coast down from 60 or a 100.
I'll do it if you want
I might need a five lap warm up just to make sure that I am completely comfortable with the monster. 
I'll do it if you want
I might need a five lap warm up just to make sure that I am completely comfortable with the monster. I'm really suprised people think its OK to let someone drive their race car to do a coast down test. As you can see, I am not too happy and it has got nothing to do with cheating! My car is an old school 911 and its behaviour off throttle is completely different to that of most cars.
In fact, if you have to get to 100 mph (and I am not sure you do) and then let the car coast down to say, 50 mph I doubt the National Straight will be long enough! Without "nailing" it it will take say 1/3 of the straight to get to 100 and then its just going to coast down to 50 mph in the rest of the straight and stop before the end. I would be happy to try it myself but to let someone with no experience of the car have a go I'm not sure. If James can arrange insurance with no cost to me then OK no problem!
Maybe I am making a mountain from a molehill (and it seems from most of the comments that I am) but I still think its not on to expect other people to do the test. I reiterate that I am not against the test, just the way in which it has been said here that it will be done.
Richard.
In fact, if you have to get to 100 mph (and I am not sure you do) and then let the car coast down to say, 50 mph I doubt the National Straight will be long enough! Without "nailing" it it will take say 1/3 of the straight to get to 100 and then its just going to coast down to 50 mph in the rest of the straight and stop before the end. I would be happy to try it myself but to let someone with no experience of the car have a go I'm not sure. If James can arrange insurance with no cost to me then OK no problem!
Maybe I am making a mountain from a molehill (and it seems from most of the comments that I am) but I still think its not on to expect other people to do the test. I reiterate that I am not against the test, just the way in which it has been said here that it will be done.
Richard.
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