Brands Hatch & the 2008 Regs - Has it gone wrong already?
Discussion
Bellly said:
JT has assured me that he has the drag coefficient for cars in the series and has faith in the DL1 loggers.
I haven't decided yet whether to enter my car for a full season or a selection of races assuming there is space. Since my car is unique JT can't possibly have a drag coefficient for it. And unless he has either full grids already, or a crystal ball, he can't know the Cd figures for all cars that will enter. What he does have is a formula for working it out, and all 2PF is doing is pointing out that there are limitations in that formula. 2PF hasn't wound me up as he seems to have done you and others. Being objective, he (or she) has a point. The DL1 is a useful tool if used properly, and hopefully even if used not quite correctly it will be consistently incorrect and therefore still useful.
Anyway, I wish you all the best of luck at Brands. Circuit racing to me is something done after Easter and should be finishing up when the Christmas decorations are in the shops. Anything outside of those dates is called rallying isn't it
I have no doubt that there are some issues to be resolved with the DL1, but there has to be a set of regulations and they have to be adhered to.
If you have a unique car then work out your own CD and present the findings to the EERC, i am sure they will be receptive.
With what we spent on racing in 2007 we have cancelled Christmas!
We are all entitled to an opinion and i recon 2PF has nothing to offer this forum and should go for a long walk [for about 10 years] and stay away from computers.
If you have a unique car then work out your own CD and present the findings to the EERC, i am sure they will be receptive.
With what we spent on racing in 2007 we have cancelled Christmas!
We are all entitled to an opinion and i recon 2PF has nothing to offer this forum and should go for a long walk [for about 10 years] and stay away from computers.
Edited by Bellly on Tuesday 6th November 07:41
I'm afraid I agree with TeamHoldenRacing. Good old James cannot know the CdA of the cars. I can almost guarantee that the manufacturers figures for the cars are also irrelevant. Any aero mod, like wings, wheels etc will destroy the nice low CdA that BMW or Seat or anyone else has spent millions on obtaining.
However, like THR I am not too worried so long as people do not take the mickey and the racing is good but I do think it is important that we all understand how the rules work and the operating parameters of the equipment used to police them. After all, the DL1 cannot ignore the laws of physics and if the wrong information is inputted then the results will be useless.
Someone said this thread is so like a previous one. Well, it is but surely that shows we are all worried about the situation. I am happy to see what happens after Brands as I hope and expect the EERC will be extremely strict. If they are not then maybe we can start to postulate about 2008. Until then I suggest we wait and see. Frankly, nothing is going to change before then anyway!
Cheers,
Richard.
However, like THR I am not too worried so long as people do not take the mickey and the racing is good but I do think it is important that we all understand how the rules work and the operating parameters of the equipment used to police them. After all, the DL1 cannot ignore the laws of physics and if the wrong information is inputted then the results will be useless.
Someone said this thread is so like a previous one. Well, it is but surely that shows we are all worried about the situation. I am happy to see what happens after Brands as I hope and expect the EERC will be extremely strict. If they are not then maybe we can start to postulate about 2008. Until then I suggest we wait and see. Frankly, nothing is going to change before then anyway!
Cheers,
Richard.
I think you are all getting stuck on a subject that you have entrusted jt to police, instead of slagging the old boy off, wait and see what he does and give him some advice.
I have spoken to Claire and all cars will be wieghed at Brands, also there will be cd compulsory tests in Feb for Britcar at Silverstone for all registered cars,.
The DL1 IS VERY MUCH MORE ACCURATE than 2 years ago before the start of the Golf war.
To those that are not aware it is used for targeting for the gunners.
I have spoken to Claire and all cars will be wieghed at Brands, also there will be cd compulsory tests in Feb for Britcar at Silverstone for all registered cars,.
The DL1 IS VERY MUCH MORE ACCURATE than 2 years ago before the start of the Golf war.
To those that are not aware it is used for targeting for the gunners.
ALEC FRANCIS said:
The DL1 IS VERY MUCH MORE ACCURATE than 2 years ago before the start of the Golf war.
To those that are not aware it is used for targeting for the gunners.
The Golf war!To those that are not aware it is used for targeting for the gunners.
Was'nt that held at Santa pod??
Arent the gunners a football team?
Edited by Simon Mason on Tuesday 6th November 18:29
ALEC FRANCIS said:
I think you are all getting stuck on a subject that you have entrusted jt to police, instead of slagging the old boy off, wait and see what he does and give him some advice.
I have spoken to Claire and all cars will be wieghed at Brands, also there will be cd compulsory tests in Feb for Britcar at Silverstone for all registered cars,.
The DL1 IS VERY MUCH MORE ACCURATE than 2 years ago before the start of the Golf war.
To those that are not aware it is used for targeting for the gunners.
Alec, nowhere on this thread has anyone slagged JT off, far from it. We all know the thing is imperfect but are happy to run with it provided a reasonable attempt is made at making a level playing field - which understand is happening. I don't think it helps to pretend the system is perfect when it clearly isn't. Is JT hiring a wind tunnel in Feburary? If so excellent as I have a few things we want to try out..... I have spoken to Claire and all cars will be wieghed at Brands, also there will be cd compulsory tests in Feb for Britcar at Silverstone for all registered cars,.
The DL1 IS VERY MUCH MORE ACCURATE than 2 years ago before the start of the Golf war.
To those that are not aware it is used for targeting for the gunners.
This gives some food for thought....
off the DL1 manufacturers website:
Calculating Aerodynamic Drag (CdA) And Rolling Resistance
Setting the aerodynamic details
The aerodynamic factors and vehicle mass are required for the software to calculate the engine power. To calculate these parameters you will need to perform a "coast down" test.
Calculating CdA and rolling resistance
The method described here is suitable for use with vehicle speeds up to 100kph (60mph). Coast down calculations should be done on a flat surface on a wind free day. Testing involves timing the vehicle whilst decelerating in neutral. Time the deceleration over two speed intervals, one high speed test (about 60-100kph or 40-60mph) and one low speed test (about 15kph or 10mph). The timing can be done accurately by using the DL90/DL1/AX22 to log speed data and then plotting graphs of the speeds. Enter the details into the table below, select the units you wish to use, then press Calculate to get the CdA and the rolling resistance values.
We have tried, it got a figure and calculated it to 38604 bhp
Only joking but we do intend to test and check against a rolling road to see the difference. At least EERC should get the same figures as us?
On the slagging off JT bit:
Everyone is free to start their own race series, but JT has done it and done a fantastic job, he can't get everything 100% but he ain't too far off.
He has given me and others an assurance that 2008 will be different, so lets wait and see.
off the DL1 manufacturers website:
Calculating Aerodynamic Drag (CdA) And Rolling Resistance
Setting the aerodynamic details
The aerodynamic factors and vehicle mass are required for the software to calculate the engine power. To calculate these parameters you will need to perform a "coast down" test.
Calculating CdA and rolling resistance
The method described here is suitable for use with vehicle speeds up to 100kph (60mph). Coast down calculations should be done on a flat surface on a wind free day. Testing involves timing the vehicle whilst decelerating in neutral. Time the deceleration over two speed intervals, one high speed test (about 60-100kph or 40-60mph) and one low speed test (about 15kph or 10mph). The timing can be done accurately by using the DL90/DL1/AX22 to log speed data and then plotting graphs of the speeds. Enter the details into the table below, select the units you wish to use, then press Calculate to get the CdA and the rolling resistance values.
We have tried, it got a figure and calculated it to 38604 bhp
Only joking but we do intend to test and check against a rolling road to see the difference. At least EERC should get the same figures as us?
On the slagging off JT bit:
Everyone is free to start their own race series, but JT has done it and done a fantastic job, he can't get everything 100% but he ain't too far off.
He has given me and others an assurance that 2008 will be different, so lets wait and see.
BellyI have to reply on behalf of Team Nero whom you say are in the wrong class
The regs read as follow’s:
The weight of the car with no fuel: 1225kg = W
Average driver weight: 90 kg = D
Coefficient of car: Which no one know’s as the car’s would have to be put through a wind tunnel to find out !!! but for this exercise we will go of the Britcar figure for the class 2 of 3.7 = C
And the formula is W + D ÷ C = V (bhp at rear wheels)
So we are 1225 + 90 ÷ 3.7 = 355
We are allowed 355bhp at the rear wheels
Our rolling road figure which measure bhp at the rear wheels says our car’s pumping out 348bhp. Spot on I think you will find, but go ahead and protest................at least we can clear it up!!!
Well, I 've got to say it! Forget DL1's, forget drag coefficients and cross sectional areas - they are all too difficult. Go to a designated rolling road and get a power at the wheels figure.
Lets ignore ECU's with two maps and other such things. People who do this sort of thing will find a way to circumnavigete all rules anyway.
Easy????? I think so but I am probably a loan voice in the wilderness!! Lets hope the scruts can sort out any confusion at Brands!
Cheers,
Richard.
Lets ignore ECU's with two maps and other such things. People who do this sort of thing will find a way to circumnavigete all rules anyway.
Easy????? I think so but I am probably a loan voice in the wilderness!! Lets hope the scruts can sort out any confusion at Brands!
Cheers,
Richard.
The coeficient of 3.7 quoted for class 2 is nothing to do with drag coeficient, it`s the minimum weight in kg per 1 bhp. It doesn`t get any simpler than that. Your weight can be checked on the weighbridge and for the moment we`ll take people`s word on the power (most people have a pretty rough idea what the various cars produce and your figure of 348, probably 390 at the flywheel? doesn`t sound out of the way).
God the EERC do make it hard for themselves. Rather than explaining how they have come about their figures just say the minimum weight in kg per bhp in class 2 is 3.7 as it races.
Then you weight the cars as they finish the race & hey presto. That way differing driver weight is negated and fuel load in the car when it`s weighed is immaterial. Weighing the cars "dry" is a total farce. If you want to ballast the car up you can, it just serves no purpose at all. Test the car as it actually races.
What happens if my car is under weight when weighed dry on Saturday but we need to have 30kg of fuel in the car to make it actually run without fuel surge. I`m not even going to mention Pete in the car
Simple is always best. So mummy tells me every day
Henry
God the EERC do make it hard for themselves. Rather than explaining how they have come about their figures just say the minimum weight in kg per bhp in class 2 is 3.7 as it races.
Then you weight the cars as they finish the race & hey presto. That way differing driver weight is negated and fuel load in the car when it`s weighed is immaterial. Weighing the cars "dry" is a total farce. If you want to ballast the car up you can, it just serves no purpose at all. Test the car as it actually races.
What happens if my car is under weight when weighed dry on Saturday but we need to have 30kg of fuel in the car to make it actually run without fuel surge. I`m not even going to mention Pete in the car
Simple is always best. So mummy tells me every day
Henry
935 said:
Well, I 've got to say it! Forget DL1's, forget drag coefficients and cross sectional areas - they are all too difficult. Go to a designated rolling road and get a power at the wheels figure.
Lets ignore ECU's with two maps and other such things. People who do this sort of thing will find a way to circumnavigete all rules anyway.
Easy????? I think so but I am probably a loan voice in the wilderness!! Lets hope the scruts can sort out any confusion at Brands!
Cheers,
Richard.
Your not a lone voice on this Richard I have been 100% behind this approach since the rules were announced in 2006.Lets ignore ECU's with two maps and other such things. People who do this sort of thing will find a way to circumnavigete all rules anyway.
Easy????? I think so but I am probably a loan voice in the wilderness!! Lets hope the scruts can sort out any confusion at Brands!
Cheers,
Richard.
As far as I am concerned there is more lap time in the drivers, then car weights and then aero and tyre size packages than in the difference in engine upgrades available after season start assuming correct base weight is enforced. A basic start of the season guide on power and therefore race weight is quite sufficient and this should only be done at one or two designated fixed rolling roads.
There are very few people racing in the Britcar GT classes that can afford to have 2 engines, let alone a grunter and an uber grunter with enough to make a real difference sat ready to go!
If someone doesnt like the way a performance is going they can protest the concern. Impound the car or seal it to death and take your chance on the official dyno.
The power logger thing for reasons already stated is a nice idea for everyone to spend more money without the reality of the situation to make it work effectively. I hope it does and want to be proved wrong but it does make life far to complicated and an already expensive sport, more expensive than it needs.
However, the DL1 is currently in play and so we all have to humour its existance.
I've said my piece
Gaberuhan said:
BellyI have to reply on behalf of Team Nero whom you say are in the wrong class
The regs read as follow’s:
The weight of the car with no fuel: 1225kg = W
Average driver weight: 90 kg = D
Coefficient of car: Which no one know’s as the car’s would have to be put through a wind tunnel to find out !!! but for this exercise we will go of the Britcar figure for the class 2 of 3.7 = C
And the formula is W + D ÷ C = V (bhp at rear wheels)
So we are 1225 + 90 ÷ 3.7 = 355
We are allowed 355bhp at the rear wheels
Our rolling road figure which measure bhp at the rear wheels says our car’s pumping out 348bhp. Spot on I think you will find, but go ahead and protest................at least we can clear it up!!!
As Henry stated, the power to weight calculations are nothing to do with drag coefficient but, in class 2, simply relate to 3.7 kgs per 1 bhp.
What is slightly concerning is the interpretation of the DL1 datalogger to give a BHP figure.
Like Team Nero and, and I am sure many other teams, we will have our car dyno’d to give us an exact BHP figure [or within a few % points] but how will this really relate to the figures that the DL1 produce for our car.
If we are permitted 340 bhp at the wheels and our car is producing 340 bhp as per the dyno, what happens if the DL1 says we are producing 420 bhp [as we understand it did do this year and we had nowhere near 340bhp at the wheels]
We know the DL1 can be accurate when all the correct facts are presented but in 2007 our M3 was far from the outline shape of a production M3.
Well, according to the 2008 regs we have to reduce our power so that it meets the regulation or we wait until someone protests and we go to the nominated rolling road to get a correct figure.
I am sure that, come 2008, everything will work just fine, but I think it would be really good for all teams to be transparent about their weight and dyno’d BHP to try to make things go smoothly.
Here`s an odd thing, I`ve spoken to lots of the teams in Britcar over a number of years and pretty much all of them seem open and fully prepared to state both their power and minimum race weights. They could be lying but you know I don`t think they are.
I had a chat with someone this week who has been entered in the wrong class for Brands and he is quite open about it. With figures he gave me his car came in at just over 3kg/bhp when the class limit is a minimum of 3.7, he`s not trying to cheat, he`s just been put in the wrong class. He put up an argument as to why his car might be better suited to class 2 rather than class 1 but the fact is he didn`t falsify his numbers.
I would love to see all the teams given a print out at brands which shows the declared power and weight of each car entered. That way we can put all the speculation to bed. In an ideal world we would also be given a printout of the EERC power logger calculations for each car as well. I appreciate this part may still be something of a "work in progress" for the EERC but remember this is a trial run. No one is going to protest anyone at Brands Hatch because it`s not part of any championship, just a one off race so we can forgive a bit of trial & error just so long as the intention is clearly there.
Henry
I had a chat with someone this week who has been entered in the wrong class for Brands and he is quite open about it. With figures he gave me his car came in at just over 3kg/bhp when the class limit is a minimum of 3.7, he`s not trying to cheat, he`s just been put in the wrong class. He put up an argument as to why his car might be better suited to class 2 rather than class 1 but the fact is he didn`t falsify his numbers.
I would love to see all the teams given a print out at brands which shows the declared power and weight of each car entered. That way we can put all the speculation to bed. In an ideal world we would also be given a printout of the EERC power logger calculations for each car as well. I appreciate this part may still be something of a "work in progress" for the EERC but remember this is a trial run. No one is going to protest anyone at Brands Hatch because it`s not part of any championship, just a one off race so we can forgive a bit of trial & error just so long as the intention is clearly there.
Henry
I've re read this thread and decided we are all giddy because we are going around in circles!
I won't be at Brands but I wish everyone luck, I hope the best car wins and I hope the EERC are seen to be doing their bit!
Have fun and see what happens. I think it just may be OK!
Cheers,
Richard.
P.S. I thought of coming to spectate but that would just be bloody!!!!!!
I won't be at Brands but I wish everyone luck, I hope the best car wins and I hope the EERC are seen to be doing their bit!
Have fun and see what happens. I think it just may be OK!
Cheers,
Richard.
P.S. I thought of coming to spectate but that would just be bloody!!!!!!
Henry, totally agree. I think you have said previously somewhere else that taking the team's car to a rolling road should be part of the conditions of entering the championship.
I believe having the car's weight & power circulated to all other teams should be another condition, with any random test results during the season also being circulated. Like you, I also believe the vast majority of teams/people in Britcar are honest and just want to go racing.
Lets keep it simple!
Another thought to throw in. As per the Grand Prix Drivers Association in F1, why not have a Brticar/EERC drivers body that represents all competitors and liases with James/Claire on all team matters. Three or four drivers/teams (one from each class?) who seek opinion from all competitors and speak/meet with James on a regular basis. This would have the purspose of presenting a united front to the EERC from its competitors, and I suspect cut down on millions of emails/phone calls etc about issues like rolling roads/class structure/lenght of pitstops/jokers etc etc.
Just a thought
Andy
Jemco Racing
www.insuremotorsport.com
I believe having the car's weight & power circulated to all other teams should be another condition, with any random test results during the season also being circulated. Like you, I also believe the vast majority of teams/people in Britcar are honest and just want to go racing.
Lets keep it simple!
Another thought to throw in. As per the Grand Prix Drivers Association in F1, why not have a Brticar/EERC drivers body that represents all competitors and liases with James/Claire on all team matters. Three or four drivers/teams (one from each class?) who seek opinion from all competitors and speak/meet with James on a regular basis. This would have the purspose of presenting a united front to the EERC from its competitors, and I suspect cut down on millions of emails/phone calls etc about issues like rolling roads/class structure/lenght of pitstops/jokers etc etc.
Just a thought
Andy
Jemco Racing
www.insuremotorsport.com
When I spoke to Claire she did say there would be the opportunity to discuss things at the driver`s briefing on Saturday. Certainly we`ve got lots of time on our hands then so it wouldn`t be any problem logistically. Conscious not everyone racing in 2008 is going to be there (no bad thing, we`ll agree to put a 500kg weight penalty on anything that looks remotely like a 935 ), but there is a cross section of people who can bat some ideas around and certainly there will be people who have no knowledge of this forum.
Henry
), but there is a cross section of people who can bat some ideas around and certainly there will be people who have no knowledge of this forum.Henry
I think the biggest problem with the DL1's is a lack of understanding and information on what exactly they do, they are something of a black magic box.... Essentially all the box does is record the acceleration, and then later with some clever software, if you know the vehicle constants you can figure out the power at the wheels.
Like anything they can be accurate if given good base information, and this will be different for each car. it the drag figures and cda are crucial to getting an accurate figure. get that wrong and it will be miles out...thats a function of mathematical calulation.
You can get usable figures with the coast down tests, although these would need to be redone if any mechanical changes i.e. a different gear box, as this may effect mechanical drag.
Just about every series I look at is having the same issues at the moment, easily policeable regs, and to be honest Im starting to think Chess might be less stressull ( certainly cheaper !!!!)
I think p/w is a good solution and logger are a good way of policing things, it does though need every one to support it and work with it. With some people being ( understandably) skeptical that can be difficult so i think it needs backing up...
IMHO any series looking to run to p/w regs and loggers need to do the folloing.
1) All cars declare weight and power
2) All cars weighed as they come off the track with driver and remaining fuel and thats the check weight for the calculation
3) at first round, all cars must do a coast down test for drag and cda calculations.
4) at each round you must provide a data burst with the car not running on a flat surface ( to calibrate accelerometers)
5) At the first round all cars will be rolling roaded to give a base line figure.
now you have the info to calculate accurate figures on dl1's and a baseline from the rolling road.
The logger data from the first round ( or any round matched to a r/r session) is then used as the base line.
at future rounds the cars are weighed and the logger data checked against the base line log. This should show up anyone who has wound things up... The logger BHP would be calculated and this would show how accurate the dl1 calculations are hopefully proving that dl1's could be used on their own without the r/r sessions in future.
That method of working, doesnt need the power calculation to be accurate as it could say at the first round you had 1000 bhp when the r/road says you've got 300 ( which would be down to incorrect vehicle constants), but as long as the later data logs ( using the same constants) also calculate you have 1000bhp and not 1100 then your ok.
G
Like anything they can be accurate if given good base information, and this will be different for each car. it the drag figures and cda are crucial to getting an accurate figure. get that wrong and it will be miles out...thats a function of mathematical calulation.
You can get usable figures with the coast down tests, although these would need to be redone if any mechanical changes i.e. a different gear box, as this may effect mechanical drag.
Just about every series I look at is having the same issues at the moment, easily policeable regs, and to be honest Im starting to think Chess might be less stressull ( certainly cheaper !!!!)
I think p/w is a good solution and logger are a good way of policing things, it does though need every one to support it and work with it. With some people being ( understandably) skeptical that can be difficult so i think it needs backing up...
IMHO any series looking to run to p/w regs and loggers need to do the folloing.
1) All cars declare weight and power
2) All cars weighed as they come off the track with driver and remaining fuel and thats the check weight for the calculation
3) at first round, all cars must do a coast down test for drag and cda calculations.
4) at each round you must provide a data burst with the car not running on a flat surface ( to calibrate accelerometers)
5) At the first round all cars will be rolling roaded to give a base line figure.
now you have the info to calculate accurate figures on dl1's and a baseline from the rolling road.
The logger data from the first round ( or any round matched to a r/r session) is then used as the base line.
at future rounds the cars are weighed and the logger data checked against the base line log. This should show up anyone who has wound things up... The logger BHP would be calculated and this would show how accurate the dl1 calculations are hopefully proving that dl1's could be used on their own without the r/r sessions in future.
That method of working, doesnt need the power calculation to be accurate as it could say at the first round you had 1000 bhp when the r/road says you've got 300 ( which would be down to incorrect vehicle constants), but as long as the later data logs ( using the same constants) also calculate you have 1000bhp and not 1100 then your ok.
G
This whole thing is way too complex and actuallly the DL1 is totally useless in this application.
Even if the DL1 is showing incorrect figures it would be impossible for them to be consistantly wrong, unless everyone was driving cars with the same Cd. As that is not going to be the case and it is unreasonable for everyone to obtain that figure accurately its all pointless.
Easy solution. Weigh the cars and work off engine size for classes. Then if someone is going significantly quicker in class then increase their minimum weight. Its simple, can be policed on the day and everyone can understand it.
Then perhaps we can get on with the driving which is (as Simon Mason says) is the biggest influence on lap time.
The only reason the DL1 is with us is to generate another revenue stream. If the EERC needs to be money then just up the entry fees or registration fee.
Even if the DL1 is showing incorrect figures it would be impossible for them to be consistantly wrong, unless everyone was driving cars with the same Cd. As that is not going to be the case and it is unreasonable for everyone to obtain that figure accurately its all pointless.
Easy solution. Weigh the cars and work off engine size for classes. Then if someone is going significantly quicker in class then increase their minimum weight. Its simple, can be policed on the day and everyone can understand it.
Then perhaps we can get on with the driving which is (as Simon Mason says) is the biggest influence on lap time.
The only reason the DL1 is with us is to generate another revenue stream. If the EERC needs to be money then just up the entry fees or registration fee.
Gassing Station | General Motorsport | Top of Page | What's New | My Stuff