Proof!Originally Posted by Legnum Breaking
That would be me then
No longer empty and frantic...
G-Techs are not too bad on the whole, but they are not reliable all the time. There is a G-Tech thread somewhere, which is just for that very purpose!
errrrrrr........what more do you need?
Proof
The timeslip is there as well
I still cant seem to update my time (which would make me top!) and the G-Techs cant count as you could just find a big hill and run down that.
Richard Batty
2.5ltr V6 Turbo FTO
top of what ??
Err ! And the point of that would be ??
Whilst we're on the subject, what about this?
We keep the existing table, but add a 'Class' section? Maybe replacing the 'Induction' section, and make it so that you can filter out a particular 'class'?
You see, I think that would be a good idea for people who want to compare like for like - What I'm thinking is something like this:
Standard/Modified non VR-4 Galants/Legnums
Standard VR-4
Modified VR-4
'Special' vehicles.
So it would all stay as one table, but people could have multiple entries if they wished, and it could be searchable - so you could compare like for like.
Example, most of the club cars would come under 'modified', however, several members did 'Baseline' tests, like Dave, Glenn, etc etc that could be entered - and new owners like Don and Wouter could see how they compare as standard.
We could then have Zentac's FTO, Dave's Frankegnum and possibly Kev's VR-4 as 'special' vehicles - Those cars that are true one-offs.
Non-VR-4s would just be Galants and Legnums only. I think cars that aren't Galants/Legnums or have a Galant/Legnum transplant have no place in our table.
Good idea/Bad idea?
I wonder if that comment by zentac was pointed at me... than no, I ran on totally flat road, but you can delete my entry from the table if you wish. I don't mind.Err ! And the point of that would be ??
However, I will still inform you, when your "official/proven" Turbos+Nitrous+"Weight reduction" times will be beaten by a full weight car on turbos only...
Last edited by valmes; 04-10-2006 at 06:16 AM.
I wonder if that comment by zentac was pointed at me... than no, I ran on totally flat road, but you can delete my entry from the table if you wish. I don't mind.
However, I will still inform you, when your "official/proven" Turbos+Nitrous+"Weight reduction" times will be beaten by a full weight car on turbos only...
I think it is aimed at anyone who has used a G-Tech and Submitted a time
Which is basically saying everyones a liar ??
I was pointing out that they are unreliable as Ive seen people with FTO's' stating 5 sec 0-60 times which I struggle to do..... What is it with people on this site recently everyone is very touchey!!!
Stating that " AND Gtechs can't count cos you can just find a big hill and run down that " isn't saying they are unreliable ? It's stating that the owners of the GTechs claims are unreliable
I recorded a 3.0 second 0-100kph on my rsm the other day as I had inadvertently altered the settings.....................I think it is aimed at anyone who has used a G-Tech and Submitted a time
Which is basically saying everyones a liar ??
If you run on a gradient you will get a different time, if you hit a bump you will get a different time. Its not that people are liars its that the unit cant take into account the different conditions. Yes they are a fun guide, but its not like comparing apples with apples!
I understand where Zentac is coming from, am i think people are taking it the wrong way...
I doubt anyone here would, but ive seen it happen... we have a Gtech ranking at overclockers and you post a pic of the result...
Needless to say we have 1.2 micras beating the 9 seconds to 60... hmmm!
But chill lads, i see what he saying, and its not directed at anyone!!
I know it's not that people are Liars ! It's that some people are suggesting that other people maybe running there car down hills to better there 0-60 or 1/4 mile times. This is suggesting that people ARE LYING ! Maybe People with FTO's like to wind up other people with FTO's
I have completed literally 100's of 0-60 run's with the Gtech and i can nearly tell you the 0-60 time without even looking at the Gtech. And when you Pull a Sub 5 0-60mph you can feel it in your head as the kick of the line is pretty incredible.As i think you well know Dave ! I can quite "HONESTLY" say that i have never pulled a Sub 5 on the Gtech without felling that Jeeeeeeeeeeeeeeeeeeeeezus Chriiiiiiiiiiiiiiiiiiiiist feel you get when it Wup Asses you up the road ! And if i did pull a Sub 5 without the feel of that kick then i would know summat was wrong with the Gtech ! Granted that nothing can be accurate all the time. But test were done with the Gtech, against the RSM and the Pod, and if i remember they were not a million miles away.
One thing i seem to notice though is ? That if the equipment don't cost a fortune then it is said to be no good
So are we to believe the figures from Bruntingthorpe ??
Dont make me get technical on your ass! Its all about how the gtech measures the 0-60 time that leads to the inaccuracy. The results from Bruntingthorpe because of the way in which they were conducted are more indicitive of real performance. The RSM has an advantage over the Gtech as it has a speed input that it can use and correct based on the g sensor reading.
Get as Technical on my Ass as you wish ?
Bruntingthorpe was done by GPS was it not ?
Does this also take consideration when it calculates speed, 1/4 mile and 0-60 mph times
Try that 3 sec run with correct settings... even downhill as suggested by zentac. I am sure you will have to find a cliff to fall off in order to hit that good of a time on CORRECT settings with G-sensor in good working condition. Then try getting consistent with those times.
Now guess what, on a dragstrip, if "you run on gradient" or if you "hit a bump" you will get a different time... since not all dragstrips are the same. In different weather condition, aka temperature, humidity etc. you will get different times... Even if two different people will run the same car - you will still get a different time. How much of a difference is a difference... for a car enthusiasts web site???
Apples to apples you say? Why not "face to face?"... after all internet is weird in this respect. How do you know I am a VR-4 owner? May be I am laying about that as well?
I did all the adjustments and compared my RSM with electronic measurement equipment that is used for local Drag Racing events. It was within +/- 0.02 sec at most. Is that accurate enough?
We do agree that the only way it can get ridiculously unreal times is when you have settings messed up, right?
The thing is, it can be either done "inadvertently" or "on purpose"...
so, what were you saying again?
I am "building" my car for 3 years now... I've been through couple big accidents that set me back for quite a while... I've ruined two differentials, 2 set of turbos and I'm on third engine now... not counting every other "good thing" that happened along the "learning curve".
Don't you think it would be much easier for me to just dial in incorrect "Tire adj" settings, Weight and find a good hill to run off... 3 YEARS AGO???? Than to go through all this to just brag?
If you don't want to accept other people achievements, that's fine with me, but calling me a person who can "inadvertently" dial in wrong settings on Apexi RSM is quite a statement... that MAKES me "touchey"...
Chill Valmes...
We all know you dont have a legnum, and that you are a super-geek thats a dab hand with paintshop pro...
OK
Bruntingthorpe was done by GPS was it not ?
Does this also take consideration when it calculates speed, 1/4 mile and 0-60 mph times
The Pod and other venues that are set up for 1/4 mile events use a series of beams at specified distances along the track. When you break the start beam the clock starts, and when you break the beams up the track the timing gear gives you a time. You ALWAYS cover a distance of 1/4 mile at these venues every time you visit as the timing lights are always in the same place. To measure your speed there are 2 timing lights a fixed distance apart. Using the equation:
Velocity = distance/time
your average speed over this known distance can be calculated. This is where your terminal speeds may be a little out from what you expect at the Pod as the second terminal speed beam is after the finish line, so you need to keep on the gas until you pass it.
Bruntingthorpe did indeed use GPS, but it was not the same standard as used in your TOM TOM, it was far far more accurate (so much so that I can see the lines people took around the bends). Using many samples per second the timing system uses the same equation as above ie:
Velocity = distance/time
As it knows with very high accuracy the exact position of the GPS device the velocity at any given moment can be calculated. Because it works in 3 dimensions it would even have taken account for anyone that decided to use the width of the runway in there timed sprints. Because it knows your velocity at any given moment it can also therefore determine when certain thresholds are passed, like for example 60 mph. It then looks at the time, looks back at the time the first movement was noticed, takes one from the other and voila a 0-60 time. For the 1/4 mile time, well it measures distance accurately so it knows when you have travelled exactly 1/4 mile from your inital point of rest.
The RSM uses a different set of inputs and equations. It has a speed input from the gearbox so it knows how fast you are going at any given time (as long as you set it up correctly) It also has an acceleration input. To measure the 0-60 times it uses both of these, primarily it uses the speed sensor though. When it senses a change in speed from 0 to anything more than about 0.5mph it starts the clock. As it has a speed input it can easily work out how long it takes to get to 60. It is quite clever though as it will also use the acceleration input to compensate for wheelspin......how? Well using a couple of equations of course. At any given time it knows your speed and the time elapsed so it can calculate what the acceleration should be using the equation:
Final Velocity=Initial Velocity + Acceleration X Time
or
Acceleration = Final Velocity - Initial Velocity / Time
Now as it also has an acceleration input it can determine whether or not the calculated acceleration and the actual acceleration are the same......it does this many times per second. If the calculated acceleration is significantly more that the measured acceleration then you have wheelspin. Easy! If it is less then something is wrong!
To measure 1/4 mile times it uses the speed signal input with the following equation:
Distance = Velocity / Time
Again taking measurements many times per second, so at any given moment it knows how far you have travelled since the previous given moment. Now again it will use the acceleration input to ensure everything tallys up:
Distance = 1/2 x Acceleration X Time x Time
And correct as approprite.
Now on the the Gtech. It has only one input and that is acceleration. Unfortunately it is the acceleration of the unit rather than that of the car (unless you have it rigidly mounted) This is where the problems start. Mount your Gtech on your windscreen and turn it in to the mode to measure Gs and give it a little tap......you will see the Gs change drastically. Now drive along with it in this mode and see what happens to the Gs as you drive along Britains fantastic roads. Now the screen update is quite slow, in the background the processor is getting loads more samples per second. So what? Well this as you will remember is the only source of measurement that the gtech has. To figure out your speed it uses the equation:
Final Velocity = initial Velocity + Acceleration x Time
If the Acceleration measurement is disturbed this can have a profound effect on the calculation. If you dont believe me I will perhaps put together a spreadsheet for you.
Similarly it uses the equation:
Distance=1/2 x Acceleration x Time x Time
To work out how far you have travelled, and shaking or erroneous readings will cause errors to be introduced. The reason that the results from testing at the Pod may have led you to believe that the units were giving reasonable results is probably more to do with the track surface than anything else.
Then there is the issue of gradients. If you start off on a level bit of road and then find during your run the gradient changes this will also affect your time. As you know from setting the unit horizontal before a run the acceleration sensor is quite accurate! Contrary to Richards post you will probably find that you get better results going uphill than down as the sensor will read a higher G than you are actually pulling that will affect the equations. Go downhill and the readings will be lower so it will take you longer to reach the target. It may be marginal with the difference in actual acceleration up and down a hill though. Now if you start to think about the effects of bumps and suspension settings along with the secure method of fastening the unit to the windscreen you may start to see the point!
So in summary, all of the methods of measuring times and speeds use input data and equations to work things out. Where the other methods always use a known physical input (speed or distance) the Gtech suffers from using data that is at best questionable pervesely due to the accuracy of its measuring device. On a similar bit of road you will always be able to get a good comparison, but comparing times from your test track and my test track and anyone elses test track, let alone different peoples car can only ever be a rough guide.
Technical enough for your ass?
OK
The Pod and other venues that are set up for 1/4 mile events use a series of beams at specified distances along the track. When you break the start beam the clock starts, and when you break the beams up the track the timing gear gives you a time. You ALWAYS cover a distance of 1/4 mile at these venues every time you visit as the timing lights are always in the same place. To measure your speed there are 2 timing lights a fixed distance apart. Using the equation:
Velocity = distance/time
your average speed over this known distance can be calculated. This is where your terminal speeds may be a little out from what you expect at the Pod as the second terminal speed beam is after the finish line, so you need to keep on the gas until you pass it.
Bruntingthorpe did indeed use GPS, but it was not the same standard as used in your TOM TOM, it was far far more accurate (so much so that I can see the lines people took around the bends). Using many samples per second the timing system uses the same equation as above ie:
Velocity = distance/time
As it knows with very high accuracy the exact position of the GPS device the velocity at any given moment can be calculated. Because it works in 3 dimensions it would even have taken account for anyone that decided to use the width of the runway in there timed sprints. Because it knows your velocity at any given moment it can also therefore determine when certain thresholds are passed, like for example 60 mph. It then looks at the time, looks back at the time the first movement was noticed, takes one from the other and voila a 0-60 time. For the 1/4 mile time, well it measures distance accurately so it knows when you have travelled exactly 1/4 mile from your inital point of rest.
The RSM uses a different set of inputs and equations. It has a speed input from the gearbox so it knows how fast you are going at any given time (as long as you set it up correctly) It also has an acceleration input. To measure the 0-60 times it uses both of these, primarily it uses the speed sensor though. When it senses a change in speed from 0 to anything more than about 0.5mph it starts the clock. As it has a speed input it can easily work out how long it takes to get to 60. It is quite clever though as it will also use the acceleration input to compensate for wheelspin......how? Well using a couple of equations of course. At any given time it knows your speed and the time elapsed so it can calculate what the acceleration should be using the equation:
Final Velocity=Initial Velocity + Acceleration X Time
or
Acceleration = Final Velocity - Initial Velocity / Time
Now as it also has an acceleration input it can determine whether or not the calculated acceleration and the actual acceleration are the same......it does this many times per second. If the calculated acceleration is significantly more that the measured acceleration then you have wheelspin. Easy! If it is less then something is wrong!
To measure 1/4 mile times it uses the speed signal input with the following equation:
Distance = Velocity / Time
Again taking measurements many times per second, so at any given moment it knows how far you have travelled since the previous given moment. Now again it will use the acceleration input to ensure everything tallys up:
Distance = 1/2 x Acceleration X Time x Time
And correct as approprite.
Now on the the Gtech. It has only one input and that is acceleration. Unfortunately it is the acceleration of the unit rather than that of the car (unless you have it rigidly mounted) This is where the problems start. Mount your Gtech on your windscreen and turn it in to the mode to measure Gs and give it a little tap......you will see the Gs change drastically. Now drive along with it in this mode and see what happens to the Gs as you drive along Britains fantastic roads. Now the screen update is quite slow, in the background the processor is getting loads more samples per second. So what? Well this as you will remember is the only source of measurement that the gtech has. To figure out your speed it uses the equation:
Final Velocity = initial Velocity + Acceleration x Time
If the Acceleration measurement is disturbed this can have a profound effect on the calculation. If you dont believe me I will perhaps put together a spreadsheet for you.
Similarly it uses the equation:
Distance=1/2 x Acceleration x Time x Time
To work out how far you have travelled, and shaking or erroneous readings will cause errors to be introduced. The reason that the results from testing at the Pod may have led you to believe that the units were giving reasonable results is probably more to do with the track surface than anything else.
Then there is the issue of gradients. If you start off on a level bit of road and then find during your run the gradient changes this will also affect your time. As you know from setting the unit horizontal before a run the acceleration sensor is quite accurate! Contrary to Richards post you will probably find that you get better results going uphill than down as the sensor will read a higher G than you are actually pulling that will affect the equations. Go downhill and the readings will be lower so it will take you longer to reach the target. It may be marginal with the difference in actual acceleration up and down a hill though. Now if you start to think about the effects of bumps and suspension settings along with the secure method of fastening the unit to the windscreen you may start to see the point!
So in summary, all of the methods of measuring times and speeds use input data and equations to work things out. Where the other methods always use a known physical input (speed or distance) the Gtech suffers from using data that is at best questionable pervesely due to the accuracy of its measuring device. On a similar bit of road you will always be able to get a good comparison, but comparing times from your test track and my test track and anyone elses test track, let alone different peoples car can only ever be a rough guide.
Technical enough for your ass?WELCOME BACK DAVE
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