Chipped S6 Part 2, Dyno Results
12-11-2001, 03:25 PM
#22
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Well, since I'm at 6000' myself...
...I'd be willing to provide a second opinion of high-altitude performance on my very own butt-dyno 
Lessee, ya think FedEx would ship that on my account #?
Lessee, ya think FedEx would ship that on my account #?
12-11-2001, 03:43 PM
#25
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use wheel HP, flywheel is a joke
Look, the fudge factors for drivetrain loss are the biggest scam going. You can say anything you want by fiddling that number.
It's best to just stick with at wheel HP and go from there. The numbers mean more there anyway, they just aren't as impressive to the uninitiated. But are you trying to impress the uninitiated or go faster?
It's best to just stick with at wheel HP and go from there. The numbers mean more there anyway, they just aren't as impressive to the uninitiated. But are you trying to impress the uninitiated or go faster?
12-11-2001, 03:45 PM
#26
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last I heard was "getting 100HP/liter isn't rocket science"
You are getting 91.6HP/liter. What happened to your bravado? Not that 91.6HP/liter is all that bad for a NA engine, but I'm still waiting for you to follow through and pony up 420HP.
Any chance, or is this the end of the line?
Any chance, or is this the end of the line?
12-11-2001, 04:28 PM
#27
Scientifically speaking there is no standard correction factor
If you want to correct to a standard temperature and pressure that is fairly simple to do but it is not a linear function of either feet or meters. It is a funtion of the change in air density, which varies non-linearly with altitude, linearly with temperature and of course with changes in local air pressure due to weather systems. In order to correct dyno readings for non-standard conditions you would measure atmospheric pressure (in PSIA or millibars or inches of mercury) and ambient pressure and then calculate the density of the air and compare that to the standard.
This calculation is quite simple and is used in a slightly different form by pilots to figure density altitude. However, all that really matters here is the difference in torque (torque is all a dyno actually measures, HP or KW is a calculated number based on torque and RPM) from befor and after the chip. If avdh's raw torque numbers are correct, and we have no reason to think otherwise, these are some pretty impresive gains for a chip on a non-turbo engine.
Someone else already mentioned it but the drivetrain losses used by dyno opperators is nothing more than a guess but it doesn't matter as long as you use the same dyno and correct the same way for your befor and after tests. Do I really care if my car has 100 or 200 hp. No, but I do care if it will do 1/4 mile in 15 or 10 seconds. We have all seen cars with less weight and more HP than our Audis that won't perform as well. The reasons are many (torque curve, gear ratios, traction, etc.) but in the end it's performance that matters. A relative increase in power, no matter the absolute accuracy, will translate to relatively better performance.
This calculation is quite simple and is used in a slightly different form by pilots to figure density altitude. However, all that really matters here is the difference in torque (torque is all a dyno actually measures, HP or KW is a calculated number based on torque and RPM) from befor and after the chip. If avdh's raw torque numbers are correct, and we have no reason to think otherwise, these are some pretty impresive gains for a chip on a non-turbo engine.
Someone else already mentioned it but the drivetrain losses used by dyno opperators is nothing more than a guess but it doesn't matter as long as you use the same dyno and correct the same way for your befor and after tests. Do I really care if my car has 100 or 200 hp. No, but I do care if it will do 1/4 mile in 15 or 10 seconds. We have all seen cars with less weight and more HP than our Audis that won't perform as well. The reasons are many (torque curve, gear ratios, traction, etc.) but in the end it's performance that matters. A relative increase in power, no matter the absolute accuracy, will translate to relatively better performance.
12-11-2001, 08:32 PM
#28
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Simply removing the catalytic converter, which I will not do but the other S6 has done, will give
another 14 bhp.
Tuned exhaust manifold another 10 bhp and a tuned exhaust system (after the exhaust manifolds) could also give another 10 bhp.
Give ot take a few hp's one get very close to 400 bhp. Of course we could also takkle camshafts, inlet manifold etc..... no that I would do it.
Please note that the post you reffering to, I mentioned 380 bhp with re-mapping.
Tuned exhaust manifold another 10 bhp and a tuned exhaust system (after the exhaust manifolds) could also give another 10 bhp.
Give ot take a few hp's one get very close to 400 bhp. Of course we could also takkle camshafts, inlet manifold etc..... no that I would do it.
Please note that the post you reffering to, I mentioned 380 bhp with re-mapping.
12-11-2001, 09:42 PM
#29
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17% correction may not the absolute scientifically correct figure, however it is the standard we
use up here and seems to work for most makes of normally aspirated cars.
I had a look at Chip-Logic's dynamometer data, for various cars including a fair amount of standard normally aspirated cars, such as M5, E46 M3, 330i, E36 M3, Audi A6 2.8, MB CLK 430 and two other S6's.
<b>for all of the above if a factor of 17% correction was applied, then and only then would the dyno results correspond more or less with the manufacturers specifications</b>
Of course one could argue that all cars are below specs......
The correct loss of pressure at 5250 ft (1750m) is .2 bar or 2.9 psi, if someone cares to work it out in percentage...
As for the drag, contrary to what someone mentioned, this is calculated by the dynamometer. From what I have seen, the first run is to calculate drag, where they first accelerate and at one point put the car in neutral and let it roll until it stops, from whatever data the dyno picks up then, it calculates the correct drag.
Furthermore, one must realise that because the S6 is automatic, they have to disconnect something in the gearbox and the run is done in <b>4th</b> gear, whereas manual cars' run are done in 3rd.
Lastly Muhammad, I don't care much if you are happy or not with these dyno figures at this altitude. What counts is that I'm happy and so is my "butt dyno".
Going to a Dyno at sea level may even be more confusing as obviously it would be a different dyno, and franfly I have better things to do when I'm at the coast than to look for a 4 WD dyno, which are not around every other corner. For instance there are only three 4 WD dynos in Johannesburg....
In my case, the data differences between standard and chipped are consistent as the same dyno was used, although done different days with different ambient temperature which did not favour the last chipped run as it was substancially warmer....
For me, since I eventually had to pay for the re-mapping and mods, what matters, is the difference between standard and chipped and if it was worth it.
$1000 for 13% (7000 rpm) to 28% (4250 rpm) improvement for power and 18% improvement for torque, or if you prefer 38 bhp (45 corrected), and up to 43.5 bhp (51 corrected) in the midrange, with 56 lb.ft. (corrected) of torque extra is excellent value for money !
I had a look at Chip-Logic's dynamometer data, for various cars including a fair amount of standard normally aspirated cars, such as M5, E46 M3, 330i, E36 M3, Audi A6 2.8, MB CLK 430 and two other S6's.
<b>for all of the above if a factor of 17% correction was applied, then and only then would the dyno results correspond more or less with the manufacturers specifications</b>
Of course one could argue that all cars are below specs......
The correct loss of pressure at 5250 ft (1750m) is .2 bar or 2.9 psi, if someone cares to work it out in percentage...
As for the drag, contrary to what someone mentioned, this is calculated by the dynamometer. From what I have seen, the first run is to calculate drag, where they first accelerate and at one point put the car in neutral and let it roll until it stops, from whatever data the dyno picks up then, it calculates the correct drag.
Furthermore, one must realise that because the S6 is automatic, they have to disconnect something in the gearbox and the run is done in <b>4th</b> gear, whereas manual cars' run are done in 3rd.
Lastly Muhammad, I don't care much if you are happy or not with these dyno figures at this altitude. What counts is that I'm happy and so is my "butt dyno".
Going to a Dyno at sea level may even be more confusing as obviously it would be a different dyno, and franfly I have better things to do when I'm at the coast than to look for a 4 WD dyno, which are not around every other corner. For instance there are only three 4 WD dynos in Johannesburg....
In my case, the data differences between standard and chipped are consistent as the same dyno was used, although done different days with different ambient temperature which did not favour the last chipped run as it was substancially warmer....
For me, since I eventually had to pay for the re-mapping and mods, what matters, is the difference between standard and chipped and if it was worth it.
$1000 for 13% (7000 rpm) to 28% (4250 rpm) improvement for power and 18% improvement for torque, or if you prefer 38 bhp (45 corrected), and up to 43.5 bhp (51 corrected) in the midrange, with 56 lb.ft. (corrected) of torque extra is excellent value for money !
