no drone at 60mph? (sometimes I hit traffic and im slowed to 55-60 on highway)
SL55/63/65/R230 AMG: SL600 vs SL65
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From: Maryland
Eurocharged 2004 E500, Eurocharged ECU/TCU 2005 SL600, 2010 Caddy SwaggerWagon
My car is 100% stock accept for a Eurocharged shelf tune. It's not even a custom tune. My custom is coming in Feb when they're in DC. It's a short trip for you, come on down. There's going to be A LOT of cars at this tune/dyno day. You can talk to the Eurocharged guys directly. Plus you can see what they're able to do with my V12TT.
Thread Starter
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From: U.K.
SL 63 W/B AMG , S600,C220
please read my posts!
I have already said I know nothing about rolling roads, you are treating this as if I own a rolling road myself. It's been more than a year since I took a car to a rolling road, all I am interested in is the figures NOT the rolling road
You have not answered my question on how you measure your cars in the US, and you seem to know nothing about how we gain our figures in the UK. Please wait and I will tell you what the rolling road is, and the figures it produces, stop throwing your toys out of the pram, just wait.
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From: Maryland
'14 E63S & '14 Audi SQ5
Tom
please read my posts!
I have already said I know nothing about rolling roads, you are treating this as if I own a rolling road myself. It's been more than a year since I took a car to a rolling road, all I am interested in is the figures NOT the rolling road You have not answered my question on how you measure your cars in the US, and you seem to know nothing about how we gain our figures in the UK. Please wait and I will tell you what the rolling road is, and the figures it produces, stop throwing your toys out of the pram, just wait.
please read my posts!
I have already said I know nothing about rolling roads, you are treating this as if I own a rolling road myself. It's been more than a year since I took a car to a rolling road, all I am interested in is the figures NOT the rolling road
You have not answered my question on how you measure your cars in the US, and you seem to know nothing about how we gain our figures in the UK. Please wait and I will tell you what the rolling road is, and the figures it produces, stop throwing your toys out of the pram, just wait.How can a chassis dyno measure hp at the flywheel? Think about it...how in the chassis dyno's infinite wisdom can it compensate for the weight of the tires/wheels (only the Dynapack takes the wheels off), the loss of hp through the rear differential, the loss of hp through turning the driveshaft, or the loss of hp through the transmission. If the dynos in the UK are spitting out "flywheel" #'s they are merely calculating/guessing the driveline loss as a coefficient factor and merely multiplying the wheel #'s by that factor....hardly scientific...and hardly accurate.
Tom
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From: U.K.
SL 63 W/B AMG , S600,C220
You can ask anyone on here what type of dyno they ran on and they will be able to tell you the name...some will go further and tell you the model #. It is important to know because each dyno results can be drastically different. Some dynos use an "eddy current load" and interia loads (Mustang, Bosch and Dyno Dynamics), others just use inertia load (i.e. large drums), and others use actually use hydraulic load bolted right to the hub (Dynapack). However, all of these dynos measure hp at the wheels.
How can a chassis dyno measure hp at the flywheel? Think about it...how in the chassis dyno's infinite wisdom can it compensate for the weight of the tires/wheels (only the Dynapack takes the wheels off), the loss of hp through the rear differential, the loss of hp through turning the driveshaft, or the loss of hp through the transmission. If the dynos in the UK are spitting out "flywheel" #'s they are merely calculating/guessing the driveline loss as a coefficient factor and merely multiplying the wheel #'s by that factor....hardly scientific...and hardly accurate.
Tom
How can a chassis dyno measure hp at the flywheel? Think about it...how in the chassis dyno's infinite wisdom can it compensate for the weight of the tires/wheels (only the Dynapack takes the wheels off), the loss of hp through the rear differential, the loss of hp through turning the driveshaft, or the loss of hp through the transmission. If the dynos in the UK are spitting out "flywheel" #'s they are merely calculating/guessing the driveline loss as a coefficient factor and merely multiplying the wheel #'s by that factor....hardly scientific...and hardly accurate.
Tom
We are talking 2 different countries and 2 different cultures. In the States people are quite concerned about value for money, I imagine if they are shelling out for their car to go on a rolling road they would want to know the inside of a cat's backside about what they are getting for their hard earned bucks. The English are totally different, we pay the money and take the car without wanting to know anything except how much more power it has, and don't say how would I know, I have American family and friends and have
visited the States more times than I can remember. Strictly speaking a dyno is something you bolt your engine too, these are rolling roads, and all I know is they measure the power at the wheels and magically give you a figure at the flywheel. Of course it's accurate as many well known companies use it to develop their cars. You obviously do not have this facility in the States, why I don't know. All I know is I have taken several stock cars on them and they have given a pretty accurate figure compared with the manufacturer.
As I said I will find out the name of the rolling road and how it works,that's all I can do! You can get an extra 20 hp on the 63 in the states, I am only claiming another 15 over that figure. Please be patient.
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From: Maryland
Eurocharged 2004 E500, Eurocharged ECU/TCU 2005 SL600, 2010 Caddy SwaggerWagon
Tom you seem to be getting hot round the collar on this one!
We are talking 2 different countries and 2 different cultures. In the States people are quite concerned about value for money, I imagine if they are shelling out for their car to go on a rolling road they would want to know the inside of a cat's backside about what they are getting for their hard earned bucks. The English are totally different, we pay the money and take the car without wanting to know anything except how much more power it has, and don't say how would I know, I have American family and friends and have
visited the States more times than I can remember. Strictly speaking a dyno is something you bolt your engine too, these are rolling roads, and all I know is they measure the power at the wheels and magically give you a figure at the flywheel. Of course it's accurate as many well known companies use it to develop their cars. You obviously do not have this facility in the States, why I don't know. All I know is I have taken several stock cars on them and they have given a pretty accurate figure compared with the manufacturer.
As I said I will find out the name of the rolling road and how it works,that's all I can do! You can get an extra 20 hp on the 63 in the states, I am only claiming another 15 over that figure. Please be patient.
We are talking 2 different countries and 2 different cultures. In the States people are quite concerned about value for money, I imagine if they are shelling out for their car to go on a rolling road they would want to know the inside of a cat's backside about what they are getting for their hard earned bucks. The English are totally different, we pay the money and take the car without wanting to know anything except how much more power it has, and don't say how would I know, I have American family and friends and have
visited the States more times than I can remember. Strictly speaking a dyno is something you bolt your engine too, these are rolling roads, and all I know is they measure the power at the wheels and magically give you a figure at the flywheel. Of course it's accurate as many well known companies use it to develop their cars. You obviously do not have this facility in the States, why I don't know. All I know is I have taken several stock cars on them and they have given a pretty accurate figure compared with the manufacturer.
As I said I will find out the name of the rolling road and how it works,that's all I can do! You can get an extra 20 hp on the 63 in the states, I am only claiming another 15 over that figure. Please be patient.
I didn't go back and read all your posts, but I thought you and your tuner is claiming 580hp. Stock HP is 518, so the gain would have to be 62, not 35.
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From: Maryland
'14 E63S & '14 Audi SQ5
Tom you seem to be getting hot round the collar on this one!
We are talking 2 different countries and 2 different cultures. In the States people are quite concerned about value for money, I imagine if they are shelling out for their car to go on a rolling road they would want to know the inside of a cat's backside about what they are getting for their hard earned bucks. The English are totally different, we pay the money and take the car without wanting to know anything except how much more power it has, and don't say how would I know, I have American family and friends and have
visited the States more times than I can remember. Strictly speaking a dyno is something you bolt your engine too, these are rolling roads, and all I know is they measure the power at the wheels and magically give you a figure at the flywheel. Of course it's accurate as many well known companies use it to develop their cars. You obviously do not have this facility in the States, why I don't know. All I know is I have taken several stock cars on them and they have given a pretty accurate figure compared with the manufacturer.
As I said I will find out the name of the rolling road and how it works,that's all I can do! You can get an extra 20 hp on the 63 in the states, I am only claiming another 15 over that figure. Please be patient.
We are talking 2 different countries and 2 different cultures. In the States people are quite concerned about value for money, I imagine if they are shelling out for their car to go on a rolling road they would want to know the inside of a cat's backside about what they are getting for their hard earned bucks. The English are totally different, we pay the money and take the car without wanting to know anything except how much more power it has, and don't say how would I know, I have American family and friends and have
visited the States more times than I can remember. Strictly speaking a dyno is something you bolt your engine too, these are rolling roads, and all I know is they measure the power at the wheels and magically give you a figure at the flywheel. Of course it's accurate as many well known companies use it to develop their cars. You obviously do not have this facility in the States, why I don't know. All I know is I have taken several stock cars on them and they have given a pretty accurate figure compared with the manufacturer.
As I said I will find out the name of the rolling road and how it works,that's all I can do! You can get an extra 20 hp on the 63 in the states, I am only claiming another 15 over that figure. Please be patient.
Tom
Member
Joined: Dec 2009
Posts: 231
Likes: 2
From: Chicago
GL550
Tom you seem to be getting hot round the collar on this one!
We are talking 2 different countries and 2 different cultures. In the States people are quite concerned about value for money, I imagine if they are shelling out for their car to go on a rolling road they would want to know the inside of a cat's backside about what they are getting for their hard earned bucks. The English are totally different, we pay the money and take the car without wanting to know anything except how much more power it has, and don't say how would I know, I have American family and friends and have
visited the States more times than I can remember. Strictly speaking a dyno is something you bolt your engine too, these are rolling roads, and all I know is they measure the power at the wheels and magically give you a figure at the flywheel. Of course it's accurate as many well known companies use it to develop their cars. You obviously do not have this facility in the States, why I don't know. All I know is I have taken several stock cars on them and they have given a pretty accurate figure compared with the manufacturer.
As I said I will find out the name of the rolling road and how it works,that's all I can do! You can get an extra 20 hp on the 63 in the states, I am only claiming another 15 over that figure. Please be patient.
We are talking 2 different countries and 2 different cultures. In the States people are quite concerned about value for money, I imagine if they are shelling out for their car to go on a rolling road they would want to know the inside of a cat's backside about what they are getting for their hard earned bucks. The English are totally different, we pay the money and take the car without wanting to know anything except how much more power it has, and don't say how would I know, I have American family and friends and have
visited the States more times than I can remember. Strictly speaking a dyno is something you bolt your engine too, these are rolling roads, and all I know is they measure the power at the wheels and magically give you a figure at the flywheel. Of course it's accurate as many well known companies use it to develop their cars. You obviously do not have this facility in the States, why I don't know. All I know is I have taken several stock cars on them and they have given a pretty accurate figure compared with the manufacturer.
As I said I will find out the name of the rolling road and how it works,that's all I can do! You can get an extra 20 hp on the 63 in the states, I am only claiming another 15 over that figure. Please be patient.
Now on to something more relevant - dynos. You are correct, in using the word magically. Why, because just like magic, the dyno operator get's to choose what coefficient of loss to use when converting your wheel HP to crank HP. And just like magic, you could have actually lost 10 hp due to your tune, but the dyno operator magically plugs in a different coefficient and magically you now think you gained 35 hp. And of course, your butt dyno confirms it cuz your but dyno isn’t gonna tell you that you lost HP after spending $2k on a software upgrade.
As others have pointed out, you should spend a little bit of time reading and understanding how dyno's work.
Thread Starter
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From: U.K.
SL 63 W/B AMG , S600,C220
First, you are correct, for the most part, we in America, like getting something other than smoke up our anus for our money. It is sad to hear that you don’t.
Now on to something more relevant - dynos. You are correct, in using the word magically. Why, because just like magic, the dyno operator get's to choose what coefficient of loss to use when converting your wheel HP to crank HP. And just like magic, you could have actually lost 10 hp due to your tune, but the dyno operator magically plugs in a different coefficient and magically you now think you gained 35 hp. And of course, your butt dyno confirms it cuz your but dyno isn’t gonna tell you that you lost HP after spending $2k on a software upgrade.
As others have pointed out, you should spend a little bit of time reading and understanding how dyno's work.
Now on to something more relevant - dynos. You are correct, in using the word magically. Why, because just like magic, the dyno operator get's to choose what coefficient of loss to use when converting your wheel HP to crank HP. And just like magic, you could have actually lost 10 hp due to your tune, but the dyno operator magically plugs in a different coefficient and magically you now think you gained 35 hp. And of course, your butt dyno confirms it cuz your but dyno isn’t gonna tell you that you lost HP after spending $2k on a software upgrade.
As others have pointed out, you should spend a little bit of time reading and understanding how dyno's work.
I am not interested how a rolling road dyno works. 3/ Because you use a different method of measuring, it doesn't make it any more accurate.
After speaking to my friend our rolling roads calculate on the run down the Resistances etc to gain an accurate figure. I dug out my rolling road figures below. My Evo had 265 bhp standard. It was remapped, exhaust, filters and an increase to 1.4 bar, and a button that gave me 1.5 bar for 30 seconds.
At 1.4 bar it has 300 bhp and 311 at 1.5 bar. I was promised an extra 30-40 bhp and that's exactly what I got. As I have said I have measured many stock cars and the figures have been the same as manufacturer's spec. No it's not magic, it's high tech, but if you are not going to believe my SL63 figure is it worth getting it done!
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Newbie
Joined: Oct 2009
Posts: 2
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From: London
SL55
Please don't try to represent the English on this site - you're embarassing us......You seem pleased with your car, so would be more worthwhile to spend your time enjoying it....
Cheers.
Cheers.
Last edited by Ginxy; Jan 18, 2010 at 12:31 PM.
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From: Lincoln, NE
2005 SL600, 2016 ES300h, 2012 Hayabusa
this was a good thread in the beginning, now it is a huge argument.... I think that which car is better depends on the intent, I'm leaning towards an SL600 because it will be a pleasure only car for occasional vacations and maybe an evening cruise or a drag race or two in the summer. On the performance side, I can't see myself needing more than stock brakes on an SL600, and as for the diff, I plan to use an aftermarket one over the amg one. The only question I have is why can't someone flash the abc software? I know the TCU can be tuned, does that work with the ABC?
Thread Starter
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Joined: Apr 2008
Posts: 2,838
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From: U.K.
SL 63 W/B AMG , S600,C220
this was a good thread in the beginning, now it is a huge argument.... I think that which car is better depends on the intent, I'm leaning towards an SL600 because it will be a pleasure only car for occasional vacations and maybe an evening cruise or a drag race or two in the summer. On the performance side, I can't see myself needing more than stock brakes on an SL600, and as for the diff, I plan to use an aftermarket one over the amg one. The only question I have is why can't someone flash the abc software? I know the TCU can be tuned, does that work with the ABC?
our cars on a rolling road differently than the States, so it's best left to agree to disagree, I am sure both methods give you a pretty accurate end result.
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Posts: 8,137
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From: Maryland
Eurocharged 2004 E500, Eurocharged ECU/TCU 2005 SL600, 2010 Caddy SwaggerWagon
More food for thought....
http://www.eurocharged.com/index.php...mart&Itemid=99
Eurocharged is one of the most popular U.S. tuners right now because of their customer service, price point and larger gains than the Big 3 of Kleemann, Brabus, and RENNtech, who are widely considered the World's leaders.
What do they advertise as gains on the 63? 15hp/15tq to the wheels.
http://www.eurocharged.com/index.php...mart&Itemid=99
Eurocharged is one of the most popular U.S. tuners right now because of their customer service, price point and larger gains than the Big 3 of Kleemann, Brabus, and RENNtech, who are widely considered the World's leaders.
What do they advertise as gains on the 63? 15hp/15tq to the wheels.
Member
Joined: Dec 2009
Posts: 231
Likes: 2
From: Chicago
GL550
More food for thought....
http://www.eurocharged.com/index.php...mart&Itemid=99
Eurocharged is one of the most popular U.S. tuners right now because of their customer service, price point and larger gains than the Big 3 of Kleemann, Brabus, and RENNtech, who are widely considered the World's leaders.
What do they advertise as gains on the 63? 15hp/15tq to the wheels.
http://www.eurocharged.com/index.php...mart&Itemid=99
Eurocharged is one of the most popular U.S. tuners right now because of their customer service, price point and larger gains than the Big 3 of Kleemann, Brabus, and RENNtech, who are widely considered the World's leaders.
What do they advertise as gains on the 63? 15hp/15tq to the wheels.
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Posts: 2,895
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From: Maryland
'14 E63S & '14 Audi SQ5
MBWorld Fanatic!
Joined: Apr 2006
Posts: 8,137
Likes: 26
From: Maryland
Eurocharged 2004 E500, Eurocharged ECU/TCU 2005 SL600, 2010 Caddy SwaggerWagon
Thread Starter
MBWorld Fanatic!
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From: U.K.
SL 63 W/B AMG , S600,C220
There is something strange going on.
Here is the simple facts, I am busting a gut to try and find out about dyno's
and everyone else seems to be making a joke about it.
When you measure the power of a car on a rolling road in the States, how do
you get a figure at the flywheel, I presume you can. Without a figure at the
flywheel I don't see how you can compare with the stock car figure especially when tuning a car. If you think it's a joke how in the UK we calculate this figure, then your making a joke of all British tuning companies because after reading through some articles and asking questions a rolling road here will give you whp as well as flywheel hp and other information such as boost and fueling on a turbo car. If you are going to Poo Poo this method of measuring, how do I get your figures for my SL63 in the UK. It's a simple question, perhaps someone in the States can answer it, without taking the mick!
Here is the simple facts, I am busting a gut to try and find out about dyno's
and everyone else seems to be making a joke about it.
When you measure the power of a car on a rolling road in the States, how do
you get a figure at the flywheel, I presume you can. Without a figure at the
flywheel I don't see how you can compare with the stock car figure especially when tuning a car. If you think it's a joke how in the UK we calculate this figure, then your making a joke of all British tuning companies because after reading through some articles and asking questions a rolling road here will give you whp as well as flywheel hp and other information such as boost and fueling on a turbo car. If you are going to Poo Poo this method of measuring, how do I get your figures for my SL63 in the UK. It's a simple question, perhaps someone in the States can answer it, without taking the mick!
MBWorld Fanatic!
Joined: Apr 2006
Posts: 8,137
Likes: 26
From: Maryland
Eurocharged 2004 E500, Eurocharged ECU/TCU 2005 SL600, 2010 Caddy SwaggerWagon
There is something strange going on.
Here is the simple facts, I am busting a gut to try and find out about dyno's
and everyone else seems to be making a joke about it.
When you measure the power of a car on a rolling road in the States, how do
you get a figure at the flywheel, I presume you can. Without a figure at the
flywheel I don't see how you can compare with the stock car figure especially when tuning a car. If you think it's a joke how in the UK we calculate this figure, then your making a joke of all British tuning companies because after reading through some articles and asking questions a rolling road here will give you whp as well as flywheel hp and other information such as boost and fueling on a turbo car. If you are going to Poo Poo this method of measuring, how do I get your figures for my SL63 in the UK. It's a simple question, perhaps someone in the States can answer it, without taking the mick!
Here is the simple facts, I am busting a gut to try and find out about dyno's
and everyone else seems to be making a joke about it.
When you measure the power of a car on a rolling road in the States, how do
you get a figure at the flywheel, I presume you can. Without a figure at the
flywheel I don't see how you can compare with the stock car figure especially when tuning a car. If you think it's a joke how in the UK we calculate this figure, then your making a joke of all British tuning companies because after reading through some articles and asking questions a rolling road here will give you whp as well as flywheel hp and other information such as boost and fueling on a turbo car. If you are going to Poo Poo this method of measuring, how do I get your figures for my SL63 in the UK. It's a simple question, perhaps someone in the States can answer it, without taking the mick!
You take your WHP and divide by .82, since the universal agreed upon drive train loss in these cars is 18%.
So, if you car dynoes at 400 WHP, /.82 = 487 crank HP.
Thread Starter
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From: U.K.
SL 63 W/B AMG , S600,C220
What whp figure do I need to get 560 at the flywheel, I can get both whp and flywheel figures done and compare.
Thanks for this info, at last somebody has told me how you do it.
MBWorld Fanatic!
Joined: Nov 2002
Posts: 2,895
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From: Maryland
'14 E63S & '14 Audi SQ5
There is something strange going on.
Here is the simple facts, I am busting a gut to try and find out about dyno's
and everyone else seems to be making a joke about it.
When you measure the power of a car on a rolling road in the States, how do
you get a figure at the flywheel, I presume you can. Without a figure at the
flywheel I don't see how you can compare with the stock car figure especially when tuning a car. If you think it's a joke how in the UK we calculate this figure, then your making a joke of all British tuning companies because after reading through some articles and asking questions a rolling road here will give you whp as well as flywheel hp and other information such as boost and fueling on a turbo car. If you are going to Poo Poo this method of measuring, how do I get your figures for my SL63 in the UK. It's a simple question, perhaps someone in the States can answer it, without taking the mick!
Here is the simple facts, I am busting a gut to try and find out about dyno's
and everyone else seems to be making a joke about it.
When you measure the power of a car on a rolling road in the States, how do
you get a figure at the flywheel, I presume you can. Without a figure at the
flywheel I don't see how you can compare with the stock car figure especially when tuning a car. If you think it's a joke how in the UK we calculate this figure, then your making a joke of all British tuning companies because after reading through some articles and asking questions a rolling road here will give you whp as well as flywheel hp and other information such as boost and fueling on a turbo car. If you are going to Poo Poo this method of measuring, how do I get your figures for my SL63 in the UK. It's a simple question, perhaps someone in the States can answer it, without taking the mick!
http://www.dinancars.com/bmw/technia...ern-bmw-engine
If you read the article it will give you a better idea of what I am talking about dyno testing in general...
Tom
Member
Joined: Dec 2009
Posts: 231
Likes: 2
From: Chicago
GL550
Sound8:
The simplest way is you take a before and after measurement on the same dyno.
But all you have is whp. the conversion factor is a "magic" number that no one uses because no one knows exactly what it is.
my understanding, and someone please correct me if I am wrong, but the only way to get true engine HP is by taking the engine out and strapping it to a dyno.
As others have pointed out, drive loss varies, and one can only assume what it is, but you cant be accurate.
For example, if I take my car to two identical dynos at two different tuners just down the street from each other on the same day with the same weather, I can run into the following scenario:
1. My car shows 486 rwhp. Tuner one assumes that the drive loss is 22% and spits out a graph that shows everyone that I have 623 hp. I come to the forums, post the graph, and everyone makes fun of me.
2. My car shows 486 rwhp at the tuner down the street 10 minutes later with same exact machine everything else the same. However, Tuner two assumes that the drive loss is 18% which yields 593 hp. Now I come to the forums, post my graph and everyone feels sorry for me because my car is underpowered. I call MB and complain that they sold me a broken car, I show them the graph and they laugh.
For this reason, no one uses conversion factors because they are inaccurate. We use whp because if you use the same exact machine then you can get relevant before and after results.
Hope this helps.
The simplest way is you take a before and after measurement on the same dyno.
But all you have is whp. the conversion factor is a "magic" number that no one uses because no one knows exactly what it is.
my understanding, and someone please correct me if I am wrong, but the only way to get true engine HP is by taking the engine out and strapping it to a dyno.
As others have pointed out, drive loss varies, and one can only assume what it is, but you cant be accurate.
For example, if I take my car to two identical dynos at two different tuners just down the street from each other on the same day with the same weather, I can run into the following scenario:
1. My car shows 486 rwhp. Tuner one assumes that the drive loss is 22% and spits out a graph that shows everyone that I have 623 hp. I come to the forums, post the graph, and everyone makes fun of me.
2. My car shows 486 rwhp at the tuner down the street 10 minutes later with same exact machine everything else the same. However, Tuner two assumes that the drive loss is 18% which yields 593 hp. Now I come to the forums, post my graph and everyone feels sorry for me because my car is underpowered. I call MB and complain that they sold me a broken car, I show them the graph and they laugh.
For this reason, no one uses conversion factors because they are inaccurate. We use whp because if you use the same exact machine then you can get relevant before and after results.
Hope this helps.
Thread Starter
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Joined: Apr 2008
Posts: 2,838
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From: U.K.
SL 63 W/B AMG , S600,C220
[QUOTE=TMC M5;3898535]
How can a chassis dyno measure hp at the flywheel?
.................................................. ........................
Apparently quite easily, according to Benz-O-Rama!
By taking your whp figure and divide by .82.
I have been waiting for this answer, why did you not give it.
I can't see it's any more accurate than our method.
How can a chassis dyno measure hp at the flywheel?
.................................................. ........................
Apparently quite easily, according to Benz-O-Rama!
By taking your whp figure and divide by .82.
I have been waiting for this answer, why did you not give it.
I can't see it's any more accurate than our method.
MBWorld Fanatic!
Joined: Nov 2002
Posts: 2,895
Likes: 53
From: Maryland
'14 E63S & '14 Audi SQ5
Tom
MBWorld Fanatic!
Joined: Nov 2002
Posts: 2,895
Likes: 53
From: Maryland
'14 E63S & '14 Audi SQ5
[QUOTE=sound 8;3900856]
How can a chassis dyno measure hp at the flywheel?
.................................................. ........................
Apparently quite easily, according to Benz-O-Rama!
By taking your whp figure and divide by .82.
I have been waiting for this answer, why did you not give it.
I can't see it's any more accurate than our method.
If you truly want to educate yourself, please read the article...
Tom
How can a chassis dyno measure hp at the flywheel?
.................................................. ........................
Apparently quite easily, according to Benz-O-Rama!
By taking your whp figure and divide by .82.
I have been waiting for this answer, why did you not give it.
I can't see it's any more accurate than our method.
Tom
Thread Starter
MBWorld Fanatic!
Joined: Apr 2008
Posts: 2,838
Likes: 19
From: U.K.
SL 63 W/B AMG , S600,C220
Sound8:
The simplest way is you take a before and after measurement on the same dyno.
But all you have is whp. the conversion factor is a "magic" number that no one uses because no one knows exactly what it is.
my understanding, and someone please correct me if I am wrong, but the only way to get true engine HP is by taking the engine out and strapping it to a dyno.
As others have pointed out, drive loss varies, and one can only assume what it is, but you cant be accurate.
For example, if I take my car to two identical dynos at two different tuners just down the street from each other on the same day with the same weather, I can run into the following scenario:
1. My car shows 486 rwhp. Tuner one assumes that the drive loss is 22% and spits out a graph that shows everyone that I have 623 hp. I come to the forums, post the graph, and everyone makes fun of me.
2. My car shows 486 rwhp at the tuner down the street 10 minutes later with same exact machine everything else the same. However, Tuner two assumes that the drive loss is 18% which yields 593 hp. Now I come to the forums, post my graph and everyone feels sorry for me because my car is underpowered. I call MB and complain that they sold me a broken car, I show them the graph and they laugh.
For this reason, no one uses conversion factors because they are inaccurate. We use whp because if you use the same exact machine then you can get relevant before and after results.
Hope this helps.
The simplest way is you take a before and after measurement on the same dyno.
But all you have is whp. the conversion factor is a "magic" number that no one uses because no one knows exactly what it is.
my understanding, and someone please correct me if I am wrong, but the only way to get true engine HP is by taking the engine out and strapping it to a dyno.
As others have pointed out, drive loss varies, and one can only assume what it is, but you cant be accurate.
For example, if I take my car to two identical dynos at two different tuners just down the street from each other on the same day with the same weather, I can run into the following scenario:
1. My car shows 486 rwhp. Tuner one assumes that the drive loss is 22% and spits out a graph that shows everyone that I have 623 hp. I come to the forums, post the graph, and everyone makes fun of me.
2. My car shows 486 rwhp at the tuner down the street 10 minutes later with same exact machine everything else the same. However, Tuner two assumes that the drive loss is 18% which yields 593 hp. Now I come to the forums, post my graph and everyone feels sorry for me because my car is underpowered. I call MB and complain that they sold me a broken car, I show them the graph and they laugh.
For this reason, no one uses conversion factors because they are inaccurate. We use whp because if you use the same exact machine then you can get relevant before and after results.
Hope this helps.
accurate than a dyno computer working out on the run down the resistance and giving a flywheel figure, it's at least measuring each individual car instead of just using a dividing figure. If you just want to see how much power you have gained then the whp figure is fine. However if you are just testing new cars to see how accurate the manufacturer's claims are, then the dyno on the run down must be used.
MBWorld Fanatic!
Joined: Nov 2002
Posts: 2,895
Likes: 53
From: Maryland
'14 E63S & '14 Audi SQ5
At the end of the day it doesn't matter whether you use a whp figure or a flywheel figure, the whp figure is still going to vary from dyno to dyno. And there is always the question of heat, every time you do a run the heat goes up and the power goes down. Working on just dividing figures must be less
accurate than a dyno computer working out on the run down the resistance and giving a flywheel figure, it's at least measuring each individual car instead of just using a dividing figure. If you just want to see how much power you have gained then the whp figure is fine. However if you are just testing new cars to see how accurate the manufacturer's claims are, then the dyno on the run down must be used.
accurate than a dyno computer working out on the run down the resistance and giving a flywheel figure, it's at least measuring each individual car instead of just using a dividing figure. If you just want to see how much power you have gained then the whp figure is fine. However if you are just testing new cars to see how accurate the manufacturer's claims are, then the dyno on the run down must be used.
http://www.pumaracing.co.uk/coastdwn.htm
Tom
