Dynojet Results...
12-30-2004, 08:22 PM
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Dynojet Results...
This is my first time posting here, but I just thought I would post these results with the rest of you. First off, I love this car, smooth power is a nice change for me. I purchased a brand new B6 S4 a few months back and have been looking at basic BPU for awhile. I decided to purchase the B&B exhaust (downpipes and cat back system). I havent installed an intake yet, but I put the car on the rollers tonight to see what it was making. The car made 267whp on a Dynojet AWD dyno. As a tuning shop owner, this is the only dyno I use, as I believe its the industry standard when it comes to power testing. Has anyone else done pulls on a Dynojet AWD dyno? Im kinda curious to compare results...I did pulls in 3rd, 4th, and 5th gear, with 3rd being the more "powerful" gear on paper. 4th gear, which is the gear I normally do pulls in, dialed in at 262whp, and 5th at 256whp. At any rate, I just wanted to share the results, I thought some of you may be interested to know. Also, if you have dynoed your S4 on another dyno, please share the results, I would like to compare if possible. I will post a link with the graph tomorrow or Saturday, Thanks!
12-31-2004, 12:36 AM
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No reason why it would
I have the full B&B system. It does not affect "driveability" any more than a Hula girl on the dash would. The car definitely benefits from having bigger lungs.
12-31-2004, 04:22 AM
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Re: All dyno's will have a different percentage on drivetrain loss. But the S4
usually has a 32-35% drive line loss on most dyno's. Looks like the B&B DP'S and Cat-back are only giving a 12hp gain at the wheels.Which is not to bad for an exhaust mod. Stock S4's will pull on a dynojet only about 250-252whp, which 340chp devided by 1.35comes out to 251whp.
12-31-2004, 06:02 AM
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Not to start a dyno war here but the Dynojet as been know to be optimistic in its readings...
It usually gives out higher HP and torque figures compared to some of the more expensive units.
Any how it does not matter very much because unless you test cars on the same dyno under the same conditions, you can not even try to compare the results. Even if Mr. X uses a dynojet in NY and Mr.Y use a Dynojet in CA, the results will be different. Even the dyno operator can make a difference. The way the car is strapped down to the ground can make a difference of up to 10 Hp on the same dyno. Tire wear, tire type can also make a difference. How are the cars tested? what is the outside air tempereture? Better yet what is the temperature inside the dyno room? What is the barometric pressure? What is the humidity percentage in the air? All these will influence the results. What kind of air is being blown across the car's front end? Are they using small fans? Is the testing done under controlled matter with certain SEA standards (barometric pressure at 29.92 inches, sea level and 15 degrees C or 59 degrees F)?I doubt it. I don't know too many tuners here that do it properly.
The car should be tested in fourth gear, not third like some known tuner do to up their numbers, your own testing as proven that. It should be the closest gear to a 1 to 1 ratio.
One of the dynos I like is the Dynapack hub dyno. APR uses one of those units. It is expensive to buy but I know that it give very good results. It takes some of the other dynos problems out of the loop, tire wear, tire type and car strap down problems. Some F1 teams are now using similar units to test their cars. The down side to this dyno is the time lost before and after to re/re the wheels. But if you want to pay even more get the MAHA, IIRC 250K US, this is the same unit Audi and VAG in general use for their testing including some very serious engine builders.
Finally the Quattro system using the TorSen as a power train loss of about 26%, give and take a few decimal points. The Quattro using the Haldex, like in the TT or VWs as a few percentage points more in loss.
Any how it does not matter very much because unless you test cars on the same dyno under the same conditions, you can not even try to compare the results. Even if Mr. X uses a dynojet in NY and Mr.Y use a Dynojet in CA, the results will be different. Even the dyno operator can make a difference. The way the car is strapped down to the ground can make a difference of up to 10 Hp on the same dyno. Tire wear, tire type can also make a difference. How are the cars tested? what is the outside air tempereture? Better yet what is the temperature inside the dyno room? What is the barometric pressure? What is the humidity percentage in the air? All these will influence the results. What kind of air is being blown across the car's front end? Are they using small fans? Is the testing done under controlled matter with certain SEA standards (barometric pressure at 29.92 inches, sea level and 15 degrees C or 59 degrees F)?I doubt it. I don't know too many tuners here that do it properly.
The car should be tested in fourth gear, not third like some known tuner do to up their numbers, your own testing as proven that. It should be the closest gear to a 1 to 1 ratio.
One of the dynos I like is the Dynapack hub dyno. APR uses one of those units. It is expensive to buy but I know that it give very good results. It takes some of the other dynos problems out of the loop, tire wear, tire type and car strap down problems. Some F1 teams are now using similar units to test their cars. The down side to this dyno is the time lost before and after to re/re the wheels. But if you want to pay even more get the MAHA, IIRC 250K US, this is the same unit Audi and VAG in general use for their testing including some very serious engine builders.
Finally the Quattro system using the TorSen as a power train loss of about 26%, give and take a few decimal points. The Quattro using the Haldex, like in the TT or VWs as a few percentage points more in loss.
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12-31-2004, 06:17 AM
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Honestly that is an excessive drivetrain loss figure.
Tip/Quattro cars don't even have true drivetrain losses that high. I guess for finding a value that correlates with stock rated hp it works, but not much else.