Dyno Tips Needed
02-27-2003, 01:47 PM
#26
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Originally posted by vadim@evosport
Rage2: I disagree with you with regard to dyno being different from day to day. In my experience of dynoying in the past seven years and of over 1000 cars - if you are using SAE correction numbers you will be very close. Less than 0.1%.
This is very true on a DYNOJET, since there are no variables to play with. In other words you can not change drum mass - it is fixed, or change load by adding brake. The only variables are humidity, altitude and atmospheric pressure. And those are taken care of by SAE correction factor.
In mid90s we ran the same car on three different DYNOJETS. All three graphs overlaid one another. SO one can use DYNOJET numbers from any other DYNOJET dyno for comparision.
Rage2: I disagree with you with regard to dyno being different from day to day. In my experience of dynoying in the past seven years and of over 1000 cars - if you are using SAE correction numbers you will be very close. Less than 0.1%.
This is very true on a DYNOJET, since there are no variables to play with. In other words you can not change drum mass - it is fixed, or change load by adding brake. The only variables are humidity, altitude and atmospheric pressure. And those are taken care of by SAE correction factor.
In mid90s we ran the same car on three different DYNOJETS. All three graphs overlaid one another. SO one can use DYNOJET numbers from any other DYNOJET dyno for comparision.
Originally posted by vadim@evosport
Just for the record - 277HP is a bit below average. Of ten C32s that we have now dynoed - the highest is 297HP and the lowest is 266HP. Please search archives for more info.
Just for the record - 277HP is a bit below average. Of ten C32s that we have now dynoed - the highest is 297HP and the lowest is 266HP. Please search archives for more info.
I've seen cars gain 20hp just from weather conditions on both Mustangs and Dynojets. I guess the dyno operators that I deal with are just idiots and setting things up wrong.
Last edited by rage2; 02-27-2003 at 01:50 PM.
02-27-2003, 02:43 PM
#27
a 31hp discrepency between your lowest and highest... that's at the wheels, so let's say 40 flywheel... If the dynojet is that accurate (0.1% was it?) then AMG must be doing a terrible QA job (they DO run all their motors on a dyno to verify output prior to installation).
BTW, we see the discrepancies in power on E46 M3s and E39 M5s. M3s vary from 255 to 277HP and M5s from 318 to 342HP. I guess BMWs QA sucks too.
Each car is different, no matter if the motor is built by hand or by a robot.
As far as you seeing the difference from run to run. Sure if you let a car heat soak, engine's DME is going to react by adding fuel and pulling timing. When we run cars on our DYNOJET we monitor ECTs to make sure that the conditions stay the same. If SAE corrections are used than the numbers will be very, very close.
If Carl runs his car again on the same dyno, but now in August at 100F and 90% humidity, he will be below 300HP. If he uses SAE correction for both runs than his numbers will be the same. This is why SAE correction is there in the first place. If your dyno operator is not using them, than you can call him an "idiot".
02-27-2003, 02:45 PM
#28
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Let's put the peak HP and TRQ numbers a side for a minute. Look how that motor holds on to the Torque from 3000 to 6000rpm. My car loses 50 Lb/FT from 3000 to redline. Maybe the 93 fuel setting is the reason!
03-04-2003, 04:05 PM
#29
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2002 C32 AMG Orion Blue Charcoal/Blue
Another Dyno Run
Since my prior run was questioned even beyond the SAE correction issue, I didn't feel comfortable that I had a true baseline dyno run so I took my car today to Autothority. I am sure many of you are familiar with Autothority for their work on ECU work on Porsche, BMW, VW, etc. They use a SuperFlow Dyno, always correct for SAE and I gave them the weight of 3600 lbs. per Vadim's instruction. Temps outside where upper 30's today although I guess it doesn't matter with an SAE corrected numbers. Well the chart shows it here as 308 hp and 293 ft/lbs of torque. The run prior to this one went to 311.8 on the horsepower but the spark plug lead didn't work so I didn't have a torque reading. A little better than I guessed by SAE correcting my prior numbers but right in the ball park. Two consistent runs on different dynos, different days and different operators.
Last edited by Carl AMG; 03-04-2003 at 04:08 PM.
03-04-2003, 04:45 PM
#30
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I can't figure out how these Dyno operators are making these dyno runs without the car downshifting. The dyno curve should be starting about 4500rpm not 3800rpm.
03-04-2003, 06:11 PM
#33
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Originally posted by Larry Sonsini
Carl: Find out who at AMG built your motor! and please let me know who did it so that I can make sure that that they build any future vehicles of mine!
Carl: Find out who at AMG built your motor! and please let me know who did it so that I can make sure that that they build any future vehicles of mine!
03-04-2003, 06:44 PM
#34
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C43, SLK32, CLK63 Black Series
Originally posted by Zeppelin
I can't figure out how these Dyno operators are making these dyno runs without the car downshifting. The dyno curve should be starting about 4500rpm not 3800rpm.
I can't figure out how these Dyno operators are making these dyno runs without the car downshifting. The dyno curve should be starting about 4500rpm not 3800rpm.
03-04-2003, 06:55 PM
#35
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Bicycle
Re: Another Dyno Run
Originally posted by Carl AMG
Since my prior run was questioned even beyond the SAE correction issue,
.........
torque reading. A little better than I guessed by SAE correcting my prior numbers but right in the ball park. Two consistent runs on different dynos, different days and different operators.
Since my prior run was questioned even beyond the SAE correction issue,
.........
torque reading. A little better than I guessed by SAE correcting my prior numbers but right in the ball park. Two consistent runs on different dynos, different days and different operators.
03-04-2003, 08:36 PM
#36
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2002 C32 AMG Orion Blue Charcoal/Blue
They are both in the Northern, VA/Washington, DC area so be my guest; call me if you come down. If I were you I would just go to your own local dyno.
SteveL gave some great tips on running on the dyno earlier in this thread. It is much appreciated as I briefed the Autothority operator before the run. The Curry's guys already knew how to run it from their experience with the SLK32 AMG.
The dyno operator today said he was trying to go down as far on the gas pedal to the point where the button on the floorboard wouldn't be pushed until he got further up in the RPM's. I don't know how soon he was pedal to metal or if the torque curve would look different if he went down earlier.
SteveL gave some great tips on running on the dyno earlier in this thread. It is much appreciated as I briefed the Autothority operator before the run. The Curry's guys already knew how to run it from their experience with the SLK32 AMG.
The dyno operator today said he was trying to go down as far on the gas pedal to the point where the button on the floorboard wouldn't be pushed until he got further up in the RPM's. I don't know how soon he was pedal to metal or if the torque curve would look different if he went down earlier.
03-10-2003, 09:35 AM
#37
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C32
Congrats Carl, you have the strongest stock C32 !
I too had my baserun on a Dyno 2 weeks ago. The weeks before doing the dyno the weather was really cold and the car felt notically stronger. On the day of the Dyno the weather was unusually warm. After the run we had a look at the filters (stock) and they where realy dirty. I wonder if that would have an impact on the results ?
Eventhough I have acces to 98 octane gas the dyno 'only' showed 279 HP at the wheel.
This week the ODPS kit will be installed and another Dyno run is scheduled about a week afterwards. I will also have the filter changed to high perform filter K&N.
Regards,
BV
I too had my baserun on a Dyno 2 weeks ago. The weeks before doing the dyno the weather was really cold and the car felt notically stronger. On the day of the Dyno the weather was unusually warm. After the run we had a look at the filters (stock) and they where realy dirty. I wonder if that would have an impact on the results ?
Eventhough I have acces to 98 octane gas the dyno 'only' showed 279 HP at the wheel.
This week the ODPS kit will be installed and another Dyno run is scheduled about a week afterwards. I will also have the filter changed to high perform filter K&N.
Regards,
BV
