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04-24-2008, 08:01 AM | #1 |
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Dyno Results (Updated with Stock vs Modded (CAI+Exhaust) Graph)
Here's the charts.
The mech changed up at 8250 (not 8400). I'm not very mech/tech minded, and my reason for doing this dyno is to form the basis for my future mods. As per my other thread on the GruppeM CAI and Exhaust, I've been advised to let the mods bed down for around 500km before doing another dyno test to show the improvements to HP and Torque (if any). Cheers Update - there appears to be a modest increase of 7bhp (at peak) and around 5-18bhp across the rev range. ps didn't get the printout for hp at the wheels... sorry. cheers Last edited by edlms; 05-02-2008 at 04:10 AM.. Reason: update |
04-24-2008, 08:55 AM | #2 |
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Is that good, bad or about right? All these dynos are different and the they come up with 3 or 4 power readings. Just cant make sense of it...
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04-24-2008, 08:57 AM | #3 |
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Beautiful! Look at that torque curve...I love it. I'm glad someone is taking the initiative to do a base line and then more after the mods are installed.
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04-24-2008, 09:28 AM | #4 | |
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http://www.m3post.com/forums/showthread.php?t=136529 Download the detailed spreadsheet in PS and Kgm units and read the values from the Corrected Power and Corrected Torque columns, which take pressure and temp differences into account. Then compare those numbers to the corrected figures on the posted output sheet. You'll see: Corrected Wheel Torque/Total Reduction: RRI: 37.3 Kgm @3911 rpm OP: 37.2 Kgm @3965 rpm If you compare the wheel torque/total reduction readings over the entire rev range, they are in agreement, so I am assuming the OP's chart does not factor in any transmission losses for the torque reading. However, there is something funky with the power figures. As you can see in the dissipated power reading, they are factoring in a %10 loss to "guess" engine power. If we bypass the engine reading, and just apply the temp and hum correction factor to get the standardize power reading from the 325.3hp figure, we get 335.8 peak hp. Corrected Wheel Power: RRI: 374.3 @7518 rpm OP: 335.8 @7570 rpm I don't understand why the wt numbers agree, but whp don't. I guess the wt numbers also include the 10% loss factor. In which case, the OP's numbers are about 10% off in general, which can be explained by: 1. RRI uses a hub dyno, whereas the OP used rollers. 2. OP's run was not close to steady-state (I don't know enough about the specifics of dyno run methodology to judge if a 5.8 sec run constitutes steady-state in this case). 3. Instrument differences.
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04-24-2008, 10:07 AM | #5 |
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im still waiting for some dynojet results.....
we have one where i work.... but i dont have my M yet..... i will be on the dyno the day mine rolls off the lot... then after brake in... then after each mod..... |
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04-24-2008, 10:22 AM | #6 | |
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Best regards, south
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04-24-2008, 10:38 AM | #7 |
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i have a specific break in i do to all my new motors.... to seat the rings.... takes about a hour.. then a oil change..... then im easy on all the other parts that need to be broken in.. the tranny.. dif and such..... but dyno pull isnt hard on any of that stuff....
you can also brake in a motor on the dyno... ive done this over 10 times.... every one showing good reliability and very strong power.... |
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04-24-2008, 10:38 AM | #8 |
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Lucid - thanks for analysis. i don't fully comprehend the intricacies of dyno runs and the readings but you've enlightened me a fair bit, especially the differences between RRI's data and mine.
hope to see some HP improvements when i do my next dyno... cheers |
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04-24-2008, 11:17 AM | #9 |
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Guys, the HP is lower than other dynoes because whoever dynoed the car let off before 8000 rpm. Looks like they let off around 7750 rpm. Doesn't this car make its peak HP at 8300 rpm?!?!?
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04-24-2008, 12:00 PM | #10 |
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If you look at the actual chart, it's obvious the throttle was cut at 7600 rpms, thats why the max was reached there. Look at the actual chart.
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04-24-2008, 12:12 PM | #11 |
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Look at the charts from RRI. They have max hp at the wheels @7821 rpm. The max power at the crank could be achieved at a higher rpm, but the transmission losses go up with engine speed, so if the crank gains are very small between 7821 and 8300, the tranmission losses could trump them, and you see what these charts tell us at the wheels.
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04-24-2008, 12:19 PM | #12 | |
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04-24-2008, 12:23 PM | #13 |
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Doesn't make sense to me. I thought drivetrain loss was just a percentage, so if the engine makes its peak power at 8300rpm then it should also make its peak power to the wheels at 8300rpm. I did take a look at the RRI graphs and it does seem like power drops off at 8k rpm. But if you look at the OP's graph, the graph reaches its peak and then drops substantially leading me to believe they let off on the gas. I think the HP coulda gone up quite a bit more if they went up to 8300rpm.
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04-24-2008, 12:29 PM | #14 | |
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The power in the RRI tests peak around 7821 rpms--not at 8000 rpms. It is possible that this was an acceleration test and they let go off the gas a bit too early. It would be good to have a few more data points after the peak to verify that the peak has indeed been experienced.
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04-24-2008, 12:43 PM | #15 | |
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2. Other parts of the drivetrain need to be broken-in as well, which can't be done on an engine dyno. 3. Race engines are for racing. Meaning, they are designed and built differently, and have a significantly different life expectation than passenger cars.
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04-24-2008, 01:20 PM | #17 | |
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In that case, I'd say that it is mainly about the controlled setting and monitoring/measurement issue. Also, did you actually follow up with the street engines to see how they were holding up with 100000+ miles? And if so, how large was that sample?
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04-24-2008, 01:59 PM | #18 | |
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The dealer who is a racer,said to ignore the manual and just seat the rings as I always done and no prolonged full throttle(top speed runs) running for a while.The result has been no oil consumption and very little blowbye and thats with 20000 kms of street riding and over 60 track days.My friends who followed the long breakin as per the manual have had blowbye problems including piston & cylinder replacements. I followed my method on the M3 and so far everything is working good so far!I am very anal about making sure that everything is totaly warmed up(oil temp) before going over 3000 rpm whether it is being "run in" or normal use.That is allways followed on all my vehicles and so far so good. |
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04-24-2008, 06:45 PM | #19 |
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04-25-2008, 01:06 AM | #20 | |
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05-02-2008, 06:34 AM | #22 |
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Nice increase. Good to see the intake is good for more than just sound and looks.
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