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Author Topic: 413 DME reving more then 6400rpm's  (Read 9459 times)

z_igoras

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413 DME reving more then 6400rpm's
« on: January 07, 2015, 12:09:42 PM »

Hello guys. I am very interested in this WAR chip, but i have only one question:
- when changing REV limiter to 8000rpm's (for example), can i change the ignition and fuel map from 6400 to 8000rpm's? Thank you, waiting for your answer
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millerperformance

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Re: 413 DME reving more then 6400rpm's
« Reply #1 on: January 07, 2015, 12:32:55 PM »

We can scale the RPM axis to better reflect the higher RPM. However, you will ultimately have to sacrifice some low end resolution.
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z_igoras

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Re: 413 DME reving more then 6400rpm's
« Reply #2 on: January 07, 2015, 12:53:24 PM »

We can scale the RPM axis to better reflect the higher RPM. However, you will ultimately have to sacrifice some low end resolution.
not sure if i understood you friend, what means if it sacrifices some low end resolution, what can happen or what is the negative part of this? Thank's for you fast response
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millerperformance

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Re: 413 DME reving more then 6400rpm's
« Reply #3 on: January 07, 2015, 02:15:41 PM »

The maps are a set size. For Wide Open throttle, the maps are 16x1. Meaning there are 16 RPM break points. The way the RPM break points are calculated interlock them so to speak. A method of "Eprom subtract" is used to calculate the real world RPM. If you change one RPM, it will affect EVERY break point below it in the map.

Obviously, you won't find yourself at wide open throttle at only 600 or 800 RPM even being around 1000 RPM would probably never be seen in a WOT condition. So, when you scale the upper RPMs up, you will have to give up RPM resolution somewhere.

This is not negative per say. This simply means you may have to give up refinement in certain regions of the RPM band. Here is an example.

Pretend that normally, you have some break points down low that are 640, 800, 1200, 1600, 2000

Now say you make some changes above those RPMs to reach a higher MAP RPM break point. Those RPMS limits COULD become something like 900, 1400, 2000, 2400, 2900

That is only an example. We can tweak the scaling to that areas that need more resolution, like peak torque, have good resolution and other areas where the ECU can easily extrapolate data between break points and doesn't need 200 or 300 RPM difference in break points to function flawlessly.

There is always an option of moving maps and expanding their size. However, we will not do this typically as it requires a new .ECU file and a bunch more work. We hardly EVER have had to move a map around to gain more size. Simply scaling the RPM limits differently is all you need to do 95% of the time.
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Alameer

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Re: 413 DME reving more then 6400rpm's
« Reply #4 on: January 11, 2015, 10:13:25 AM »

very interesting info, thanks for the question and the answer guys :)
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jdparke3

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Re: 413 DME reving more then 6400rpm's
« Reply #5 on: January 16, 2015, 09:34:01 AM »

I have a similar question, just got back from the dyno and on the first run at ~6100rpm where it was made peak power it felt like it was up against a rev limiter, on the next two runs it did the same thing but at ~6300rpm. Would expanding the rpm scale to the 7000rpm rev limit help this? Also what does the software use for the fuel values between the last value in the table (6400rpm in this case) and the rev limit?
This is on an M50TU with M54B30 crank, pistons and intake cam. The first run was the S50performance.mpc file and the next two I just adjusted the WOT fuel up.
Thanks
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millerperformance

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Re: 413 DME reving more then 6400rpm's
« Reply #6 on: January 17, 2015, 08:59:14 AM »

Is your speed sensor hooked up or present but damaged? There is a rev limiter at 6K when there is a problem with the speed sensor. That definitely looks like what's happening there and is not related to the last break point being 6400.

After 6400 the ECU extrapolates data, just like there isn't a break point for EVERY SINGLE RPM during WOT it manages pretty well to 6.8 7K without much change in the scaling.
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jdparke3

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Re: 413 DME reving more then 6400rpm's
« Reply #7 on: January 18, 2015, 10:21:51 AM »

Ok thanks, I wasn't sure if there was hard coded value for the rev limit that it interpolated in-between. The speed sensor, I assume you are referring to the one that monitor crankshaft position (and not the wheel speed sensor in the diff?) was hooked up, I'll have to investigate to see if its damaged. The car idles great though, maybe this particualar sensor just doesn't work correctly at the higher frequencies
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Alameer

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Re: 413 DME reving more then 6400rpm's
« Reply #8 on: January 19, 2015, 06:51:35 PM »

Dear jdparke3, millerperformance is actually referring to the sensor located at the diff.
The 413 DME gets a signal from that sensor to operate the car correctly, and having that sensor to be damaged or faulty will significantly affect the performance of the car when the wheels are running.

please check if the diff sensor is working properly or not because in your graph there is a cut off / rev limit at 6100 then at 6300 RPM which is not normal.

both the crank sensor and diff sensor are designed to work and handle high frequencies.
if the sensor at the diff is not working correctly then checking the DME for faults with a code scanner will most probably give you the code for a VSS fault code (Vehicle Speed Spensor).

I personally had a problem with this particular sensor 2 times in the past, one time 4 years ago where the sensor was damaged, second time about 3 months ago or less where the wire transferring the signal from the sensor to the DME was a short and caused a fault code.

check it out and let us know.
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jdparke3

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Re: 413 DME reving more then 6400rpm's
« Reply #9 on: February 01, 2015, 01:54:26 PM »

Thanks for the help, the wheel speed sensor wasn't hooked up to the DME, so I spliced into the signal at the back of the OBC and ran it over to the engine wiring harness
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Alameer

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Re: 413 DME reving more then 6400rpm's
« Reply #10 on: February 18, 2015, 10:53:57 AM »

all going well now? problem solved i hope
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