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RPM limit dont match request


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Hello

I m pro mapper but i struggle with my own R32 GTR

RPM limit is set at 9300 in normal mode. and in my logs it always cuts at arround 8000rpm. It is not really better in advanced mode.

I tuned several link ecus and never had this issue. but other cars didnt had such high rpm limit.

Another rpm issue is that when i use GP limits for fuel and oil pressure, it also cuts very soon (around 4000rpm), even if in the table it should allow 10000rpm

I join my tune.

 

r32 220717.pclr

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I bet your RPM trace in your logs looks like the Himalayas, am i right?

 

Edit. As for your fuelpressure.. Your sensorcalibration says you got a 689 bar (6890 kpa). Im pretty sure thats not correct.

And likevise the oilpressure calibration says 1723.7 bar seosr (17237 kpa)

Get those fixed and i bet it will help alot.

Also i would use differential fuel pressure as the axis for that gplimit. Not that fuelpressure wont work but DFP makes alot more sense.

Edited by Steve
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here is a screenshot of a pull in the logs. you think of a bad rpm sensor ?

 

I know for the calibration, it s there to match the ple tuning dash i have. I need to sort that. but i tested with a good calibration and same isue. 

I wiill play with that tomorrow,

Capture d'écran 2017-07-22 23.01.23.png

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Sensor in its self isnt nessesarily bad. Just that its mounted on the cam with a rubberbelt between it and whats its supposed to meassure the posittion of. Google timingscatter.

I would do a pclog and check for timingerrors in it. Could try to put the trigger in the low resolution mode and see if it helps. But in the end you really need a crankfitted triggersystem to get rid of it for real.

Also i notice your voltage is rather low on that log...

Edited by Steve
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We would need to see a log to confirm but I'm highly suspicious that your issue is trigger error.  

The Nissan 360 trigger works ok on relatively stock engines when all mechanical parts are in good condition, however they become much less useful in heavily modified engines, or when parts of the CAS drive become worn.  Heavier valve springs, more aggressive cam shafts and extended/higher RPM means there is much more torsional vibration on the camshaft drive and since the "slots" are only 1 deg wide it doesnt take much of a "shake" to cause trigger error.

If you want to run an RB engine to 9000RPM you should have a proper crank trigger.  You may get away with one of the aftermarket "24 slot" discs but really they are still not ideal.

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Just to add... We've seen this a few times now and had to convert to aftermarket trigger wheels. On stock triggers we were getting false RPM readings when we looked at logs - as crazy as a 10,000rpm jump in 2/1000 of a second!!!

MGT Motorsport in the UK sell a kit that converts to a "Crank" trigger (36 teeth IIRC) and a single tooth "ref" signal on cam.

Works a treat :)

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