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      07-19-2016, 04:10 PM   #1
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Over-rev "Money shift" max RPM log?

I made a stupid mistake trying to quick shift from 4th to 5th but caught 3rd. When I was trying to shift to 5th I was close to redline in 4th so I know I had an over rev event. I don't think I ever fully disengaged the clutch which may have saved my engine but I'm still worried. Nothing popped up and the car seems to be completely fine. I'm kinda worried about this and I don't want to grenade my engine in a month so I want to know is there a way of figuring out what RPM I actually hit? I would assume the ECU would log this value as dealers would want to know this for warranty claims for blown engines. How would I go about looking for this? Would it just be a shadow code that states this?
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      07-19-2016, 04:34 PM   #2
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Maybe.

But BCP was over 8000RPM and hand minor valve float, I think you will be ok.
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      07-19-2016, 06:21 PM   #3
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the max rev event is stored in the DME as n_h_max. If you have INPA I can tell you how to find it. Mine was 7393rpm last time I downloaded it.

I think though if you actually damaged something, you would already know it - rod knock, poor idle, clanking sounds, etc.
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      07-19-2016, 11:09 PM   #4
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How could you over rev? Isn't there a red line to prevent that? Doesn't that dme cut fuel to the injectors at redline?
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      07-19-2016, 11:15 PM   #5
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Quote:
Originally Posted by Cdutch513 View Post
How could you over rev? Isn't there a red line to prevent that? Doesn't that dme cut fuel to the injectors at redline?
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Even when you mistakenly put it into the wrong gear going faster than that gearing can handle?
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      07-19-2016, 11:20 PM   #6
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Quote:
Originally Posted by Cdutch513 View Post
How could you over rev? Isn't there a red line to prevent that? Doesn't that dme cut fuel to the injectors at redline?
Serious question
It does, but that does stop the engine from spinning higher from you dropping from a higher gear.
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      07-20-2016, 08:58 AM   #7
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Quote:
Originally Posted by Cdutch513 View Post
How could you over rev? Isn't there a red line to prevent that? Doesn't that dme cut fuel to the injectors at redline?
Serious question
Shifting to a lower gear mechanically forces your engine RPM's up regardless of whether there is fuel or not because the engine speed has to match the wheel speed (when the clutch is engaged). If you're already at redline and you downshift, there's no more room on the top end for the engine to increase RPM's to match the wheel speed - something has to give.

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Originally Posted by TheAxiom View Post
It does, but that doesn't stop the engine from spinning higher from you dropping from a higher gear.
FTFY
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      07-20-2016, 09:38 AM   #8
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I dunno....but one would think a fail-safe would have been engineered to prevent money shifts from ever occurring:
Guess blown engines are good for business
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      07-20-2016, 09:49 AM   #9
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Quote:
Originally Posted by Needbmwpartzz View Post
I dunno....but one would think a fail-safe would have been engineered to prevent money shifts from ever occurring:
Guess blown engines are good for business
It was option 205, $1375 (in 2011).
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      07-20-2016, 10:12 AM   #10
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Quote:
Originally Posted by Needbmwpartzz View Post
I dunno....but one would think a fail-safe would have been engineered to prevent money shifts from ever occurring:
Guess blown engines are good for business
It's really not that easy to do. It's not even clear that the OP actually did so.

I'd rather money shift 10 engines in a row than be stuck with a slushbox...
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      07-20-2016, 10:54 AM   #11
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Quote:
Originally Posted by hassmaschine View Post
the max rev event is stored in the DME as n_h_max. If you have INPA I can tell you how to find it. Mine was 7393rpm last time I downloaded it.

I think though if you actually damaged something, you would already know it - rod knock, poor idle, clanking sounds, etc.
I used to have IPNA, can this be pulled from a standard mechanics code reader?
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      07-20-2016, 11:23 AM   #12
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The only way for there to be something to prevent a money shift from taking place would mean there is electronics in the way, and therefore the clutch would have to be electronically controlled/actuated. A manual gearbox car is exactly that, you are in control of what takes place. A rev limiter will prevent the engine from accelerating or revving beyond the rpm limit, but if the engine is "driven" by an external force, as in the wheels and a lower gear to raise the engine speed, there's nothing the rev limiter can do, it's simply a mechanical relationship at that point. So there are only two options to avoid this, DON'T money shift, or rather ditch the clutch pedal...
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      07-20-2016, 11:27 AM   #13
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Usually when you money shift you break whatever was going to break, keyword usually.
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      07-20-2016, 11:54 AM   #14
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Quote:
Originally Posted by Volasko View Post
I used to have IPNA, can this be pulled from a standard mechanics code reader?
no I don't think so. it's stored in non volatile RAM, you need a way to read the string directly.
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      07-20-2016, 02:03 PM   #15
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I'm with hassmaschine on it should be fine if it has no noises. Mechanical failures usually let you know through sounds. It would be interesting to find out how high you actually got.
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      07-20-2016, 05:37 PM   #16
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Yeah I'd be interested in seeing the actual value as well.
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      07-21-2016, 07:17 AM   #17
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Maybe we should start a pull on how high he got.

I say that he did not exceed 7600rpm.

If he was almost at redline in 4th, that means he was going about 120mph. I highly doubt that he was waiting to shift at redline since there is not much to pull after 6500k at that speed. so I will assume he tried to shift at around 6500. If he put it in 3rd instead of 5th, end started releasing the clutch, he would've felt his mistake immediately - thus disengaging the clutch. I don't think he over revved it that high.
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      07-21-2016, 07:40 AM   #18
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Quote:
Originally Posted by W37V View Post
Maybe we should start a pull on how high he got.

I say that he did not exceed 7600rpm.

If he was almost at redline in 4th, that means he was going about 120mph. I highly doubt that he was waiting to shift at redline since there is not much to pull after 6500k at that speed. so I will assume he tried to shift at around 6500. If he put it in 3rd instead of 5th, end started releasing the clutch, he would've felt his mistake immediately - thus disengaging the clutch. I don't think he over revved it that high.
I did a rear diff swap that changed my final drive ratio, so it was more like 100mph.
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      07-21-2016, 09:49 AM   #19
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Quote:
Originally Posted by hassmaschine View Post
the max rev event is stored in the DME as n_h_max. If you have INPA I can tell you how to find it. Mine was 7393rpm last time I downloaded it.

I think though if you actually damaged something, you would already know it - rod knock, poor idle, clanking sounds, etc.
I'm going to try and have and pull this from a friends IPNA, how would I dig this up?

PM's don't work if you need to message shoot me an email to adamvolasko at hotmail dot com
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      07-21-2016, 10:26 AM   #20
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Quote:
Originally Posted by W37V View Post
Maybe we should start a pull on how high he got.
I say less than his rev limiter, because from what he said, he caught it as it was happening and re-engaged the clutch, so I don't think he actually overreved. However if he went lower than the rev limiter we won't know, so I say if he reads the dme, the value will be 69xxxrpm, meaning the value logged the last time he hit his revlimiter.
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      07-21-2016, 10:34 AM   #21
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Quote:
Originally Posted by hassmaschine View Post
It's really not that easy to do. It's not even clear that the OP actually did so.

I'd rather money shift 10 engines in a row than be stuck with a slushbox...
Quote:
Originally Posted by Three_thirty_I View Post
The only way for there to be something to prevent a money shift from taking place would mean there is electronics in the way, and therefore the clutch would have to be electronically controlled/actuated. A manual gearbox car is exactly that, you are in control of what takes place. A rev limiter will prevent the engine from accelerating or revving beyond the rpm limit, but if the engine is "driven" by an external force, as in the wheels and a lower gear to raise the engine speed, there's nothing the rev limiter can do, it's simply a mechanical relationship at that point. So there are only two options to avoid this, DON'T money shift, or rather ditch the clutch pedal...
F56 Mini coopers have rev-matching on downshifts for manual trans models

I don't see why you can't program the DME to monitor engine speed compared to road speed and have a line lock type device on the clutch line to prevent it from engaging in the event an over rev condition would occur.
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      07-21-2016, 01:42 PM   #22
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Quote:
Originally Posted by Volasko View Post
I'm going to try and have and pull this from a friends IPNA, how would I dig this up?

PM's don't work if you need to message shoot me an email to adamvolasko at hotmail dot com
you need to go to "memory" and I think it's the 2nd button from the left which reads RAM. the address for n_h_max is 0x7FABCE (if you have the current program version 921s, which has been around for ages - you should have it). Post a screenshot up here and I'll convert it to RPM for you.
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