[tscdennab]

I was thinking, what does the DME do in case a fuel injector suddenly clogs and flows too little fuel ? How does it react ? Will there be knock or will it be able to compensate soon enough ? And if BMW engineers thought of this and knock will not occur because it is compensated fast (pulling advance, closing the throttle), why wouldn't this be also true in case of methanol failure which is basically the same thing ?

[Former_Boosted_IS]

The DME will detect the knock and retard timing as fast as it can. If it fails on high boost, I just don't think it can react fast enough to be honest.

[GeorgeSmooth]

Originally Posted by tscdennab

I was thinking, what does the DME do in case a fuel injector suddenly clogs and flows too little fuel ? How does it react ? Will there be knock or will it be able to compensate soon enough ? And if BMW engineers thought of this and knock will not occur because it is compensated fast (pulling advance, closing the throttle), why wouldn't this be also true in case of methanol failure which is basically the same thing ?

If a fuel injector clogs competely the DME will see there is a increase in rail pressure number one and number two it will cut the spark and not retard the timing as most people think it would do. If it registers a knock it will retard timing on the one cycle and if the knock is evident in the next cycle it will throw a superknock code and engine check light.
In the event of methanol failure it will retard timing again. It is not basically the same thing because it is reacting to what it thinks are stock parameters and the reaction is based on what the DME perceives as is correct but in the event of very high boost what the DME does might not be enough to save the motor.

[tscdennab]

Originally Posted by GeorgeSmooth

If a fuel injector clogs competely the DME will see there is a increase in rail pressure number one and number two it will cut the spark and not retard the timing as most people think it would do. If it registers a knock it will retard timing on the one cycle and if the knock is evident in the next cycle it will throw a superknock code and engine check light.
In the event of methanol failure it will retard timing again. It is not basically the same thing because it is reacting to what it thinks are stock parameters and the reaction is based on what the DME perceives as is correct but in the event of very high boost what the DME does might not be enough to save the motor.

You mentioned cutting spark. Cutting spark on which cylinder ? On all ? Increased Rail pressure does not tell which injector failed.

One other question is, can any 3rd party failsafe system react soon enough as to save more of the engine as the DME tries to do ? I know the N54 DME can pull timing event on the next engine revolution. I wonder how many revolutions will take place from a flow sensor low-flow detection until the wastegate is open in order to drop boost, for example.

I wonder if there are any timing-pull tables that flash tuners can rewrite such that the DME would react very abruptly to knock events (or at least according to the higher boost), and not like "cut a few degrees and see what happens on the next cycle", etc. In fact, even piggybacks could read the knock sensor value from CAN bus and react abruptly to knock.

Reading the forums I have never seen an abrupt engine failure due to knock. Makes me wonder if the DME is in fact better than failsafes at protecting the engine. I mean, how can someone prove live that 3rd party failsafes do work better than the DME ?

[Former_Boosted_IS]

Originally Posted by tscdennab

You mentioned cutting spark. Cutting spark on which cylinder ? On all ? Increased Rail pressure does not tell which injector failed.

One other question is, can any 3rd party failsafe system react soon enough as to save more of the engine as the DME tries to do ? I know the N54 DME can pull timing event on the next engine revolution. I wonder how many revolutions will take place from a flow sensor low-flow detection until the wastegate is open in order to drop boost, for example.

I wonder if there are any timing-pull tables that flash tuners can rewrite such that the DME would react very abruptly to knock events (or at least according to the higher boost), and not like "cut a few degrees and see what happens on the next cycle", etc. In fact, even piggybacks could read the knock sensor value from CAN bus and react abruptly to knock.

Reading the forums I have never seen an abrupt engine failure due to knock. Makes me wonder if the DME is in fact better than failsafes at protecting the engine. I mean, how can someone prove live that 3rd party failsafes do work better than the DME ?

Severe knocks of "superknock" or "glow events" are all not good for your engine. That take a toll on your rings, crowns, etc. It is not advisable to have any of these events.

[GeorgeSmooth]

Originally Posted by tscdennab

You mentioned cutting spark. Cutting spark on which cylinder ? On all ? Increased Rail pressure does not tell which injector failed.

One other question is, can any 3rd party failsafe system react soon enough as to save more of the engine as the DME tries to do ? I know the N54 DME can pull timing event on the next engine revolution. I wonder how many revolutions will take place from a flow sensor low-flow detection until the wastegate is open in order to drop boost, for example.

I wonder if there are any timing-pull tables that flash tuners can rewrite such that the DME would react very abruptly to knock events (or at least according to the higher boost), and not like "cut a few degrees and see what happens on the next cycle", etc. In fact, even piggybacks could read the knock sensor value from CAN bus and react abruptly to knock.

Reading the forums I have never seen an abrupt engine failure due to knock. Makes me wonder if the DME is in fact better than failsafes at protecting the engine. I mean, how can someone prove live that 3rd party failsafes do work better than the DME ?

It will cut spark on all.
The tables in the DME can be adjusted to a certain degree.
The DME can not protect the engine in all aspects of knock. Search for Enritas thread for his engine failure which was related to knocking.
The only way to have proper failsafe is for people running flash tunes is to run a piggy back concurrently that reacts to meth flow sensor. The primary map can be the pass through map running the flash tune and the secondary which will be the parachute map will have a emergency map stored. Switching maps can happen in split seconds.