[farbmw]

Very interesting!

[Slidewayz]

I just threw up in my mouth a little bit

[AltecBX]

Originally Posted by SennaZ

Can't believe Shiv would have missed the concept that on-demand, electronic fuel pumps all use a square wave variable duty cycle to control the pump speed...strange.

Can you elaborate on this?

[vase330]

I think he is being sarcastic.

[SennaZ]

Originally Posted by AltecBX

Can you elaborate on this?

Just saying that for the past many decades one does not generally control the output of a motor [pump] by simply altering the voltage to it - even a $25 Home Depot shop equipment speed controller will use electronic circuitry to vary the duty cycle of a square or pulsed waveform. This is done for a number of reasons, but one of them is to reduce heat buildup and it obviously allows for much better control, especially at the lower end of the voltage range where the motor might stall or draw excessive current.

Now the consequences of not taking this into consideration would vary depending on what kind of voltage multiplier circuit you designed to drive the fuel pump. A simple transistor-multiplier one would probably pass the waveform and be OK, a more sophisticated electronic one might not.

This info is not new so I would be very surprised if Shiv wasn't aware of it.

[Mike@N54Tuning.com]

Originally Posted by SennaZ

Can't believe Shiv would have missed the concept that on-demand, electronic fuel pumps all use a square wave variable duty cycle to control the pump speed...strange.

I found it quite odd BMW would run the fuel pump at 11v while everything else runs at 14v but I'm glad we got to the bottom of it. The good news for all of us is the factory pump is good for a lot more "theoretical" horsepower than that incorrect data suggests. Of course we already knew that from the 100s of greater than 400rw dyno charts with the stock fuel pump. But it's always nice when theory and reality are at least in the same ballpark.

Mike

[pentaxis]

It sure would be nice if there were some exclusive developments from BMS instead of just blatant "me toos". It might actually push for the advancement of the platform.

Oh wait. What am I thinking. They developed the "full exhaust flapper control" before anyone else. Nice work.

[Mike@N54Tuning.com]

Originally Posted by pentaxis

It sure would be nice if there were some exclusive developments from BMS instead of just blatant "me toos". It might actually push for the advancement of the platform.

Oh wait. What am I thinking. They developed the "full exhaust flapper control" before anyone else. Nice work.

You realize the data presented in this thread directly refutes data Vishnu presented re: the factory fuel pump capacity right? You also realize BMS added low fuel pressure to their logging software two months ago? That BMS is the only tuner to have exceeded 540hp to the wheels with an N54? Writing 10 page long technical articles based on incorrect information doesn't move the platform further. Collecting data and testing different solutions to the same problem does. I see this is a collaborative effort to move more of the 500rw guys to 550rw regardless of what tuning is used. So please take your hate over to the nearest "which tune should I buy" thread.

Mike

[Brey335i]

And I thought that after Shiv and Mike had beers together in Canada, comments like those from a few people in here wouldn't happen anymore...

Anyways. I'm always curious to see any new information posted. What is BMS's next step towards solving the fueling problem? Any numbers forthcoming?

[zerep1]

I wish there was a like button I personally don't care were it comes from as long as it works properly and safely if the company's can fight for our money the only people winning are us.

[AltecBX]

Originally Posted by SennaZ

Just saying that for the past many decades one does not generally control the output of a motor [pump] by simply altering the voltage to it - even a $25 Home Depot shop equipment speed controller will use electronic circuitry to vary the duty cycle of a square or pulsed waveform. This is done for a number of reasons, but one of them is to reduce heat buildup and it obviously allows for much better control, especially at the lower end of the voltage range where the motor might stall or draw excessive current.

Now the consequences of not taking this into consideration would vary depending on what kind of voltage multiplier circuit you designed to drive the fuel pump. A simple transistor-multiplier one would probably pass the waveform and be OK, a more sophisticated electronic one might not.

This info is not new so I would be very surprised if Shiv wasn't aware of it.

So what kind of circuitry will you imply, with the current information out from Vishnu & BMS?


---
Mike on another note, why hasn't implemented the speed limiter defeat with the JB4?

[Mike@N54Tuning.com]

Originally Posted by AltecBX

---
Mike on another note, why hasn't implemented the speed limiter defeat with the JB4?

Most are unwilling to sacrifice their factory warranties by using it. Besides 155mph is already pretty fast. BMS has always offered it as an $80 add on for those that want it. Their new CPS module also has a built in SLD that can be enabled/disabled based on user preferences.

Mike

[AltecBX]

Originally Posted by Mike@N54Tuning.com

Most are unwilling to sacrifice their factory warranties by using it. Besides 155mph is already pretty fast. BMS has always offered it as an $80 add on for those that want it. Their new CPS module also has a built in SLD that can be enabled/disabled based on user preferences.

Mike

Thanks. JB4 now has CanBus built in as well so I thought it can easily be implemented..
I just get a few PM's about this and it make sense to give the users the ability to disable the governor especially when you don't have the Sport package which is governed at 130mph.

[SennaZ]

Originally Posted by AltecBX

So what kind of circuitry will you imply, with the current information out from Vishnu & BMS?

A question I'm sure Shiv will address in Part 3, but I suspect something like this:

ECU ------>EPK------> Voltage Multiplier----> LPFP

where the volt. muti is set to trigger at 14v or simply multiplies the voltage by say 1.3X

[AltecBX]

Originally Posted by SennaZ

A question I'm sure Shiv will address in Part 3, but I suspect something like this:

ECU ------>EPK------> Voltage Multiplier----> LPFP

where the volt. muti is set to trigger at 14v or simply multiplies the voltage by say 1.3X

30% higher!
Couldn't there be a better logic at applying the voltage?

[ianthegreat]

Originally Posted by pentaxis

It sure would be nice if there were some exclusive developments from BMS instead of just blatant "me toos". It might actually push for the advancement of the platform.

Oh wait. What am I thinking. They developed the "full exhaust flapper control" before anyone else. Nice work.

How many other technical forums do you frequent? Oh yea nvm..

[SennaZ]

Maybe more

But as I mentioned in the other thread, if over-driving it affects longevity, they can be purchased for around $200, so price wise it's not a critical issue. Anyway, that's something a few alpha-testers could find out.

[Sparky66]

Originally Posted by Mike@N54Tuning.com

You realize the data presented in this thread directly refutes data Vishnu presented re: the factory fuel pump capacity right? You also realize BMS added low fuel pressure to their logging software two months ago? That BMS is the only tuner to have exceeded 540hp to the wheels with an N54? Writing 10 page long technical articles based on incorrect information doesn't move the platform further. Collecting data and testing different solutions to the same problem does. I see this is a collaborative effort to move more of the 500rw guys to 550rw regardless of what tuning is used. So please take your hate over to the nearest "which tune should I buy" thread.

Mike

Mike, thanks for the pictures but where is the data presented by BMS?
Care to elaborate, or at least present this here that shows or refutes the capacity of the fuel pump pressure tabled in Shivs research.

[Mike@N54Tuning.com]

Originally Posted by SennaZ

Maybe more

But as I mentioned in the other thread, if over-driving it affects longevity, they can be purchased for around $200, so price wise it's not a critical issue. Anyway, that's something a few alpha-testers could find out.

A cheap drop in fuel pump that supports higher flow is probably a better choice given how easy it is to access the pump in this car. But boosting the OEM voltage is a good way to determine whether the low pressure pump is really the limiting factor. We may find as soon as its shored up that some other limitation quickly takes its place. Also it's not clear whether a new drop in pump would really cost the $150-$200 one would expect. If lots of fabrication is required, etc, it could go to triple that making voltage boosting a better choice. Then there is the whole low pressure regulation issue that BMS has identified. The OEM pump with better regulation (eliminating the oscillations) may wind up being all we need for another 30-40hp. At this point who knows.

Mike

[domrep]

Originally Posted by Mike@N54Tuning.com

You realize the data presented in this thread directly refutes data Vishnu presented re: the factory fuel pump capacity right? You also realize BMS added low fuel pressure to their logging software two months ago? That BMS is the only tuner to have exceeded 540hp to the wheels with an N54? Writing 10 page long technical articles based on incorrect information doesn't move the platform further. Collecting data and testing different solutions to the same problem does. I see this is a collaborative effort to move more of the 500rw guys to 550rw regardless of what tuning is used. So please take your hate over to the nearest "which tune should I buy" thread.

Mike

+1

and farbmw has contributed alot to the forums, so dont be so ignorant mycoupe.

[ar design]

Originally Posted by Mike@N54Tuning.com

You realize the data presented in this thread directly refutes data Vishnu presented re: the factory fuel pump capacity right? You also realize BMS added low fuel pressure to their logging software two months ago? That BMS is the only tuner to have exceeded 540hp to the wheels with an N54? Writing 10 page long technical articles based on incorrect information doesn't move the platform further. Collecting data and testing different solutions to the same problem does. I see this is a collaborative effort to move more of the 500rw guys to 550rw regardless of what tuning is used. So please take your hate over to the nearest "which tune should I buy" thread.

Mike

Reading escapes some people.... LOL

[Mike@N54Tuning.com]

The question was asked on another forum what does the DME and FP controller do if you just unplug the low pressure sensor. Here are the results.