Stuttering at Spa? - Page 7

The Gorilla · 24-10-2010, 12:39 PM

Hi,

If an engine requires 5 Bar fuel pressure at 200 GPH
then revs do not enter into it.

Going faster or slower does not alter the
delivery of fuel made by the pump, whereas
the engine may burn more or less fuel, if
its delivered at 5 Bar, there will always be
enough fuel.

There are no problems on long straights at WOT
pulling 7500/8000 rpm.

The only issue is when the pump is starved of fuel
and can not make the 5 Bar required, due to the
factor of G forces on longer radius bends washing
fuel away for prolonged periods from the pick up.

This has nothing to do with the pump.

Regards,

Thje Gorilla.

**cantfind1** · 24-10-2010, 01:39 PM

Quote:

Originally Posted by The Gorilla

Hi,

If an engine requires 5 Bar fuel pressure at 200 GPH
then revs do not enter into it.

Going faster or slower does not alter the
delivery of fuel made by the pump, whereas
the engine may burn more or less fuel, if
its delivered at 5 Bar, there will always be
enough fuel.

There are no problems on long straights at WOT
pulling 7500/8000 rpm.

The only issue is when the pump is starved of fuel
and can not make the 5 Bar required, due to the
factor of G forces on longer radius bends washing
fuel away for prolonged periods from the pick up.

This has nothing to do with the pump.

Regards,

Thje Gorilla.

Yes people do have problems on long straights pulling 7000-8000 rpm and no sometimes the oem fuel pumps are not producing enough flow to give the required 5 bar. But you do not need 5 bar of pressure at low rpm!! Have you ever driven your car with a pressure gauge attached to see what happens??

5 bar is not required by the engine at low rpm the requirement for fuel to the engine increases with rpm therefore you have less flow back to the tank, this in turn affects the siphon system and makes it less efficient in cornering.

I am not going to argue the point anymore with you as it is tiresome Gorilla.

The Gorilla · 24-10-2010, 02:41 PM

Hi,

Cantfind1 - your correct that it is tiresome.

There is no flow back from the rail on a s54.

Regards,

The Gorilla.

azrael · 24-10-2010, 03:44 PM

Quote:

Originally Posted by cantfind1

I am not going to argue the point anymore with you as it is tiresome Gorilla.

I thought it was a discussion, no need to argue here

**glendog74** · 24-10-2010, 10:48 PM

Quote:

Tiresome

**shimmy** · 24-10-2010, 11:44 PM

I love all our technical discussions ESP when NZ_M3 and The Gorilla are involved.

Trouble is I am not clever enough to understand who is right everytime

**cantfind1** · 28-10-2010, 06:33 AM

Quote:

Originally Posted by The Gorilla

Hi,

Cantfind1 - your correct that it is tiresome.

There is no flow back from the rail on a s54.

Regards,

The Gorilla.

BMW seems to think otherwise.
Check pipe number 3 in the diagram.
http://www.realoem.com/bmw/showparts...84&hg=16&fg=15

_Nathan_ · 28-10-2010, 10:40 AM

That doesn't come back from the rail though which was the point being made - go and look at the rail on your car, it just stops at the front of the engine.

http://www.realoem.com/bmw/showparts...09&hg=13&fg=15

**cantfind1** · 28-10-2010, 05:51 PM

yes true, didn t read that bit but the point is it flows back to the tank to the siphon system and if you haven t got much flow back then the siphon system will be less efficient.

cslnutta · 28-10-2010, 07:32 PM

Quote:

Originally Posted by cantfind1

BMW seems to think otherwise.
Check pipe number 3 in the diagram.
http://www.realoem.com/bmw/showparts...84&hg=16&fg=15

Please keep this going guys, this is getting very interesting

You guys are obviously very knowledgeable, please continue to bless us mere simpletons with your plethora of info!

Fascinating stuff

24-10-2010, 11:44 PM	#66
shimmy CSL Register Uber-poster! Join Date: Apr 2008 Location: Uk Posts: 14,646 Casino cash: $43909	I love all our technical discussions ESP when NZ_M3 and The Gorilla are involved. Trouble is I am not clever enough to understand who is right everytime __________________ .

28-10-2010, 10:40 AM	#68
_Nathan_ Driving it like I nicked it Join Date: Sep 2008 Posts: 2,099 Casino cash: $13060	That doesn't come back from the rail though which was the point being made - go and look at the rail on your car, it just stops at the front of the engine. http://www.realoem.com/bmw/showparts...09&hg=13&fg=15 __________________ Nathan

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24-10-2010, 12:39 PM	#61
The Gorilla S5, Sport Off, DSC M-track Join Date: Apr 2008 Posts: 740 Casino cash: $14401	Hi, If an engine requires 5 Bar fuel pressure at 200 GPH then revs do not enter into it. Going faster or slower does not alter the delivery of fuel made by the pump, whereas the engine may burn more or less fuel, if its delivered at 5 Bar, there will always be enough fuel. There are no problems on long straights at WOT pulling 7500/8000 rpm. The only issue is when the pump is starved of fuel and can not make the 5 Bar required, due to the factor of G forces on longer radius bends washing fuel away for prolonged periods from the pick up. This has nothing to do with the pump. Regards, Thje Gorilla.

24-10-2010, 02:41 PM	#63
The Gorilla S5, Sport Off, DSC M-track Join Date: Apr 2008 Posts: 740 Casino cash: $14401	Hi, Cantfind1 - your correct that it is tiresome. There is no flow back from the rail on a s54. Regards, The Gorilla.

28-10-2010, 05:51 PM	#69
cantfind1 S5, Sport Off, DSC M-track Join Date: Oct 2009 Location: Sydney Australia Posts: 675 Casino cash: $6490	yes true, didn t read that bit but the point is it flows back to the tank to the siphon system and if you haven t got much flow back then the siphon system will be less efficient.