Bosch Motorsport nozzles bashing thread

You can calculate bowl and wall contact based on straight line numbers but your missing that each hole sprays as a cone and the fuel is breaking up into a gas as it travels. Then you add in the air turbulence and pressure differences caused by the bowl design and compression, things are going to change more than a little. Now add in the changing rail pressure and it all changes again. The only true test is to run it and then see what it looks like unless you have big bucks and can drill the cylinder for a high speed camera to watch it in slow mo.
 
So what are the differences between the motorsport nozzle and the marine nozzle? Is one more beneficial than the other? Anyway to ID one to the other?
 
Diesel Tech said:
The only true test is to run it and then see what it looks like unless you have big bucks and can drill the cylinder for a high speed camera to watch it in slow mo.
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Exactly, and many of us work from examples and make comparisons to form some sort of a calculation.
 
Ok, I have not entirely been reading this whole thread, but have been glancing through it here and there. What exactly are you guys trying to prove or accomplish with this thread?

My question is, if you let loose in a cummins warehouse and were allowed to build an engine with only Cummins parts, what piston bowl and nozzle spray angle would you choose??

Edited to please the doughnut faced forum police.
 
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I must have misread Weston's post then. I read it as they were different but marine being passed off as motorsport nozzles. Thanks for clarifying.
 
I have nothing to add except to say;

This is a THREAD with several POST made in it....




Just sayin.....lol
 
Sry to confuse earlier, I was trying to get a clarification of when the event is actually fired vs commanded timing. I was wondering if the duration of the event was split half and half centered on desired timing, or started at desired timing. Also if it is at the actual desired timing number, if it is the pilot shot that is fired at the time, or main event...... I know most of us can kill the pilot shot these days, but still curious about it.
 
Technically speaking it's not called timing in the diesel development world. It is referred to as "SOI" Start of Injection. Everything is based from the starting point and you need to work it back from there.
 
With the talk of timing and the cylinder wall I got to looking at the stock pilot timing. The pilot is 50-55° ahead of the main event from about 2000 rpms up. Looking at all the math in here that runs a good change of being able to contact the wall since the piston is too low, especially with advanced timing on the main event (even as low as a 50:50 with stock duration). The fuel will come out with a cone and the spray will disperse and mist, but how far does it reach?

Is this, or isn't it, an issue?

Would this show up on a UOA as fuel dilution? I think it would, but maybe soot?

Here is an example of the spray angles for additional visualization. I have no experience with anything but stock nozzles in my 05, but from a purely fluid dynamic stand point I don't see the 143° nozzles being more efficient.

pistons.jpg
 
Wall impingement is not a concern when talking about the pilot event.

AH64ID said:
I have no experience with anything but stock nozzles in my 05, but from a purely fluid dynamic stand point I don't see the 143° nozzles being more efficient.
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More time for the fuel charge to mix with available oxygen, in almost every instance making the cone angle wider will increase power. However, power is not the reason the factory pistons are designed the way they are, the design is soley emissions driven.
 
Why is wall impingement not a concern? (I am not saying it is, just curious how firing fuel maybe as much as 70° BTDC doesn't touch the wall).

I am not disputing the factory angle being 100% emissions based, I am simply advocating matched parts. The generally higher pressure that the 04.5-07's run is probably due to the narrower angle and time for atomization prior to contacting the piston.

It's been mentioned that the 6.7 reverted to a wider cone angle, but they also reverted to a reentrant piston. Who is to say that the piston was changed and that demanded a nozzle change, and not the other way around.
 
AH64ID said:
Why is wall impingement not a concern? (I am not saying it is, just curious how firing fuel maybe as much as 70° BTDC doesn't touch the wall).
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As has been said, the quantity is too small when taking cylinder air density into account.

AH64ID said:
Who is to say that the piston was changed and that demanded a nozzle change, and not the other way around.
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That was exactly what was said, the 124° cone angle nozzle should not be used with any other piston.
 
Let's look at this in a simple way, both the Duramax and 325hp Cummins have pilot injection, see the following;

Cummins - 124° angle 76mm bowl
Duramax - 158° angle 64mm bowl

Why is everyone so worried about spraying out of the bowl on the Cummins engine but not on the Duramax engine? People seem to be missing the obvious here.
 
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Smokem said:
Let's look at this in a simple way, both the Duramax and 325hp Cummins have pilot injection, see the following;

Cummins - 124° angle 76mm bowl
Duramax - 158° angle 64mm bowl

Why is everyone so worried about spraying out of the bowl on the Cummins engine but not on the Duramax engine? People seem to be missing the obvious here.
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With late enough timing...a 179 would work too!
 
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