Bosch Motorsport nozzles bashing thread

AH64ID said:
I see two differently designed pistons, that would take different nozzles.
Click to expand...

Yet the Cummins piston design is very very similar to many pistons used with wide cone angle nozzles in multiple applications, I think this is the part you are missing.
 
Similar is not equal to. The airflow will be different in both of those pistons, despite being within 2° of each other, the walls, shoulder, and peak are different. When your talking airflow and combustion it doesn't take much to make a big difference, that is the part I think you are missing.

A good example would be to take one of each piston and put a stream of high pressure water exactly in the center of each, the flow of the water would be very different despite that 2° angle difference.
 
And the Cummins late CR is non-reentrant, so they are not the same design of a piston. Different piston designs will require different nozzles, so I am not sure why you are comparing a non reentrant Cummins piston to a reentrant Duramax piston.
 
Because changing the cone angle changes the type of injection...and therefore the numbers for cone angle and bowl width are comparable.
 
Smokem said:
Yet the Cummins piston design is very very similar to many pistons used with wide cone angle nozzles in multiple applications, I think this is the part you are missing.
Click to expand...

Refering to the non-reentrant 04.5-07 5.9l piston bowl? Correct?
 
Simulation model of a 144° cone angle nozzle @ 30° BTDC for the '03-04 piston bowl, notice it is being contained in the 56mm bowl.

BBbowlw_144inj-30btdc.jpg
 
Smokem said:
Because changing the cone angle changes the type of injection...and therefore the numbers for cone angle and bowl width are comparable.
Click to expand...

Are you saying that going to a wide angle on the late CR piston will make it reentrant?
 
The reason there are not many nozzle options in that tight of a cone angle is simple, very few OEM's use that injection style. If you want an explanation as to why, think of how many warranty claims Dodge has had with melted engines in stock applications with the 325hp engine vs the 305hp engine.
 
Was the 325 piston designed around using the 124*nozzle? Or was it taken from another application because the 2 together could meet the emissions requirements? I think everyone is hung up on the idea that they are made for each other and running any wider spray is going against the design and could lead to premature failure.
 
Its always been my understanding that piston bowl geometry defines weather the combustion chamber is re-entrant vs non re-entrant.
 
It plays a role, but does not dictate completely whether or not it can be used in either form.

For example; use a Duramax nozzle(158°) with the 325hp Cummins piston, if the spray moves from the dome onto the bowl wall, isn't it re-entrant?

The same can be said for the 143° nozzle, if it is still spraying onto the dome, isn't it still non re-entrant?
 
Last edited:
So were going to try and drive home one more time the bowl width vs cone angle and get the basic understanding that IF the narrower bowl can handle the timing a wider one will just as well and then some!


Bowlwidth_zps56d5278e.jpg


We should have some good data on a piston only swap from 03-04 to 04.5 and keeping the 143 degree tips.

IMO this pattern is going to be sex on a set of monotherms.

ehyty2yz.jpg
 
Joesixpack said:
So were going to try and drive home one more time the bowl width vs cone angle and get the basic understanding that IF the narrower bowl can handle the timing a wider one will just as well and then some!


Bowlwidth_zps56d5278e.jpg


We should have some good data on a piston only swap from 03-04 to 04.5 and keeping the 143 degree tips.

IMO this pattern is going to be sex on a set of monotherms.

ehyty2yz.jpg
Click to expand...

This is an interesting topic, no doubt. I'm seeing this piston here and the fuel marks on it. So this might be a stupid question so please forgive me. I don't see any signs of swirl in the bowl, or am I looking at wrong? Is the fuel atomizing properly? or is there other factors in play for the cone to make a difference? What should it look like if the Nozzle is doing it job correctly, or is that correct?

I have seen this in many power plants and I have always wanted to ask this question?
 
Joesixpack said:
So were going to try and drive home one more time the bowl width vs cone angle and get the basic understanding that IF the narrower bowl can handle the timing a wider one will just as well and then some!


Bowlwidth_zps56d5278e.jpg


We should have some good data on a piston only swap from 03-04 to 04.5 and keeping the 143 degree tips.

IMO this pattern is going to be sex on a set of monotherms.
Click to expand...

I'm very interested to see your results. I'm about to order a set, and was planning on running the new bowl with my early injectors.
 
Smokem said:
It plays a role, but does not dictate completely whether or not it can be used in either form.

For example; use a Duramax nozzle(158°) with the 325hp Cummins piston, if the spray moves from the dome onto the bowl wall, isn't it re-entrant?

The same can be said for the 143° nozzle, if it is still spraying onto the dome, isn't it still non re-entrant?
Click to expand...

Does reentrant vs non-reentrant deal with the pre-combustion fuel or the post-combustion airflow?
 
You must log in or register to reply here.
Back
Top