Bosch Motorsport nozzles bashing thread

[cquestad]

Depends on your timing, it has been said that a 50/50 split is optimal for power, mpg, and durability but in the case of a tune running big duration you would have to run 35+ degrees to keep a 50/50 split.

How does fuel get into the cylinder before the injector is fired? The split your talking about it spliting it 50/50 on piston position.

 

[Joesixpack]

Depends on your timing, it has been said that a 50/50 split is optimal for power, mpg, and durability but in the case of a tune running big duration you would have to run 35+ degrees to keep a 50/50 split.

I took his comment (mikmaze) as latency between the actual signal to fire the injectors and when they start spraying.

Your talking about a mm3 split between BTDC and ATDC? Which seems impractical to try and accomplish.

 

[cquestad]

Duration includes electrical/hydraulic latency.

Sure...but it does not predict when the injector is going to open like was suggested earlier!

What rod length were you using? I got more like 38 degrees or so on a 143 degree on a stock bore before it hits the walls? 49 degrees on a 124...so I doubt my previous comment.

But it takes only ~33 degrees to hit the lip at the top of the wide bowl with a 143 degree spray.


All this was assuming that spray speed is FASTER than the speed of light.

Pistons can have a linear velocity of 600 or more inches a second average...so even if the fuel was 10 or 100 times faster...it still would calculate delay.

 

[Smokem]

So when the 143° nozzle is used in a 56mm bowl with a tapered opening of 70mm no one worries about the spray pattern or timing.

Yet when the same 143° nozzle is used in a 76mm bowl everyone assumes it will cause automatic destruction...interesting.

 

[phale]

Some how I read the post wrong. disregard my first post in reference to what was asked.

 

[cquestad]

So when the 143° nozzle is used in a 56mm bowl with a tapered opening of 70mm no one worries about the spray pattern or timing.

Yet when the same 143° nozzle is used in a 76mm bowl everyone assumes it will cause automatic destruction...interesting.[/QUOTE

You are ignoring the point about piston construction...both shape and thickness.

 

[Smokem]

The same piston is used with mechanical nozzles up to 160° cone angle, still no automatic destruction. Piston construction is relevant, that bowl design could easily and often is used with a wider cone angle in a re-entrant style injection event.

But I suppose the arguing will still go on by those that wish to scare people away from using something beside a stock nozzle, and those that have done it will just continue to do so, successfully.

 

[homewrecker]

Its been stated by a few people that 28-30° advance timing is what's being used to make some big numbers. So is there a way to determine where that is spraying in the bowl. 143° nozzle, late model piston. Anyone got a pic of the late model piston cut in half?

Tapamaxxing

 

[Joesixpack]

Just had one handy I cut apart years ago.

 

[ENafziger]

Are most people running the 143° injectors, running only a main event? Or is the quantity of the pilot not significant enough to warrant concern about wall impingement/oil dilution?

 

[homewrecker]

Just had one handy I cut apart years ago.

Thanks. Bare with my ignorance here, why is there a color difference at the top ring land? Different material?

Tapamaxxing

 

[Tate]

Steel ring land.

 

[Smokem]

Are most people running the 143° injectors, running only a main event? Or is the quantity of the pilot not significant enough to warrant concern about wall impingement/oil dilution?

The later bowl design is 6mm wider, why would one worry about wall impingement if both used a pilot event and the same cone angle?

 

[cquestad]

The later bowl design is 6mm wider, why would one worry about wall impingement if both used a pilot event and the same cone angle?

Because the pilot is before the main...so if the timing of the main might be in suspect...the pilot surely is. I wish you would answer a question with an answer...not another question.

So much has already been skipped. Lets tie down the exact timing it takes to hit the wall and edge of the bowl. What rod length were people using...i am trying to make sure i didnt make a mistake. Also...there is a delay for sure from commanded injection till the fuel hits piston, cylinder, whatever. It can be quantified...so we should do this as well too.

Just a geometry observation...once fuel is hitting the edge of the bowl on the 04.5 to 07 piston, it would clearly not deflect back to into the middle of the cylinder but rather right towards the wall. So...when we are discussing spray pattern we should stop thinking the streamthe has zero thickness...ie he spray sttream widens

 

[ENafziger]

why would one worry about wall impingement if both used a pilot event and the same cone angle?

Advanced timing + higher pressure + larger orifice nozzles can result in wall impingement. With an open ECU trying to run HCCI, we had rapid oil dilution...like 2 gallons of fuel in the oil in 60 hours. Hence, the investigation and prototyping of dual spray angle nozzles and variable cone angles...utilizing a tight cone angle for the pilot(s) and wider for the main. Sometimes I'm more consumed with the "research" end of things, and don't have a good feel for how things are playing out in the performance world.

I'm still in the dark ages on my personal vehicle with my Smarty PoD/TST, so I have no clue what my actual timing is. I just wondered if those running advanced timing with lots of fuel and big injectors were running with a single injection event. Maybe it's not an issue.

 

[dvst8r]

Well I can't say for sure what the timing is in degrees that we ran (thank you arbitrary Smarty), nor the duration (again thank you arbitrary Smarty).

We ran the standard injection events.

We did tune on a dyno to peak timing numbers (until they fell off and then went back) and peak duration numbers (until it fell off and then we went back).

Here is what the piston looked like when we pulled it out, sorry for the cell phone pic, but the piston its self is not what we are looking at just the spray pattern. Obviously in the bowl, at 1200whp+ on fuel and 1500whp+ on the juice.

To get every last drop of fuel needed to make a 149.72mph pass out of a nearly 7000lbs truck, we were using enough duration that we were getting such late fuel it did this to our expansion tube AFTER the JGS external wastegate:

It also tuliped all of the exhaust valves.

We obviously have a new plan for this year, as while that made power, it was hard on parts, and the longevity of the power was short.

The long of the short is: If you are spraying out of the bowl with the 143 degree nozzles, you are doing it wrong.

 

[dvst8r]

Advanced timing + higher pressure + larger orifice nozzles can result in wall impingement. With an open ECU trying to run HCCI, we had rapid oil dilution...like 2 gallons of fuel in the oil in 60 hours. Hence, the investigation and prototyping of dual spray angle nozzles and variable cone angles...utilizing a tight cone angle for the pilot(s) and wider for the main. Sometimes I'm more consumed with the "research" end of things, and don't have a good feel for how things are playing out in the performance world.

I'm still in the dark ages on my personal vehicle with my Smarty PoD/TST, so I have no clue what my actual timing is. I just wondered if those running advanced timing with lots of fuel and big injectors were running with a single injection event. Maybe it's not an issue.

I would say if we left the oil in for more then a few passes we would probably start to see some dilution, however we never have, so I can't say this with complete certainty.

 

[Smokem]

Advanced timing + higher pressure + larger orifice nozzles can result in wall impingement. With an open ECU trying to run HCCI, we had rapid oil dilution...like 2 gallons of fuel in the oil in 60 hours. Hence, the investigation and prototyping of dual spray angle nozzles and variable cone angles...utilizing a tight cone angle for the pilot(s) and wider for the main. Sometimes I'm more consumed with the "research" end of things, and don't have a good feel for how things are playing out in the performance world.

I understand what you are explaining, and this is the reason for the taper in the bowl design of the '03-04 and 6.7L engines. However, if both nozzles are the same size, cone angle, and using the same tuning, how could fuel impinge the walls in a cylinder where the piston has a larger bowl?

Because the pilot is before the main...so if the timing of the main might be in suspect...the pilot surely is. I wish you would answer a question with an answer...not another question.

See above. You don't like the fact I make you answer the question yourself?

 

[dvst8r]

Well I was just corrected, and then double checked the flow sheets from these injectors.

I was wrong. Those are the 124 5 hole.

Our new injectors are the 143 degree variants, probably what I was thinking of, which we will still be running with the same pistons. I highly doubt there will be an issue.

 

[Joesixpack]

Advanced timing + higher pressure + larger orifice nozzles can result in wall impingement. With an open ECU trying to run HCCI, we had rapid oil dilution...like 2 gallons of fuel in the oil in 60 hours. Hence, the investigation and prototyping of dual spray angle nozzles and variable cone angles...utilizing a tight cone angle for the pilot(s) and wider for the main. Sometimes I'm more consumed with the "research" end of things, and don't have a good feel for how things are playing out in the performance world.

I'm still in the dark ages on my personal vehicle with my Smarty PoD/TST, so I have no clue what my actual timing is. I just wondered if those running advanced timing with lots of fuel and big injectors were running with a single injection event. Maybe it's not an issue.

HCCI would have been some truely silly timing along with a large quantity where as a pilot is really a very small quantity that in all likely hood is in the vapor fraction well before SOC working with the pressures we are at.