Heading to the dyno Saturday

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Re: Heading to the dyno Saturday

Postby Sutter1stgen » Thu Feb 07, 2013 9:44 pm

^^^^^ I often thought the same thing. I couldn't understand how a more free flowing injector needed more timing if in fact it let's the fuel flow better. But from mine your and everyone else's expirience more timing with larger injectors makes more power.
Eric

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Re: Heading to the dyno Saturday

Postby RCCUMMINS89 » Thu Feb 07, 2013 9:58 pm

Because it puts in larger droplets of fuel, and therefore takes longer to burn. Only surface area of the fuel burns. Which is why higher injection pressures require less timing (cp3, vp44, p pump)

Like oldestof11 said with the pool example.
89 RC on shortened 92 diesel frame - NV4500 w/dual disc/4.10s on 37s. - Self built pump, "hot screw", lots of timing, True high volume low pressure lift pump, 62fmw/68/.7gated, 77lpm SAC Inj., Studs/O-rings,- 423/1220 Mustang - 11/16/2013 http://www.TheHungryDiesel.com full line dealer, if you don't see it please ask.
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Re: Heading to the dyno Saturday

Postby Sutter1stgen » Fri Feb 08, 2013 7:20 am

It makes sence now.
Eric

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Re: Heading to the dyno Saturday

Postby 1STGENFARMBOY » Fri Feb 08, 2013 2:53 pm

RCCUMMINS89 wrote:Because it puts in larger droplets of fuel, and therefore takes longer to burn. Only surface area of the fuel burns. Which is why higher injection pressures require less timing (cp3, vp44, p pump)

Like oldestof11 said with the pool example.



With this beeing the case, looks like the injectors with more holes and smaller dia holes 7-12 or so IE smaller droplets
would burn faster/better than say a 5-25 like is in project rustbucket.

rite---wrong

im trying to learn something here.
93 W250 STD CAB, AUTO 3.55, GAUGES, 80HP DDP STICKS, DENNY T ,16CM HOUSING, 60MM GILLETT, VE MAXED,BHAF, BHFF, 366 SPRING,P/S INTERCOOLER, TIMS COOLER TUBS, TIMMING 1/8 BUMP,4in TURBO BACK TO DUEL 5IN STACKS,33 12.50 BFG, HOLLEY BLACK, CONVERTER COOMING.
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Re: Heading to the dyno Saturday

Postby cmann250 » Fri Feb 08, 2013 3:07 pm

1STGENFARMBOY wrote:im trying to learn something here.

I'm in the same boat. What's logical in my head doesn't always work in real life :lol:

I have seen power made with with multi hole injectors (more than 6 holes) with the 24v and Common Rail engines. I think injection pressure combines with injector pattern and size for them. Take say a 7x12 being fed by a VE and compare it to a 7x12 being fed by a CP3. Assuming the internal volume is the same, the fuel coming out of the CR injector is a fine mist compared to the dribble out of the VE. It's dramatic, but the pressures a VE puts out are not much compared to a CR.

Then again, that's just my theory. I don't have any Bosch certifications hanging on my wall.
Caleb, Certified Shade Tree Mechanic Extraordinaire :mrgreen:
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Re: Heading to the dyno Saturday

Postby RCCUMMINS89 » Fri Feb 08, 2013 3:51 pm

Think of it like hand loading ammunition.
Different powders are used with different weight bullets and different length barrels, to ensure proper burning and best accuracy and velocity.

Back to the multi hole injectors....7 hole injectors don't get good bowl penetration in ve pump applications, so Ive been told :roll: .

I think it is more of the fact that it creates more back pressure and therefore the ve pump doesn't move as much fuel. Similar to turning a 409 spray bottle from squirt to mist, it is harder to spray it AND you don't spray as much...but it is misted more. It takes energy to conform fuel into a mist, so in order to mist 60lpm it creates more pressure... not matter how you do it. The ve pump doesn't produce the pressure to do this, it simply just won't move as much fuel.

Also brings up the point of spray angles...not specifically of the spray angle but how broad the spray angle is. such as flow honing broadens the spray angle of the injector....this both can increase effeciency and decrease efficiency depending on how much it is done.
89 RC on shortened 92 diesel frame - NV4500 w/dual disc/4.10s on 37s. - Self built pump, "hot screw", lots of timing, True high volume low pressure lift pump, 62fmw/68/.7gated, 77lpm SAC Inj., Studs/O-rings,- 423/1220 Mustang - 11/16/2013 http://www.TheHungryDiesel.com full line dealer, if you don't see it please ask.
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Re: Heading to the dyno Saturday

Postby 1STGENFARMBOY » Fri Feb 08, 2013 3:57 pm

I knew the high preshure pumps would atomise the fuel better, i just didn't know on a VE if more or less holes
is better.
93 W250 STD CAB, AUTO 3.55, GAUGES, 80HP DDP STICKS, DENNY T ,16CM HOUSING, 60MM GILLETT, VE MAXED,BHAF, BHFF, 366 SPRING,P/S INTERCOOLER, TIMS COOLER TUBS, TIMMING 1/8 BUMP,4in TURBO BACK TO DUEL 5IN STACKS,33 12.50 BFG, HOLLEY BLACK, CONVERTER COOMING.
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Re: Heading to the dyno Saturday

Postby oldestof11 » Fri Feb 08, 2013 4:00 pm

The big thing the CR's have over any mechanical pump (VE, P, VP44) is they can open their injectors infinitely for what ever time is commanded. That is why they can have multiple smaller holes but still make big power.

The mechanicals' have the cam which controls the rate the fuel gets injected (how quickly it ramps up pressure) and how quickly it plateaus (how long the ramp is). A 7x12 may have the same cross section as say a 5x18 but the 5x18 burns slightly slower due to bigger droplets. That is why the 7x is better for towing and 5x18 good at top end.
Jon
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Re: Heading to the dyno Saturday

Postby RCCUMMINS89 » Fri Feb 08, 2013 4:18 pm

All true....

But I guarantee a 7x12 will not move as much fuel as the 5x18
89 RC on shortened 92 diesel frame - NV4500 w/dual disc/4.10s on 37s. - Self built pump, "hot screw", lots of timing, True high volume low pressure lift pump, 62fmw/68/.7gated, 77lpm SAC Inj., Studs/O-rings,- 423/1220 Mustang - 11/16/2013 http://www.TheHungryDiesel.com full line dealer, if you don't see it please ask.
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Re: Heading to the dyno Saturday

Postby fatty » Fri Feb 08, 2013 7:08 pm

RCCUMMINS89 wrote:All true....

But I guarantee a 7x12 will not move as much fuel as the 5x18

Ok then let's see a flow chart stating that.
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Re: Heading to the dyno Saturday

Postby RCCUMMINS89 » Fri Feb 08, 2013 8:07 pm

Well... I do know that I have been told by my flow honer that with the same cross sectional area the higher the holes, the less they flow in real life on his flow machine.

It's simple fluid dynamics. It takes more energy to convert mass (fluid to spray), also there is more surface friction of where the fuel is touching the nozzle itself.

So when talking about nothing more flow..... the larger the hole the greater the flow. However, there is of course a happy medium.... one needs both flow and a quality of spray.



But do I have a flow chart to prove....... no. I could probably get one, but is it really worth the effort? Maybe.
89 RC on shortened 92 diesel frame - NV4500 w/dual disc/4.10s on 37s. - Self built pump, "hot screw", lots of timing, True high volume low pressure lift pump, 62fmw/68/.7gated, 77lpm SAC Inj., Studs/O-rings,- 423/1220 Mustang - 11/16/2013 http://www.TheHungryDiesel.com full line dealer, if you don't see it please ask.
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