Fuel injectors & fuel pressure for best atomization, MPG and low to mid RPM power?

General engine tech -- Drag Racing to Circle Track

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NewbVetteGuy
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Re: Fuel injectors & fuel pressure for best atomization, MPG and low to mid RPM power?

Post by NewbVetteGuy »

Here's a turnkey crate engine for sale from RCS Racing Engines that uses the FIRST fuel injection intake: http://rcsracingengines.com/Perf%20Crat ... 20EFI.html

They claim 460HP @ 5,200 RPM and 520ft lbs @ 4,000 RPM on the engine dyno out of their 383. With those RPM #'s, that's got to be with a smallish cam, too. -Can you imagine building a lower CR version of this thing with a turbo or two? -Use the torque to spin the earth backwards and go back in time, ala Superman 2 and convince GM to just make this thing the original GM TPI intake. :D

I'm sad that they seem to be the only professional engine builders using this intake. GOOD big block torque #s in a lightweight small block package; an aluminum SBC block would have just ridiculous torque #'s for the weight for a naturally aspirated engine.


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Re: Fuel injectors & fuel pressure for best atomization, MPG and low to mid RPM power?

Post by 1989TransAm »

I would have liked to see the dyno graph. Too bad they did not post it.
NewbVetteGuy
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Re: Fuel injectors & fuel pressure for best atomization, MPG and low to mid RPM power?

Post by NewbVetteGuy »

1989TransAm wrote:I would have liked to see the dyno graph. Too bad they did not post it.
It never hurts to ask... In my experience, they aren't really into digital communication and prefer olde fashioned phone calls.

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Re: Fuel injectors & fuel pressure for best atomization, MPG and low to mid RPM power?

Post by David Redszus »

If best atomization of fuel is the objective, use injectors with low flow rates (small orifices) at maximum allowable pressure, for the maximum length of time, usually 85% of normal duty cycle. Use a fuel with a low mean boiling point and high RVP.

For best MPG, run as lean as you can (15-16-1) using a higher specific gravity fuel.

For best mid RPM power, you will have to experiment or simulate intake runner length combinations, to find the sweet spot.
Gasoline is cheap. Go for the power. It's a lot more fun and you can always drive at partial throttle.
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Re: Fuel injectors & fuel pressure for best atomization, MPG and low to mid RPM power?

Post by peejay »

joe 90 wrote:EGR is more for emissions.

There's plenty of engines made without EGR but maybe not in US of A.
EGR is a huge benefit for fuel economy because it cuts down on pumping losses.

EGR working versus not was the difference between 41mpg (US) and 35mpg in my GA16i engined Sentra.
NewbVetteGuy
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Re: Fuel injectors & fuel pressure for best atomization, MPG and low to mid RPM power?

Post by NewbVetteGuy »

peejay wrote:
joe 90 wrote:EGR is more for emissions.

There's plenty of engines made without EGR but maybe not in US of A.
EGR is a huge benefit for fuel economy because it cuts down on pumping losses.

EGR working versus not was the difference between 41mpg (US) and 35mpg in my GA16i engined Sentra.
;-(

I do really regret buying headers before I fully thought through my combo and goals, but I drive a Vette and not a DeLorean so not much I can do about that now...

Adam
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Re: Fuel injectors & fuel pressure for best atomization, MPG and low to mid RPM power?

Post by MadBill »

EGR significantly improves light load mileage and reduces NOx emissions, but lean cruise can do just as well or better for economy, albeit at the cost of higher NOx.
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Re: Fuel injectors & fuel pressure for best atomization, MPG and low to mid RPM power?

Post by peejay »

Indeed. If you're not interested in keeping a cat happy, you can play with lean burn under cruise. OEMs have to keep the cat happy at all times, so they use EGR and nowadays wildly variable cam timing.
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Re: Fuel injectors & fuel pressure for best atomization, MPG and low to mid RPM power?

Post by englertracing »

NewbVetteGuy wrote:
peejay wrote:
joe 90 wrote:EGR is more for emissions.

There's plenty of engines made without EGR but maybe not in US of A.
EGR is a huge benefit for fuel economy because it cuts down on pumping losses.

EGR working versus not was the difference between 41mpg (US) and 35mpg in my GA16i engined Sentra.
;-(

I do really regret buying headers before I fully thought through my combo and goals, but I drive a Vette and not a DeLorean so not much I can do about that now...

Adam

Can't you have some bungs welded on?
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Re: Fuel injectors & fuel pressure for best atomization, MPG and low to mid RPM power?

Post by turbo2256b »

Its possible. big thing is does the intake have provisions for it. Ford had an external EGR set up around the time I LEFT THAT SUPPOSEDLY didnt need to be controlled by the ECM. Did the design work to fit them to a couple engines but never had the chance to learn much about how it worked. Supposedly it worked much better than the earlier version.
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Re: Fuel injectors & fuel pressure for best atomization, MPG and low to mid RPM power?

Post by NewbVetteGuy »

englertracing wrote: Can't you have some bungs welded on?
I'm too vain. I have nice shiny, coated headers and I don't want to ruin the nice coating.

I guess the good news is that I don't have cats so lean burn is a really good option for me.


Adam
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