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Discussion Starter #1
Guys, I'm planning a single turbo install on my 331 stock block. I currently have 42# injectors installed, will they be enough or should I get 60's while I'm at it? Who can figure the duty cycles to see whats best? Planning a mild tune to keep under 500 whp due to stock block for now.
 

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I think the right injector for the car is always the one that provides right around 80 - 85% duty cycle at WOT. This provides the best fuel atomization, mileage, emissions, and lines up correctly with the injection timing.

If you are truly building exactly 500 rwhp, let's work the math backwards. Considering a 15% loss for drivetrain losses, that's about 588 fwhp. Add in another 15 or 20 HP for accessory drive losses, and your talking a gross fwhp number of around 608.

That may be dead on, or just close, but we have to use some sort of calculations to take our best shot, so there it is. 608.

Now, the math is easy. Using the industry standard for injector size calculations, we get (@ .6 BSFC):

608 FWHP @ 80% duty cycle = 57.00 #/hr
608 FWHP @ 85% duty cycle = 53.65 #/hr
608 FWHP @ 90% duty cycle = 50.67 #/hr

Now remember, just because you only netted 500 rwhp doesn't mean that the block, crank, pistons, rods, bolts, combustion chamber, head gaskets, and fuel system didn't feel the 608 HP pinch. So if you don't want to push a stock 5.0 block to 600+, you might want to reconsider your RWHP goals.

If we were to bump that FWHP number down to 550, that's about 450 rwhp, and here's the math on that 550 FWHP requirement (@ .6 BSFC):

550 FWHP @ 80% duty cycle = 51.56 #/hr
550 FWHP @ 85% duty cycle = 48.53 #/hr
550 FWHP @ 90% duty cycle = 45.83 #/hr

The Lightning 42# injectors flow 43.01 #/hr @ 39.15 PSI, the standard Ford pressure. As you can see, all of the above scenarios require more fuel than that, so an upgrade is in order. We always want to use a Ford Racing injector, or a Siemens 60 or 80 #/hr injector (also sold as Ford Racing). Your choices are 42#, 47#, and 60# for EV1 and EV6 type injectors. The EV6 type is more desirable, as it is a much newer/superior design. The 47# would work in some of the above scenarios, but would require a connector adapter. But it appears the Siemens Deka 60 would be the best choice, and it comes in either type connector. Stock 5.0 connector is the Bosch/Minitimer.
 

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Good choice.

To elaborate a little on the post above you, technicaly you can't go past 85-90% duty cycle on a injector anyway (85-90% is 100% for an injector), unlike a fuel pump which can be modulated to full on at 100% dc, the injector pulse will become static as you aproach 90% since the next command to open is given before the previous pulse can finish. Running an injector static can lead to a loss of a/f control in the upper rpms or a wavy/choppy a/f curve. Which is why it is important to select the injector size based on no more than a 80% max duty cycle. If your getting close to this dc another work around is raise your base pressure to bring injector duty cycle down, however keep in mind as delta pressure increases, overall flow of the pump/sysem decreases. So why you can effectively make your injectors support more hp like this you will start to limit your pumps capability.
 

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are the ev6 a better choice with an adapter?
Ev1 and ev6 are the same height and moutning dimensions, only thing that makes them different is ev1 uses a jetronic connector and the ev6 has an uscar connector, so with connector adaptors they are both interchangeable to whats on the car.

The adpators are one more thing to fail and an extra piece to the puzzle though. Some guys will just cut the jetronic plugs off their harness and solder uscar plugs on etc.
 

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A little clarification. The EV1 is the old fat-body injectors. They're fat like your thumb. They're the long body, and the upper half is plastic and fat, the lower half is metal and tapers from fat to skinny. I've only ever seen them with the jetronic/minitimer connector on them.

The EV6 is a much newer, better design injector. It's also long, but it's skinny like your pinky, and all plastic. They're generally 4-hole injectors. They often come with the USCAR connector, but you can get them with the jetronic/minitimer connector.

The Jetronic/minitimer connector is rectangular with a locating tab in the middle. The USCAR connector is kind of oval, and has the clip off to one side, with two alignment tabs to align the connector up right.

The Siemens Deka 60's come in 3 varieties. The shorties, and two longs. The two longs are the same injector, but one has the jetronic connector and one has the USCAR connector. Other than that, they are identical.

The body style (EV1, EV6) often gets mistaken for the connector style. This happens because most EV1 injectors have the jetronic connector and most EV6 injectors have the USCAR connector. But the two are not necessarily linked.

http://www.google.com/url?sa=t&rct=j&q=ford racing injector tech&source=web&cd=1&cad=rja&ved=0CCEQFjAA&url=http://www.fordracingparts.com/download/charts/Fuel_Injectors_and_Adaptors.pdf&ei=ixqQUIjEF4nY9ATFi4G4Cw&usg=AFQjCNHXO5oSzH7RrKqsjdzLovkTqId7dg

You can get the Siemens Deka 60's flow matched for about $50 more from places like Racetronix. That's a good idea, since 1 or 2% of a big injector means more fueling errors than 1 or 2% of a small injector.
 

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Discussion Starter #16
so... the ev6 is a drop in fit as long as it has the correct plug on it correct??
 

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so... the ev6 is a drop in fit as long as it has the correct plug on it correct??
Yes sir. Drops right into a 5.0L. Just gotta make sure you get the one with the Jetronic/Minitimer connector, otherwise you would need the connector adapters.

Here's the flow matched ones: Racetronix - L107 - 63 lb/hr Siemens High-Z Fuel Injector MT

Equivalent Part Numbers:
Siemens FI114961 or 107-961 ( 107961 )
Mototron INJ-GAS-006 ( L107)
Accel 74620L
MSD / Edge 2030

Racetronix calls them 63 #/hr. That's true, if you turn up the pressure to 43.5 from the stock 39.15 (standard Ford pressure). These ARE the 60# Siemens Deka injectors.
 
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