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Blown EFI small block experience


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I am gathering up the parts to assemble my SBC. I plan on a 6-71 blower, with an ECM to control the 50lb injectors above the blower. The ECM will handle the fuel and spark for me
So far I want to use the Redline brand aftermarket ECM and harness kits, and enderle plumbing and hat.
as for the Injectors I haven't picked a brand yet.
Does anyone have experience trying this type of injection?
I'm still trying to understand carbs. There a few guys here that are good with blowers and may be able to help with the EFI too.
hey pop, just wanted to say hello! been wondering if we were going to hear from you pretty soon. tell us or better yet show us what you've been doing with yur project.

The enderle plumbing and hat are mechanical injection systems. You can convert a hat to electronic injection. I was just making sure I understand what you are wanting to do. If you want a good stand alone ECM for street I would use FAST it uses GM sensors I have had good luck with them in mustangs.
Hi Pop,

I plan on using the enderle bugcatcher converted to EFI also. I am not familiar with the redline system. Is it a Speed density system?

As far as the injectors are concerned, there are a few things you need to know. The aftermarket systems usually base the injector sizing on horsepower. A mild, blown motor with eight 50 lb/hr injectors at 43.5 psi of fuel pressure and 80% injector duty cycle should work up to approximately 492 hp. Using 55lb/hr injectors should be good for approximately 542 hp. The 43.5 fuel pressure is the standard pressure used for EFI calculations.

The Bosch pintle style injector is probable the most commonly used injector for EFI conversions. You can also buy fittings from a couple of companies to adapt the Bosch type clip to an AN fitting so that you can use the individual stainless steel line and keep the blower injector look. A common fuel rail just doesnt look as good to me.

You also need to check sure your ECM and injectors are compatible. There are high-impedance and low-impedance injectors. The high-impedance injectors are usually 12-16 ohm. The low-impedance injectors are usually 2-5 ohms and are common with the higher flow injectors. They normally require more voltage. The ECM has to have the right driver or you could have problems.

There are some other things to keep in mind with a blown motor. MAP sensors come in 3 configurations, 1 BAR, 2 BAR and 3 BAR. Most OEM MAP sensors are 1 BAR sensor and will read vacuum at atmospheric pressure. This is used for aspirated engines. 2 BAR sensors are used to measure up to 15 PSI of boost while 3 BAR sensors will measure up to 30 PSI of boost.

O2 sensors are narrow or wide band. Narrow band is designed to work around the 14.7 air fuel ratio plus or minus about a point. This is good for idle and mid throttle. A wide band o2 sensor will work in the 9-20 air fuel ratio ranges. This will work in the 11.5 to 12.5 air fuel ratio range where the best performance is at. A wide band sensor is what I would use.

Another thing you will need to do is block off one or two of the 3 areas inside the bugcatcher casting. The bug catcher casting flows, if I remember correctly about 2300 CFM. If you block off one of the side plates, it restricts it to about 1400 CFM.

Here are a couple of pictures from the PRI show of a BDS 16 injector setup and a 8 injector fuel rail.



I just caught this post, thanks ofr the props RPM!

Looks like Bill covered it pretty well. Just to reinforce, you'll definatly want a speed density type computer. Otherwise you'll need a mass air sensor which would be difficult to plumb using a bug catcher.

Hope this helps
Well sorry it took so long to get back to this.
I have been in Afghanistan since March and just now returned.
But I have bought the Dyers blower, Enderle hat and lines.
I am going to use the redline computer system with the fuel pump and wiring options.
So far I have had to re build the ss lines. Using the BDS plate with screw in injectors made the fit very poor. Not a big deal to build new ss lines for the injector.
I have only been home for less than a week, but can't wait to hear this blower whine!!
Welcome back home Pops, thank you for your service.
Thanks for all the kind words.

I managed to get the motor assembled and the blower mounted with the EFI. Its not as easy as I thought but I managed. Before I got to fire it up I had to leave again!!
Hopefully I will start the beast by May.:)

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