EFI Recommendations - Blown Early Hemi

[Bored&Stroked]

I'm an EFI newbie -- but pretty experienced in engine building, tuning, etc.. I'm just about completed the build of an early 392 Hemi, with Donovan heads, 6-71, .550 lift cam - 245degrees @ .050, MSD 7535, special locked down distributor with MSD trigger. The car is a street car, 5 speed trans, Q.C. rear end, etc..

Anyway, am pondering purchasing a FAST XFI and going the EFI route. The Donovan blower manifold is plumbed for mechanical injectors - obviously too small for EFI injectors (easy fix). Am pondering taking a Hilborn 4-port mechanical injector and converting it to EFI -- running 8 injectors in the injector and maybe 8 more in the manifold ports. I've got a BG Mighty Enduro fuel pump - so I believe I'll have enough fuel capacity and pressure to handle the EFI. Though I've not yet put the engine on a dyno, believe it should have 600 or so HP (conservative).

Any EFI experts here who have built blown setups? What do you think for the injectors . . . do injectors above/below the blower make sense?

I welcome all your ideas and opinions. Anybody know an expert tuner who could map a setup for me? Thanks a bunch!

[camcojb]

no need for 16 injectors at that power level. I think you need all eight above the 6-71 as they're made to have the fuel run through them. I have heard of issues with running them dry, but that may be a rumor.

The FAST XFI should handle that combo easily.

Jody

[64duece]

A cheaper yet viable alternative is Holley's Cmdr950 w/ twin throttle bodies. As posted above, the clearances are setup and the atomized fuel will help seal and cool the charge.

It can be done for less than $2K with a base TBI kit, auxillery injector driver and added WBO2. The only area I've seen some folks have issues is with the idle air control.

[Bored&Stroked]

I'm probably going to put a Hilborn 4-port or Enderle Hat on the top-end --- obviously with EFI for the fuel system. I already have a couple Barry Grank Mighty Demon carbs . . . will start the motor on these, then switch over to EFI after break-in. I'd like to go the 60's mechanical FI look -- but with all the benefits of EFI and a digitial ignition.

Have you guys seen anybody who runs EFI injectors both above and below a blower? (I know - sounding like a mechanical old-school guy!). I was pondering whether you could create two complete different maps (configurations) - one that only used the above-blower setup, and another that used both. I'm probably over-imagineering on this --- just wondering what others have done and what the Pros/Cons are.

Thanks for for help . . . keep it coming.

[64duece]

You can run a bottom/top configuration with staged injection. Both FAST and Big Stuff offer upgraded controllers to support this feature.

[andrewb70]

With a 6-71 I would run dual quad carbs. All the downsides of a carb go away when you have a supercharger mixing the air and fuel. You will also get better cooling of the air/fuel mixture through the superior atomization of a carb.

Andrew

[Bored&Stroked]

Thanks - will explore what this option costs and how you setup the mappings for it. I've heard that some people use stages that are triggered by boost -- to richen up the mixture when the boost gets high. This seems like the right approach to me for EFI and a higher boost situation. Appreciate the help.

[Jim Craig]

Call Andy Starr @ Hilborn (215-643-4607) or just wait I'm sure he'll show up on this thread eventually. There is a lot of mis-information about blowers & EFI out there, listen to Andy he won't steer you wrong.

[BrianP]

I don’t know if you already have a Hilborn setup but they do sell one already setup for EFI. I think that you can purchase the injector hat assembly separately.

http://www.hilborninjection.com/product.asp?Id=366&CatId=158

You might also want to contact Hot Hemi Head. They have a lot of nice hemi stuff.

http://www.hothemiheads.com/intake_manifolds/hilborn_EFI_with_scoop.html

[Rolling_Thunder]

no need for 16 injectors at that power level. I think you need all eight above the 6-71 as they're made to have the fuel run through them. I have heard of issues with running them dry, but that may be a rumor.

The FAST XFI should handle that combo easily.

Jody


A big issue with running them dry is the lack of cooling... as the fuel usually is used to aid in cooling the rotors... :headbang:

[Bored&Stroked]

Thanks to everybody for the input and suggestions. I'm looking for somebody who really knows the FAST XFI unit - for blown applications. I'm probably going to build a "mule" motor to experiment and learn on . . . before I head down the high dollar early Hemi route. I'll update the site as I know more and come up with combinations.