Ive been thinking of running a throttle body fuel injection system on my 540. The engine makes good vacuum and is really not built to wild. The heads are the big merlins its 9.5:1 it has a solid cam 630 lift and 259 duration at .050 on 114LSA runs a 950cfm. Any suggestions on the size of the throttle body and injector sizes. I really dont know where to begin. I was looking at some of the hardware at wilson manifolds website and there are a lot of different sizes. Big question on electronics as well, appreciate your suggestions

Thanks Rich

I think you mean a multiport, not TBI. Wilson's makes billet air valves for MPFI.

For the cost, you couldn't be a Holley MPFI system with wideband oxygen sensor. Holley has some new setups for BBC's that don't have the regulator and pump. Comes with 42 or 50 pph injectors and a WBO2, ECU, harness, manifold, software and 1000 or 2000 CFM TB. I'd actually consider the 2.25" bore 2000 CFM piece with progressive linkage on a 540. I've dynoed some pump gas 540's and they've made an easy 650 HP with this setup.

In any case, unless you make things yourself, you're looking at $3k for a complete unit with WBO2 setup.

The driveability really is tremendous.

Yes, you are right Doug, please excuse my illiteracy when it comes to MPFI. Perhaps you could awnser a few basic questions for me. Is idle vacuum a major consideration in using a MPFI system? Do I need to have my intake manifold modified to fit the injectors and if so is there a problem fitting the 4150 style opening to a 4500 TB. Does the system from Holley include the intake? What kind of fuel system requirements are there? I currently have a sumped tank with a mallory 140 and a return line back to the tank all 8AN. Thanks for the education.

Rich

Rich,
Idle vacuum is a concern for a street driven vehicle. Don't get confused like most people do when camming for a factory computer. Then maintaining similar vacuum to stock IS a major concern unless they go in and tune the factory ECU. The less the vacuum with an aftermarket setup, the more tricky off idle tuning gets, but not much. I'd like to see at least 8-10" for a street strip car. With the control of EFI, and the timing control, you can usually get a lot of vacuum even with a hot cam. My 388" sbc has a 110 lc 242/248 solid roller and I have PLENTY of vacuum.
You can get bungs welded into any single plane intake. I wouldn't be too keen on a 4500 TB on a 4150 manifold with an adapter. Some people make a 4150 1300 or so CFM tb.

The Holley system I speak of has intake, throttle body (2000 or the 1000), fuel rails, ECU, software, wiring harnesses and sensors along with the NTK wide band O2 sensor. You need to plumb it (-6 or -8 in your case is fine) and add regulator and pump and filters. Your pump and reg won't work. You can run some Holley stuff or Aeromotive has really nice stuff. Having a sump is perfect.

You'll also definately want to control the ignition timing. There are several options there.


For a real education download the following Holley manual. It applies to anyones aftermarket EFI:

http://www.holley.com/HiOctn/ProdLine/Products/C950/199R10149-6%20Cmdr%20950.pdf

If done correctly, I don't know of anyone that regrets going to EFI except for the pocket book.

Nothing like being able to start a big solid roller in the winter with the crank of the key and drive off and have it drive like a new car, along with the response and other benefits.

I run accel Gen 7 on my car. I am very pleased with everything about it. Tuning was great, the "Virtual dashboard" is awesome, and it is really price competitive. I run a Holley 2000 cfm throttle body with the built in IAC. I have a little motor(427) so I get alot of low throttle "tip in". But on your motor it would work perfect. You can't go to big on the throttle body for making power. Go with a low impedence injector in the 50-70lb range. As far as vacume goes, you will not have a problem with whatever system you choose. I have 5lb of vacume at idle and have been able to tune my system perfectly in closed loop.

Scotty,

What do you mean when you refer to "tip in" as a problem. Is this an off idle stumble. Whats your opinion on the accel electronics vs the holley. Did you set up your own manifold? What type of fuel system are you running? Is there a prefered manufacture of injectors? Hope you dont mind the 1001 questions, thanks for your opinions.

Doug,

I run the digital 6, will the box work with the holley system? Is this the timing control you refer to.
Thanks again for your help

Rich

Scotty,

What do you mean when you refer to "tip in" as a problem. Is this an off idle stumble. Whats your opinion on the accel electronics vs the holley. Did you set up your own manifold? What type of fuel system are you running? Is there a prefered manufacture of injectors? Hope you dont mind the 1001 questions, thanks for your opinions.

Doug,

I run the digital 6, will the box work with the holley system? Is this the timing control you refer to.
Thanks again for your help

Rich

The off idle he refers to I believe would not be a stumble, but too much response causing jerkiness or spinning tires. A progressive linkage helps.

If the MSD controls timing (has a programmable curve) than it might not work or it might, I haven't used a digital 6 box with anything. What you want to use is the 16x16 RPM vs load maps the EFI has.

Doug is corect. The "Tip in" I refer to is basically an oversensitive throttle at real slow driving speeds. It seems I can touch the gas pedal only a little bit, but I get a major increase in horespower. The Holley body I have has the progressive linkage. It is just huge (2000 cfm), so on a real small motor like mine the throttle is extra sensitive at low throttle. BUT... I know I have max horespower at WOT. :D

As far as the Accel Vs. Holley thing goes. The holley is not sequential, and has no wide band option. I believe it is also lacking in some other options that Accel has. I like options! And so do most hot rodders!

I run the Aeromotive 1000 pump with -10 feed and -8 return. I sumped my tank.

For ignition, all you need is something that will produce a strong spark. I used to run a Holley Pro-Strip Annihilator ICT with individual cylinder control($750). Being that the Accel DFI does EVERYTHING the Holley ignition did and more. I sold it. It is pointless to run a high dollar ignition box with loads of options. I just bought a cheap Holley Annihilator box($150). It has no options but the same power output of the expensive system. Basically I would recommend you sell the Digi-6 and buy something like a 6AL box or something. You will be money ahead. I custom made my entire intake system myself. I had to because nobody makes an EFI 18 degree intake. If you have access to a machine shop, it only costs roughly $100 for bungs and rails. And as for injectors, Siemans are the best.
I like to answer questions. ;)

You can get an NTK wideband with the Holley as of this year with any MPFI system. For that matter the new PRO software allows you to use any aftermarket wideband unlike a FAST or Accel which make you buy their setup.

The kit I spoke of above comes with the wideband.

For that matter the PRO that comes standard with all Holley systems now has many nice std features that are options with other systems.

Internal datalogger (you can datalog with no laptop in the car)
Programmable inputs and outputs
Nice features like programmable MAP scale, temp vs. timing and capability to run several ignition systems that a unit like the FAST can't
Enough tuning parameters to tune anything I've come across, one of my friends just got done with his 1550 HP SBC single turbo engine for example.

The GenVII Accel has 3 stage nitrous control which the Holley does not.