Fuelishly Simple

Radical fuel management made real easy!

Jim Moore - August 12, 2011 09:00 AM


Magazine editors DO have to work! You’d never know Andy had just flown in from Florida and it was 3 a.m. when this picture was taken, would you?


Doug Flynn, me and Chris Bennett making the swap.


Doug and Chris “changing the jets and bumping the timing”!


All ready to make a pull. Just your average sweet little 860-plus horsepower pump gas street motor!


Heading back home with more power and fuel mileage!


The Holley 2000cfm throttle body is just pure billet artwork. It’s almost a shame to cover it up!


It may be high-tech, but Holley has made it a long way from complicated. Simple is good! Check out the Holley D.I.S. ignition system “4 pack” of coils.


It ran great before, but it took a LOT of work to get there. The Holley EFI beat it with only 10 minutes of run time!


Just a couple of nine-second pump gas big blocks having fun! Doug and I have been doing this for years!


The first drive around the block lasted 2,500 miles! Here we are at the “Vettes in the Valley” show in Maggie Valley, North Carolina, at the halfway point of our 2,500 mile shakedown cruise. The .774-inch lift solid roller cam never required a bit of attention.

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"I'm going to drag your knuckledraggin' butt into the 90's if it kills you!" — Holley’s Doug Flynn

For 15 years I’ve been running my homebuilt Holley 1050cfm 9375 Dominator on my 540-cubic inch Corvette and on the 427 that preceded it.

It took some work, but I had created a really sweet street carb that never hesitated or fouled a plug, idled and cruised clean and could literally drive to the track and run 9-second ¼ mile times without touching it. I was pretty happy … or so I thought.

Over the last few years, I’ve watched Doug Flynn as he developed the Holley HP and Dominator EFI systems on his personal test car that he’s owned since high school. Doug’s ’72 Nova runs a 491ci stroker with aluminum Holley oval port heads and solid street roller cam along with a T-400 and 3.73 gears in a Dana 60 rear. The coolest of cool is the old-school Tunnel Ram that tops it off. But a little closer look reveals it’s been converted to EFI and uses two “fly by wire” throttle bodies from a Z06 Corvette! Oh yeah … there’s also some N20 solenoids that combine with Holley’s “dry” fuel capabilities (no additional fuel solenoids) that have taken the 3,750-pound cruiser from its normal 10.30 at 128 mph performance all the way to a 9.57 at 138 mph so far.

And when I say I watched, I mean up close and personal from the lane beside him at the track during our annual grudge races at Bowling Green, Kentucky. I’ve yet to see it stumble or run poorly despite wildly changing temps and conditions. Doug hits the key to fire it up dead cold and lets it warm up like a new pickup truck without touching the throttle. While I thought I was happy with my carb, I will admit to being very impressed with the driveability and tuneability of the Holley EFI setup. Doug always made me drool as he displayed all the features he could play with while never getting a drop of gas on his hands!



Aftermarket EFI systems have been out for awhile now and, until recently, have been divided into two very distinct camps. The end user could choose between the “plug and play, auto-tune as you drive” version and the “hardcore racer” system that requires you to build complicated tables and manipulate the entire tune. Both have their place, but with each came drawbacks.

The simple versions will fire right up and idle immediately and their baseline tunes really will adjust themselves as you drive, changing the air/fuel ratio to meet whatever the engine requires at that instant. How much better could it get? The “race” versions also come with base tunes to get you started, but after that you pretty much need to build the tables by looking at all the various parameters to meet the needs of your combination. It’s very much like carburetor tuning and if you can tune a carb, you can tune a race-type EFI system. You just have to know what you’re looking at and what each change brings to the table. On the other hand, you can get way out of whack real quick with just a few keystrokes! The neat part is that you can put it right back just as easily.

After looking at the good and bad of each system on the market, Holley wiped the slate clean and combined the best of both worlds. With the Avenger, HP and Dominator EFI systems, Holley claims to have created products versatile enough to drop on a daily driver all the way up to a 2,000-plus horsepower nitroused/supercharged/turbo’d monster or any combination in between. Seriously! The systems are very similar but add features as you move up the scale depending on your needs.

You may remember a few months ago we covered the buildup that turned my 540-inch into a 555-inch, as well as a round of dyno testing with heads, cams and intakes. Sandwiched between all of that testing at Judson Massengill’s School of Automotive Machinists in Houston, Texas, Doug and I cooked up a plan to pit the Holley Dominator EFI against my carb on the dyno and then get some street time on it with a little cross country 2,500 mile road trip. What better way to cut through all the theory and advertising (as well as call Doug’s bluff!) than a little back-to-back dyno session with no prior preparation. Just pull it out of the box, hook it up and see what it could do.

For my car, we are using an HP Dominator version, which allows a lot of room for growth later on as my horsepower cravings continue to get the better of me. This thing can do just about anything without the need for multiple controllers and complexity. (There’s some more information at In addition, we added Holley’s ultra-trick Distributorless Ignition System … D.I.S. for short, which uses four separate coils and a crank trigger arrangement to allow totally dead accurate timing control. You can run the Holley EFI with your current ignition setup, but we got caught up in the dreaded “while you’re at it” syndrome.

To start things off, the engine was configured just as it was during all the times Doug and I had raced other than the added 15 cubes and a half-point more compression. That means 555ci, standard tension street rings, no vacuum pump, ported Brodix 2Xtra heads (377cc after porting), 11.56 compression ratio, and an Engle 266°/272° at .050-inch solid roller cam on a 112° LSA. The lift is .774/.731-inch before lash. The intake was an Edelbrock Super Victor with some good port work and my trusty old Holley 1050 Dominator sitting on a one-inch open spacer. I’ve worked the carb by adding a power valve and converted it to a two-circuit configuration (instead of three) on the primary side only, as well as adding soft progressive linkage. All of this just helps streetability more than power. When S.A.M. instructor Chris Bennett hit the throttle there was straight 93 octane in the tank just like I always drive and race with.

After a few quick pulls to break everything in a little, the baseline with my fresh-off-the-street tune using 82/95 jets produced 861.3hp at 7,000 rpm and 722.3 lbs-ft of torque at 5,300 rpm. We tried increasing the jetting to 84/96’s but it got a little fat and dropped a couple of horsepower. The old Holley performed excellent as always. Now at this point Doug was ready to start turning wrenches, but I said “Hold on just a minute there big boy”! I mean if we’re going to see how great this new whiz bang stuff is, we better test it against some REALLY good stuff right?

Right about here is where Doug was crying as I pulled out my favorite high end/high-dollar Braswell Dominator that I routinely bum from my friend John Wilson for dyno testing different combos. That custom built carb always does an incredible job filling in the torque curve and we were going to give it a shot once more. As Doug put the new intake and throttle body back on the workbench, he shook his head and grinned as he took his place back at the dyno console to see how much I was going to stack the deck against him!

As expected, we picked up torque to 732.9 lbs-ft. But looking at the peaks, we dropped to a 4,900 rpm peak instead of 5,300! Horsepower climbed a few notches to 864.2 at 6,900 rpm. That’s an increase of about nine lbs-ft and nine horsepower average, which is very impressive for just a carburetor change when the first one was working well already. At this point we decided to add some fuel as all indications pointed to it being a little lean. With a simple jet change to 94/95 versus the original 93/93 combo and a slightly cooler engine temp, we printed 869.1 hp at 6,900 rpm and 735.6 lbs-ft at 5,200 rpm. This raised the average horsepower and torque another few points. While this carb was killer on the dyno, and would be on the track as well, streetability would be another matter.


On With the EFI

Out of the box came the new Holley EFI intake which is no little piece for sure. It’s nearly as tall as the Super Victor/one-inch spacer combination and the plenum is huge, but the first thing Doug will have to overcome is that this intake is stock and as cast versus the Super Victor with a lot of interior work and port matching. The intake was plumbed with Holley’s 66-lb injectors and billet fuel rails. On top, we bolted the beautiful billet 2,000cfm throttle body in place, but there are smaller 4150 flanged versions available. We already had the D.I.S. ignition system ready to run with the crank trigger wheel and sensor bolted in place (easy) as well as the recommended GM sync pulse distributor used on some 1990s big block vehicles, AC Delco PN 213-350. This allows sequential fuel injection control … which we didn’t use for these tests. Sequential injection will help driveability more than power. Once all the wiring was plugged in, it was put up or shut up time!

These systems can be monitored and manipulated with everything from a small handheld programmer (Avenger) to a nifty LCD screened handheld device (HP and Dominator) to just a regular laptop. The laptop gives you a bigger screen and makes it easier to play with things, so that’s the way we did it. To start things off, Doug programmed a base tune by selecting “496/650hp” (sorta sounds like it might have come from a certain red Nova, huh?) from the drop-down menu within the Holley software and then selected a few other basic parameters. The power was turned on, the fuel pump buzzed, but would it start? It fired right up and sat there idling just like it thought it was a new car! OK Doug … first hurdle down!

Now here’s where it got interesting. The fact that this motor is making a lot more than 650hp isn’t really an issue. This is a speed density system that monitors vacuum, engine rpm, throttle position, engine and air temp as well as O2 readings to deliver any air/fuel ratio you want. In this case we were commanding a 13.0 ratio. So no matter what happens, that’s what we’re going to get since it will add or subtract fuel as needed to get there. And even though we’re running the “baddest of the bad” setup, it can still “self-tune” as it runs, just by checking the box on the screen and letting it go. Or, for more options, you can tell it to do anything you want at any given rpm and load point. We ran the engine at a light load on the dyno to let it “learn” and then cycled it up to 4,500 rpm, and then to 6,000 rpm a couple of times to let it get a feel for what was about to happen. All looked well, so Chris positioned himself in his usual stance where he can view the dyno cell as well as scan the data screens while he mercilessly shoves the throttle forward. I really think he enjoys torturing my engines!


Dyno and Drive

After the first hard pull, we were looking at 861.7hp at 6,900 rpm and 742.3 lbs-ft at 5,100 rpm. Ouch! Did that thing just put the hurt on my homebuilt stuff by 20 lbs-ft and tie it for horsepower? Couldn’t be that easy, so we whacked it a few more times and pushed the coolant temp up 30°-plus which usually hurts power. Guess what? The stupid thing learned a little more and ended up with 15 more average horsepower and lbs-ft of torque over my old carb and even beat the Braswell overall. At this point we were all wishing we had some injector bungs welded on that ported Super Victor to see how much better it might do!

The next part of the challenge was to see if it would actually make as good a showing while driving as it did in the dyno cell. After all the flogging sessions were over, I went home to bolt the engine back in place and start installing the EFI components. Now I had a little help here. Auto Enthusiast Tech Editor Andy Bolig flew in to take the planned road trip, but when I picked him up at the airport I had to admit that even though it was 4 p.m. on Monday and we were scheduled to leave at 7 a.m. Tuesday, I hadn’t actually cranked the engine in the car yet! “We” had a little work to do!

Since my car is a heater delete version, I had a nice place to mount the 11x 5½x1-inch thick ECU on the inside of the firewall where the heater box would normally be by using the supplied vibration insulators. You can mount it anywhere really and in any position because it’s “potted,” but it’s best to put it somewhere away from extreme heat. The wiring harness that comes from Holley has all OEM-style main connectors already attached, and since they only fit one slot and are labeled, you just plug them in. You do need to hook up battery connections and depending on options like N2O, methanol, cooling fans, fuel pumps, ignition etc., you will need to make a few connections as needed, but most things are ready to go. One thing you MUST pay attention to is the wiring connections. You’re going to want to solder everything you can and use good heat shrink tubing to seal the connectors. This is NOT where you want a bunch of ugly wire splices with gobs of electrical tape everywhere or cheap blue crimp terminals. Besides looking tacky and having all your buddies laugh at you, you’re asking for trouble with any electronic circuit that is dealing with small voltage levels. Resistance is a terrible thing and is the main cause of many EFI problems.

For the fuel system, we were able to use most of what I already had, which included an Aeromotive A1000 fuel pump feeding a -10 feed line and a -8 return back to the top of the fuel tank. I stuck with Aeromotive for the regulators also because they’ve always been dead reliable, but swapped my 7 psi carbureted #13204 regulator for a #13101 that keeps pressure at 43 psi. I was able to use a couple of adapter fittings and some short -8 hose sections to hook up to the Holley fuel rails. Since I had already fabricated a bracket to mount the Holley D.I.S. coil package above the short sync pulse distributor, all I had to do was plug in the wires to it as well as the injectors and various sensors (they’re all labeled too). I turned my throttle cable bracket around and placed it on the rear throttle body studs and then made some slight mods to position the cable as well as drill some holes in it to mount the manifold absolute pressure and ambient air temperature sensors. No rocket science involved at all.

Somewhere around 3 a.m., we hit the key and it fired up! Assuming my neighbors wouldn’t really be too impressed if I did burnouts up and down the road, we decided to call it a night and get a few hours sleep before hitting the highway. When we awoke, we strategically loaded a week’s worth of clothes, gear for two and tools (as well as a few spare parts just in case) in every available space in the rear of the ’Vette, and without so much as a run around the block we headed to Memphis, Tennessee, from Fort Worth, Texas, for the first leg of our journey. You can read all about the trip that eventually took us to Maggie Valley, North Carolina, and back in last month’s AE (Road Worriers), but I can tell you that other than a batch of bad gas that had us scratching our heads a little and a wiring snafu from the midnight thrash, the Holley EFI ran flawlessly.

We left it in “dyno tune” mode for the first part of the trip mainly because it was running so well. On the way home, I tweaked it a little for fuel mileage by adding some advance (much like vacuum advance would do) and leaned it a little in the light throttle highway cruise areas and found fuel mileage hovered in the 16.2 to 16.5 mpg range! Remember, this was with a 555-inch motor, ambitious cruise speeds with no overdrive transmission and a pretty decent-sized cam. Again, all it took was a couple of keystrokes and from then on, it just keeps doing it regardless of weather etc.

Well, it turns out Doug was right. He took the Holley EFI out of the box and with 10 minutes of run time and tuning, beat my carb setup that had 15 years of tinkering involved to get it where it was. And he even beat a very nice true race carb while using an as-cast intake manifold. For anyone that has created a perfectly tuned carb on a serious high horsepower motor, you know how impressive that is. And for the rest of us mortals who have beat our heads on the wall trying to get a big cammed, radical street toy to cruise around without burping – spitting and fouling the plugs in two blocks, you can surely appreciate how valuable this is also. You can now build it and enjoy it without all the tuning headaches.

If you’re contemplating a carburetor/intake/ignition upgrade, you should really take a close look at all the features that Holley has incorporated into their systems. You get easy installation, self tuning as well as nearly unlimited manual tuning ability and performance that allows you to quickly enjoy all that new horsepower on the street or track. All without “skinned knuckles” from tearing apart carbs or from “knuckledragging” the ground! Having seen this thing make well over 800hp with points and a carburetor for years, my wife is still struggling with the thought that I use a computer instead of a screwdriver to tune it!

Holley Performance Products
(270) 782-2900

School of Automotive Machinists
(713) 683-3817

Aeromotive Inc.
(913) 647-7300


  • Twelve sequentially driven 8:2 peak and hold injector drivers, capable of driving up to 24 low or high-impedance injectors as a standard feature. Multiple staged injector strategies
  • Twelve-channel Distributorless Ignition (DIS) outputs capable of directly driving “Smart” ignition coils or Holley DIS coils. Will drive two wire coils with the addition of PN 554-112 high current coil driver module
  • Controls GM 4L60E and 4L80E transmissions
  • Integrated dual-channel wide band oxygen sensor controls. Works with NTK or Bosch sensors.
  • Integrated drive-by-wire throttle body control. Can control two drive by wire throttle bodies
  • Four stage progressive nitrous control
  • Integrated water/methanol injection control
  • Integrated “Data Acquisition and Control” allowed with massive amount of programmable inputs and outputs
  • Internal data-logging standard with a huge 2GB of memory
  • Self-tuning fuel table strategy greatly simplifies tuning process
  • Store and change between four calibrations
  • Individual cylinder fuel and spark control allows you to unlock your engine’s potential
  • Optional 5.7-inch full-color touchscreen LCD allows easy on-the-fly tuning, data-logging or can be used as an easy to see graphical gauge panel
  • Unique lb-hr-based fueling strategy greatly simplifies tuning
  • Advanced idle, closed loop, and enrichment strategies allow for very stable operation
  • ECU is fully potted and can be mounted in the engine compartment or interior
  • Sealed automotive and marine grade connectors
  • Works with 4, 6, 8 and 10 cylinder engines
  • Allows for use of common OEM sensors as well as customer sensor calibration input
  • 1-5 Bar MAP sensor capability
  • Ignition Plug and Play with GM 24x and 58x LSx engines, GM HEI, Ford TFI, magnetic and hall effect trigger, and other ignition systems. New Plug and Play applications in process. Custom settings can be configured to allow many other applications.
  • Two channel knock control sensor inputs for both one or two wire knock sensors
  • Dedicated fuel and oil pressure inputs
  • Controls both stepper and PWM Idle Air Control (IAC) motors
  • Speed density, Alpha-N, or combination fueling strategies
  • Three rev limiters
  • Massive amount of inputs and outputs allow for limitless combination of options. Allows for unit to be used as a complete data acquisition system as well.
  • Thirteen “Multi-Inputs” – Can be configured as a 0-5V sensor input, 0-20v sensor input, thermistor temperature input, or high or low voltage input
  • Thirty 0-5V Sensor Inputs – Configures any 0-5V sensor as well as some can be used as switched high or low inputs
  • Four Speed Inputs – Can be configured as a digital (square wave) input or an inductive input
  • Twenty 12v PWM Outputs – Can be configured as PWM or switched 12V outputs. Rated at 2A maximum
  • Sixteen Ground PWM Outputs – Can be configured as PWM or switched ground outputs. Rated at 2A maximum
  • All inputs and outputs are programmed using innovative new “pin mapping” strategy that allows inputs and outputs to be pinned as desired by the user, allowing for inputs and outputs to not be “wasted” by non-used dedicated functions.
  • Four stage nitrous oxide control
  • Fully featured nitrous control eliminates the need for a separate nitrous controller device
  • Can be configured “wet” or “dry” with closed loop feedback
  • Progressive control based on time, rpm, or boost, requires part #554-111
  • Lean or rich safety cutoff
  • Full timing retard/control configurability per stage based on RPM or time
  • Integrated water/methanol injection control
  • Uses Holley water/meth solenoids specially designed and calibrated for use with this EFI system to allow the user to enter water/meth flow as a percentage of fuel injector flow for water/meth tuning precision unmatched in the industry
  • Allows for two nozzles to be controlled
  • Nozzles available from 400 to 1,000 cc/min
  • Complete control of pump activation, and low system safety features
  • Turbocharger boost control
  • Fully featured boost control capability eliminates the need for a separate boost control device
  • Can be configured to control boost based on time, gear, speed, and manual inputs
  • Gear-based boost control configurable by several different methods
  • “Boost Builder” functions offer the ability to assist building boost on the starting line by altering ignition timing, fueling, as well as nitrous oxide activation. Also can be used as an anti-lag function
  • User configurable input and output programming
  • Outputs can be programmed as pulse width modulated or switched.
  • Unique circuitry allows inputs to be programmed as speed/frequency, 0-5V, 0-20V, thermistor, or switched high or low
  • User configurable inputs and outputs can be programmed to have a variety of different inter-dependencies
  • Configurable for dual cooling fans, dual fuel pumps, AC inputs, basic TCC lockup, and multiple timing retard inputs
  • User programmable caution and warning outputs for all sensors.


#1 Brodix 2Xtra's, Engle 266*/272*cam, Super Vic,1" spacer, Holley 1050 Dominator, 84/96 jets, 37* timing, 122* temp
#2 Brodix 2Xtra's, Engle 266*/272*cam, Super Vic,1" spacer, Braswell Dominator, 93/93 jets, 37* timing, 122* temp
#3 Brodix 2Xtra's, Engle 266*/272* cam, Super Vic,1" spacer, Braswell Dominator, 94/95 jets, 37* timing, 114* temp
#4 Brodix 2Xtra's, Engle 266*/272* cam, Holley Dominator EFI, 37* timing, 128* temp
#5 Brodix 2Xtra's, Engle 266*/272* cam, Holley Dominator EFI, 37* timing, 147* temp
  #1 TQ #2 TQ #3 TQ #4 TQ #5 TQ   #1 HP #2 HP #3 HP #4 HP #5 HP
4600 703.4 718.5 721.7 728.1 725.5   616.1 629.3 632.1 637.7 635.4
4700 707.1 723.0 723.7 730.1 730.3   632.8 647.0 647.6 653.4 653.5
4800 709.3 728.0 729.5 734.6 738.5   648.3 665.3 666.7 671.4 674.9
4900 711.3 732.9 732.1 738.3 741.8   663.6 683.8 683.0 688.8 692.1
5000 715.6 731.1 733.5 740.7 741.9   681.3 696.0 698.3 705.2 706.3
5100 717.2 728.6 734.2 742.3 742.1   696.4 707.5 713.0 720.8 720.6
5200 720.4 726.5 735.6 741.8 742.4   713.3 719.3 728.3 734.5 735.0
5300 722.3 725.8 732.1 739.3 740.7   728.9 732.4 738.8 746.1 747.5
5400 719.6 725.9 730.8 735.8 738.5   739.9 746.4 751.4 756.5 759.3
5500 717.8 725.0 728.1 732.0 736.8   751.7 759.2 762.5 766.6 771.6
5600 715.1 724.6 723.7 730.7 735.2   762.5 772.6 771.7 779.1 783.9
5700 714.1 721.9 720.4 727.9 732.6   775.0 783.5 781.9 790.0 795.1
5800 711.9 720.4 717.6 725.3 728.7   786.2 795.6 792.5 801.0 804.7
5900 710.7 718.1 716.1 721.3 724.3   798.4 806.7 804.5 810.3 813.7
6000 706.8 716.4 715.3 719.1 719.6   807.5 818.4 817.2 821.5 822.1
6100 702.3 713.2 713.7 714.8 715.3   815.7 828.4 828.9 830.2 830.8
6200 698.4 705.2 709.2 707.1 710.1   824.5 832.5 837.2 834.7 838.3
6300 694.8 697.6 702.3 694.8 704.1   833.4 836.8 842.4 833.4 844.6
6400 687.1 692.8 696.7 687.4 696.0   837.3 844.2 849.0 837.7 848.1
6500 680.3 688.4 688.8 680.9 686.4   842.0 852.0 852.5 842.7 849.5
6600 675.0 681.4 681.9 675.7 681.2   848.2 856.3 856.9 849.1 856.0
6700 667.4 672.5 675.1 669.0 672.2   851.4 857.9 861.2 853.4 857.5
6800 660.8 667.1 667.8 663.6 662.7   855.6 863.7 864.6 859.2 858.0
6900 653.2 657.8 662.1 655.9 654.1   858.2 864.2 869.9 861.7 859.3
7000 646.2 644.9 647.9 644.5 642.4   861.3 859.5 863.5 859.0 856.2
AVG 698.7 707.5 709.6 711.2 713.7   769.2 778.3 780.6 781.8 784.6