Between the time we completed the installation on the 1970 Olds and the writing of this chapter, 30 days have passed. This time has afforded the opportunity to assess the system’s performance. In that time the Holley Dominator system has performed flawlessly. So, is Bill equally impressed with its performance? That would be an understatement. Bill is a tuner at heart. The Holley system allows him to spend his time doing just that, not pulling the fuel bowls, not drilling out air-bleed blanks, not calling me asking if I have some red accelerator pump cams lying around (I don’t), etc. Basically, not getting his hands dirty.
This Tech Tip is From the Full Book, EFI CONVERSIONS: HOW TO SWAP YOUR CARB FOR ELECTRONIC FUEL INJECTION . For a comprehensive guide on this entire subject you can visit this link:
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During this time, Bill and I have spent a few hours fine-tuning his Olds to achieve the best fuel metering possible. We had only a single problem crop up: the gap between the pickup and reluctor wheel of the crank trigger was too large. This caused the timing to drift slightly when we made adjustments to it via the software and then looked at that on the balancer with a timing light. We reduced the gap of Holley’s spec and the problem was solved.
Because Bill had been monitoring the A/F ratio via his LM-2 when driving around, he noticed two things: The mixture was a bit lean as he accelerated (not WOT) and the right bank was slightly leaner than the left bank. We decided to fix both.
The Holley software provides numerous parameters to enrich the mixture during acceleration. We focused our efforts on two of them:
acceleration enrichment versus TPS rate of change and AE versus MAP rate of change.
AE versus TPS Rate of Change: Using the white boxes at the top of the menu, I simply added to each of the values, except for the left two boxes. This is a starting point and it’s easy to get back to where we started if needed.
AE versus MAP Rate of Change: Using the white boxes at the top of the menu, I simply added to each of the values, except for the left two boxes. Again, this is simply a starting point.
Right Bank Leaner than Left Bank
We drove the Olds a bit to verify this, and sure enough, the LM-2 showed 1.00 Lambda on the left bank and 1.02 Lambda on the right bank when cruising at a steady speed; the right bank was 2 percent leaner than the left. We pulled over and I added 2 percent more fuel to each of the injectors of the right bank. Problem solved. We instantly had 1.00 Lambda left and right at idle.
With an EGT in each primary, you could really fine-tune each injector to achieve the ideal mixture in each cylinder. Oh, the possibilities here!
When you make changes to the fuel metering aspects of the tune, you need to get some drive time to allow the ECU to remap the Learn Table to reflect the changes you’ve made. This is accomplished by driving the vehicle at various RPM and engine loads throughout the drivability area. The more you drive the vehicle, the more finely tuned the tune becomes.
Bill drove while I monitored the results of our efforts via the Holley software and the LM-2. Based on the live data available, Bill had me increase the acceleration enrichment a bit more. Afterward, he was happy with the results. Some additional driving around town and we were convinced the drivability was about as ideal as we could have ever hoped from a vehicle with a 2,000-cfm throttle body and a 4,500-rpm converter. Our original tune required very little adjustment to achieve this and the Holley software couldn’t be easier to use. Grandma could drive this Olds around town in Drive without even realizing that she had more than 600 hp under her foot. In addition, the exhaust tone was as mild as it’s ever been, giving no clue that this is a mid-10-second car. Throttle response is instant. When you get aggressive with the pedal, the 455 responds without hesitation and the exhaust tone comes alive
Bill and I found a deserted stretch of road to make a few WOT passes. Now, I had told Bill at the beginning of this project that his 950-cfm E85 was restrictive. I speculated that we would be easily able to prove this as the throttle body was more than double the size of the carburetor we removed. Let’s see what our seat-of-the-pants dyno has to say.
WOT Pass 1 from 25 mph
This pass was aborted nearly immediately. When Bill floored the throttle, the Olds blew the tires off it. This had happened only maybe one time in the past that I can recall and not nearly to that extent. We elected to warm up the Mickey Thompsons a bit and try again.
WOT Pass 2 from 25 mph
We had nearly the same results. Pass aborted.
WOT Pass 3 from 25 mph, Roll into Throttle
Bill finessed into the throttle in first gear. Upon shifting into second gear, he was able to go WOT. Second and third gear happened so fast, it was as if it happened in slow motion. The exhaust tone was so much louder than we had ever heard from the 455. Our collective jaws dropped and we looked at each other in amazement. I had never felt Bill’s Olds pull this hard through second and third gears. I was supposed to be monitoring the A/F ratio on the LM-2 . . . Yeah, Okay. Fail.
It was immediately obvious that the 2,000-cfm throttle body had allowed the 455 to ingest all the air it could take and the ECU metered the fuel to achieve the A/F targets. Even though Bill had calibrated the carburetor to achieve the identical A/F ratio at WOT, the mass of air ingested by the Olds was greater with the larger throttle body.
The end result is that the 455 is now able to burn more fuel at WOT than before. The power comes from the fuel and Bill’s Olds simply wasn’t able to burn the same mass of it with the 950-cfm carburetor. It was also immediately obvious that we now had a traction problem that needed to be addressed. Welcome to my world, Bill! Time for some fresh tires.
Putting the Power of the ECU to Work
The ECU is the brains in the game and it controls all the parameters of the fuel injection. In this case, it also controls datalogging functions and input/outputs.
The internal datalogging capability of the Holley ECUs is a powerful tool. It allows you to datalog every parameter that you have a sensor monitoring. Bill made a few WOT datalogs in the following days. Man, do things look nice.
It goes without saying that WOT passes should only be done on a drag strip in a controlled environment. This is the best way to collect meaningful data, as traction problems are all but eliminated. Bill is quite fluent in tuning so he’s able to readily interpret the data and use it for fine-tuning without fear of damaging his engine. If fine-tuning your engine isn’t something you’re comfortable with, datalogs can be shared (even by email) with an experienced tuner.
Depending on the system (or meter), you can program some units to datalog automatically. This is ideal for drag racing, so you can keep your mind on staging the car correctly and cutting a good light, not on whether you’ve remembered to activate the datalogger.
The Dominator ECU has seemingly endless connectivity. Let’s make use of some of it. Specifically, let’s do the following:
- Interfacetherollcontroltoactivate a low-speed rev limiter
- Automatetheoperationofthe electric fans
- Automatetheoperationofthe second half of the fuel pump
It’s important to note that the Holley Dominator and HP ECU inputs and outputs are not specific to wires that pre-exist in the harness. This offers the utmost in flexibility. The idea here is to simply automate a bunch of existing circuits. Each is an incredibly simple interface, and similar to the ones I did on my own Olds in Chapter 4. Keep in mind that you need the Holley connector and pin kit (PN 558-408) to do so with the Dominator ECU.
After our local drag strip re-opens, Bill intends to use a 100 shot of nitrous in an attempt to get his Olds into the 9s. This will come via a plate system under the throttle body. We elect to run a dry system and use the power of the Dominator ECU to enrich the mixture via the injectors as well as reduce timing automatically when using the nitrous. The additional fuel required should be well within the window of safe operating for the 83-pph injectors.
The Dominator ECU allows you the option of bringing the nitrous in progressively to avoid traction issues. Also, the Dominator ECU allows complete management for up to four stages of nitrous. We just need one.
Before we can begin setting up the inputs and outputs, we need to add a nitrous configuration file to our base tune. To do so, we simply add an Individual Configuration to the tune. Here’s how:
Click the down arrow to the right of Toolbox; select Add Individual Config.
In the Files of Type box at the bottom of the window, click the down arrow at the right and select Holley EFI Nitrous Config (*.nitrous).
Click the Up One Level button (folder with green arrow pointing up) at the top of the window a few times until you get to the EFI folder.
Double click on the Individual Configuration Library folder.
Double click on the Nitrous folder.
Double click on the Base – Single Stage Dry. nitrous file.
We now have a nitrous configuration in the tune at which we can easily set up when we install the nitrous system. For now, let’s proceed with programming the inputs and outputs.
Before connecting anything, we need to go into the ECU and program the appropriate inputs and outputs accordingly. This is easy. Before you do so, it’s important to know how each of the systems we want to automate is triggered. In Bill’s Olds, they are as follows:
- ElectricFans:fanrelaysare triggered via +12V from dash-mounted switch
- Fuel Pump: each half of the pump has a relay, which is triggered via +12V from a dash-mounted switch
- Roll Control: depressing the button sends +12V to the solenoid
- Nitrous: master arming switch switches +12V
Click on the System ICF icon on the toolbar at the top of the screen.
In the SYSTEM PARAMETERS box in the left column, click on Basic I/O. This brings up the outputs for the electric fans and fuel pumps. Set them as shown in Figure 7.12.
In the SYSTEM PARAMETERS box in the left column, click on Ignition Parameters. Enable REV LIMITER #1 as shown in Figure 7.13.
Click on the Nitrous ICF icon on the toolbar at the top of the screen.
Click on Inputs/Outputs. For a single stage, this should resemble Figure 7.14.
In the SYSTEM PARAMETERS box in the left column, click on Inputs/Outputs. We set ours as shown in Figure 7.15.
Click on the PIN MAP icon on the toolbar at the top of the screen. This brings up the Pin Map for the ECU. You are looking at the View Inputs tab when this opens. The UNASSIGNED INPUTS show the inputs we’ve set in the previous steps as well as their polarity (H = +12V, G = Ground). (See Figure 7.16.)
For this installation, we populate CONNECTOR J3 with the above inputs and outputs to simplify things. Now, we simply click and drag the Rev Limiter #1 and N20 Enable each to an input on CONNECTOR J3 that has the same Input Type (third column) as our programmed input as an option for the Pin (first column).
Click in the View Outputs tab at the top of the window. Repeat the process for the UNASSIGNED OUTPUTS, also to CONNECTOR J3. (See Figure 7.17 and 7.18.)
Click on the Done button to close the window.
Click on Save to save your changes.
Electrical Interface Changes
Now, we need to make the actual electrical interfaces to the existing systems in Bill’s Olds. At this stage, we need to interface the roll control to activate a low-speed rev limiter. Just as before, this interface activates a low-speed rev limiter and puts the ECU into open loop as long as the roll-control button is held down.
Next we need to automate the operation of the electric fans. Bill’s fan circuit is more traditional than the one in my Olds. I set the ECU to turn on one fan at 160 degrees and the second fan at 180. Because the circuit is pre-existing, you can see the before and after in Figure 7.22 and Figure 7.23.
It’s time to automate the operation of the second half of the fuel pump. Anytime you run a fuel pump with a variable output, it’s a good idea to install a manual override to run the fuel pump at its maximum output when going WOT. That being said, any manual override is only as good as the operator’s memory. Do you really want to chance forgetting this?
This interface allows the ECU to activate the second half of the fuel pump automatically. This allows you to focus more on operating the vehicle and less on flipping switches. Refer to Figure 6.21 on page 104 for the original way that we set this up.
Interface the Nitrous System
Setting up this interface requires a master Arming Switch; the Holley 554-111 Nitrous Solenoid Driver is a simple interface. Bill has an additional switch in his switch panel for this, so we make use of it. For now, we install the driver, but not the nitrous kit as Bill needs to park a few more cars to afford that.
Building a Vehicle-Specific EFI Harness
Just before completing this book, I was called to assist my buddy Frank Beck with an all-aluminum 540-ci big-block Chevy he was building for one of his best customers. Frank liked the results we obtained with the Holley Dominator system and wanted to use a similar setup for this project. This 540-ci package will have a single shot of nitrous oxide, managed progressively, and make more than 1,000 hp.
Frank ordered a custom-built Hogan’s intake manifold with dual throttle bodies to top off this engine (you saw a glimpse of it in Chapter 3). It’s outfitted with a Nitrous Proflow wet fogger system and the overall packaging is super clean.
Frank also ordered a system similar to what we used in Bill’s Olds. Frank added a Holley 8-cylinder DIS (waste fire) ignition system (PN 556-101) and elected to purchase an un-terminated harness assembly (shown on page 109) as the vehicle builder specified that Frank provide a custom harness assembly that fit the vehicle perfectly.
That’s where I came in. I was hired to shorten, terminate, and loom the harness. This was a serious job, taking numerous days to complete. In addition, a job like this requires access to several expensive crimping tools, each specific to a certain family of connector.
Frank does all tuning in-house, so once the harness was shortened and terminated, I delivered it to him un-loomed and without the nitrous relays so that he could get to work making naturally aspirated pulls on the engine dyno. As I mentioned earlier, Frank elected to do a bunch of the tuning in open loop, using an Innovate LM-2 and his dyno to monitor the A/F ratio.
After Frank was happy with the power and torque numbers the engine made naturally aspirated and he was happy with the tune in general, I got the harness back to set up the nitrous solenoid drivers and loom it. As the Nitrous Proflow solenoids require approximately 25 amps of current on each side of the manifold, it was necessary to use a pair of the Holley 554-111 nitrous solenoid drivers to drive them. Because these drivers require minimal current to operate, it is perfectly acceptable to drive them both from the same output of the ECU.
Frank added a Nitrous ICF file to his base tune, set it up for one progressive wet stage, and in short order he was off to the races making nitrous pulls.
So, what kind of power did this 540 make? Insane power. Naturally aspirated, it produced 782 hp at 6,400 rpm and 707 ft-lbs of torque at 5,000 rpm on 91-octane pump gas. With one stage of nitrous, it made 980 hp at 6,200 rpm and 948 ft-lbs of torque at 4,700 rpm with 91-octane pump gas and a 175-hp shot of nitrous.
Like Bill, Frank is very happy with the tuning flexibility and ease the Holley software offered. I’m amazed at how quickly Frank was able to achieve the results he was after. I sat in on several tuning sessions with Frank. When he needed to make changes, we could do so quickly and easily via the software. We configured the datalogger to automatically create logs once TPS exceeded 90 percent, so Frank was able to easily and readily access this data after any power pull.
Heck, I’ve been sold on EFI conversions ever since I converted my Olds. After completing the projects in this book, I simply can’t fathom hot rodding any other way.
Written by Tony Candela and Posted with Permission of CarTechBooks