We dyno Holley’s self-tuning EFI replacement for GM’s Rochester spread-bore induction.
The early days of aftermarket EFI systems promised much, and while they were mostly capable of delivering, they were not exactly simple to tune. If you were wanting to run a twin turbo, nitrous-injected big-block into the four-figure zone, they were practically a necessity, but for the average resto or mild build the benefits might not have been worth the effort. It was just easier to run a carb. They are predictable and safe and not hard to set up correctly.
It is true that it’s not that tough to get the correct vintage carb to work on classic muscle, but if you want to optimize it that will require some dyno time. That was the initial plan for the restoration of this 1968 Olds 4-4-2; run the correct QuadraJet and let Muscle Car Restorations use their Mustang Dyno to dial it in for best drivability and power. They did exactly that and managed to pull 304 pounds of torque and 230 hp (at the rear wheels) out of it.
Somewhere along the way though, the car’s owner decided that a Holley Sniper EFI system might be a better way to go. This provided a great opportunity to do a head-to-head comparison between the stock Q-Jet and the Sniper on an otherwise stock spec 4-4-2 Olds 455. Of course max power will be compared, but like with the Q-Jet, MCR will also be able to test overall drivability even if that’s more of a subjective “how does it feel” sort of thing.
Perhaps the more important test though is the install, set up, and tuning. What’s involved in installing it and once in place what does it take to get it tuned? Installation couldn’t really be any simpler. Yes, a new fuel tank with an in-tank fuel pump is the best way to go, but an inline pump from Holley can be used. A return fuel line will be necessary and an oxygen sensor will need to be fitted. Wiring is just two leads to the battery and ground, one to the coil, and one to a new temp sensor. There is a long lead included to bring power to the fuel pump, but that’s pretty much it.
As far as tuning, there really wasn’t any—not by a human, anyway. Initial start up was no more difficult than with the carb. Give the pump a moment to get fuel to the throttle body and it popped right off and then quickly settled into a normal idle. After warm-up, the throttle plate screw needed to be tweaked slightly to get the IAC motor within range but after that it was ready to go cruising on the Mustang Dyno.
There is actually a lot of control within the Sniper programming, such as accelerator enrichment, cold start enrichment, and target A/F ratios at idle, cruise, and WOT, but the default settings proved to work more than fine in this case. Relatively normal driving did not show any issues. No hesitations, no stumbling, no hot start problems. It just worked.
After enough miles to get the drivetrain thoroughly warmed up, MCR went for some full-power runs and after only three pulls the system seemed to learn what it needed to know and produced 329 pounds of torque and 244 hp. Huge gains were not expected, but neither was having to do anything to get them. Literally no changes to the default settings were made. The Sniper did this all on its own.
So what’s the verdict? The QuadraJet is a direct bolt-on and it did work fine but it does require some dyno time to optimize. The Sniper needs a new fuel system but it’s not real hard to do. It optimizes itself very quickly and does provide some tuning options via the target A/F tables that would be very difficult with the carb. The touch screen allows close monitoring of engine vitals and it can be data-logged if one really wants to dig into the numbers.
Q-Jet or Sniper EFI? Your call, but no need to let fear or cost of EFI tuning be a factor.
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