Project Stranger Things has reached the point where every change has to be made with the next step in mind. The turbocharged 408 Windsor-powered SN95 has continued pushing deeper into the 5-second eighth-mile range, and as boost has increased, so has the demand placed on the fuel system.
That is why the car recently moved from its previous 120 lb/hr injectors to a set of DeatschWerks 2200cc injectors. On paper, going from 120 lb/hr injectors to 2200cc units is a substantial jump. The more important question, however, is what that additional capacity actually looks like once the car is on track and the boost starts climbing.
With three complete Holley Terminator X data logs from separate tune-ups, we can now put real numbers behind the upgrade. The logs cover passes at roughly 10 psi, 13.5 psi and more than 26 psi of boost, giving us a clear look at how fuel demand and injector workload increase as the same engine combination is pushed harder.
Why Injector Headroom Matters
An injector does not make horsepower by itself. What it does is provide the fuel-delivery capacity necessary to support the airflow and power the rest of the combination is capable of producing. Once an injector begins operating near the upper end of its usable duty cycle, there is progressively less room for additional fuel demand.
Duty cycle is the percentage of available time the injector is commanded open. As engine speed increases, the amount of time available during each engine cycle becomes shorter. That means high RPM and high fuel demand can quickly turn an injector that looked adequate at a lower power level into a limiting factor.
Holley has noted that once an EFI combination begins approaching roughly 80 to 85 percent injector duty cycle, it is reaching the range where additional injector capacity should be considered if more power is planned. Holley also describes roughly 60 to 75 percent as a useful operating “sweet spot” for many applications. The goal is not to chase one universal number, but to maintain enough control and margin that the injector is not effectively becoming the restriction in the fuel system.
Three Passes, Three Very Different Fuel Demands
The most revealing part of the DeatschWerks upgrade is the way the fuel demand scales through the three Holley logs. Because peak boost, peak injector duty cycle and peak fuel flow do not always occur at the exact same instant in a pass, the table below uses the maximum recorded value for each category rather than pretending every peak happened at one data point.
From the 10-psi pass to the 26-psi pass, peak recorded fuel flow increased from 608.4 lb/hr to 1,461.3 lb/hr. That is an increase of roughly 140 percent, or about 2.4 times the fuel flow. Peak injector duty cycle followed almost the same progression, climbing from 32.61 percent to 78.85 percent.
That is exactly why sizing the injector around the future version of a combination matters. At the lower boost level, the DW 2200s have a tremendous amount of unused capacity. At more than 26 psi, that capacity is no longer theoretical — the car is legitimately using it.
The 10-PSI Pass: Plenty of Room to Grow
On the lowest-boost pass, Project Stranger Things reached a maximum of 10.29 psi. At the exact point of peak boost, the engine was turning 5,094 rpm, injector duty cycle was only 22.44 percent and Holley calculated fuel flow at 420.3 lb/hr.
Fuel demand continued to increase after the peak-boost sample. At 5,301 rpm and 9.78 psi, injector duty cycle reached its maximum for the run at 32.61 percent, with an 8.081-millisecond injector pulse width and 608.4 lb/hr of fuel flow.
There is another useful point hidden inside this pass. At 4,983 rpm, the log recorded 9.016 psi of boost. At that exact operating point, the DeatschWerks injectors were at just 20.45 percent duty cycle with a 5.570-millisecond pulse width and 383.0 lb/hr of fuel flow. That gives us a very clean reference for what the current injectors are doing at approximately 9 psi, rather than relying on an estimate based on the run’s maximum boost.
13.5 PSI: Fuel Demand Starts Climbing Quickly
The next log shows how quickly that comfortable low-boost margin begins to get used as airflow increases. The second pass reached 13.50 psi at 6,296 rpm. At that point, injector duty cycle had climbed to 46.25 percent, injector pulse width measured 9.528 milliseconds and fuel flow had increased to 866.3 lb/hr.
Later in the run, peak fuel flow reached 974.4 lb/hr at 7,658 rpm and 11.87 psi. Peak injector duty cycle was 51.64 percent at 7,679 rpm. Compared with the 10-psi pass, maximum fuel flow increased by roughly 60 percent, while peak injector duty cycle increased by roughly 58 percent.
That middle data point is important because it shows that injector demand does not simply stay low until the combination suddenly reaches 25 or 26 psi. The workload is already increasing substantially as the turbo combination moves through the middle of its operating range.
26 PSI: Now We Are Using the Injector
The high-boost pass is where the reason for the 2200cc upgrade becomes obvious. Project Stranger Things reached 26.22 psi at 6,389 rpm. At that point, injector duty cycle was 77.01 percent, injector pulse width had increased to 15.312 milliseconds and Holley calculated fuel flow at 1,445.5 lb/hr.
Peak injector duty cycle occurred shortly afterward at 6,579 rpm and 25.90 psi, reaching 78.85 percent. Fuel flow at that point was 1,454.8 lb/hr. The highest fuel-flow reading of the run came at 6,864 rpm and 25.14 psi, where the ECU calculated 1,461.3 lb/hr while injector duty cycle remained at 78.02 percent.
Those numbers put the DeatschWerks 2200s in a much different operating window than they were seeing at 10 psi. Peak fuel flow increased another 50 percent from the 13.5-psi pass to the 26-psi pass. More importantly, injector duty cycle is now approaching the range where every additional step in power needs to be evaluated carefully rather than assuming there is unlimited capacity left.
The remaining percentage between roughly 79 percent and 100 percent should not be viewed as a simple horsepower reserve. As duty cycle approaches the extreme upper range, dynamic control over the injector becomes increasingly limited. The rest of the fuel system — pumps, voltage supply, filters, fuel lines, regulator and fuel pressure — also has to maintain the delivery the injectors are being commanded to provide.
The Fuel-Flow Numbers Tell the Story
Injector duty cycle is usually the number enthusiasts focus on first, but the fuel-flow data adds another layer to this comparison. Across these three passes, peak recorded fuel flow moved from 608.4 lb/hr to 974.4 lb/hr and finally 1,461.3 lb/hr.
That progression is significant because it shows how dramatically the engine’s fuel requirement has changed as the boost has been increased. The injectors that look oversized at 10 psi suddenly make much more sense when the same engine is consuming nearly two-and-a-half times as much fuel on the high-boost tune-up.
It also reinforces an important lesson for any boosted build: buying an injector solely around what the engine needs today can be an expensive way to build a car that is expected to evolve. Project Stranger Things did not need 78-percent injector duty cycle at 10 psi. The point of stepping up to the 2200s was making sure the fuel injector would still be in the conversation once the combination moved far beyond that boost level.
The Next Limit Has to Be Found in the Data
At more than 26 psi, Project Stranger Things is finally beginning to use the injector capacity that looked enormous at lower boost. That does not mean the fuel system has reached its absolute limit, and it does not mean there is a predetermined amount of horsepower left simply because the injector is below 100-percent duty cycle.
What the three logs do prove is that the DeatschWerks 2200cc injectors have allowed the combination to scale from a low-boost tune-up with considerable injector margin to a much more serious high-boost setup without immediately forcing another injector change.
For a project that continues to get quicker and continues to ask more from every component around the engine, that is exactly what the upgrade was supposed to accomplish: give the fuel system room to grow, then use the data to determine when the next part of the combination becomes the restriction.
For anyone planning a fuel-system upgrade of their own, DeatschWerks also offers a Fuel Injector Calculator that can help determine the injector size a combination may need based on target crank horsepower, injector count, induction type, fuel type, ethanol blend, BSFC and maximum duty cycle.
