NEW!!! WEAPON-X Secondary Port Injection Kit [Camaro Corvette CTS-V]

Posted by Ben Herndon on

WEAPON-X SPI Port Injection Kit: Plug And Play, Tank to Tip, No More DI Limits!

Purchase here:

We have been working closely with some of the supercharger manufacturers to provide a complete fuel solution for all manifold options as well as model platforms, and we're pleased to announce after months of testing, we're ready to release the WEAPON-X Secondary Port Injection Kit or abbreviated as WEAPON-X SPI Kit (pronounced SPY)! This complete package sets a new unprecedented secondary fuel solution from fuel tank to injector tips, allowing the end user to hit 1,000+ wheel HP with just a few basic mods on LT4 cars and this kit can support up to 1,500 wheel HP! The SPI Kit comes with the low side kit, rails, injectors, regulator, plumbing, control module, and a complete wiring harness, so you or your shop can get this installed in a day! 

Needless to say, the days of having to spend a lot of money on:
  • Larger High Pressure Fuel Pump ($2,000 installed)
  • Larger DI Injectors ($4-5,000 insatlled)
  • Meth Injection Kits ($1,200 installed)
  • Cam Kits ($4,000 installed, heads add $2,000)
or combinations of the aforementioned exceeding $8-9,000 to barely hit 800+ HP are OVER! Now basic is relative of course, but with our modified Whipple or Procharger F1 kit, headers, head studs, WEAPON-X SPI port injection kit, you can see 4 digit power. So, for those guys shooting for reliable big power, this kit is unparalleled, plus we offer full support with installation and can provide a base file to start with, or even setup to remote tune your car. 

What is Port Injection?
Let's start off with the basics; port injection is the way engines were fueled since the 80s with an electronic ignition based fuel supply. The fuel injector is located in the intake manifold or on a positive displacement supercharger. When the signal is supplied, the injector opens and the amount of fuel sprayed depends on a plethora of parameters (ultimately by the gen IV LS engines), but to dumb it down, the milliseconds the injector is open, the size of the injector in lbs/hr or cc's, and the fuel line pressure supplying fuel to the injector from the tank to the fuel rails. The fuel sprays through the ports in the cylinder head and travels with the air entering the engine and travels through the valves into the cylinder where it is ignited and you have your robust combustion. It was always relatively easy to make big power numbers then, larger pump to supply the fuel to the engine and larger injectors to spray that fuel into the ports was about all it took as long as you had the capabilities to program the added fuel.

What is Direct Injection?
As technology evolved and emissions regulations became more and more stringent, direct injection hit the automotive world stage. Direct injection is very similar to port injection until the fuel supply reaches the engine, then it goes through a second "high pressure" fuel pump, driven off of the camshaft, which increases the fuel pressure from 72 PSI to nearly 3,000 PSI! It then goes through the high pressure injectors and enters the engine directly into the cylinder. This is great for a lot of reasons including more precise fueling, higher air fuel ratio ability when boosted, and of course emissions; however, the inherent problem that quickly arose was the limitations of fuel supplied. 
The lack of pumps and injectors capable of reaching those pressures made it extremely difficult to achieve big power numbers safely or running ethanol based fuels which are very inexpensive higher octane fuel right out of the pump. For a more in-depth explanation of how the GDI system works, checkout my other thread discussing this in much greater detail:
Guide to fueling for higher horsepower LT4 ZL1s

The Solution: WEAPON-X Secondary Port Injection Kit

The solution for big power needs is our secondary port injection and this is the same type of kit that GM opted to go with on the 2019 C7 ZR1 as well as many other high performance DI cars. We have come up with the complete solution for your high powered LT car. Our secondary port injection kit has it's own low side solution with a large pump to get fuel from the tank to the engine. This pump ties into the OEM fuel line as well as running up to supply it's own system. It is fully regulated and has a return, essentially transforming your stock fuel system into a high power capable system. Once the fuel reaches the engine, it ties into our custom billet fuel rails that tuck nicely against the supercharger/manifold, and what is needed fires through the 1300cc injectors and then the fuel returns back to the tank. The system is easily controlled with a proprietary piggy back controller with it's own software and we offer a base tune file and full support. Installation is made easy with our complete plug and play wiring harness! 

WEAPON-X SPI Kit Features:

  • Secondary Control Module with:
    - Closed Loop Wideband 02 Fueling 
    - Boost Control Capabilities
    - Tach Outputs
    - Programmable Custom Outputs
  • Plug and Play Harness for your vehicle
  • Low Side Kit with 500GPH Pump, lines, fittings, etc
  • Flex Fuel Sensor
  • High Side Kit for your specific application with rails, lines, fittings, regulator
  • FIC 127 LB/HR Fuel Injectors
  • Optional supercharger manifold port injector bung modification

We also have patents pending on the port injection kit itself as well as port bung modifications for the Whipples and Procharger manifolds, as well as the way we're doing it with the Eaton supercharger. So, as a result we are also pleased to announce that we are now open to publicly display and offer port injection bung modifications to your existing Whipples and Procharger manifolds! These options are listed under the SPI kit or you can contact us directly to have your blower/manifold modified at

Supported Manifold Options:

  • LT4 Supercharger (no blower modification needed)
  • Whipple Supercharger (we sell the Whipples with the port bungs in them)
  • Procharger Intake manifold (we modify the manifold too)
  • Other manifolds with typical port locations like: LME, Frankenstein, G1Pro, MSD, etc

Models Supported:

  • Camaro gen 6 SS, 1LE, ZL1, ZL1 1LE - LT1 LT4
  • Corvette C7 Stingray, Grand Sport, Z06 - LT1 LT4
  • CTS V gen 3 - LT4
  • GM Trucks are up next!

The best part about our kit aside from it being plug and play, is the fact that the ENTIRE KIT is $4,999! This might sound like a big investment if you're just looking at the number, but this is a complete fuel solution from tank to injector tip including the secondary controller and tuning software as well as support. Not everyone needs port injection for moderate power of course and we use all of the other options on customer builds as well, but for big power gains/goals, the WEAPON-X SPI Kit is a great bang for the buck and allows for future growth.

Case Study #1: 2017 C7 Z06

WEAPON-X SPI Secondary Port Injection Kit with E85 sensor
Procharger F1X with ATA Intercooler
WEAPON-X Griptec Pulley
1-7/8" American Racing Headers (we would recommend 2")
Corsa Exhaust (not necessary for the power)
WEAPON-X Cam kit (not necessary for fuel supply)
WEAPON-X Valve Covers with PCV system

Troy came to us and wanted some moderate power at first, but we all know that it's never enough. He had meth injection and a low side fuel system, then ended up doing a cam kit as well, and later wanted to do a larger blower. So, we swapped the blower system to Procharger's big boy F1X. This Z06 is only setup for 18psi and in 5th gear made 715 wheel HP with just 15* timing on 93 octane. We weren't pushing it with the timing on this because when spraying methanol, there is no guarantee of even cylinder distribution. So, 715 wheel HP seems low, but 6th gear is 1:1, so 5th is about 10-12% low when we've tested the two and this is a Mustang dyno. So, 6th gear would be right around 800 wheel HP on our dyno, 880 wheel HP on a Dyno Jet, if we're bench racing LOL. We usually tune in 5th gear and verify in 6th gear, but Procharger's C7 Air to Air intcerooler is notoriously undersized and heat soaks terribly in 6th. So, 5th shows better comparison numbers. 


We developed the Procharger SPI Kit on this car, so Chris worked through the setup of the controller with our engineer David and the resulting harness makes it very simple for the installation! 

When we first started out, we only had 63lb injectors from a ZR1 in the rails. In 5th gear, without any other changes other than the meth off and three degrees more timing, and the power output shot up over 100 wheel HP! 

With another degree and a half, we were up over 900 wheel HP in 5th and we ran out of injector!

So, we cut to the chase and went to the 127 LB/HR injectors we had in my ZL1 port setup and these were up to the task! We added three more pounds of boost and timing up 4* over where we were with 93 and meth. The gains and correct fueling were just incredible, especially considering we hit 1,000 wheel HP with 22 PSI in FIFTH gear! That same combo with 93/meth doesn't even hit 900 wheel HP in 5th usually. 

This higher HP was achieved with only E72 pump gas, no meth, and it's worth noting that without the 45GPH of meth spraying, the Manifold Air Temps as well as the IAT sensor readings were much higher, the meth air temps would go down, and the SPI readings were going up. We certainly could've pushed more timing too, but felt we would do that at the track when the car goes with closer to E85 too.

The benefits of the SPI kit is the ability to run full ethanol, the fuel is spraying across the back of the intake valves which naturally cleans them, and the fuel will cool the incoming air some additionally too since the high pressure pump will naturally increase the temperatures of the fuel as it is compressed. I have always been curious as to how much because there are PIDs in there to see rail temps, but no sensor to log. 

Older Post Newer Post

1 comment

Created on Posted by Nick Ruoti Comment Link

Have you used your system on either single or dual turbo charger applications. I am building a 421 inch ls motor with nelson racing mirror image 60 mm turbos and need manifold and fuel system. any suggestions.

Leave a comment

Scroll To Top