Ultimate Control: Making The Switch To An Aftermarket ECU

We truly live in exciting times right now — legitimate 1,000 horsepower street cars aren’t unicorns anymore. These days they’re something you see at the track and cars and coffee events on a regular basis. You can create one of these street-driven monsters with off-the-shelf parts and even control them with an OEM ECU, but there are limits to doing this. An aftermarket ECU gives you more control over your engine, so you can safely push it even harder at the track while adding numerous helpful features to your tuning toolbox.

There’s absolutely nothing wrong with making big horsepower and racing a car that uses the OEM ECU, the problem is that you’ll eventually hit a performance wall due to its limited abilities. Haltech’s line of ECUs is extremely versatile, so we decided to use one of its Elite 2500s for this project. We paired the Elite 2500 with a premade Haltech LS wiring harness, flex fuel sensor, and a WB2 Dual Channel CAN wideband controller to run Scott Cordell’s boosted 1,000 horsepower 2002 Camaro that also uses nitrous, while still using the OEM gauge cluster.

Cordell’s Camaro may look tame, but this F-body makes over 1,000 horsepower to the tires and needed the extra options an aftermarket ECU provides.

Why You Need A Standalone ECU And How To Plan A Swap

Boost is addictive, and a little bit is just never enough. The more boost you add, the more stress you start to put on your engine, and tuning the engine becomes more difficult. The stock ECU that controls most modern EFI vehicles can account for boost, but they’re limited on how well they can do it. If you decide to run dual power-adders, things can get dicey in a hurry, but that’s where the aftermarket ECU can help.

An aftermarket ECU also doesn’t have to contend with all of the additional requirements an OEM ECU does. There are far fewer layers of additional controls that can make tuning the car more difficult. The aftermarket ECU is more user-friendly and makes managing complex functions much easier for the person behind the keyboard taking care of the tuning. You also have the ability to add countless custom functions that can control virtually anything on a vehicle.

An aftermarket ECU like the Haltech Elite 2500 provides a user with so many options when it comes to tuning, fail safes, outputs, and vehicle control.

Nik Czzowitz handles tech support for Haltech and he’s helped countless customers with their project vehicles. He explains why he likes to steer customers toward an aftermarket ECU for high-powered street car projects.

“With an aftermarket ECU, you’re going to have a lot more adjustability versus the OEM computer. The safety functions you can use with the aftermarket ECU are much better than OEM. The ECU can use the sensors you hook up and look at the protections that you program in and shut an engine down before a problem becomes critical. You can use three levels of engine protection with the 2500. It can be set up to give you a check engine light, put the car into a limp mode, or shut it totally down. An OEM won’t give you the ability to adjust these types of fail-safes on your own.”

The support that’s available when you move to an aftermarket ECU is another reason to consider making the switch. You really can’t call up GM, Ford, or Dodge and ask them how to make something work with a stock ECU on a high-performance build. An aftermarket company like Haltech can help you select the right parts that will work with your build in regards to engine management. Chances are, they’ve helped someone else with a similar build, and have a better idea of what you’ll need to finish an ECU swap.

 Don’t buy the ECU that fits your car now, buy the ECU that’s going to fit your car for the next five years. – Nik Czzowitz, Haltech

If you’re racing a high-horsepower street car at the track you should be looking at the data from each pass. Data logging is an area that the aftermarket ECU really shows how useful it is. The aftermarket ECU will provide you with more options for data to look at and it makes data-logging itself much easier.

“An aftermarket ECU gives you the ability to look at tons of data after each run. You can data log so many items versus what the stock ECU can do. You don’t need to have a laptop or extra box in the car to data log with an aftermarket ECU. There’s a lot of adjustability with an aftermarket ECU versus the stock ECU. An OEM ECU is going to be limited because it’s not designed to be a racecar ECU. The aftermarket ECU really fills your tuning toolbox with more weapons to use,” Czzowitz says.

Haltech designed the Elite 2500 to have a very small footprint. This makes it easy to mount like an OEM ECU.

So, you’ve exceeded the capabilities of your stock ECU and identified you need to make an upgrade, now what? Well, like any other project you need to come up with a plan before you spin a wrench or spend a single dollar.

“It’s important to consider how you plan to use the vehicle when choosing the ECU. This will influence the ECU you choose, as higher models of ECU are more powerful and therefore have more features, functions, and control strategies available within the software. It’s important to know how your chosen power-adder will affect your engine, and what engine vitals will be most important to monitor in order to properly tune and protect your engine,” says Haltech’s Chris Law.

If you want to run multiple power-adders with an OEM ECU, be ready to add extra electronics to your vehicle. Boost controllers, progressive nitrous controllers, and other devices are necessary for power management, but they don’t integrate directly with an OEM ECU. The aftermarket ECU solves that problem for people who are using two different power adders.

It's important to have a solid plan before you attempt an ECU swap like this. There's a lot that goes into it and you want to be sure that you have all the right parts on your shopping list.

“An aftermarket ECU brings everything into one house. You can control the nitrous independent from the boost, but you can also blend it into the rest of the engine thanks to the full control the ECU provides. You can use air bleeds with the blower if needed, and then use the progressive with the nitrous. Since everything is now controlled by the same brain, the ECU can make changes to each power adder based on what it’s seeing. That means the ECU can tell all the systems to do everything at the same time,” Czzowitz states.

Inside the Elite 2500 software, you can tune every aspect of the engine. The power management functions that control boost and nitrous are all integrated into the software. You also have better control over general tuning functions thanks to the design of the software.

Making the switch to an aftermarket ECU isn’t cheap and can be complex depending on your project. The better the plan you come up with before you start the project, the more likely your project will be a success.

“The best way to approach this if you’re starting from scratch is to call the manufacturer directly. We are going to know what you need for your car…that’s our job. You can do research online — in fact, I recommend that to get info from real-world users. After that, you can call the manufacturer to compare what they recommend with what you learned when you were doing your research to see if it lines up. That’s the best way to make sure you’re going to get exactly what you need for your specific project. We can cover things you didn’t think of to make your build easier,” Czzowitz explains.


Hard Parts For An Aftermarket ECU Swap

The parts you select will be tailored to your specific application and you plan on using it.  Our project vehicle for this swap is powered by a Vortech supercharged 408 cubic-inch LS engine that also has a wet shot of nitrous thanks to a Nitrous Outlet plate kit. This combination has laid down over 1,000 horsepower to tires and run a best of 10.19 at 143 MPH with the stock ECU on E85.

Haltech’s Elite 2500 ECU is the backbone and brain of this project. This ECU is extremely versatile and has the ability to manage the functions of an entire vehicle. The Elite 2500 can take care of the engine, run the vehicle’s climate control systems, handle cruise control, and work with multiple power adders.

The Haltech Elite 2500 is more than just an engine management system, it can control your entire vehicle. Scott was able to set up the Elite 2500 to use its built-in engine protections, switch the car's tune based on what fuel he was running, and set up his A/C to function just like it came from the factory.

“This type of project is a great fit for the Elite 2500. It can work in anything from a street car to a full-on drag car that needs a lot of inputs. The 2500 ECU is good for a high-horsepower street/strip car because you can grow into it if you start to go faster. There’s a lot of options that are more race-oriented that you can tap into, rather than having to buy another ECU if your car turns into a racecar,” Czzowitz states.

With an aftermarket ECU, you’re going to have a lot more adjustability versus the OEM computer. Nik Czzowitz

A wiring harness is required to connect any ECU to a fuel-injected engine, and most of the time when you’re doing a custom swap you’ll need a custom harness, but Haltech has a way to avoid that problem. You can get a fully terminated harness for GEN III and GEN IV LS engines from Haltech that is designed to work with the Elite 2500. This is a great option for people who either hate wiring anything or don’t have the skills to make a custom harness. Haltech’s harness uses high-quality components, has plenty of material so you’re not stretching any wires, and everything is labeled. Scott was able to use this harness to integrate the Haltech ECU to the Camaro’s stock gauge cluster, too.

The premade wiring harness from Haltech uses the correct OEM connectors for your engine. It also includes a fuse block so you don't have to worry about trying to find a solution to wire one up yourself. Each wire is labeled, as well, so there's no confusion on where it needs to go.

Your typical analog-style wideband sensor that an ECU uses is limited on how well it can interpret data since it just uses a zero to five-volt signal. The WB2 – Dual Channel CAN O2 Wideband Controller Kit that Haltech offers is more robust and a great fit for a high-horsepower street car project.

“The CAN wideband goes to the WB2 box where there’s a small board inside. It processes the signal, turns it into a CAN message, and sends it to the ECU. The cool thing is you’re not dealing with a single line of communication like an analog system, the CAN controller will tell the ECU if the wideband failed, or is heating up, so it’s getting more accurate information than just a zero to five-volt signal. It allows the ECU to work better thanks to the improved signal provided by the WB2 box. The WB2 is great because it takes up fewer inputs thanks to the CAN architecture and its plug and play too,” Czzowitz explains.

The WB2 Wideband Controller Kit is something you should really consider when building a Haltech ECU swap system. This controller's CAN protocol is more accurate and will make tuning easier for you.

E85 has become the fuel of choice for those with boosted street cars that are making a ton of power. You can use E85 as a substitute for high-octane racing gas in most applications, it’s affordable, and has become widely available. You can run a car on E85 and regular pump gas, but the tuning side of things can get tricky.

Most aftermarket ECUs make it easier to run on both and when you’re able to run a flex fuel sensor it allows you to switch from a pump gas tune to an E85 tune seamlessly.

If you're running E85 a flex fuel sensor is a must-have item. The Haltech flex fuel sensor is very robust and helps the Elite 2500 make the choice to switch between fuel maps based on the fuel you're using.

“The flex fuel sensor makes things easier because you don’t have to load an E85 specific map into your ECU when you switch fuels. The Elite 2500 can use a scaler in the software to read the flex fuel sensor and adjust the tune based on the math equation to make sure the engine is getting plenty of fuel. You can also go in and do 4D tuning with the 2500 to create tables based on the flex-fuel value that comes from the flex sensor. Our sensor also reads fuel temperature. That’s important because the density of fuel changes based on its temperature, so you can scale the tune based on that and it will change the tables based on the input you provide,” Czzowitz says.

The Haltech CAN Gauge is another trick part that provides you with plenty of display options. You can program this gauge with your laptop to show different outputs.

Scott was able to keep the Camaro’s OEM gauge cluster intact and mount the Elite 2500 out of sight inside the cabin of the Camaro. There are certain things you need to monitor when you’re running a boosted vehicle that’s making high levels of horsepower like air-fuel ratio, boost levels, and much more. Instead of filling the Camaro’s A-pillar with gauges and taking up valuable ECU outputs, Scott used Haltech’s Multi-Function CAN Gauge. This gauge works off CAN protocol, plugs right into the ECU, and can be configured to show readings from numerous sensors.

The Haltech 2500 is extremely powerful and gives you more options when it comes to tuning your vehicle. This becomes important when you start making a lot of horsepower and need a very accurate way to tune.

An aftermarket ECU is a great solution for people with high horsepower street cars that are starting to outgrow an OEM ECU. You can set one of these ECUs up to work with virtually any engine combination and power-adder.

Article Sources

About the author

Brian Wagner

Spending his childhood at different race tracks around Ohio with his family’s 1967 Nova, Brian developed a true love for drag racing. Brian enjoys anything loud, fast, and fun.
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