When it comes to tuning your car, you are inundated with choices. Not only do you need to decide whether you will reflash your factory ECU, piggyback it, or replace it with a standalone but once you have made that decision, there are untold options for each. Depending on your car, your options may be quite limited and your choice made easier. On the other hand, the full range of options may be available which can be a little overwhelming. In this article, you will learn the pros and cons of each tuning method along with how to choose between the plethora of different manufacturers available.
In this article: Things to Consider First | Your Tuning Options? | Which Option Is Best For You? | You've Chosen Your Best Option - Now what? | How to Choose a Specific ECU | Training OR Tuner | Conclusion
Things to Consider When Choosing a Tuning Option For Your Car
There will never be one overall best option that suits everyone, this will depend on your budget and your car. You need to ask yourself the following questions to help you make the right decision:
- How modern is your car? - Depending on the car’s age certain options may not be available to you.
- What will you be using it for? - A street car will have very different requirements to a drag car for example.
- What is your budget? - Remember, purchasing the ECU is only the start. You then need to install it, tune it, and purchase the supporting hardware and components.
- What is your level of knowledge? - If you don’t have a lot of experience, you should be looking at products from manufacturers who can support you.
Your Tuning Options
Piggyback ECU
A piggyback ECU works by intercepting the signals into and out of the factory ECU which allows you to manipulate those signals and make tuning changes. In most instances, we wouldn’t recommend this option as when you get into some more serious modifications, it rarely gives you a consistent repeatable tuning result which makes the process end up costing a lot more than you thought you were going to save in the first place. Another issue that comes into play is that modern ECUs are very smart and can adapt which can lead to them overriding the changes you have made via your piggyback ECU.
The only time we would recommend a piggyback ECU is on a very lightly modified car with no better option. You could get good results with the likes of a four-cylinder, naturally aspirated Honda B18C with light modifications where perhaps the factory tune is pretty close but you just need to make small changes to the fuel and ignition.
Standalone ECU
A standalone ECU replaces your factory ECU and is designed to be able to operate almost any engine once you have adapted the software to suit. There are upwards of 100 standalone manufacturers, some a lot more popular than others. Standalone ECUs can be broken down into universal wire in or plug and play replacements. A universal wire in has a generic Superseal style connector which you can wire directly to your engine or adapt into your wiring harness. A plug and play comes with the same factory header plug as the car it was designed to go into which makes for a very quick installation. The factory CAN messages will also be decoded and replicated which means all your electronics will still be able to function without any corrections required.
Reflashing Stock ECU
Reflashing allows you to make tuning changes to the factory ECU by downloading the factory tune data with a hardware interface into the associated software on your laptop where you will find all the maps you may need to adjust. These can be viewed graphically to help you visualise the data. Once you have made your tuning changes, you can load the data back into the ECU and you’re ready to go. Reflashing can be broken down into either commercial packages or open source which are either free or very cheap.
Which Option Is Best For YOU?
Especially if your car is a popular late-model, your platform will likely be supported by a wide range of options so you will need a way of deciding which option will be best for you. Let’s look at a few different scenarios.
Late-Model Car
If you have a late model car from about 2007 onwards, these cars will rely heavily on CAN communication to send data between the various electronic modules such as ABS, power steering and the gauge cluster to name just a few. With cars like this, unless yours is for motorsport use, you are best to go with a reflashing package. This is because if you installed a standalone ECU, the engine would run but chances are that lots of your electronically controlled features won’t operate. There are fixes for this but it is easiest to simply reflash your factory ECU. A lot of people think that you are limited to what you can do with reflashing but these days you can do just about anything even fit a supercharger to a car that was naturally aspirated. The only time you would be better to go with a standalone ECU with a modern car is if it is for motorsport use. In this case, it is likely that most if not all of the factory electronics have been removed which means there is now no requirement to retain the CAN communications. Also one area reflashing can fall short is with data logging which is, of course, critical in motorsport.
Car With Both Standalone AND Reflash Tuning Options Available
Next, let’s look at the scenario where you have a car from around the early to late 2000s era where both reflashing and standalone is a choice. It is almost always going to be more cost-effective to go with reflashing over a standalone ECU as you already own all the hardware to run the engine and are only going to be modifying the tuning data in your factory ECU. The only cost to consider here is that of the reflashing package.
Another factor to think about is that since a standalone ECU is designed to run any engine, the code is very universal. On the other hand, your factory ECU has been designed with solely your platform in mind and with the massive budget that the manufacturer had, you know it will do the best possible job of running your engine. It is easy to see that you will be better off with reflashing your factory ECU. As mentioned in the previous example, if your car will be for motorsport use, you are still better off switching to a standalone ECU.
Older Or Less Popular Car
Lastly let’s look at the scenario where you are running an older car before CAN communications becoming popular, around the early 2000s or older and equally if you have a platform that is less popular for modification. In this case, a standalone ECU may be your only option. If you wanted to go with reflashing, your only option would likely be to remove a chip, change the data on an EEPROM and replace the chip as it is probable that reflashing packages will not support your platform.
You do need to be careful if your older car has an automatic transmission when you fit a standalone ECU however as it is likely that it will still have a transmission control module which will have some reliance on the factory ECU. The way to get around this is by disconnecting the factory ECU but keeping enough signals going into it to make it think it’s still in control of the engine. This means it will still be able to communicate with the transmission control module and keep it running well.
You’ve Chosen Your Option - Now what?
You may have chosen the option that best suits you but your job is far from over, you now need to decide which of the two variants within each option suits you best.
Reflashing Stock Computer/ECU
As we have discussed, there are commercial software packages and open-source which is either free or very cheap. To decide which is best, you need to start by researching what options are available for your car and the best place to start is on enthusiast forums for your particular car. If both of these options are available to you, next you need to consider their effectiveness. Reflashing involves taking a raw hexadecimal file and displaying it in a way that you as the tuner can understand and manipulate. This is done with a definition file which pinpoints the address at which each map is located and the size of that map.
The issue with open source reflashing, particularly if your platform is uncommon, is that these solutions are developed by the enthusiast community and often the definitions can be incomplete or even non-existent. The issue this causes is that you might not have access to the maps you need or you may think you do but they are not having the effect you expect. Commercial packages, on the other hand, are very reliable because if they didn’t give you accurate definitions, tuners would not support them and they wouldn’t sell many packages. Also, if you can’t follow the step by step guide that comes with commercial packages, you will get phone or email support from the manufacturer in case you get stuck. Of course one of the biggest deciding factors for most people will be the cost which is why open source is often attractive.
Standalone ECU
As we covered off earlier, this tuning option can be broken down into universal wire ins and plug and plays. Generally speaking, if there is a plug and play available, that will be the cheapest option as it costs a surprising amount to wire in an aftermarket ECU. The plug and play option will likely be more expensive upfront but cheaper in the long run. A lot of people think that plug and play ECUs limit your ability to expand the capabilities of the ECU at a later point. There are certain cases where this might be the case but overall, the manufacturers do think ahead and will build in options for expansion, for example, connectors to connect expansion looms to enable the addition of sensors not supported by the OE manufacturer.
A situation where you might be better to go with a universal wire in ECU is if you’re dealing with an older car with high mileage where the factory wiring harness is starting to deteriorate. The plugs become brittle and you can end up with the harness being unreliable and causing massive diagnostic issues. Likewise, if your car is for motorsport use and you will be stripping out all the factory wiring, a universal wire in would also make sense.
How To Choose A Specific Standalone ECU
So you’ve chosen your tuning option and within that, which type. You’re nearly there, now you just have to decide on the specific ECU and the first thing you need to do is make a list of everything you need your ECU to be able to do. The key points are how many cylinders it needs to control and how many ignition outputs are required as this will likely eliminate a lot of ECUs right off the bat, particularly if you have a 10 or 12 cylinder engine and need a lot of ignition inputs. Other points for consideration are variable valve timing, drive by wire throttle control and multiple drive by wire throttle bodies where applicable?
We’ve said it before and we’ll say it again, budget is one of the most important considerations when choosing an ECU. It is not just the price of the ECU that you need to think about, but also the price of any auxiliary hardware you will require. You will be wasting your time if you look into ECUs that you simply cannot afford.
Another important factor to consider is future-proofing your investment. It might be tempting to buy the cheapest ECU that fits your needs right now but if you will be keeping the car for any length of time and if it is within your budget, it is a good idea to buy an ECU that has additional input and output capability. This way, if you decide to do further modifications, you won’t have to upgrade your ECU which would end up costing you more in the long run.
Next, you need to make a shortlist of the ECUs that suit your requirements. Most manufacturers will have a tool that enables you to compare features across their range of ECUs, for example, the one below from MoTeC’s website.
Chances are your shortlist is going to include more than one option. If you are using a professional tuner, go with the option they recommend as there is no point purchasing an ECU that they know nothing about and expecting them to do a perfect job. Since you are reading this article, however, you most likely will be tuning your car yourself. In that case, you should consider which manufacturer gives the best technical support as no matter how good you are at tuning, you are still bound to come across the odd time where you get stuck with a certain function. Even better than this is a manufacturer that provides good support and is in a similar time zone to you as that way, you won’t have to wait until the next day to get a response. Along with these points of consideration, you can also turn to enthusiast forums to see which of your shortlisted options people have had the best experiences with.
Training OR Pro Tuner
The last item on our must-have tools list is perhaps the most important. Tuning carries an inherent level of risk and there’s a lot that can go wrong if you don’t know what you’re doing. It doesn’t take much to do some real damage to your engine, so it really pays to prepare yourself with the correct knowledge right from the start.
If you plan to tune your chosen option yourself, you want to make sure you are armed with the right tools to do so. High Performance Academy’s EFI Tuning courses are the perfect place to find everything you need, as well as practical worked examples to follow along with, and support from tutors and other students as you learn and embark on your own tuning projects.
The best part is, if you find that any of these courses aren’t for you, you have 60 days to return them for a full refund — so what have you got to lose? We hope to see you in our community forums soon.
So what are you waiting for? Click here to get started with a package deal that covers whatever option you find is best for you application.
Alternatively if you decide to employ the services of your local tuner, this article will help you find the best one for the job.
Conclusion
Choosing a tuning option and a specific ECU may initially seem like information overload as you will probably be told many different things by different people, not to mention the fact that there are a plethora of options out there. However if you look at it methodically as we have laid out in this article and take your time, you are sure to pick the best option for your needs.
