The P28 ECU – Everything You Need To Know

The P28 ECU is an ingenious bit of kit that can make a huge amount of difference to your performance and overall driving experience. Honda is ahead of the curve in the ECU department so you can feel rest assured that you are getting the best of the best. But what makes the P28 ECU so special? What even is an ECU and why does it matter? This quick blog post will cover all of that and more.

What Is An ECU?

ECU stands for an engine control unit. It is a type of computerized control module that controls the actuators which in turn affect several aspects of a combustion engine’s performance. In this instance, an actuator is a little mechanic device that opens and closes valves.

Source / 380DB Forum

In terms of engine performance control, these valves could be used to adjust the airflow into the combustion chamber, increase/decrease fuel consumption slightly, or do any other number of things. A common use for the ECU is to control fuel injection to increase performance and improve fuel consumption.

Why Are ECUs Important?

The ECU is quite an important aspect of any combustion engine. Many of its more niche benefits are really only applicable to racing, where every edge you manage to gain yourself is vital for winning the race. In terms of our everyday drivers, or morning commuters, it mostly affects how smooth the ride is.

A well-tuned ECU can ensure that you are minimizing fuel needed by better controlling the burn rate as well as ensuring that you are getting enough fuel at all times. The ECU can help stop the car from feeling so jittery to drive in low gear.

What Is The P28 ECU?

The P28 is a model of ECU that is well known for being easy to find and easy to install. Don’t get the wrong idea, you are still probably better off getting it installed by a professional (Honda themselves if possible) than attempting to do so yourself.

An incorrectly installed ECU is going to be more unpleasant than it is catastrophic. But, when it comes to the fuel intake it’s probably best to leave it well enough alone. The p28 is quite common because it is a solid choice of ECU that doesn’t really have any major flaws or weak spots. Nor does it tend to excel in any particular area.

What Makes The P28 ECU So Special?

The P28 ECU has developed a reputation for being kind of a jack of all trades. It isn’t exceptional as standard by any means but it does all of its jobs well and it’s pretty darn reliable. It is also quite reasonably priced given that both supply and demand are present.

You can probably pick up a P28 ECU for about $100-$300 depending on where you are looking and what the stock currently looks like. The 92 Civic is probably the most famous example of a car that embodied the P28. You could argue that the P28 was so popular this year because it came as stock. Or maybe, the 92 Civic was so popular because the P28 made it so?

What is an IABS?

The IABS controls the secondary intake valves on the b18c1 intake manifold. Why does this matter? Because the P28 is one of the only ECUs in that price range that is able to do so. It may need to be chipped to be suitable for hybrids but that still makes it a heck of a lot better than some more expensive ECUs like the P30 VTEC.

What Is The Difference Between The P28 ECU And A P30/P61 ECU?

The biggest differences are quality of programming right off the production line. The P30 and P61 are much better “technically” in terms of factory programming. They will be slightly more advanced (a lot more in regards to the P61) and better equipped to deal with new engines. The P30 also contains a GSR computer, not just a single VTEC civic computer. The biggest difference, to us as consumers, is the price. You can expect to pay a heck of a lot more for a P30 or P61 than a P28.

If you were planning on going all out on a refurbishment project then you would probably go with the P30. It doesn’t have as many pre-written programs but you can get quite a lot more out of it at the higher end. Additionally, VTEC kicks in fully at a lower RPM on the P30 and P61 so you will notice the difference more as you accelerate at lower speeds.

Is the P28 Better Value For Money Than The P30/P61?

This is a hard question to answer because it all depends on whether or not the P28 ECU has been chipped or not. If it has not then most people would consider the P30 and P61 to be better value for money. They are more adaptive, provide better performance increases, reduce fuel consumption more, and are even usable on hybrid models. They are harder to find and a little more costly but for many people, the added benefits far outweigh the costs.

However, if you chip the P28 then suddenly the playing field is a lot more level. A chipped P28 is absolutely comparable to a standard P30 and given the difference in price and availability suddenly the P28 is looking like a much nicer option. It can be chipped to work for automatics, manuals, or hybrids and there are suddenly millions of options available to you in terms of minor tweaks to make. However, if you were to get the P30 chipped it is suddenly the better choice. Again. And far more expensive. Again.


So, now you know. The P28 ECU is such a great value-for-money addition to any Honda vehicle. You don’t have to be a professional racer to want/need one! While it isn’t completely necessary, chipping your ECU to ensure that you are getting the most out of it is normally the go-to move by people who know what they are doing. Remember, while the stock P30 and P61 are arguably better than the standard P28 once chipped you are getting much of the same performance for a fraction of the price.

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