What is a Hondata ECU?

A Hondata ECU is a factory Honda ECU modified so that it is programmable. We can change the behavior of the ECU, adding features like expanded fuel and ignition tables for boost. The Hondata ECU allows dynamic user control over VTEC engagement, rev limit, shift light (included with all Hondata kits), and launch/full throttle shift settings (Stages 3 and higher). We offer software tools which allow you to re-program the ECU. and datalog all sensor readings.

How much power increase will I get from using a Hondata ECU?

There is no 'silver bullet' when it comes to ECUs. The Hondata simply gives you the tools to unlock the true potential of your engine. When changes are made to your engine (addition of a turbocharger, supercharger, higher compression pistons, different cams, etc), the fuel and ignition maps offered by the stock ECU are usually not optimized for these changes. OBDII ECU's have ignition and fuel settings geared towards emissions so greater power gains are seen with OBDII ECUs.

Can Hondata tune my car for me?

No. Hondata provides tools for you to tune your car, or can recommend dealers in your area who can tune your car for you.

Can I run my ______ engine with a Hondata ECU?

(motorcycle, GM V8, airplane, turbo diesel, jet-boat are some of the engines which have been suggested).  The Honda ECU expects 4 cylinders, a Honda distributor, an engine which runs backwards and which has spark plugs. There are many stand-alone ECUs which are suitable for your non-Honda engine.

How does Hondata compare to ______ (someone who provides replacement chips)?

Be careful when dealing with a company or individual who is offering a 'chip' for your ECU. One well known company does not touch the ECU program or data - they simply put their stickers on the ECU. Other chips which we have looked at were stock programs from a different model ECU, or were simply the stock chip from the same ECU! The problem with buying a "custom chip" from someone is that the chip was designed for a particular engine configuration. Unless your setup is exactly the same, the "custom chip" will be a compromise at best. In addition, if you wish to make changes to ignition curve or rev limiter, you are stuck with the settings from that "custom chip". With a Hondata ECU you can tune the ECU to the optimal settings for your engine. The ECU can always be later retuned if necessary by either a Hondata dealer or by yourself if you purchase a Stage 4 kit.

How does Hondata compare to ______ (a replacement ECU)?

Generally using a Hondata modified Honda ECU will be cheaper and easier to install and tune, since the factory wiring harness and sensors are used, and stock ignition and fuel tables are provided as starting points. Most other standalone systems require you to start from scratch with the fuel and ignition maps. Most other standalone systems require the use of different sensors and/or major modifications to the engine wiring harness. Other factors in favor of using the Honda ECU are reliability, cost, closed loop operation (management of the engine at partial throttle -- something the Honda ECU is very good at, and ability to retain control of secondary outputs like A/C and the radiator fan.

Does Hondata sell ECUs?

Hondata has a limited number of P28 VTEC ECUs for sale. We can, however, provide you with a swap guide found here which details which ECU is appropriate for your application. Generally speaking, if your car is OBDII (96 or later), you will need an adapter conversion harness and an OBDI ECU. You can buy ECUs from wrecking yards, online sites like eBay, thepartstrader.com, etc. If possible, open the ECU before you purchase it, because many ECUs from wrecking yards have water damage.

Why is the Hondata ECU so much better than the stock ECU for tuning high horsepower engines?

Most power upgrades (turbocharger, supercharger, long duration cams etc) require substantially more fuel to be delivered to meet the engine. Out of the box, most forced induction setups rely on the use of extremely high fuel pressures (over 100 psi under boost), a rising rate regulator, and a noisy fuel pump. This method is inaccurate (as the fuel pressure will usually rise too slowly when the engine first goes into boost, then will over fuel under sustained boost), unreliable as all the fuel system is subject to 100-120 psi, and unsafe as the fuel pump is overworked, and will cause engine damage if it cannot delivery sufficient volume of fuel at the required pressure.  

Cars which have forced induction from the factory use a relatively modest fuel pump, big injectors, and their computers are programmed such that they can accurately control those injectors under boost.  Hondata follows a similar philosophy. We replace the stock 240cc Honda injectors with larger injectors, extend the fuel and ignition tables in the ECU so that it can deliver the correct amount of fuel and still idle like stock. Piggyback devices, rising rate fuel pressure regulators and ignition retard devices are not needed. The end result is a much cleaner and safer system that is infinitely adjustable and offers substantial room for growth.

How do I make my car faster?

Throw another hamster on the wheel.

I have ECU problem codes.  Can you program these out?

The ECU generates problem codes because there is something wrong. If you want your engine to run correctly you should locate and fix the causes of the problem codes. Here is a list of problem codes.

I have been using a _____ ECU (a much-pirated ROM from a Japanese performance company) without any error codes. Why do I get error codes when I use a stock ECU or a Hondata modified ECU?

The ROM in question was designed for racing applications only.  It does not have the extensive redundancy and sensor verification like a stock ECU. You can prove this by unplugging sensors, and no error codes will be generated. The disadvantage is that you do not know when there is a problem, even if it affects performance.  One car we looked at recently using on of these ROMs had errors from faulty wiring which caused the ignition advance to be fixed at 22 degrees. These was no way of knowing when using that particular ROM.

How much boost can I run with a Hondata ECU?

The stock MAP sensor can see 11 lbs boost. If you replace the MAP sensor with a 3 bar MAP sensor you can run 28 lbs boost.

What are the biggest injectors I can run?

The ECU can be re-calibrated to suit any sized injector (make sure you match injector impedance if you are replacing you injectors). However, injectors take a finite amount of time to open and close, so the bigger injectors tend to be less accurate with their fueling at low durations, such as idle. Much depends on the mechanics of the injector, and how quickly it can open and close. With disk type injectors (such as RC 440cc injectors) you can not tell the difference between stock injectors and injectors which flow twice as much as stock injectors, once the ECU has been reprogrammed for the larger injectors (and there is no difference on the dyno either). With race engines we have run injectors up to 4 times the size of the stock injectors.

How come people say that the biggest injector I can run is 310 cc?

This assumes that you are not re-calibrating the ECU to the new injector size.  If you don't, the bigger injector will over-fuel. If this happens then the ECU will compensate to some degree using closed loop operation to reduce the injector duration. The limit of the long term closed loop adjustment is about 40%, which is close to the increase in size from stock to 310cc injectors.

What is the maximum power of a Hondata system?

There are no inherent limits in the ECU which limit engine output.  In all cases the limiting factors are the engine itself and fuel supply system.

How fast is the processor in the Honda ECU?

The processor type and speed of the ECU does not mater - it is the ECUs ability to accurately supply fuel and spark timing which is important. Part of this is the speed at which the ECU can measure engine parameters and adjust fuel and spark. The Honda ECU can read all engine parameters, update fuel and spark settings, usually in less than an engine revolution. Another part is the accuracy which the ECU can open and close the injectors and fire the spark plugs. The Honda ECU is capable of opening and closing the injectors, or firing the spark plugs, with accuracy of 3 millionths of a second, which is far in excess of what is required.

What are the fuel units in ROM Editor not milliseconds?

Injector duration varies with a number of different conditions (water temperature, air temperature etc) and is not linear. E.g. an injector duration of 4ms will not deliver twice the fuel of an injector duration of 2ms (it will be almost three times the fuel).  The numbers in the fuel tables are arbitrary linear fuel values. A fuel value of 500 will deliver twice the fuel of a value of 250. You can see the approximate injector duration on the 2d and 3d graph views by selecting Show Injector Duration.

How long can HondaLogger record?

A recording is essentially unlimited in size, but requires memory from Windows so ultimately will be limited by the amount of available virtual memory. It is possible to record for several hours with most laptops without any problems.

Can I make my own skins for HondaLogger?

HondaLogger is supplied fully clothed, and cannot be undressed.

What operating systems does ROM Editor and HondaLogger work with?

Both applications will run on Windows 95, Windows 98, Windows ME, Windows XP, Windows NT and Windows 2000. 

Can you add engine sound to HondaLogger?

You are welcome to make appropriate engine sounds yourself during playback.

What is an Easter Egg?

A hidden feature of an application, written by developers in less productive moments.  Usually Easter Eggs are invoked by using combinations of the shift, control and alt keys while clicking on different parts of the about screen.