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Настройки v-afc для H22a
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СообщениеДобавлено: 26 окт 2006, 18:47
Аватара пользователяСообщения: 4590Откуда: Деревня в тульском уездеЗарегистрирован: 16 дек 2005, 10:05Машина: JDM Уазик)

What exactly is this thing, what does it do and do I need it? All so common questions. Well, to start off, the Apexi V-AFC is a fuel and Vtec controller. It gives you the flexibility to adjust fuel settings according to the modifications you have on your car. Why change fuel settings, you may ask? Because as you modify your car you're changing the way it breaths and performs, thus having a different need for fuel. In addition, you also have the ability to set when Vtec engages. Many people say, "oh cool, if I change my Vtec point to 2000RPM I'll be in Vtec all the time and have a fast car!" Sorry to burst your bubble, but this isn't true. If you set the RPM engagement point for Vtec too low then you're going to be loosing performance, because the vtec cams' intake charge is open for too long for the speed you are traveling(2000RPMs). So when you're tuning your car, be sure to set an optimal crossover point. A general rule is setting it no lower than 4500RPM. OK, you might be saying to your self this thing does a lot, I bet it gives good gains. The answer to that is yes and no. If you have good amount of mods you'll gain more horsepower, cause you'll have the need to alter the fuel curve. But if your car is bone stock(or close), there is no need to alter the fuel curve. Saying that, you should put this unit at the end of your to-buy list.

Once you purchase this unit make sure you take your car to the dyno and tune it accordingly. You cant rely on other people's settings to work as good as it did for them on your car. Every car is different and has different needs. The best thing you can do to yourself is spend about $100 and take your car to the dyno. It shouldn't take more than an hour to get your settings straight.


The Apexi V-AFC unit is very easy to install. Patients and accuracy are a key factor. The instruction manual comes will all the instructions you will need. Just follow the diagram and make sure you splice and crimp all the wires very carefully. This process shouldn't take more than an hour or two. It's time consuming, not because its hard but you need to do everything very carefully. The diagram does have one wire missing in it, and this wire happens to be one of the wires needed for "VTEC" to engage. Its called the VTM wire. The reason it is not shown in the diagram is because they tested this device on vehicles in Japan, on which this wire is not needed. The US model Preludes however do need this wire tapped and cut. A few months after Apexi released this unit, they became aware of the problem and now have an updated version of a wiring diagram up. You can view this diagram here. Unfortunately, this updated diagram has all the correct connections except for the VTM wire(once again). The VTM wire in their diagram is pointing to a null connection(pin #21), there actually is no wire there and is just an empty slot. You can use Apexi's updated diagram when installing this unit with the correction of the VTM wire found on my diagram. Please note that you should use diagram #WH2 for all 97+ Preludes. They(Apexi) have a different diagram for the 97-98 and the 99-01 preludes. This is another error on their part, so please be informed. Use diagram WH2 if you have a 5th generation prelude. Below is the diagram I have made and currently use on my car. Its close to the Apexi diagram with a difference in the ground and VTM location. Either one of the grounds should work fine(mine vs. apexi). Note: The old diagram that is still found in some manuals uses the H6-a diagram. This diagram also has the VTM wire, labeled "Vtec Signal", at a wrong connection. Once again connect the VTM as shown below in my diagram.


There has been some concern by some people about the ground wire on the ECU because Apexi uses a different pin for the ground wire in their updated diagram. There is a simple(rather complicated) explanation to this, try to follow closely. On ECM Connector A, there are two Power Source wires; and each Power Source wire has two ground wires. Now lets concentrate on the Power wire used in the diagram. This wire is labeled "Power Source for the ECM Control Unit". And this Power Source has two ground wires labeled, "Ground Wire for the ECM Control Unit", and "Ground Wire for the ECM Power Circuit". As you can see, the "Power Wire for the ECM Control Unit" matches the "Ground Wire for the ECM Control Unit", and this is the ground that I have used (and shown in the diagram above). Apexi, on the other hand, has used the "Ground Wire for the ECM Power Circuit", which does not match with the "Power Source for the ECM Control Unit". I'm not sure if it really does make a difference which ground wire you choose, because they are both grounds, but it is preferred to use the ground wire shown in the diagram above. Note: Apexi's original wiring diagram and the Field Vtec Controller use the same ground wire as I have used above.

If you are too paranoid in splicing the stock ECU wires, you can do what I did. Simply go out and buy the Field Wiring Harness(model# VT-H6). Once you get that; tap, splice, cut the wires on the harness to make the Apexi unit work. This way, if you wish to remove your Apexi unit at a later time, it will be much easier. Plus, if you have problems in making the unit work, you can simply pull out the harness and work on it whenever you wish. This way you wont have a handicapped car while you attempt to install the unit. The Field wiring harness can be purchased from a local performance store. If there is none in your area try calling Options Auto, http://www.optauto.com/. That is where I purchased mine from for about $160US. Yes, very steep for a harness, but I think its well worth it. A picture of this harness is shown below.


Courtesy www.vtec.net

Another important issue when installing the Apexi V-AFC are the two ground wires. Be sure to splice these wires into the ECU as shown in the manual. One of these wires(brown wire) must be closer to the ECU than the other(black wire). Try to leave at least a 1cm gap between both these wires. This for grounding purposes and is used to prevent a "ground loop."

Another minor issue people have had trouble with is the splitting caps that are supplied with the unit. These are used to tap into the wires for the throttle position, RPM, power and ground wires on the ECU. Apexi has failed to show the proper way to use these splitting caps in the manual. Follow the diagram below to ensure a proper connection. Make sure to wrap all connections with electrical tape or something equivalent.


One last thing to talk about is finding and getting to the ECU. I've heard too many times of people saying that their ECU doesn't have 3 connectors. Once you pop the panel on which the ECU is bolted into place you'll notice that there is two electronic units. One is to the left and one is to the right. They are both mounted on the panel. The ECU is the unit that's on the right side, it has 3 connectors. The unit on the left side has 2 connectors. So be sure you are working on the unit(ECU) mounted on the right. Click here to see both these units mounted on the panel, Note: the ECU is on the right hand side. If you're having trouble finding the ECU click on this link, it has some pictures that'll help you get there.

http://prelude.vtec.net/gen5/performanc ... ation.html


A good place to mount the unit is right below the stereo. You can simply remove the empty pocket underneath the stereo and use a dremel tool and trim the sides as needed. After which, position the unit and use a hot glue gun to secure it in place. You can cover up the sides with ABS plastic to give it a nice clean look. Its a tight fit, but it looks great. Any good stereo shop can mount this for you professionally, but expect to pay up to $100 for the job.

Now that you have everything hooked up and mounted into place you need to worry about the settings. The best thing to do here is to take it to a dyno and tune it yourself. It'll take about an hour to get everything straightened out, but it assures that you have the perfect settings for your car. If you aren't comfortable tuning the unit yourself, some shops actually do the tuning for you for a small charge, but make sure they are experienced and have worked with this unit before. You can always take settings from another person, but as you've been told and already know, each and every car has different fuel needs according to the mods and the car itself. But you can take a look at my settings and use those as a place to start. I could add that the settings I've seen in other cars do look similar, so using these settings are your default settings wont cause any harm.

Wide Throttle___________________Narrow Throttle

Lo Camside_____________________Lo Camside

RPM______Fuel Correction________RPM_________Fuel Correction









Hi Camside_____________________Hi Camside

RPM________Fuel Correction______RPM__________Fuel Correction









VTEC Engagement Point Setting

Lo Cam -> Hi Cam: 4700

Hi Cam -> Lo Cam: 4500

VTEC Unmatch Fuel Correction

Hi<<L: 0%

Lo<<H: 0%

Throttle Position Setting

Lo Throttle: 10%

Hi Throttle: 50%

NE Point

LVt (Lo Camside)___________________HVt (Hi Camside)
Ne1: 1000_________________________Ne1: 4000
Ne2: 2000_________________________Ne2: 4500
Ne3: 3000_________________________Ne3: 5000
Ne4: 4000_________________________Ne4: 5500
Ne5: 5000_________________________Ne5: 6000
Ne6: 5500_________________________Ne6: 7000
Ne7: 6000_________________________Ne7: 8000
Ne8: 6500_________________________Ne8: 9000

You can download a hard copy of these settings for future reference from the following links:
In MS Word Format:
In MS Excel Format:

Performance Gains:

Initially my car made 170.1 hp, and 134.6 ft/lbs torque at the wheels, pretty impressive and not bad at all. After 11 dyno runs tuning the controller my car made 178.2 hp, and 138.5 ft/lbs torque. Thats an 8.1 increase in horsepower, and a 3.9 increase in torque.

All curves on the dyno now go straight up, and keep climbing. Where as before, there were some dips and spikes. The most impressive part was the gains I achieved from lowering the VTEC engagement point. Right when VTEC kicks in, there is a slight dip in horsepower(on all cars), and then there is a sharp spike when the cam lobes switch over. By lowering the VTEC engagement point I was able to straighten out that dip and gain 33.7 hp at that specific point. Thats a jump from 118.7 hp to 152.4 hp. Very nice.

My overall gains were the following:
Horsepower: 8.1 hp
Torque: 3.9 ft/lbs
Maximum Gain(when vtec kicked in): 33.7 hp!!
(Note: All horsepower and torque numbers are measured at the wheels!)

Below is a before and after dyno for the Apexi unit. At the time of the dyno, my car had the following modifications:
DC-Sports Ceramic Coated Header
Tanabe DTM Exhaust
AEM Short-Ram Intake w/ Custom Heat Shield
MSD SCI-L Ignition
MSD Blaster SS Coil
Magnacore 8.5mm Wires
Apexi Vtec-AFC
AEM Tru-Power Pulleys


So to conclude, I highly recommend this unit to all others. My other mods surely made a difference in the results I got. If your car is fairly stock or even bone stock, this wouldn't be a good place to start. Unless your car has changed the way it performs, there is no reason to change fuel and vtec settings. However, if you have an intake and exhaust, your car is getting more air in and taking more air our. To fully utilize these mods, you can change the fuel settings accordingly to achieve maximum horsepower. The Apexi unit can be very giving if you have a nice amount of mods, but can also be very disappointing if you see no gains from it whatsoever due to a lack of mods.

VTEC Unmatch Fuel Correction Setting:

This setting has confused and misled many people. What this setting does is it adjusts the fuel delivery exactly at the point where VTEC kicks in. This overrides all other settings at that instant. This setting is important because when your car switches over the cam lobes for VTEC to kick in, your car might need more/less fuel. By tuning this setting, you can give your car the appropriate amount of fuel it needs at that split second when VTEC kicks in. There are two settings for this option, one when VTEC kicks in(switches from lo cam to hi cam), and one when VTEC turns off(switches from hi cam to lo cam).

Field vs. Apexi Fuel/Vtec Controller:

Many people have asked this question and have been searching for an answer for a long time. Hopefully, this will help you decide.

To start out, lets examine how both the units look like. The Field controller has a green LCD display, with backlit buttons surrounding it. It's about 1/4 din size. This display is rather small, and hard to see during the daytime, as it gets "washed out." The Apexi however has a nice dot-matrix blue display capable of showing nice graphics and displaying settings in clarity. The brightness changes during the day as it senses the brightness of its surrounding and adjusts automatically. The Apexi has three types of display options, Analog, Digital, and Graphical. In Digital mode you can have up to 4 settings displaying at the same time. In Analog mode, you can have two analog gauges graphically showing on the display.

Now lets get down to performance issues. When tuning the controllers, you adjust the fuel settings according to the RPMs. The Field unit lets you adjust fuel at 1000, 2000, 3000, etc. RPMs. These RPM's are preset, and you can only adjust the fuel settings on those RPMs. It also has one RPM value you set to switchover to VTEC, and turns off when RPMs drop below that set value. Does the job in the most simple and straightforward way. The Apexi also works on RPM values also, but you get to choose the RPM values. So you can have a combination like 1000, 1500, 2000, 2200, etc. RPMs. This gives you a nice range of tune ability. In addition, you have two sets of fuel settings. One setting for Lo Cam, and one settings for Hi Cam(vtec). This is very nice, because you can have two different settings going at the same time switching back and forth according whether you are in VTEC or not. In addition to that, you have separate settings according to Low Throttle, and Wide Throttle. The Apexi unit calculates whether or not you have your foot mashed on the gas, or are driving regularly. And whether or not the throttle is low or wide, it chooses different fuel settings(that you have set). Finally, there are two values for the VTEC part of the VTEC controller. You have one value for VTEC to engage, and another separate value for VTEC to disengage. Unlike the Field which uses the same value to engage and disengage. These options by itself set the Apexi unit far on top from the Field unit.

To finish up, the nice graphical interface the Apexi has makes using it much easier to use, and its performance points make it the better choice to fine tune your car. There are a lot more options in the Apexi that I have not mentioned, like showing peak values and instant replay of settings you choose to monitor. Without a doubt, the Apexi places first.


For information, questions or comments feel free to drop me an email at mailto:Arax@mail.com.

Any part of this file may not be edited, reproduced, used, or tampered with in any way, without my written consent. All graphics withhold their original copyrights and belong to their rightful creators. All brand names are registered trademarks of their respective owners. Thank you.

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