ECU Swap?

Im looking at getting a VFR800. I like that the 06's have a lower VTEC point but if I end up with an 02-05 model can I change the ECU to an 06+ unit?

Thanks,
Frankie

 

I'm wondering the same thing. Can somebody with a newer service manual confirm that the ECU pinouts are the same? My manual only covers 02-05.

 

How much does an ECU go for? Would it really be worth the cost just to change the VTEC engagement point by a few hundred RPM's? Now if you could get a programmable ECU (pipe dream) that would be very cool because you could alter timing as well as fuel delivery.

Action

 

I'm guessing a used ECU goes for about $250 if you can find one. I'd pay that much to eliminate the huge flat spot that my bike has at 6500-7000 and smooth the VTEC transition. I just wonder if it's a plug-n-play deal.

There's an '03 ECU on Ebay now for $175. I'll price a new '06+ one next time I'm at the dealer, but I'm guessing it will be $600-800. For now I'm just going to order a PCIII and hope I can smooth it out with that. I've heard good things.

 

alter timing?

so has anyone looked into whether or not the dynajet ignition module is applicable to our bikes? the website says that that ignition module can be used in conjunction the power commander USB on certain models. but im not sure if the vtecs are one of those models...

 

CBR - I would try eliminating the O2 sensors first. Costs a dollar if you use resistors from Radio Shack and you'll have to do it anyway if you get a PCIII.

CR - I haven't looked on the Power Commander website lately. I would think because of how their PCIII is placed in the system an ignition module would not work. I would love to be wrong on this.

Action

 

I've done the O2 delete, it cured some problems but made others worse IMO. I also blocked off the PAIR valve and all that did for me was make the exhaust stink at idle. I'm going to return everything to stock until I get a PCIII, because I think it ran better before any of the mods.
I'd still like to try a late model ECU. The people at Honda thought something needed to be changed, so that sorta tells me it's worth doing. Do people with the '06+ VFRs have all the same fueling issues we do with the '02-05s? Maybe the VTEC transition wasn't the only change, maybe they smoothed out some other things with the upgrade too. Just a thought.

 

The only issue I had was a snatchy throttle in the real low rpm range (Parking lot speed). That was fixed entirely by eliminating my O2's. The VTEC transition was one of the biggest improvements with 06 and above. The biggest difference IMO is not the earlier engagement point but the later disengagement point. That stops it from coming in and out when your playing around in that range which could set up a harsh transition. My transition has always felt like hitting that torque curve in a smaller engine car.

 

Hey Action, I'll sign your pipe dream application. I wish there was someone out there that could jailbreak the ecu so we could hook her up and play around. Makes ya miss the carbs and distributor days don't it.

 

02-05 ECU is 38770-MCW-L03, $575.60
06-09 ECU is 38770-MCW-K01, $402.44
Prices are from RonAyers as of today. I still don't know if it's a plug-n-play swap. The injectors and throttle body are also different part numbers, but I have the the complete '06 throttle body assembly on my '04 and everything seems to work fine. I don't know what the difference is.

I did something a little crazy yesterday. I had a feeling that the engine was running out of air at 6500 before the VTEC engaged. That would explain why Honda lowered the transition point on the later models. I disconnected the VTEC spool valve from the ECU and connected it to a switch so I could control it manually. This way VTEC is engaged whenever the switch is on. I rode the bike about a mile with VTEC engaged full time and it did completely eliminate the transition but it still had the flat spot at 6500-7000 RPM. It really didn't feel any more or less powerful and I feared I was going to run it lean so I stopped the test. I did play around with switching it on and off while driving, besides a slight change in the exhaust sound there is really no perceivable difference at part throttle. I learned enough to know that it's a tuning issue at 6500 RPM, not an airflow issue. If I'd thought about it a little more I would have known that already, because it goes flat at part throttle but not so much at full throttle. Duh.

I downloaded the power commander maps just to look at them (didn't get my PCIII yet, it's in the mail). No surprise, I see all the maps they provide are dumping a ton of extra fuel in from 6500-7500 rpm at 10-40% throttle. The factory table must go really lean there for some reason, and that's what I'm feeling.

I also theorize that because the VTEC transition was completely eliminated by having the VTEC solenoid on full time, the ECU is not adding to the injector pulse width when it commands the transition. This will be confirmed by hooking up a wideband O2 and monitoring the AFR during the transition, or by viewing the injector pulse on a scope and looking for a step in the fuel delivery rate. Most likely the MAP sensor is taking care of any extra fuel requirements by using speed density calculations and a VE table. During normal operation when extra valves open, the manifold pressure changes, and the injector pulse is calculated from a different cell on the table. What this means, and it's just a guess at this point, is that if someone wanted to, they could hotwire the VTEC spool valve to be on all the time (5th gen mode!), or even control it with a RPM window switch and set it wherever desired. All that's required to satisfy the ECU is a resistor to prevent an open circuit error, same as we do when unplugging the O2 sensors. A PCIII and dyno tune would be a good idea too.

I've returned my bike back to stock, O2 sensors and all. I'm going to put a few hundred miles on it. When I'm feeling ambitious again I'll hook up a wideband and get it on the dyno for some more testing. I have a dyno and all I need here at my shop, it's just a matter of finding the time to do it.

Nobody else has hotwired the VTEC solenoid yet?

 

wow!
so where is this shop of yours?

 

I'm in eastern PA. I own a small business specializing in automotive engine swaps. Motorcycles are a hobby of mine, I don't work on other peoples bikes.

 

CBR
Interesting post. How would you create a "RPM window" switch for the ECU? Would you do it in a similar fashion as guys running nitrous? Could you still have it engage at one point and disengage at another? Would you be able to include engine temp? Sounds like a cool idea if you could get it all sorted out. If you made it into a kit I bet you could sell a few.

Action

 

RPM switches are readily available for all sorts of uses in auto racing like the nitrous window switch. To have different engage/disengage point you would just need one with programmable hysteresis. Some have additional analog and/or digital inputs besides RPM, which could be used for things like coolant temp and gear position. I don't know if there is one avaialble that would be perfect for this application, but it would be a fairly simple device to design using a small microprocessor. I have developed and marketed similar products in small quantities in the past (~1000 units each). This specialty niche stuff is what I like to do.

The best solution would be to hack the stock ECU, but that is beyond my abilities. Then you could also eliminate the Power Commander completely and be able to play with timing and VTEC. There are people who can do it, you just need to get them interested and put in a lot of time for R&D. Some of the popular Denso motorcycle ECUs have already been hacked. I've been involved with automotive ECU reprogramming for years, but I don't hack.

 

Did you have time to check this? I'm quite interested in overcoming VTEC abruptly increased power. This is probably the most commented issue about VTEC and I was quite surprised to find out that nobody has proposed, i.e. selling a solution (e.g. hotwiring VTEC solenoid)

Could you explain more this? Are there any hidden tricks that I should do prior to performing the change? Do you have any pictures? They would be very helpful!

Thanks in advance!

 

disconnect the vtec spool.
hook up a toggle switch.
get a power commander 5, so you can toggle between maps.
get the auto tune.
maybe pick out different rpm dependent switches.
you could build different maps with the auto tune, for different rpm activation points...
that would be a good starting point.
only problem with too low of a vtec activation point, is that you would be constantly running in and out of vtec. it would wind up being even more annoying.
i dont know, i think i would just try to pop in the 06 up ecu and get a pc and call it a day.

 

Its not just a few hundred rpm change, the transition is supposed to be alot smoother too. But i was under the impression those were actual engine hardware changes not ecu software, but i could be wrong.

 

The VTEC solenoid is located in the valley of the engine under the throttle bodies. It has a single wire, green with yellow stripe, connects to a sub harness that comes out to a six pin connector behind the left fairing. From there it goes up to the ECU pin B3. Disconnect that wire anywhere between the solenoid and the ECU. Connect the engine side to +12v to run four valves per cylinder at all times. Connect the ECU side of the G/Y wire (ECU B3) to one side of a 1k resistor, and the other side of the resistor to ground. The resistor will provide enough current on the VTEC circuit to pass the ECUs diagnostic check and eliminate an error, same as what is done for the O2 elims. You now have a non-VTEC 6th gen. Get a good tune and enjoy!