Here is some more info on how the ECU is working. Thanks to Austin for getting some of this info for us. As we know the RSX has a microprocessor for a ECU. Which means it is very smart and learns very quickly. I wish Acura had a book on all of the functions and how they worked. But I feel we will never really know all of it.

As I suspected since these cars are low emission vehicles. They must be able to run efficently to pass smog. It appears that the variable intake cam timing is used to create large valve overlap at low engine speed to reduce emmissions. And with the high compression of the motor it is timing sensative to say the least. Intake temp. plays a big role in taking timing out to stop any detonation. Especially with the gas we have of 91 octane.

I would also assume that removing the variable cam timing and fixing it like the exhaust cam will definately help perfromance. How much, well we will find out. We plan on fixing the cam timing so it wont' move. The we will also need to piggy back it with one of three different systems. AEM, Pectel, and Hondata are all working on it. I am hopeful we will be able to get the power that they are capable of with out to much hassle. Once we cross that hurdle you will see more performance parts available and bigger power gains along with them.

 

then what is the point of i-vtec anymore?
then why not just buy a dc2?

 

The point of i-vtec is for the grocey getting people...economy...

 

The benefits of a VVT system are:

-improved emissions because as John @ HyTech mentioned at low rpms the timing is changed to help emissions. VVT allows such drastic changes that the system acts like an internal EGR valve. That's why these engines don't even have EGR valves.

-and improved torque.

 

You are correct MugenDC2R that is exactly why. The overlap is so great at low speed it actually uses the reversion of the exhaust to fill part of the cylinder to reduce the NOX. It won't be to long before people start changing the gear to lock out any VVT. I know we will be doing it.

 

i agree that the way honda designed vtc its used for emissions and not performance, but, look at bmw, etc and their use of pneumatic or variable valvetrains - it works to their advantage..

john, i agree with you, it would be nice to see honda divulge some ecu info, but we know that would never happen.

i think that if the ecu is programmed properly, vtc can work TO our advantage. heres my reasoning. when dynoing, you aim for one thing with cam gears, to make the most power across a given range. well, as we all know, you are sacrifcing torque in some instances to gain upper rpm HP, and vice versa, depending on your desire/application. vtc, ideally, removes this train of thought.

wouldnt it make more sense to have vtc to work with us? create more scavenging at lower rpms, AND create more overlap at higher rpms, the best of both worlds.

granted, its more work, but i think the payoff is greater...

if you disagree, can you explain why?

john, excellent research non-the-less!!

 

Actually VVT systems do improve performance. They are not only there for emissions. Almost all car companies have at least one model using VVT and guess what? they're always the highend or performance vehicles.

VVT has A LOT of benefits, but tuning an ECU using the VVT system can be VERY hard. I had a 30 minute discussion about this with Ali over @ TODA and he explained about the interna EGR benefits and also said that because of the VVT the ECU would need 16 different fuel & ignition maps based on load, rpm, throttle position, etc.

It might be eaiser just to eliminate it for racing purposes.

 

It sounds like there is considerable potential in the ECU IF somebody can figure out how to get into it, but the work involved would basically mean re-writing almost every parameter of engine operation under the ECU's purview, which would not be a piece of cake.

 

You are right about rewriting the whole program to get VVI to work to our advantage. I'm sure it can be done, but I will be long gone by that time. AEM has said they are trying to write one for it, but we will have to wait and see. It is pretty complicated task. I think VVI would work better on cars with out any type of VTEC system. It would enhance overall performance to a small degree. But I do not think it will make any large gains. We have run motors with different cam timing on them and were able to move the power band around a little but it was not earth shattering. But again every little bit helps. When we get into our motor in the next few months we will disengage the VVI and set the cam timing and make some runs to see how much of a difference there actually is. And how it effects the ECU and fuel curve.


[Modified by hitechex, 12:15 AM 3/3/2002]

 

Wouldn't you encounter problems by simply disabling the VTC?

I'd suspect that the ECU would "see" this, interpret it as a mechanical failure, thow a check engine code and revert to a default set of fuel and timing maps, especially considering how Honda is using the VTC as more of an emissions reducer than a performance enhancer.

Maybe I'm completely wrong, but I don't think it'll be as easy as disabling the VTC mechanism. I think either way somebody will have to reprogram the ECU.

 

It all depends on how the ECU looks at the VVI and how it regulates it. It just might have a preprogramed setting and doesn't know if is working or not. Or my feeling, is, it's connected with a whole bunch of other functions. Like emission. We plan on just letting it function like it normally would, but lock the cam gear in a fixed place. We will have to see. I do not know how it will turn out, but we will investigate as much as possible to determine what is going on. Of course it will be a mute point if someone comes out with a ECU for it.