In a few months or so I'm going to be ordering a cusom ecu and I was wondering if there is a better place to move the Vtec engagement over stock? This ECU will be for autocrossing only so I don't care about fuel economy or anything like that.

 

For DSP? Are you sure this is legal?

Rules say fuel injection and ignition are free, don't think it says anything about cam timing (if it doesn't say you can, you cannot).

 

unless you've done something to your engine, why would you want to move the engagement point? Otherwise, do one dyno run with vtec engaging way early, and another way late.. where the two plots cross is your ideal engagement point.

(I don't know about the legality, though..)

 

I haven't done anything to the cams. I'm going to have the ECU chipped to OBD1 and I have a new throttle body/intake manifold in the works. The only problem is that the guy chipping the ecu is in Canada so I can't do the dyno test method. I was hoping someone had figured out a good engagement point so I don't have to do all the R and D myself

 

The rules do allow any igntion and any intake/fuel delivery, but nowhere does it explicitly state the entire ECU is free.

[edit]And cams (and their timing) must be stock.


[Modified by Crack Monkey, 1:32 PM 10/7/2002]

 

Since you have a GSR--4400 rpm is probably about ideal with that car. ANy lower and the car would start to bog.

Try the integra forum.

 

no need to move it.

 

exactly.
they put it there for a reason

 

I don't see how chipping a factory ECU is any different then replacing it with a Tech3 system which I know is legal.

 

That my general opinion about Honda OEM stuff but I figured Honda also had fuel economy in mind when setting the ECU parameters. I was just wondering if anyone in this forum has had an success with tuning the ECU with stock internals.

 

Dyno is the best way. On the H22A engines, for example, you can get a nice boost of torque/power (i've seen dynos of anywhere from 10ft-lbs to 15 ft-lbs depending on car) between about 4500 and 5000 by moving the VTEC switchover to 4500 from the factory 5000... But then again, the H22 has a notorious flat spot in that RPM range... I dunno what there's to be gained on the B18C though...

 

14.1.D

Alternate computer control modules may be used whenever an equivalent change to the conventional system is allowed. For example, alternate computer module control of ignition settings or fuel injection is allowed. Direct turbocharger boost control by alternate computer control is not, since there is no equivalent mechanical allowance.

 

There is no legal mechanical way of changing the VTEC crossover, therefore it is not legal in SP to change it via the computer. Even with an Electromotive system it would not be legal to do which is one of the main reasons I'm still not sure I'll get the Tech 3 for next year. Since the change is audible in or cars I wouldn't advise trying to sneak this one by. Oddly, Street Touring does have an allowance for it directly in 17.10.d.5.

Just out of curiosity Jeremy, are you doing an OBDI conversion? If not, who is going to do the computer work for you? I've found one company that says they can do it (JET) and everyone else (including Hondata) says OBDII computers are a no-go.

Mike

 

I guess I'll just play it safe and leave the Vtec where it is.

There's this guy in Canada named Yoshiro (sp?) who said he can reprogram a Honda OBD2 ecu to OBD1. I decided to try this route because this way I can swap ECUs without a harness and P72 OBD2 ECUs are so much cheaper. Some people I talked to have said thet the JET OBD2=>OBD1 reprograms aren't very good.

If things don't work out I might be going Tech3 as well.

 

To stir the waters a bit, what about the secondary intake runners? I guessing it also doesn't have a mechanical equivalent? You might be able to gain something by opening THOSE early.

 

Well since the intake manifold is open (i.e. a mechanical equivalent exists), I'd guess this would be legal, although I'm not sure there is much to gain here.

Mike

 

sure there is...ITB's!! run the king manifold....run a type R manifold.....the overall feeling I've got is people don't like the dual runner intake manifold of the GSR...but what do I know...my integra doesn't even have VTEC

 

The reason I decided to stick with the GSR manifold is to keep the low end. Two of my competitors switched to the ITR manifold and are switching back because it's too much of a sacrafice on the low end.

 

For autocross I'm having my RSX S VTEC engagement point lowered because I don't like the way the car jumps side ways when the VTEC comes in during a corner, or worse yet in a slalom. It may reduce power a small amount, but I'm counting on improved smoothness.
Del Long

 

I have started a new thread that covers what my main goal is.

https://honda-tech.com/zerothread?id=300518

 

If you ever do decide to lower the engagement point, don't go below 4000 or 3500 or something because you'll run into oiling problems (that could be bad).

 

Thanks, generaly I'm hearing somewhere between 4400-5000 if I could change the vtec.

 

You can get more power by lowering vtec. Think about this...

The ideal crossover point is where both torque curves cross. Set at that perfect point, you wouldn't feel the "kick in the ***" when it activates. Since you still feel that kick at 4700, it follows that a lower crossover would release a bit of power.

I'm boosting 10psi and I set mine at 3500 when autocrossing and STILL get the kick. <edit - 3500 is crazy low and only works for me because of boost. Stay over 4000 whatever you do.>

One of the reasons Honda set it so high is that it is very annoying to cruise on the vtec cam. It's too loud. I leave mine at 4700 unless I'm racing.


[Modified by Holden, 5:32 PM 10/7/2002]