Instead of the Mugen ECU, what about replacing the air and water temp sensors with ones that say the car is running cooler that it really is.

That way, even if the engine warmed up a bit, the ECU wouldn't retard it.

Is this possible? costly? Pros/Cons?

-r

 

Hi krazik-s2k-

You could try it, but I'm sure if that were possible, Mugen would have offered it as an alternative. It's not like Mugen doesn't have access to testing lab facilities, you know.

-Nick

 

[QUOTE]Originally posted by GTRPower:
[B]Hi krazik-s2k-

You could try it, but I'm sure if that were possible, Mugen would have offered it as an alternative.

 

From the looks of it (from a thread in the waiting room), mugen makes a lower temp Thermostat for the car, which does exactly this.

What other sensors would prematurely cause the car to de-tune itself?

 

OK, don't rip me too hard. What's an ECU or ECM?

 

Originally posted by S2KPHX:
OK, don't rip me too hard. What's an ECU or ECM?

Electronic Control Unit/ Electronic Control Module. It is the "brains" of your car. It controls/ monitors all of the sensors in the vehicle.

 

I know that some aftermarket chips will ignore a little more detonation before retarding timing, so I would guess that the Mugen ECU would.

You could, however find out what the resistance is at certain temps and change the sensor signal by adding an in-line resistor, and then make the engine think the ambient temp is a few degrees lower.

I have thought about it but havn't gotten into it. You have to find the sensor that it responsible and then observe the resistance curve.

Then there is the question of if you really want to do this? Are you going to change your fuel to a higher octane? and do you want to run that much closer to detonation?

 

Exactly what I was thinking... does any one know which sensors?

As for detonation, I would leave the knock sensor alone. I want the ECU to think the car is running cooler, but if the engine starts to detonate, I want it to correct the settings.

 

I have stalled on getting a tech-manual but I think there is a sensor at the intake box.

 

Almost every modern car (can't think of an exception at the moment) retards timing in relation to the intake air temperature sensor signal. Knock sensor retard tends to be very aggressive by comparison so the ecu backs off the timing right away to save the motor and then gradually brings the timing back. If done right the knock sensor will seldom kick in.

Having said that, most ECUs start to retard as IAT rises past 68 degrees F. (bonus points if you can guess why) Usually small high output motors need more retard than slumbering giant motors.

Sometimes you can avoid unnecessary retard by repositioning the sensor. For example some vettes and f-bodies benefit since the IAT sensor is near hot underhood areas. You wind up with a truer IAT reading and don't risk hurting anything and enjoy less frequent retard. There are also a few things you can do to reduce heat soak issues. One example is high tech exhaust coatings. Some of them work amazingly well. There are even some aftermarket items for some cars that reduce the effect or even disconnect the IAT signal. Generally speaking IATs use a negative tmperature coef (NTC) resistor although there are various methods used. In other words the IAT sensor basically has a resistance that varies with temp. It is very easy and inexpensive to fool this sensor but you better know what you are doing! Some folks simply wire in a voltage divider (pot). I don't have specific info on the S2K sensor though.

Stan




[This message has been edited by E30M3 (edited November 30, 2000).]