rocketman

It's getting cold outside now (most of the place, anyway), so there is not much discussion right now about heat effects on the car.

I would like to throw this out for comment:

what if the air temp sensor was changed to a different location somewhere at the front end of the air intake system?

Right now it is located towards the end of the intake manifold, but what if it was located in the airbox, for instance?

Would this screw up the ECU? Would the car still run OK? The most obvious thing to me would be danger of detonation when it truly is hot. It seems like there would be advantages, but I don't understand the whole air/fuel ratio ECU mapping thing, so I don't really know.

marcucci

All the IAT wants is a temp, and I believe it is used to control a/f mixture and timing. The ECT (coolant) is used for the warmup procedure and possibly some controls (no VTEC, etc.). I don't believe the IAT is "critical" in that a certain temp is needed.

All that said, I think you could move it. What I would ask, though, is why not actually make the manifold cooler? All you might do by moving it is remove some of the "safeties" that Honda has in place regarding timing and fuel mixture.

Personally, I'd blow $60 for the manifold insulator and the coolant bypass. That, or a lower temp thermostat and fan switch ($140). Either one would lower IAT by 10-20

jschmidt

Is there, perhaps, a Camaro in your past?

rocketman

This was common, huh?

It's funny you should ask, though, we have a 68 camaro in our present (my son's car). I was at a speed shop to get some parts and was talking about the heat problems with the S2000 and another customer with a blown z28 suggested moving the IAT sensor. Said camaro guys do it all the time.

BTW, marcucci, I do have those things you mentioned on my "to do" list. I was just interested in pros/cons of moving the IAT sensor.

marcucci

Well... the "big" con that I can think of is pushing things past their limit (resistance to detonation). I'm sure Honda was too conservative, but I'm not sure where their conservativeness and reality meet. I'm sure that you can move the sensor, but all other things considered... you'd have to move it to the airbox, and I'd bet you'd see a 30 or 40 degree drop in IAT. This is comparable to what I've seen with the intake manifold insulator and probably thermostat combined- I'd suspect you'd run will into "reality" moving it that far.

I'd suggest waiting until you can do all the other stuff- honestly, it's like a different car. Every time I drive it now, since doing all that, I'm astonished at how much more torque it has and how much peppier it is. It feels MUCH stronger.

cmnsnse

Im looking at the same thing, Turns out there is also a barometric sensor in the ECU and that is said
to controle a basic duration of the fuel map. Im sure the IAT has a large influence on the timing just because above 85* the car is a dog. Thats what started my whole insulation thing a couple years ago, Im just a bit hesitant to change up and feed the engine really cool air instead of it expecting hot air.

jschmidt

[QUOTE]Originally posted by rocketman
[B]It's funny you should ask, though, we have a 68 camaro in our present (my son's car).

rocketman

Rockville Speed and Custom off Gude drive.

cmnsnse:
I think the barometric pressure sensor in the ECU works in conjunction with the MAP sensor. Moving the IAT sensor shouldn't affect this at all.

Although that makes me think (danger, danger!) - does the air temp have to closely correlate with the air density? Maybe where the IAT sensor is right now is a "conservative" position. If it was moved to the air box or thereabouts, that would be an "aggressive" position.

In the end, marcucci is right - do what is possible to keep the heat down. Then just wait until someone comes up with a programmable chip

marcucci

[QUOTE]Originally posted by rocketman
[B]
- snip -
Although that makes me think (danger, danger!) - does the air temp have to closely correlate with the air density?

cmnsnse

I was thinking more along the lines of the baometer effecting the fuel duration, and the IAT effecting the timing. But Im sure they all work together for 3D mapping. I would just like to know the parameters.

Maybe I can check the timing and see if it changes with temp input