Reasonable to force users to run both MAT AND IAT always?

[AbeFM]

I do think that's the best way out, the rest is hashing out theoretical details (which, well, I do for fun).

So, getting to that, why do you not like using the MAT? Just because it is so prone to error? (That's ENTIRELY reasonable)

My question is, if you had a 100%, idealized MAT, with no radiative coupling, no heat soak, it just somehow knew the exact temperature in real time of the air in a particular place.... Why would you mount it outside of the manifold?

I would think you'd want the MAP and MAT to be in the same place at the same time, since really you're just counting molecules/sec entering the engine.


If it were me, I'd have four flow meters, one in each runner, and do my fuel and timing based on that, with direct injection. To quote our beloved Jean-Luc: Make it so.

[Fred]

So, getting to that, why do you not like using the MAT? Just because it is SO prone to error? (That's ENTIRELY reasonable)

Fixed it for ya. Correct, they are rarely an accurate representation of incoming air temperature. The transfer of heat from manifold and tubes etc to the air is negligible unless the air is stagnant. Therefore the external IAT on the outlet of the cooler near the front of the car is the best representation of air temp. My thoughts when posting this thread were two fold. Forcing people to use two would give you a good way to judge things at startup/idle, AND, it would force them to realise what the difference is.

It is unfortunate that this has been ignored and confused in MS docs over the years to the point where some hardware has MAT on it and some IAT, but they all mean the same thing. They are not the same thing.

My question is, if you had a 100%, idealized MAT, with no radiative coupling, no heat soak, it just somehow knew the exact temperature in real time of the air in a particular place.... Why would you mount it outside of the manifold?

You wouldn't. That would be ideal. However we are living in the real world :-)

I would think you'd want the MAP and MAT to be in the same place at the same time, since really you're just counting molecules/sec entering the engine.

Ideally yes, really, no.

To quote our beloved Jean-Luc: Make it so.

LOL, I haven't seen an episode of that for about 13 years!

Admin.

[AbeFM]

As in Love, Fred again teaches us the value of paying attention to the harsh realities of the real world verses the idyllic hopes one might have based on how the world should be.

Thanks! I think I've got a better understanding of it myself now, and the thread should be (brief) required reading.

Edit> Vote Cast!

Also, the coolant-based-leaning leads into something I was thinking about today....
http://www.diyefi.org/forum/viewtopic.php?f=8&t=228