Got to tinkering over at a friends shop this am. He had a few PTI manifolds layin around. Upon further investigation, the MATs should be moved. If for no other reason then if your's has any carbon on it. They are very slow to respnd anyway, and just a trace coating of C will really even slow that down.
I don't have any real options for where other then maybe tapping a new hole RIGHT behind the TB.

 

This is getting just a little confusing(for me at least). I can understand what Glenn said about moving the MAT causing a rich condition on SD cars. But on MAF cars, wouldn't it make sense to move the MAT as close to the MAF wire as possible? Seems to me that doing that would give more accurate measurements of the air being inducted, vice any other location for the MAT.

 

The whole point to EFI is accurate fueling and timing. The perfect setup would have instant reading devises, right at the intake valve to have the best info for for figuring timing and fuel. Their are several flies in the ointment. The MATs and IATs sensors are terribly slow. The MAFs (like on the 165s), are also terribly slow, in response.

Having really accurate info the base calculations makes just so much easier.

BUT, we also get to the stage of deminishing returns for what we really need, and engine wants.

I've been tweaking chips for years, and it's still confusing at times

 

I have to agree with Grumpy's "ultimate solution" that the MAT/IAT should be as close as possible to the valve as possible AND not be influenced by the heat of the runners. But, again as Grumpy said, there is a point of diminishing returns and while it would be GREAT to have 128/128 perfect at ALL rpm/load/cts/mat or maf/ readings, it probably won't ever happen. Unless, you are pretend to spend a collosal amount of time and a very understanding wife.

Right now, I figure it is going to take me an entire year to get a perfect (or as perfect as I am prepared to live with) MAT correction table. And then there is the Baro Correction table for elevation that I am dying to analyze...

 

Ahh, maybe 9 months,
gets really easier after the first couple hundred chips <g>...

 

Couple of hundred? Hell, I'm going to be there in a couple of months. I expect to have done a thousand on my car by this time next year.

But, I really can see the importance of a GOOD VE table and how many tables are really dependent on having good values. Without good values, I would not have been able to see this nor make proper corrections when the temperature dropped. When I am finished, I expect to have good correction values from -20*C to +45*C (ambient air temperature).

Heck, in another year or two, you might even think I am a "promising pupil".