Adding MAT to 350 TBI $0D/7247

[JeepsAndGuns]

I'm cheap, so I would probably go grab a couple of the IAT's from the pull a part with their connectors. I remember seeing crapload of them on diffrent GM cars while going through there the last time.

One thing that makes me interested, is woody's discription of his engine. My MPFI intake does not have a exhaust crossover like my old one does, plus I am seriously concidering a set of headers after seeing a back to back dyno run with stock manifolds and two diffrent types of headers.

[woody80z28]

I'm cheap, so I would probably go grab a couple of the IAT's from the pull a part with their connectors. I remember seeing crapload of them on diffrent GM cars while going through there the last time.

One thing that makes me interested, is woody's discription of his engine. My MPFI intake does not have a exhaust crossover like my old one does, plus I am seriously concidering a set of headers after seeing a back to back dyno run with stock manifolds and two diffrent types of headers.

I think a MAT would be more functional than IAT, but that's another option to try and test.

My setup, from a cold-drivability standpoint is a big step back from stock I've come to realize. Stock TBI has the exhaust through the intake to the EGR and a coolant passage under the runners with a heater pipe from the exhaust to the air cleaner. I have none of that. I assume this is why the MAT wasnt needed stock and mine is a bear.

[gregs78cam]

I think a MAT would be more functional than IAT, but that's another option to try and test.

My setup, from a cold-drivability standpoint is a big step back from stock I've come to realize. Stock TBI has the exhaust through the intake to the EGR and a coolant passage under the runners with a heater pipe from the exhaust to the air cleaner. I have none of that. I assume this is why the MAT wasnt needed stock and mine is a bear.

That's the way the Camaro is, 2 TBIs on a RPM AirGap manifold. I just don't know if I will get the MAT sensor put in before I go MPFI, or not.

[EagleMark]

G1 has brought up another point. Does the intake have somwhere to put a MAT sensor? If not you need to drill and tap, with manifold off and big job.

But in thinking this through intake manifold temps are differant/higher than IAT temps becuae the intake is bolted to engine, engine is behind radiator getting warm, attached to heads etc... but you guys have eliminated major heat sources like exhaust heat crossover, EGR into intake and coolant passages? So not even coolant flow now?

So MAT are probably a lot closer to IAT temps. Without a place to put MAT sensor then IAT would be better than nothing and in your cases not as far off as regular engine.

So it boils down to what the mask has in it's paremeters it's looking for and adjusting to.

[woody80z28]

G1 has brought up another point. Does the intake have somwhere to put a MAT sensor? If not you need to drill and tap, with manifold off and big job.

But in thinking this through intake manifold temps are differant/higher than IAT temps becuae the intake is bolted to engine, engine is behind radiator getting warm, attached to heads etc... but you guys have eliminated major heat sources like exhaust heat crossover, EGR into intake and coolant passages? So not even coolant flow now?

So MAT are probably a lot closer to IAT temps. Without a place to put MAT sensor then IAT would be better than nothing and in your cases not as far off as regular engine.

So it boils down to what the mask has in it's paremeters it's looking for and adjusting to.

My biggest issues are when the truck is cold started on my 1mi trip to work in the morning. And from what I understand, in that situation the MAT will actually be colder than ambient temp due to the atomized fuel until the engine starts to get up to temp. I have noticed (even when up to temp) that the TBI itself is much colder than the runners and the runners are colder than the valve covers, for example. I think the closer my reading is to the combustion chamber, the more accurate I can be with the calibration.

Stock TBI intakes and also my Edelbrock Vortec carb intake have a provision for the sensor in the #8 runner with a plug. Piece of cake. (Visible in this pic:)

[EagleMark]

True if your engine was stock and using stock calibration. But your engine is not stock.

We found enough paermeters to change that I beleive it can be tuned by adding this IAT/MAT part to the equation!

NY is pretty cold in winter. A hot air tube from header to air cleaner with GM valve and cold air intake would help too! You start to get warmer air within a minute. When watching IAT temps with mine in winter it would stay closed at start and half way, blend most of day. Was shut very fast in summer.

[EagleMark]

I was just looking through $OE and found "MAT & CTS Blend Multiplier vs. Airflow" since we have been told CPI uses MAT sensor, does it also use MAF sensor? In V8 TBI it is set to all 0s. So would have to know what vs. Airflow is?

Now this one looks promissing for AE which seems to be issue with cold engines. In V8 TBI $OE it is set to all 1.0 for all temps.
"TPS Difference AE Correction Factor vs. MAT"

[EagleMark]

Also found this but would not have noticed it had anything to do with MAT if it weren't for comments written by 93V8S10!

"MAP Difference AE Correction Factor vs. Temperature" "Tips: Used to make corrections to TPS AE in relation to MAT/ IAT sensor data."

[woody80z28]

That's the way the Camaro is, 2 TBIs on a RPM AirGap manifold. I just don't know if I will get the MAT sensor put in before I go MPFI, or not.

Do you have a thread about said Camaro? Mine also has an RPM Airgap and it is a cold-blooded son-of-a... One more reason I'd like to go MPFI with a single plane and dump the 750.

Also found this but would not have noticed it had anything to do with MAT if it weren't for comments written by 93V8S10!

"MAP Difference AE Correction Factor vs. Temperature" "Tips: Used to make corrections to TPS AE in relation to MAT/ IAT sensor data."

Good catch, Mark. I'll take a look at that table on the 4.3 BIN and see how far off it is from the 5.7 one.

[EagleMark]

Here's Gregs thread:
http://www.gearhead-efi.com/Fuel-Inj...highlight=dual

There were 2 other options I noticed in post on last page too that should be compared to CPI bin. Maybe more but that is all I saw at the time. The CPI settings should be a good start point.

[93V8S10]

Sorry, but that was a mistake.

The correct comment for "MAP Difference AE Correction Factor vs. Temperature" is "Used to make corrections to MAP AE in relation to temperature."
The correct comment for "TPS Difference AE Correction Factor vs. MAT" is "Used to make corrections to TPS AE in relation to MAT/ IAT sensor data."