MAT sensor in hotair intake

[6SENSE]

Anyone try this? Any known ideal spot for placement?
Would be the ideal tool (other than EGT) for us "intercooler-challenged" guys (especially when trying to compensate and tune with alky/H2O).

 

[JayLashua]

the mat isnt used very much.. you should save $60 or so and buy an EGT gauge my car runs great with the mat screwed in just before the throttle body, where the beather hose used to go (and wehre you probably have a rubber cap now)

 

[6SENSE]

My MAT sensor has been in the stock 86-87 location, between the air filter and MAF sensor (actually in the neck of the K&N cone filter). What Im proposing is a actual (more accurate) reading of the intake temperature. lowering intake temps (and subquently cylinder temps) is what the addition of an intercooler is meant to accomplish. Lowering the intake temp is what many of us have added alky injection for, thus it would be nice to know what I am actually accomplishing. This isnt anything new, there are 86-87 guys that have already done this. I was just wondering if anyone with a hotair have done it, or have any ideas about it (i.e. where would be a good spot on our intakes to relocate to).

 

[bruce]

Originally posted by 6SENSE
My MAT sensor has been in the stock 86-87 location, between the air filter and MAF sensor (actually in the neck of the K&N cone filter). What Im proposing is a actual (more accurate) reading of the intake temperature. lowering intake temps (and subquently cylinder temps) is what the addition of an intercooler is meant to accomplish. Lowering the intake temp is what many of us have added alky injection for, thus it would be nice to know what I am actually accomplishing. This isnt anything new, there are 86-87 guys that have already done this. I was just wondering if anyone with a hotair have done it, or have any ideas about it (i.e. where would be a good spot on our intakes to relocate to).

Inless your editing your own chips you'll do more harm then good. The MAT is used in the fueling calculation. And the timing vs MAT is 0'd out.

If you go to the 87 ecm and then the Translator, and edit your own chips you can do good things.

 

[6SENSE]

Ahhh, okay. Thanks bruce.
Since Ive usually got the MAT unhooked anyway for TLink's boost sensing hardware, couldnt it be used (installed in the intake) to get readings for a gauge?

The MAT is used in the fueling calculation. And the timing vs MAT is 0'd out.

I guess MAT stands for Mas Air Temperature not Manifold Air Temperature, huh? Because if it were Manifold Air Temp, youd think that it would get more accurate #s if istalled in the intake maifold.

If you go to the 87 ecm and then the Translator, and edit your own chips you can do good things.

Got the ECM, translator was a possible future mod, and chip burning has always been a dream of mine

 

[TType84]

the stock mat sensor is really slow to react.. i hooked it to a dvm and put it infront of my ac vents in my house and the voltage change was very very sllow, it did this on tlink too.

basically, if you put it in the intake, unless you stay in boost for awhile, youre never gonna see the actual intake air temperature cause the sensor takes so long to heat up..

 

[bruce]

Originally posted by TType84
the stock mat sensor is really slow to react.. i hooked it to a dvm and put it infront of my ac vents in my house and the voltage change was very very sllow, it did this on tlink too.

basically, if you put it in the intake, unless you stay in boost for awhile, youre never gonna see the actual intake air temperature cause the sensor takes so long to heat up..

Try blowing some 250dF air across/near it, say 250 gm/sec, it's response gets better. There is a table for enrichment based on time in PE.

 

[bruce]

Originally posted by 6SENSE
Ahhh, okay. Thanks bruce.
Since Ive usually got the MAT unhooked anyway for TLink's boost sensing hardware, couldnt it be used (installed in the intake) to get readings for a gauge?
I guess MAT stands for Mas Air Temperature not Manifold Air Temperature, huh? Because if it were Manifold Air Temp, youd think that it would get more accurate #s if istalled in the intake maifold.
Got the ECM, translator was a possible future mod, and chip burning has always been a dream of mine

MAT
Manifold Air Temperature

Some body goofed in the literature at GM so ever since it's been misidentified. In oem form it should be IAT, as that what all the air cleaner mounted temp sensors are called in the GM manuals.

The closer you take ALL YOUR measurements to the INTAKE VALVE the more accurate your fuel calulations will be in the ecm.

I also have mine relocated to just behind the Throttle Body (87) so that there is as much air flow as possible across it.

 

[JayLashua]

perhaps you could modify the throttle body with a bung to screw the sensor in so it will see the air after the throttle blade? I think that screwing it into te breather hose outlet in the MAF tube is quite reliable as well, also much easier, all you have to do is seal the rest of it with a little ultra-black - looks much better than mangling a throttle body, or having a ghetto hole in your air filter.

 

[b4black]

When you buy a digital thermometer to run an EGT, pay the extra $10 and get a dual channel model. Then get a second probe, use an 1/8" compression fitting and screw it into a 1/8" NPT hole (which you drill and tap anywhere you want.).

Then watch EGT and MAT or IAT or ambient or coolant or anything that's hot (or cold).

 

[TType84]

the biggest used for that would be before/after probes in the ic hoses.

1 probe before, 1 probe after.. if you wanted this to work in 2 1/6" gauge form, call up westach and i guarentee they could make a gauge to read 2 channels of temperature data side by side, ive seen it before in their catalog. 2 needles in 1 gauge, youd have an easy comparison then, seeing the IC inlet temp and the outlet temp.

that would definitely help out in this scenario.

 

[Jerryl]

Anyone try this? Any known ideal spot for placement? Would be the ideal tool (other than EGT) for us "intercooler-challenged" guys (especially when trying to compensate and tune with alky/H2O).

I am still behind the 8-Ball.
Reason I am looking at this is becasue my chip writer says that the IAT is used. (It will actually be a MAT)

6SENSE,
Did you ever place this in the intake?
Did you ever record before and after "Alky temps"?

 

[6SENSE]

I am still behind the 8-Ball.
Reason I am looking at this is becasue my chip writer says that the IAT is used. (It will actually be a MAT)

6SENSE,
Did you ever place this in the intake?
Did you ever record before and after "Alky temps"?

Nope never got around to making it happen.

 

[Jerryl]

Decided that this is a BAD idea for a Hot Air.
The IAT (in this case MAT) element is soldered and solder melts around 450F
The Hot Air intake air charge can possibly get into the 300-400F range.

Probably already figured that out.

 

[bruce]

Decided that this is a BAD idea for a Hot Air.
The IAT (in this case MAT) element is soldered and solder melts around 450F
The Hot Air intake air charge can possibly get into the 300-400F range.
Probably already figured that out.

Have you unsoldered one?, or are you just looking at it's apprearance?.

http://www.geocities.com/jeffhendrix67/lv2000/solder.html
Solder flows at a fairly low temperature, around 360-370 degrees Fahrenheit.

 

[Jerryl]

Have you unsoldered one?, or are you just looking at it's apprearance?.

http://www.geocities.com/jeffhendrix67/lv2000/solder.html
Solder flows at a fairly low temperature, around 360-370 degrees Fahrenheit.

Bruce,
Just looking at the appearance and never unsoldered one.
I was being generous with the 450F melting temp.
Not rolling the dice here and would only be confortable with a margin around 2:1 (Heat soak, vibration, etc)

I belief you are in agreement that it is a bad idea for a true Hot Air.

 

[cool 84]

My dad ran the westech guages when it was a hotair in the plug in the front of the intake manifold. At 20psi it was around 340 degrees. After the 87 conversion, it went to 120 degrees with big turbo and intercooler. With the alky triggered it pegged the guage as low as it would go at 60 degrees on a 70 degree day. I'm very interested to see how cold it gets with alky on a hotair. It should have a bigger effect without the intercooler.

 

[Jerryl]

My dad ran the westech guages when it was a hotair in the plug in the front of the intake manifold. At 20psi it was around 340 degrees. After the 87 conversion, it went to 120 degrees with big turbo and intercooler. With the alky triggered it pegged the guage as low as it would go at 60 degrees on a 70 degree day. I'm very interested to see how cold it gets with alky on a hotair. It should have a bigger effect without the intercooler.

First off, I am no expert and KNOW that methanol works.
No debate at all. Remember, this is ALL theoretical. I only did this to get me some idea what steps to take to get me the biggest “bang for the buck”. From what I gather, here is a summary:

Ambient temp 70F

Hot Air intake charge at 20 psi (70F ambient) and XX% turbo efficiency will result in an intake charge as follows:
60% Efficiency: Intake charge will be around 312F
65% Efficiency: Intake charge will be around 295F.
70% Efficiency: Intake charge will be around 278F

Injection rate with an M15 Nozzle = 950 cc/min (15 gal/hour).
Hot Air intake charge temp drop at full 950 cc/min delivery is estimated as follows:
100% Methanol: Temp drop is 120F
50% Meth, 50% Water: Temp drop is 180F
100% Water:Temp drop is 226F

My conclusion:
As you already know, there is a fine balance between temp and octane.
First off, it is clear to see why it is important to spec. and run the turbo in it’s efficiency range. The “Mass Air” is substantially REDUCED at higher intake temp PLUS the detonation tendencies are drastically increased at the higher “chicken baking equivalent temperatures”.

So, while the largest temp drop is with water, water does not burn and does not increase the octane. Methanol not only cools the charge, but adds octane to permit higher boost and temp levels. Will a 50/50 mix work better in a non-intercooled engine? Don’t know, but sure looks good on paper.

While you have not read anything you did not know yet from countless “real life research” and actual results, it was just amazing to see the temp rise at boost and the temp drop with meth (something I have in fact been wondering about)


PS
Some GREAT links!
http://not2fast.wryday.com/turbo/glossary/turbo_calc.shtml
www.onlineconversion.com/

 

[6SENSE]

I know for a fact that 100% h2o does a great job at controling knock. It doesnt give the instant power adder that the methanol does though. A few years ago I spent alot of time playing with straight h2o, 50/50, isopropyl, denatured, and methanol. Over all the straight Methanol turned out to be the easiest to deal with and gave the best results [and was cheaper than the denatured]. The h2o though kept kr at 0! Its going to depend on your approach and what your trying to do with the injection. When I first started playing with h2o/alky injection in the lated 90's my thoughts were strictly for the cooling benefit [not enrichment of the fuel]. With cylinder temps drastically cooled then you can run much more boost and make much more power. That is how most people out there typically view the idea of "h2o" injection. I think its us Turbobuick people that really started pushing the alcohol idea until it was no longer h2o in the equation. !As much fluid as we are spraying if its not being atomized just right I have always felt safer spraying alcohol rather than water (h2o wont burn off like alky/fuel). I feel like the margin for error in that regard is a bit less with 100% h2o but if things are just right there is a definate benefit to the cooling effect that it has. I might start playing around with a 50/50 mix again, but just a bit weary about the h2o with the BIG m15 nozzle fed by the mighty surflo if I dont know that its definately being atomized. Dont want to dump a bunch of h2o in the block. I have a theory that my .030 over block that I initially had in my car may have lost its bearings and killed the crank due to this (not positive).

 

[Jerryl]

........I feel like the margin for error in that regard is a bit less with 100% h2o but if things are just right there is a definate benefit to the cooling effect that it has. I might start playing around with a 50/50 mix again, but just a bit weary about the h2o with the BIG m15 nozzle fed by the mighty surflo if I dont know that its definately being atomized.

Agree 100%, no pun intended. :smile:
I always thought that a smaller nozzle with H2O (resulting in slightly higher pressure) would have decent atomization in a stock Hot Air intake in sprayed just below the turbo. I bet with 100% H2O, you may not need an "alky chip" to "remove fuel". One may "get away" with just playing with the pressure. Don't know.