Lets talk compressor size and IATs....

[5mall5nail5]

So yeah we all know I am running a LARGE holset turbocharger on my 2.5L.


The IAT is the green MAT line

My IATs are low - in my opinion. I cruise and they're ~ ambient + 10 or 12, under boost they're about 100 - 110 degrees. According to my logs I peaked 118 degrees once but I am pretty sure thats while I was parked with my buddy waiting for like 5 - 10 mins.



I am running a 16x13x3" front mount intercooler with 2.5" piping throughout - so it seems my setup is efficient?

This graph also shows how reasonably well my turbo is reaching my full boost level of 166KPa (9.5psi). You can see it peak there at about 4000 rpm.. car feels great.


So what are other peoples IATs while running other turbos?

[good & tight]

Seems a little high if the ambient temp is 75 degrees

Here's on of my logs ambient temp is 91 degrees. This is with a 46mm wheel .60 compressor.

[paul e]

>>ambient + 10 or 12<<

This was on a well warmed engine? ie, results taken after driving for at least 20 minutes?

If so, theyre the lowest IATs on an FI M3 IVe ever seen. But an accurate determination of ambient is crucial.

>>under boost they're about 100 - 110 degrees<<

Most of us who have done these measurements use the OBC to determine Ambient. Its crucial to have an accurate ambient reading in order to gauge how well your intercooler is doing in comparing IATs. The OBC is ideal because its taking the reading from the exact same location where your intake air is being ingested, ie, a foot or two off the road surface. If you dont have an OBC, then I suggest using a thermocouple attached to an inexpensive multimeter . Best would be to stick it down near where the air is entering your air filter and run it to the multimeter in your cabin.. Less good, but still better than using the nearest radio station or thermometer attached to your house would be to just hang it out your window as you drive.

>>Here's on of my logs ambient temp is 91 degrees<<

If Im reading it right, your peaking out at 112, ie, ambient plus 21? Sensational. Many of us supercharged guys are getting readings of about ambient plus 30-40 or so.. Many turbo guys I know are getting similar readings to these sc readings. But, again, a true ambient, as taken in the vicinity of the brake duct thermocouple is crucial to interpreting these values accurately.

[techno550]

When reading fluxuating temperatures (like intake air temp in a boosted car, EGT's, etc...) response time of the sensor is also a big factor.

It might be worth taking that sensor out and hitting it with a hair dryer on high and measuring the time to peak temp reading.

The readings from my extremely low mass thermocouple in the exhaust manifold are *fairly different* than the readings the other turbo M3's in the area get with their autometer EGT probe. For a sustained WOT reading they both work fine, but for catching misfires or things like that, they really aren't fast enough.

It might also be worthwhile getting a pre-IC reading. (though this may not be terribly different than hitting it with a hair dryer.)

as for turbo response time, I'd call that laggy. I definately wouldn't want to autocross with that. As a counterpoint, my E34 525 in one incarnation made full boost by 1200 rpm. (hard fast boost onset like that just made the car a handfull though.) Staying with a small-ish housing and going to a clipped turbine wheel brought the boost on later and smoother. Full boost well before 3k still, but with less melting of the rear tires.

Boost should come in early enough and smooth enough that nobody knows the car is turbocharged.

[5mall5nail5]

Techno550 -

I have a GM open element sensor - there is no response time. What you see is what you get as opposed to coolant sensors which are elements nestled in brass contact. This is the element just hangin out there in a plastic guard. the 119 degrees or so what when I was registering the car on campus letting it idle. As soon as I started driving the temps fall. I personally prefer the larger turbo - it makse the car more controllable in lower RPM (as I needed in the rain the other night) and more of a rush to drive. I've driven all sorts of turbo cars from Mk4 1.8Ts, to VR6 3.0L T04E's, and I like this best. Its not ridiculously laggy, its just right to me. I much prefer getting a shove in the back at 3800 rpm than gliding around - it comes down to preference on that.

For ambient I used the OBC. It was in fact AT LEAST 72 - 75, though I think it was more like 80 at the time of day I did the logging, but if you want, I'll get real pics

paul- the car not only had been running for over 20 mins, i was ripping on it! I think I found a good spot for an intercooler

[///3oris]

Last time I was logging my IAT's I recall them being about ambient + 30 in ~75 degree weather. I might still have the datalogs... I'll check.

I'm also running front license plate, which sucks! Additionally, just like you, my temps will drop when I go WOT, but after some time of sustained boost I'll see temps climb higher than +30.

I'll try to get the logs at some point...

Boris

[Def]

Those cheap IAT sensors have horrible response times to even a larger mass thermocouple. You need a thin wire Type T for this application.

Turbo seems fairly laggy for 9 psi to me as well. Looks like you'd be waiting forever for that thing to reach some real boost(1 bar+).

[5mall5nail5]

Those cheap IAT sensors have horrible response times to even a larger mass thermocouple. You need a thin wire Type T for this application.

Turbo seems fairly laggy for 9 psi to me as well. Looks like you'd be waiting forever for that thing to reach some real boost(1 bar+).

sooo laggy

Im hitting my wastegate spring at like 3800, its really not that laggy. I guess to a baby 28R it is but uh yeah - i guess huge T turbos on supras are laggy too... im not about having boost at 2k rpm, I am about ripping up high.

[MPD47]

Turbo seems fairly laggy for 9 psi to me as well. Looks like you'd be waiting forever for that thing to reach some real boost(1 bar+).

Dude, do you have a clue how many lbs/hour-cfm's Jon's turbo flows?

[5mall5nail5]

Oh yeah, let me also point out something...


See the blue line? That's TPS positoin in %

46% throttle...

[techno550]

Techno550 -

I have a GM open element sensor - there is no response time. What you see is what you get as opposed to coolant sensors which are elements nestled in brass contact. This is the element just hangin out there in a plastic guard.

There is always a response time. If your $20 GM IAT sensor were that good, that precise, and that fast, I doubt there would be much of a need for the high dollar low mass thermocouples out there.

Sometimes "good for a $20 sensor" doesn't mean its really all that good.

Thus, back to my hair dryer test. Measure the response time, time to peak temp, etc... and start making the logged data meaningful.

The sensor probably isn't too terribly slow, but you probably have a decent amount of cooling air and a decent amount of time between boost events. Running around a small racetrack is usually the best test. (lots of on boost time, not tons of cooling air, etc...) Cooling on street circuits was always our biggest problem.

the 119 degrees or so what when I was registering the car on campus letting it idle. As soon as I started driving the temps fall. I personally prefer the larger turbo - it makse the car more controllable in lower RPM (as I needed in the rain the other night) and more of a rush to drive.

The car being laggy actually makes it less controllable. Sure, its adequately slow off boost, and it might even be quick on boost, but that *in between* bit is what will bite you in the ass.

I've driven all sorts of turbo cars from Mk4 1.8Ts, to VR6 3.0L T04E's, and I like this best. Its not ridiculously laggy, its just right to me. I much prefer getting a shove in the back at 3800 rpm than gliding around - it comes down to preference on that.

A kick in the back means laggy. It also means more stress on parts which isn't necessary. Torque should be brought in as smooth and refined as possible. That's a big distinction between a car that feels fast and a car that is fast. A constant smooth pull with as much *on boost* time as possible means you're actually going somewhere... not just waiting around for boost to *hit*.

For ambient I used the OBC. It was in fact AT LEAST 72 - 75, though I think it was more like 80 at the time of day I did the logging, but if you want, I'll get real pics

paul- the car not only had been running for over 20 mins, i was ripping on it! I think I found a good spot for an intercooler

So you are using the OBC temp sensor stuff as "ambient reference" then a completely different sensor and circuitry as "reference 2". How bout measurements from calibrated sensors for both? or the same sensor for both? Or at least similar sensors for both. We don't really know how accurate either sensor might be. especially compared to each other.

[5mall5nail5]

So you are using the OBC temp sensor stuff as "ambient reference" then a completely different sensor and circuitry as "reference 2". How bout measurements from calibrated sensors for both? or the same sensor for both? Or at least similar sensors for both. We don't really know how accurate either sensor might be. especially compared to each other.

I will compare by turning the ECU on later and comparing OBC to the ambient temp of the sensor on a cold motor.

You do realize the Tec3 sensors are the same ones I am using, yes?

And like I noted, my TPS is clearly reading 46% in that datalog... imagine if it were 100

[Def]

Dude, do you have a clue how many lbs/hour-cfm's Jon's turbo flows?

Not that many lb/min at 9 psig on a 2.5L(maybe 35-38 lb/min if I'm being generous), and the CFM probably hasn't changed all that much. I could do some math, but it's really not necessary because it's not really awe inspiring. Let me guess, you're also a subscriber to the "the more max CFM the better" school of thought when it comes to turbo sizing?



You can "poke fun" at my turbo all day long, but it still doesn't change the fact that the more boost you run the longer it will take to reach said boost. That turbo is just a bit laggy when you can't rev your engine all that high IMO. I like at least 3.6-4k RPM of powerband.



The response of that cheap sensor is probably very slow. I don't care what EMS uses it. It's got considerable mass, and is partially shielded from flow(not a good thing when you're looking for response). Like I said before, you want a low mass Type T thermocouple for this situation.

[MPD47]

You can "poke fun" at my turbo all day long, but it still doesn't change the fact that the more boost you run the longer it will take to reach said boost. That turbo is just a bit laggy when you can't rev your engine all that high IMO. I like at least 3.6-4k RPM of powerband.

I make full boost at 3000rpm, run my engine to 7000rpm and make 400whp? (Oh yeah, and it's a 4 cylinder). I'm well aware of differences in powerband. Jon's car subscribes to more of the supra mentality than track car mentality. Nothing wrong with that, despite what you think.

[Def]

I make full boost at 3000rpm, run my engine to 7000rpm and make 400whp? (Oh yeah, and it's a 4 cylinder). I'm well aware of differences in powerband. Jon's car subscribes to more of the supra mentality than track car mentality. Nothing wrong with that, despite what you think.

Who pissed in your wheaties? Not sure what your first sentence is getting at either, but I'm thinking maybe you want a cookie or something???

I never said anything was wrong with a turbo with a fair bit of lag(I've seen much laggier ones, trust me), I just was a bit surprised at the spool time on a turbo that was described as being "fast spooling." It just seems a bit lazy for only 9 psi, that's all. UM had his usual "I'm smarter and have years more experience than you" response to my on-topic post, which is fine and expected, but this whole thing with you jumping on his sac is a bit new... maybe I just need some adjustment time.

[paul e]

Those cheap IAT sensors have horrible response times to even a larger mass thermocouple. You need a thin wire Type T for this application.
.

Question.. It may be cheap, and have horrible response times, but doesnt our ecu use it somewhere in its equations? After all, it may be laggy, but its got to meet the bmw standard, which in turn must meet the obdii standard. So laggy as it may be, it must be sufficient for the ecu to use in its calculations. In addition, while it might be laggy with respect to the fastest sensors available, its easily fast enough to record cooling by WI with no problem. I think its easily fast enough for the purposes of these tests.. As soon my WI comes on trigger, there is what appears to be an immediate response at my IAT sensor. Why do you consider this inadequate for the purposes of these comparative tests?

So you are using the OBC temp sensor stuff as "ambient reference" then a completely different sensor and circuitry as "reference 2". How bout measurements from calibrated sensors for both

Well, even if you do have a fast response time iat sensor, why would that also be required by the ambient temp sensor? After all, while IATs change and change quickly under boost, so far as Im aware, the ambient value is a relatively stable value. IN a perfect world, while you might want the same sensor type/model giving you all youre temperature readings, I dont think its a big drawback using the brake duct tc to get your ambient readings.

[techno550]

I will compare by turning the ECU on later and comparing OBC to the ambient temp of the sensor on a cold motor.

You do realize the Tec3 sensors are the same ones I am using, yes?

And like I noted, my TPS is clearly reading 46% in that datalog... imagine if it were 100

yeah, and you might have an idea of what I think of the tec3... and its sensors.

[Def]

Question.. It may be cheap, and have horrible response times, but doesnt our ecu use it somewhere in its equations? After all, it may be laggy, but its got to meet the bmw standard, which in turn must meet the obdii standard. So laggy as it may be, it must be sufficient for the ecu to use in its calculations. In addition, while it might be laggy with respect to the fastest sensors available, its easily fast enough to record cooling by WI with no problem. I think its easily fast enough for the purposes of these tests.. As soon my WI comes on trigger, there is what appears to be an immediate response at my IAT sensor. Why do you consider this inadequate for the purposes of these comparative tests?

A slow response time on a sensor doesn't mean it DOESN'T respond, it means it's SLOW to respond. Yea, I'm sure you see it cooling down pretty quickly when triggering your WI, but keep in mind that the temps drop dramatically when you trigger it, and I'm sure it takes some noticeable amount of time before they stabilize(in fact, they're still probably dropping slowly by the time you end your pull). It's like dipping a big block of steel in a bucket of ice water, it's going to immediately start cooling down, but it's not going to get to 32 deg F very quickly. Thin wire thermocouples are pretty high response, but not all that quick. You need some very expensive stuff to get temperature measurements that are very quick(less than a second) in duration.

Well, even if you do have a fast response time iat sensor, why would that also be required by the ambient temp sensor? After all, while IATs change and change quickly under boost, so far as Im aware, the ambient value is a relatively stable value. IN a perfect world, while you might want the same sensor type/model giving you all youre temperature readings, I dont think its a big drawback using the brake duct tc to get your ambient readings.

The issue here is with calibration. You can have two systems that react the same, but they're biased/calibrated 5 deg off very easily. In fact, most commercial grade thermocouples, which are far more accurate than either of the sensors mentioned here, commonly have a tolerance band of +/- 2-2.5 deg C depending on the type. That's 9 deg F worst case scenario(and not all that far from reality). Who knows what kind of accuracy a cheap GM IAT sensor has to meet.

[good & tight]

I use the $20 GM IAT sensor on the left , response time is instant when placed in direct air path.

[Def]

I use the $20 GM IAT sensor on the left , response time is instant when placed in direct air path.

Read the post right above that one. Response time does not equal when it starts changing, it describes the amount of time to read the ACTUAL temperature in changing conditions. It's typically expressed as some number of degrees per msec or microsecond for the high dollar stuff.

Even a 100 lb block of steel will experience a temperature change when you dunk it in a 5 gal bucket of ice water, but how long until it goes to 32 deg F? *THAT* is the response time of a temperature measuring device.


Using that analogy on the cheap GM IAT sensor, since your data logs are still rising at a steady rate for a full WOT pull, how do you know that your IATs aren't stable but about 20 deg higher and the sensor is just "soaking" up to that temp with a slow response?

[5mall5nail5]

Read the post right above that one. Response time does not equal when it starts changing, it describes the amount of time to read the ACTUAL temperature in changing conditions. It's typically expressed as some number of degrees per msec or microsecond for the high dollar stuff.

Even a 100 lb block of steel will experience a temperature change when you dunk it in a 5 gal bucket of ice water, but how long until it goes to 32 deg F? *THAT* is the response time of a temperature measuring device.


Using that analogy on the cheap GM IAT sensor, since your data logs are still rising at a steady rate for a full WOT pull, how do you know that your IATs aren't stable but about 20 deg higher and the sensor is just "soaking" up to that temp with a slow response?

Ok so you essentially criticize every IAT sensor used 99% of motorsport teams by saying it is inaccurate and slow to show actual temps. I have no issue with a sensor reading 100 degrees when Im parked, andt hen when I drive it goes down 98...95....93.....90.... because in reality, the AIR is slow to respond, so what exactly is your point? Its not like I move the car, the FMIC sees cold air, and ZAP the intake charge is chilled. It's all relative. Additionally, it doesn't even matter how fast the sensor is to respond - I am not tuning to the IAT, I am merely making a point. Whether my charge is 85 degrees or 95 degrees, my fueling/timing is the same. If it goes HIGH, then we have issues, but this is not critical.. what nit pick?

I didn't criticize by claiming to have worlds of experience... I am merely commenting that this turbo is spooling ~10 psi by 3800 rpm at 46% throttle!

You fail to acknowledge that this is not a "soaking up the temperature" issue - its a freaking thermistor in a plastic shield. You can take your T type temp gauge if you want, but a thermistor is just a wire wound up... this is the same shit that you find in computer motherboards monitoring $100,000 main frames at my work... its not INSTANT... its not that it even matters... because you're NEVER going to read the temperature of an object in realtime relative to the thermal conductivity of said object - sure, spend $1,000 on an iR probe.. ok... we're talking about freaking engine management here.

I just love how you criticize the open-element, fast changing GM temp sensor but make no mention of the OEM Bosch intake air temp sensor that is closed element.

[Def]

Ok so you essentially criticize every IAT sensor used 99% of motorsport teams by saying it is inaccurate and slow to show actual temps. I have no issue with a sensor reading 100 degrees when Im parked, andt hen when I drive it goes down 98...95....93.....90.... because in reality, the AIR is slow to respond, so what exactly is your point? Its not like I move the car, the FMIC sees cold air, and ZAP the intake charge is chilled. It's all relative. Additionally, it doesn't even matter how fast the sensor is to respond - I am not tuning to the IAT, I am merely making a point. Whether my charge is 85 degrees or 95 degrees, my fueling/timing is the same. If it goes HIGH, then we have issues, but this is not critical.. what nit pick?

You should be tuning to IAT, it changes charge density...

The sensor IS slow and inaccurate compared to off the shelf cheap thermocouple readers and low mass thermocouples. I don't care who uses sensors like this, it doesn't change their physical response. Air does absorb heat as it is going through the charge piping, but I don't think it's as slow to respond as what your datalogs show...

I never said it was a bad sensor to use in IAT tuning with an EMS, as obviously the low price helps offset its sensing deficiencies. For comparing what kind of IATs you are likely getting in fast temperature swing environments, I would say a cheap thermocouple reader is probably a better bet.

I didn't criticize by claiming to have worlds of experience... I am merely commenting that this turbo is spooling ~10 psi by 3800 rpm at 46% throttle!

I'm glad you're happy with your turbo, I never said it was bad, was just expecting a bit faster spool since it's sometimes touted as a "fast spooling" bigger turbo by you and others.

You fail to acknowledge that this is not a "soaking up the temperature" issue - its a freaking thermistor in a plastic shield. You can take your T type temp gauge if you want, but a thermistor is just a wire wound up... this is the same shit that you find in computer motherboards monitoring $100,000 main frames at my work... its not INSTANT... its not that it even matters... because you're NEVER going to read the temperature of an object in realtime relative to the thermal conductivity of said object - sure, spend $1,000 on an iR probe.. ok... we're talking about freaking engine management here.

I just love how you criticize the open-element, fast changing GM temp sensor but make no mention of the OEM Bosch intake air temp sensor that is closed element.

It IS a "soaking up the temperature" problem, that's what the sensor is doing everytime the IATs change, trying to equalize with its surroundings. A thermistor is not the hottest thing for fast response usually, but they're cheap, hence why they're used in a relatively steady state environment like your "$100,000 main frames." I do all sorts of temperature measurements and get to see the difference of even what the gauge of wire used on the thermocouple does to response. The response difference is noticeable, even to the naked eye going from thin, medium and thick gauge wires of the same TC type. You can read temperature much better than a thermistor, it's just more expensive - exponentially so when you get to microsecond response times on a TC. An IR reader wouldn't work for air temp...

So I guess just take my word, there is a noticeable lag in your IAT measurements, that's why it's best to do a LONG pull if you want to compare intercooler efficiency or something like that. A quick 2 gear pull likely doesn't let the sensor catch up, and at 46% throttle you're letting your intercooler cool less massflow than at WOT, so it makes it seem a bit better there than it would be at WOT.

I don't see why bringing up that the Bosch is worst than the GM changes anything that I've said.



If you want more accurate results, stick a thin wire Type T TC in your intake tract somewhere. That's all my post was getting at, and hopefully explaining things a little better to anybody that wanted to know. I didn't expect to have someone talking down to me that knows nothing of the subject that I brought up...

[5mall5nail5]

You should be tuning to IAT, it changes charge density...

Yeah, but 20 degrees doesn't change anything... these are street cars, I am not going to add .3 degrees of advance because my charge is 20 degrees coolder than before.

I never said it was a bad sensor to use in IAT tuning with an EMS, as obviously the low price helps offset its sensing deficiencies. For comparing what kind of IATs you are likely getting in fast temperature swing environments, I would say a cheap thermocouple reader is probably a better bet.

I'd really just like to know what sort of temperature and air metering sensors you're using in your system...

I'm glad you're happy with your turbo, I never said it was bad, was just expecting a bit faster spool since it's sometimes touted as a "fast spooling" bigger turbo by you and others.

Seriously - how is it not fast. It's a hell of a lot larger than a GT28, its journal bearing, LARGE AR, and it's making my wastegate springs worth of boost less than half throttle at 3800 rpm... my friends K03 Jetta 1.8T does the same thing!

So I guess just take my word, there is a noticeable lag in your IAT measurements, that's why it's best to do a LONG pull if you want to compare inteArcooler efficiency or something like that. quick 2 gear pull likely doesn't let the sensor catch up, and at 46% throttle you're letting your intercooler cool less massflow than at WOT, so it makes it seem a bit better there than it would be at WOT.

That's not the point - that log is after the car has been flogged HARD on a very retarded timing map (EGTs, IATs go up) and then it was parked for about 10 mins heat soaking, and THEN you see the IAT.. and its very very reasonable and the air temp falls JUST as the car starts moving again.
I don't see why bringing up that the Bosch is worst than the GM changes anything that I've said.

If you want more accurate results, stick a thin wire Type T TC in your intake tract somewhere. That's all my post was getting at, and hopefully explaining things a little better to anybody that wanted to know. I didn't expect to have someone talking down to me that knows nothing of the subject that I brought up...

I guess I could put a thin wire in my intake track but personally I'm going to stick to what 1200hp supras, the Swedes, and all the tuners in the world are using for street cars (and track cars, at that).

[Def]

Yeah, but 20 degrees doesn't change anything... these are street cars, I am not going to add .3 degrees of advance because my charge is 20 degrees coolder than before.

But you're directly basing fuel calculations of that factor. 20 degs isn't a huge number, but again, the sensor is used because it gets "alright" response time and is cheap.


[QUOTE=UrineMachine;7332366]
I'd really just like to know what sort of temperature and air metering sensors you're using in your system... [/quote[

I use a factory Nissan MAF, I don't need to know my IAT. I have enough electronics boxes as it is. It really doesn't matter though, as I'm not talking about my car, but thanks for trying to bring in a "who's is bigger" discussion into this.

Seriously - how is it not fast. It's a hell of a lot larger than a GT28, its journal bearing, LARGE AR, and it's making my wastegate springs worth of boost less than half throttle at 3800 rpm... my friends K03 Jetta 1.8T does the same thing!

I guess we just have different definitions of fast. My car makes that much boost much lower down, and even "larger fast spooling turbos" aren't that much behind it. I'm not making a big deal out of it though, but you certainly are. Again, glad you are happy with your turbo.

That's not the point - that log is after the car has been flogged HARD on a very retarded timing map (EGTs, IATs go up) and then it was parked for about 10 mins heat soaking, and THEN you see the IAT.. and its very very reasonable and the air temp falls JUST as the car starts moving again.
I don't see why bringing up that the Bosch is worst than the GM changes anything that I've said.

Again, response time is the TIME it takes the sensor to reach equilibrium with its surrounds, it's not that it won't change for 5 seconds after there is a temp change. I don't know why this is hard to understand when I've explained it multiple times here.

I guess I could put a thin wire in my intake track but personally I'm going to stick to what 1200hp supras, the Swedes, and all the tuners in the world are using for street cars (and track cars, at that).

Just don't try to play it off as some ultra accurate, fast response temperature measuring device. It is a $20 off the shelf sensor, and someone brought up that it likely has a slow response time and to interpret results as such, which then caused you to throw a giant hissy fit...

[techno550]

I use the $20 GM IAT sensor on the left , response time is instant when placed in direct air path.

instant? bullshit.
Why would a $20 temp sensor have an INSTANT response time, and the $200 temp sensors give response times in deg/ms? They can't be instant too?

Using that analogy on the cheap GM IAT sensor, since your data logs are still rising at a steady rate for a full WOT pull, how do you know that your IATs aren't stable but about 20 deg higher and the sensor is just "soaking" up to that temp with a slow response?

Precisely.

Ok so you essentially criticize every IAT sensor used 99% of motorsport teams by saying it is inaccurate and slow to show actual temps.

What motorsport team uses that POS? We used low mass thermocouples for intake air temp. We used highly responsive pressure transducers for manifold pressure. Low mass thermocouples for EGT. etc...

You fail to acknowledge that this is not a "soaking up the temperature" issue - its a freaking thermistor in a plastic shield. You can take your T type temp gauge if you want, but a thermistor is just a wire wound up... this is the same shit that you find in computer motherboards monitoring $100,000 main frames at my work... its not INSTANT... its not that it even matters... because you're NEVER going to read the temperature of an object in realtime relative to the thermal conductivity of said object - sure, spend $1,000 on an iR probe.. ok... we're talking about freaking engine management here.

Outside air temp doesn't change too terribly fast. Processor temps likewise don't spike up or down too quickly either. The heat builds slowly, and so a slow responding sensor will easily keep pace. If you have quick temperature swings, you need a faster temperature sensor. (seems obvious enough to me. )

I just love how you criticize the open-element, fast changing GM temp sensor but make no mention of the OEM Bosch intake air temp sensor that is closed element.

do you know the response time of either?