Air Temperature Sensor - Improving Engine Performance?

[OwenM]

Applying resistors to the Lambda circuit is a totally different ball game and not relevant to this discussion.

Adding resistance to the air temperature sensor circuit is safe; the ECU just thinks the intake air is colder and adds more fuel across the range to compensate. The original thermistor (temperature dependant resistor) is still in use so the temperature signal (resistance) will still vary as real air temperate changes, although tracking will obviously be off.

Commercial products like the FRK and others that connect to the air temp sensor input are doing the same thing, some with a simple resistor and others with different components. No matter what is used the ECU is given a cold signal and alters fuel and ignition timing according to its internal maps for that temperature.

There is nothing mysterious or complex about all this and you have the tools to monitor the results so give it a go man.

[boxercup]

Originally Posted by JOHN-DYNOSTAR

owenM as instructed I have read this thread.

My experience of bmw's is that they don't like a permenant resistance on the lambda
when using aftermarket fuel controllers.

Lambda resistance variants will alter the fueling only

so I think a permenant resistance anywhere in the system is not good.

John why not? Andrew's experiment although without empirical verifiable data was productive he achieved his goal - to tune out the flat-spot he spoke of. He achieved both Injection and Ignition modifications! This particular IAT resistance tuning is not new technology.

I think modern ecu's are a little more intelligent these days and read all the sensors actively.

Yes but not quick enough for performance tuning. You have to accelerate their reporting artificially.

Wait until you see the ECU for the BMW S100RR and the new R series. It is really quite interesting! The data logging is amazing.... Part of big brother - BMW watching you. Have a blown engine.... It will tell you how many times the bike bounced off the rev-limiter. When brakes were applied and at what speed.... SORRY NO WARRANTY! ....

all credit to AndrewA and you.I would be willing to independantly test this spoofer if you like
to show if it works safely and ultimately it will save my customer loads of dosh

That would be good John!

Greetings,

John are you going to EICMA?

Need tickets - Call my office we have some available.

Again nice work Andrew!

[boxercup]

Originally Posted by OwenM

Applying resistors to the Lambda circuit is a totally different ball game and not relevant to this discussion.

Adding resistance to the air temperature sensor circuit is safe; the ECU just thinks the intake air is colder and adds more fuel across the range to compensate. The original thermistor (temperature dependant resistor) is still in use so the temperature signal (resistance) will still vary as real air temperate changes, although tracking will obviously be off.

Way off... seconds instead of microseconds - you are right - TOO SLOW!!

Commercial products like the FRK and others that connect to the air temp sensor input are doing the same thing, some with a simple resistor and others with different components. No matter what is used the ECU is given a cold signal and alters fuel and ignition timing according to its internal maps for that temperature.

There is nothing mysterious or complex about all this and you have the tools to monitor the results so give it a go man.

Owen,

You once again have display that you have no clue as to what the Power FRK Module does!

One hint - When you open the throttle the ECU knows it instantly thanks to the workings of the Power FRK Module!

Clueless - And that is ok - no one is expected to know everything!

Oh BTW - Owen, good to have other people do your work eh?

Andrew started and finished his device - Where is yours?

Again Andrew, nice work!!!

[JOHN-DYNOSTAR]

tickets to EICMA are free on trade days.

thanks for the Bribe

we have to find some cheap flights.difficult in the uk at the moment.Its probably
cheaper to fly to australia than milan

[quote]
"You have to accelerate their reporting artificially."
[quote] by boxercup

yes but it is preferably to convince the ecu the signal/report is active not static
I think .
but I could be wrong



[quote] owenM
There is nothing mysterious or complex about all this and you have the tools to monitor the results so give it a go man. [quote]
I will ask my tame electrician if he has time to manufacture this gizmo

Most of my bmw twin testing has been replacing chips etc to see the results
and shortening and altering intake snorkels back in 2001/2ish

I am well aware that twins need a richer fuel mix than other engine designs
and that torque is more important or should I say relevant in the bmw's case

[boxercup]

[QUOTE=JOHN-DYNOSTAR;4995185] tickets to EICMA are free on trade days.

thanks for the Bribe

Your Loss! These are Press Passes! You have full access to all the Press Events, New Bikes to Demo and also the Parties - Oh and BTW - the Wine and the Women are nothing but fantastic... Wine and Women are put in that order alphabetically! Not necessarily my order!

we have to find some cheap flights.difficult in the uk at the moment.Its probably
cheaper to fly to australia than milan

[quote]
"You have to accelerate their reporting artificially."
[quote] by boxercup

yes but it is preferably to convince the ecu the signal/report is active not static
I think .
but I could be wrong

lyYes the maps have to be floating! Thus a dynamically active and very quick IAT signal report is needed. HINT: Also - with higher dynamically reporting voltage signals!!!



[quote] owenM
There is nothing mysterious or complex about all this and you have the tools to monitor the results so give it a go man.

I will ask my tame electrician if he has time to manufacture this gizmo

Most of my bmw twin testing has been replacing chips etc to see the results
and shortening and altering intake snorkels back in 2001/2ish

I am well aware that twins need a richer fuel mix than other engine designs
and that torque is more important or should I say relevant in the bmw's case

Torque is all that can be measured and quoted.

HP is just an equation!

Best to you John!!

Greetings John,

Will remember the word BRIBE when you ask for assistance with the Rapid Bike questions....

Anyhoo.

Best

[JOHN-DYNOSTAR]

[QUOTE=boxercup;4995287]

Originally Posted by JOHN-DYNOSTAR

tickets to EICMA are free on trade days.

thanks for the Bribe

Your Loss! These are Press Passes! You have full access to all the Press Events, New Bikes to Demo and also the Parties - Oh and BTW - the Wine and the Women are nothing but fantastic... Wine and Women are put in that order alphabetically! Not necessarily my order!

Greetings John,

Will remember the word BRIBE when you ask for assistance with the Rapid Bike questions....

Anyhoo.

Best

aaaah ! yes the italian women

bribe

[OwenM]

Originally Posted by boxercup

You once again have display that you have no clue as to what the Power FRK Module does!

That so.

Originally Posted by boxercup

One hint - When you open the throttle the ECU knows it instantly thanks to the workings of the Power FRK Module!

Really, want to prove that, I am sure we will all be fascinated but do it in the FKR thread if you please.

Originally Posted by boxercup

Clueless - And that is ok - no one is expected to know everything!

I’ve got enough of a clue to know BS when I hear it.

Originally Posted by boxercup

Oh BTW - Owen, good to have other people do your work eh?
Andrew started and finished his device - Where is yours?

ROFL, that’s pretty funny considering I built and tested my temperature spoofer 2 weeks before this thread started and a full month before Andrew build his unit, I have done over 1000 miles with it. I would say you are well and truly “too slow” buddy, how’s that crow tasting?

Power FRK product review

[boxercup]

Owen,

The only thing that is too slow is your alleged device.

1980's technology at it's half best!

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In fact this is like Tweeting at it's worst.

Ciao!

[AndrewA]

Originally Posted by OwenM

One of the guys on the i-bmw forum has tested a FRK on his K12GT, the GS-911 shows the air temperature to be around 20 degrees C below true ambient, certainly not -25C as was the case with the Triumph, this ties in well with my testing on the RT which seems to run best when spoofed to about the same level. A 10k to 16.8k resistor is series with the temp sensor should give a similar result according to my testing.

Although a negative 20C (relative) puts my bike in the much smoother / richer category, it is clearly not in the area of aggressive ignition advance. It appears that the optimal spoofed" temp for the R1200S has been around - 26.3C relative to ambient (based on four data points). I also need all of 26k Ohms to get there.

The testing temps been pretty consistent: (11.3, 7.5, 13.8, 13.3), and the GS-911 readings have been consistent as well - intake readings and kohms seem to match within a degree regardless of the ambient temps.

I have been charting ambient, voltage, intake temp, and ohms, and hope to get in a "warm weather" ride this weekend.

FYI - I put a 100k pot into the circuit and could only get a reading of -33.8C - that appears to be the maximum on the low end...I also changed the GS-911 to read my bike as a RT, and got the same exact readings (intake temp) as the R1200S. Fun stuff indeed.

[tm1100s]

Andrew, are you getting any DTCs as the resistance is changed towards the limits?

The reason I ask is that some auto PCM/ECUs will substitute an in-range value for some sensors once an out-of-range sensor is detected. Most of the time this will throw a code.

[OwenM]

Originally Posted by boxercup

Owen,

The only thing that is too slow is your alleged device.

1980's technology at it's half best!

------
---

In fact this is like Tweeting at it's worst.

Ciao!

A resistor does not have a speed, the Bosch thermistor that it’s in series with is limited in how quickly it can respond to changes in ambient air temperature but it is more than fast enough to track any expected change, that’s why manufactures use such devices in this application.
When spoofing very cold temperatures (as we are) the effect of resistance changes in the temp sensor have only a small influence anyway.

[OwenM]

Originally Posted by AndrewA

Although a negative 20C (relative) puts my bike in the much smoother / richer category, it is clearly not in the area of aggressive ignition advance. It appears that the optimal spoofed" temp for the R1200S has been around - 26.3C relative to ambient (based on four data points). I also need all of 26k Ohms to get there.

My tests have all been conducted under warmer conditions in the 15 to 30C range so it makes sense results would be different. Even then the RT is a different animal to the 12S, I always felt the 12S was doing odd and inconsistent things with ignition advance as the engine behaved differently depending on how quickly the throttle was opened. I put this down to BMW safety measures; they did not want the R12S to be a dangerous wheelie monster so they damped response down via the throttle linkage and ECU programming. Other manufacturers use different mapping for each gear to keep things under control and the RT has a lot more weight over the front wheel and therefore does not need such “safety” measures.

[OwenM]

Originally Posted by tm1100s

The reason I ask is that some auto PCM/ECUs will substitute an in-range value for some sensors once an out-of-range sensor is detected. Most of the time this will throw a code.

Yes, I would expect to see a fault logged if the temp sensor was too far out of the expected range, did the GS-911 show anything?

[AndrewA]

Originally Posted by tm1100s

Andrew, are you getting any DTCs as the resistance is changed towards the limits?

The reason I ask is that some auto PCM/ECUs will substitute an in-range value for some sensors once an out-of-range sensor is detected. Most of the time this will throw a code.

Good question Tony,

Originally Posted by OwenM

Yes, I would expect to see a fault logged if the temp sensor was too far out of the expected range, did the GS-911 show anything?

Not a one.


No faults have registered, other than when I've physically pulled the IAT circuit apart. This is an easily clealable fault, and specifically says something like "IAT sensor disconnected"

I've run a scope on the IAT circuit, and don't see how this circuit would effect any canbus functions that might trigger a fault on anything but a gross non-continuity fault. Not to beat a dead horse, but the IAT circuit clearly has a single purpose.


The ECU may be going through spasms during all of this, but no faults are thrown.

[AndrewA]

Originally Posted by OwenM

My tests have all been conducted under warmer conditions in the 15 to 30C range so it makes sense results would be different. Even then the RT is a different animal to the 12S, I always felt the 12S was doing odd and inconsistent things with ignition advance as the engine behaved differently depending on how quickly the throttle was opened. I put this down to BMW safety measures; they did not want the R12S to be a dangerous wheelie monster so they damped response down via the throttle linkage and ECU programming. Other manufacturers use different mapping for each gear to keep things under control and the RT has a lot more weight over the front wheel and therefore does not need such “safety” measures.

Exactly. Different map "tilting", (different concentric twist grip-throttle openings!), different bikes.

Unfortunately, we are going into the cold season here. I tried to heat the sensor with a hair dryer to see if the corresponding temps would change relative to resistance, but got distracted and moved onto something else.

[boxercup]

Originally Posted by OwenM

My tests have all been conducted under warmer conditions in the 15 to 30C range so it makes sense results would be different. Even then the RT is a different animal to the 12S, I always felt the 12S was doing odd and inconsistent things with ignition advance as the engine behaved differently depending on how quickly the throttle was opened. I put this down to BMW safety measures; they did not want the R12S to be a dangerous wheelie monster so they damped response down via the throttle linkage and ECU programming. Other manufacturers use different mapping for each gear to keep things under control and the RT has a lot more weight over the front wheel and therefore does not need such “safety” measures.

Owen,

If you got em smoke em!

You must be high.

Bizarre statement - With no basis in fact.

BMW WHEELIE MONSTERS!!!

Now that IS funny! BMW could only hope!!!

[OwenM]

I have never ridden a standard R12S so I don’t know what they are like but on my modified R12S I could not use full throttle in first gear without the front coming up very violently and if the road was not smooth the front would lift in second as well. The inconsistency in throttle response and engine output made predicting and controlling the first gear wheelie difficult so I was always carful.
It would be interesting see what a R12S with a different ECU and ground up maps without any BMW “engineering” would behave like. I was told by a local tuner that a MoTeC unit would transform the BMW and I am inclined to believe him. It certainly feels like BMW are doing something to keep the R12S under control other than just the throttle linkage.

[Merrimac]

Just curious, would the use of a resister on a R1100S air temperature sensor provide a similar result?

[AndrewA]

Originally Posted by Merrimac

Just curious, would the use of a resister on a R1100S air temperature sensor provide a similar result?

Hey look. It's Merrimac!!!

The R1200S has a more pronounced flat spot between 3k rpm and 5k rpm, which I believe is attributable to leanness. The IAT spoofer smoothed this over. The bike also starts better and idles very smoothly. A significant mod imho.

My recollection of my R1100S was that it didn't have this same leanness, but it did exhibit significant vibration and maybe a slight dip in torque in these ranges. I've ridden a R1100S with a similar device, and felt nothing but a very smooth power band from idle to red line. It felt very different than the R1100S that I had.

The only unknown to a project like this is exactly what size of resistors to use (which I suspect will be different for everyone, depending on what they feel constitutes "improvement"), so some experimentation may be needed, which is very easy to do if you use an adjustable pot (potentiometer).

For those that like to tinker, and maybe have an extra $40.00 or so to pee away, it is worth trying. It can't harm the bike and is instantly reversible.

[Merrimac]

AndrewA!

I think I will do some tinkering. However, it will have to wait until the 2010 riding season. (It's starting to get cold in Wisconsin.) In the mean time, I'll purchase the components on your BOM and and follow the drawing you put together. The pictures are a big help!

Thanks for putting so much time, $, and effort into this project!

Merrimac!