Air Temperature Sensor - Improving Engine Performance?
 

Did I read where some board members added a resistor to their air temperature sensor to simulate riding in colder temperatures? The outcome was an increase in fuel richness and a change in engine timing?

Is my understanding correct? :confused:

If it is correct can someone provide a description and pictures so an electrical/electronic novice would be able to select the correct resistor and properly install the modification? Would any one with real world experience want to describe the change is performance?

Thanks!

PS - I have a 2004 R1100S Twin Spark

Oh, boy................don't need another thread on this:

http://forums.pelicanparts.com/bmw-r1100s-r1200s-tech-forum/495368-power-frk-product-review.html

Instructions on how to do it would be very welcome!

Have these been posted elsewhere?


It would be really useful to have the info regarding pin outs, model/part numbers for the connectors, and which resistors are needed.

From glancing at the lengthy mobius "FRK" thread it is clear that OwenM has spent a considerable effort on this topic. Although I've read his description on how he did it, I'd love to have more DIY info...is anything documented anywhere?

Bosch spec sheet is all you need. But only you can do the next step: just pick the temperature you think suits your bike as modified. Or ask Foster.

"Pin out" is two pins. Wire resistor in series with either wire or if you remove the sensor, between the leads from the ECU. With a big resistor, just won't matter much to the "temperature" if you choose to keep sensor in the circuit or not (but size of resistor will be a bit different).

Can't get much simpler.

if you know enough to take if from there, then you can take it from there. But if you don't, you shouldn't try.

How many times and for how many months have I posted this same information?

Which pins on the connector??? Are there only two showing?

The sensor only has two wires connecting it, a resistor needs to placed in series with either one, it makes no difference which. A 10k ohm resistor should be enough but you may need to go higher depending on your bikes needs. The simplest and cheapest method is to cut one of the wires in the harness, solder the resistor in place and insulate it will heat shrink or tape. If you really don’t want to cut a wire you will need a male and female pair of connectors (they are the same type as used on the fuel injectors), this will enable you to put a resistor in series with one wire and simple length of wire in series with the other. Another alternative is to use a 20k ohm variable resistor (pot) in place of the fixed resistor; this will give you ample adjustment to cater for most needs.
I should get around to implementing a more permanent setup for my RT, when I do I’ll take photos and post.

How much difference does a fake FRK make? :D Well that depends on your bike, anything from almost none to a significant amount, it depends on how well your bike is running now. On my standard RT the difference was insignificant, but with Lennies sprockets installed there was a noticeable improvement.

Sorry Ben. I must have missed that.

Excellent info. Thanks!

The connectors have been ordered.:p

Bosch Type EV1 Injector Connector MATE Connector Pigtail $5.99
Bosch EV1 Type Injector Connector Pigtail Push to seat $5.99
Shipping $ 4.90

Total so far $ 19.38

Yikes!

Adjustable pots have three connectors! Is one not used? What do the three connectors connect to?

The connections are shown right on the side. Full Resistance is between the far pins. The center offset pin is the slider.

You will want to connect between one end and the slider.

Thanks Bill!

If I understand this theory correctly, Andrew and I are just coming into prime riding weather!;)

Andrew -

Great moves.

With those connectors (forming an "extension cord" configuration with the sensor), you might retain some cold weather function, if the external resistance ends up being low.

Pretty inexpensive connectors. Hope they are right ones. Length of wiring not critical, but might be helpful to add a ferrite bead taken from an old computer cable.

It is proper practice to connect the slider lug to one end lug in this kind of application (won't affect resistance).

You have to measure resistance each time you set it and so you have to disconnect both plugs. With that pictured pot, you won't be able to eyeball the setting and re-setting, esp. since you are likely to be choosing among resistance values that are low and close (on that pot), too bad/ You have to think of human factors when humans are involved and maybe you can get away with a tiny paint dot to mark the settings.. esp if you can do this beforehand.

After you post your preferred resistance values, people can buy pots in that range (plus maybe 30%) or use a fixed resistor plus a far smaller, eyeballable, pot.

Based on my Techlusion tuning experience (a little scoot circling Lake Superior), it might take 3-5 tries to get the right setting. Since this is such a crude approach, it is likely to be different from different routes and even bad on some. So to reduce your testing confusion, optimize for one route before trying on another kind of route. An AIT spoofer might be a suitable mod for people who do nothing but ride two-lane twisty country roads in warm weather but less suitable for guys in Boston with much more variable routes and weather.

If you can figure out any way to see if spark timing is influenced by adding the resistor, that would be great.

Good luck.

Andrew, maybe you could find a 3 position switch and apply full partial and off positions for the added resistance. What a great test bed that would be on the dyno.

Andrew is going to need a dyno, a large range of variable resistors and a great deal of time to make anything that resembles an FRK.

Perhaps. I'm just trying to richen the 3 - 5k rpm range where I spend most of my fun time. If it works, great. If not, Ill have wasted $20.00 that I should have put toward sprockets and beer.

The FRK is clearly much different , being much more well thought-out and involved.:D

Nope. That's wrong in almost every sense.

We are talking of a single variable: temperature (AKA resistance). That's pretty straightforward to track, eh.

Little that an inertial dyno can tell you about the sort of benefits you might get from gross changes of the sort BMW built-in to compensate for ambient temperature and which Andrew is hoping will track with the mods on his bike.... lucky if it does. Inertial dyno curves might bulge here and there, but not likely to find orderly and interpretable results or bulges big enough to be worth bothering about. Test rides, on the other hand, might show the sort of benefits that others have claimed. Same is true for Techlusion.

It is no trick at all to duplicate an FRK: with some testing, you can hit the same temperature set point. The trick is to find a temperature that kind of tracks what your engine wants. That's hard (or impossible) with a single variable. With Foster's FRK, he mails you replacement FRKs (each FRK has a different temperature.... if your unit is too rich, he mails you a warmer one) till one suits your mods and your riding style, as we have seen. With a pot, you twist the knob up and down till you like the results. Then you measure the resistance and post here (including details of your other engine mods, state of tune, test ride route, etc.).

when you guys are done with this thread we will ask Roger to splice it on the end of the FRK review, where we just had 600+ posts worth of the same discussion.

give it a rest dude ;)

Right you are Bill!

It takes a lot of data to analyze and perfect!

R&D is not riding around a lake!

Without repeatable verifiable empirical data you can not quantify anything!

The Dyno is the only way you can quantify!

Then you can take a ride around the lake with a portable 5 gas analyzer/data logger to proof your work.

Ultimately, only then you can have the data needed!;)