TR650's need a Power Commander, a Booster Plug, a Wuka King or similar to correct the all-to-common lean mixture in the open loop portion of the FI map.
Some people don't even know their bike COULD BE RUNNING BETTER.
What if you found a mod that corrects the issue for $20?
What if it worked BETTER than those other plug-n-play devices with the sensing probes?
What if it added NO clutter to your already cluttered bike?
Introducing...
IAT Modification
(intake air thermistor mod, cross-posted from ADV)
Dateline 8-1-13
I received my new thermistors from Avnet yesterday, $20.12
including the $8 for FEDEX. 8 qty part #B57861S 104F 40.
Vendor list here...
http://octopart.com/b57861s104f40-epcos-851024
International vendor here (search for part #706-2765P) ...
http://www.rs-components.com/index.html
These little guys look exactly like the thermistor inside our bike's IAT. It is highly likely they are the SAME mfr & build specification as the OEM, here are the semen swimmers...
I sawed off the cage of my OEM IAT with a dremel, you can see the thermistor supported inside now...
I cut the head off the thermistor - cutting the plastic center support thingy is optional...
I pulled back the teflon insulation on the new thermistors, no need to try & strip the wires, though I did use a razor to sort-of scrape & pick the insulation off the wires from the IAT...
There's 8 thermistors, twist them in pairs, you'll now have 4-sets, then twist those in pairs, you'll now have 2 sets, OK to use pliers to tighten up your twists, looks like this...
Twist again & cut the ends off to make them even, slip over some heatshrink tubing, looks like this...
Solder away, tin your leads first, use rosin core solder, plumbers solder & flux would be OK if you cleaned the flux off, picture shows bottom connector is cleaned top connector still dirty...
Apply heat with heat gun or use the fast waiving bic lighter technique to shrink your tubing...
I applied a few layers of heat shrink until I was happy with the rigidity-ness of the thing. I protected the thermistor heads from being exposed unnecessarily to heat while blasting it with the heat gun, it now looks like this...
Yes it is taller than the OEM, I left the leads on the new thermistors their full length b/c they would be better protected from heat while soldering & for ease of working with them. But you
can cut them shorter. Considering the new height I'll have about 1/2" clearance to the ceiling once inside the airbox.
A note from the thermistor mfr about cutting the leads & soldering...
When soldering, care must be taken that the NTC thermistors are not damaged by excessive heat. The following maximum temperatures, maximum time spans and minimum distances have to be observed:
Dip soldering Iron soldering 360 °C max. Soldering time max. 2s.
Distance from thermistor min. 6 mm min.
Under more severe soldering conditions the resistance may change.
Congratulations!! You have The ERUPTION!!!
It measures & compares like so...
The ERUPTION - about this mod
This mod is for anyone who wants a spoofer
for their TR or for any BMW that uses an IAT that's interchangeable with the TR's. A spoofer is a device designed to fool the ECU into richening up the mixture to improve engine ride-ability. A lot of new bikes suffer from overly lean fuel mixtures. For the TR, it’s commonly reported the bike benefits from fuel enrichment in the open loop map.
Some popular spoofers have evolved into devices that use external temperature probes that plug inline with the IAT (intake air thermistor). Because they endeavor to modify the existing IAT R/T curve, & b/c their external probes are sometimes subjected to false temperature influences, they can be a bit imprecise at hitting their target. Depends on the device, the installation & the ambient temperature. By comparison
The Eruption is simple & accurate at hitting its target fuel enrichment through the widest temperature range.
Should you ever want to reverse the mod, simply reinstall a stock IAT, cost has been reported to be around $25 with shipping. BMW P/N 1739510.
It's not clear how dealers or mfrs would view any spoofer installation should an engine warranty situation occur. Probably the same way they view a PC but who knows?
The Eruption replaces the single 5k NTC in the IAT with 8- 100k NTC thermistors to spoof the ECU into thinking it's 20C colder than it really is to get a 6% enrichment while operating in the open loop map. It maintains that 20C offset really well no matter what the
real temperature happens to be. This gives a nice consistent fuel mixture. Credit to Italian friends Gaspare & Belinassu for their development & testing work.
Don't do this mod if you already have a spoofer.
Some benefits over other spoofers are..
- This arrangement follows the non-linear curve of the existing OEM 5kNTC thermistor IAT VERY well.
- The temperature measured IS the actual air temp for combustion with no false heat influences.
- The IAT stays dry & isn't subject to false cold influences (wetbulb temps).
- Bike outwardly looks stock, no extra wires, switches or sensors running about.
Q & A
Will this mod stop stalling problems?
That was the motivation for this TR owner to find a solution. The Strada would stall & though the dealer's "program update" helped matters it didn't eliminate the occasional & sometimes ill-timed lean stall. Several magazine articles have also mentioned the issue. After
The Eruption & post engine warm-up, I have never had an engine stall.
How do I get to my IAT to do this mod?
Remove the left side plastic body panel, see
High Five's "How to" post #189.
Remove the IAT Bosch connector plug (hint; depress the metal clip)
third picture down here.
Depress the small plastic dog leg release on the side of the IAT (see photo above) & pull down from the airbox.
Why is there eight thermistors?
It had to be to get the correct T/R values. The new thermistors look identical to the OEM but they
are higher values. Combining them gets us to our target values. The new thermistors measure 100k ohms at 25C & once completed
The Eruption will measure 12.5K ohms at 25C. If you own an ohm meter it would be a good idea to check each thermistor before performing the mod, they should all measure very close to each other with their heads subjected to the same temperatures. Then check one at 25C. This will verify that your vendor did in fact ship the correct thermistors.
I have The Eruption now there's a symbol displayed on my dash?
The little snowflake symbol would otherwise warn the rider of potential hazardous conditions. Also if you select to display ambient temp the dash will now show 20C colder than what it really is. This is a common tradeoff for all of the IAT spoofers used on the TR as it uses the same thermistor for outside air temp display & ECU computations. The snowflake is small & not annoying.
I have The Eruption now the Check Engine Light comes on when it's freezing outside, why? With the stock IAT the CEL will come illuminate on the TR around 0F. It's not known with any specificity why the engineers designed this to happen. All of the IAT spoofers will fool the ECU into thinking it's colder than it really is & so they will cause the CEL to illuminate around freezing temperature on the TR.
Are there any noticeable downsides?
Expect the bike to run rich during cold-start / warm-up but not smokey rough running rich. Any 20C offset spoofer like BP or The Juice will be the same in this regard, they just don't mention it.
OK I'm going to do it - is there anything else I should know?
While you have your side panels off you may want to consider doing a
canisterectomy (tips,
small fuel filter can be found at O'Reilly autoparts, also vinyl (colored) vacuum plug caps like
these will last longer than the rubber Dormer brand ones, it's not too difficult to remove the hose at the throttle body & use a vinyl plug there).
The Eruption works well with a
cat-be-gone mod & is expected to work well with after market slip-ons.
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This section is for those that want to know more, please ignore what follows...
This table was used for proof of concept purposes...it compares our OEM IAT's 5k NTC thermistor temp/resistance readings with a typical 5k NTC (just to see that it doesn't have any odd characteristics) then two targets for a 20C offset (just to see that using either as a target would be OK) & a look at how we could expect our modded IAT to do at hitting those targets…
Credit to hassepfeffer for making this graph...
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BTW this is how I think the cabled spoofers like "BoosterPlug" & "The Juice" are constructed, in case anyone wants to make one or improve on it...
But why would you want to make a cabled spoofer when you can have
The Eruption!
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If anyone has a cabled spoofer & you'd like to see how close to target it gets, post the resistance values at 0, 25 & 50C so we can compare.
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If I didn't have one already I'd take you up on it. BTW I'm not opposed to anyone making these & getting compensated for their efforts, so you may want to make this a limited time offer!
