I wonder how thermosistors are measured and spec'd. With that info, your reverse engineering would be complete.
On the ADV forum a couple of guys are cooking up a few different motor mod farkles for the 800 and the 658.

 

Well, the way for me to figure out what this one is would be to have a controlled water tank where i could adjust the temperature, put the sensor in and measure it's resistance across a range of different temps. After that it would be easy to just compare that data to production ones, there's tables for that.

either way, i'm now absolutely confident $150 is unreasonable and at $63 the accelerator wins hands down.

 

there is no need of resistence or other wirings
using the appropriate NTC inside the original IAT
i got better results and the mod is completely hidden

 

I saw what you did, very cool. The problem with your design is that the NTC resistor(s) you added aren't out in the air at all and will read a tad warmer than the actual IAT sensor, they may also make the bike overly rich under 0 degrees Celsius. Is any of that actually a real world issue? Not really I bet that way works just fine for the most part.

Oh and Digital, don't worry I didn't pay full price, only reason I bought it in the first place was so I could review it.

 

great info!! glad i didn't spend all that money for it.. but sad that you did and now you have thrown it all away just to give us this great insight!!
bravo my friend!! BRAVO!!

 

my iat mod produce a 23°C offset (from 0°C to 40°C), no problem at all till now...
maybe it'll be better when i remap the ecu restoring original iat (work in progress)

 

Interesting im also into boosterplug would try to do this.

 

/geek over and out.

who was that masked man? . .. "with a slide rule in his hip pocket?"
again, you're a prince. Still trying to power my EVO and haven't finished my plate lighting either, but saved your input

 

maybe it wil tell more on the spcs of the ntc used in de boosterplug.

What will happen if we replace original ntc witch is 4k7 or 5k type, for a 6k8 version or higher one[?]

http://www.epcos.com/inf/50/db/ntc_13/NTC_Mini_sensors_S867.pdf

 

That's cool (seriously) that you reverse engineered this thing and the cost of the parts is always interesting to see. But that said, people have to remember that in addition to parts there is research, development, marketing, construction, and item fulfillment expenses involved in the final real cost.. I think it is great when someone sees a need and tries to figure a fix and then makes it available to others.

 

I don't have a water tank...but I do have access to some temperature chambers that can do -60 to +75. If I were to aquire a booster plug and take it apart, I wonder if that would give enough info to figure out the specs of the NTC?

 

Could it be 12K.

 

The original NTC measures temperature and flow .
Flow measure by cooling down heated ntc witch is heated by tension 5V.
Wrong measurment wil be by serieal resistance.

 

Did anyone ever manage to determine what temp probe is used? It will be much cheaper to build one than to buy one.

 

Andrew, Thanks a lot for the info. I was gearing up for one of these. I think I'll save up a little more and go for the power commander.

 

Hi guys,

I'm new here. I have just started to create my own (customized) boosterplug like device. I decided to approach the problem on scientific way.

At first I started to measure the characteristic of the original IAT sensor. It seems the R25 value (resistance measured on 25 Celsius) is 5K.

Next decide how much fuel do we want to add. Boosterplug says it makes +6%. I think it is a bit too much. I don't want to kill my catalytic converter. Lets say +4% should be enough to smooth the low rev behavior.

If I want +4% more fuel the IAT sensor must say the weight of the incoming air is 4% heavier. So the temperature should be 4% lower. At 0 Celsius (273 Kelvin) should lie 11 Celsius colder air.
At 27 C air temperature this value is 12 C.

To combine the original IAT chart and the required offset chart we will get the new chart which describes the modified characteristics. Finally subtract the original and the new resistance values and you will get the additional serial circuit parameters.

As far as I measured the slope of the BMW IAT sensor is not as steep as the NTC resistors can be bought. So if you use simple serial NTC it results more fuel than expected in the very cold and less fuel in the warm. That could be the reason to use parallel resistor in the boosterplug.

That is the theory and let's see the practice.

I wouldn't want to dig the internet for connectors so I just cut the wire goes to the IAT sensor. I know it is rude but cheap []
I had no NTC at home so I installed a simple resistor first. The value is 2.2K. It is suitable for the 25-30C range. If is just a temporary solution but good for the first test.

The first results are quite impressive. I haven't experienced cut off during the ride before but sometimes the engine stopped after cold start. This phenomenon disappeared. I feel the low rev range is better now as I expected.

Now I am here. I already ordered 2.2K NTC thermistors and continue the tests with different temperature environment.
I try to access to a climate box to make more precise characteristics about the IAT and the modified circuit. I plan to build in a switch temporary to make sure it is not placebo.

I'm getting back later to share the results and plan to make a step by step guide about this modification.

Waiting for the comments and sorry for my English.

 

Good on you Peter. I finally weakened the other day and ordered an Accelerator module - even though it seems I might be able to build something much cheaper using your eventual results. Happy to have done so for the plug-and-play outcome, but good on you for having a go.

 

That is inspiring stuff you're doing Peter ..... best of luck with the project and keep up the posts

 

Others including myself have been down this road for the GS bikes. You make want to check to see if the ST and the GS use the same IAT.

Belinassu ended up replacing the IAT with several thermistors connected in parallel.

I ended up using a 6.9 K Ohm NTC thermistor having a Beta of 4200 connected in series with the IAT. This device is extremely close to the Boosterplug. I have installed one on two F650GSs and another went on an F800GS.

Have fun.

mike

 

OK, so Motorcycle Consumer News USA just tested both of these items on a F650GS and as they are famous calling something "snake oil" when they find it I read it expecting to read exactly that; that these devices are all smoke and mirrors.

Evidently these things actually work and they found the performance of the $150 Booster Plug to be IDENTICAL to that of the $45 Accelerator Module.

What they found REALLY surprised me.

The December issue just came out and is not available free on line yet so I will paraphrase:

Acceleration from stop is smoother.

Shifting is smoother due to no delay in off-throttle response.

Immediate response to throttle rotation unlike stock.

Dyno testing revealed an insignificant 1hp boost.

1800 mile test of each product vs stock revealed a surprising +9%mpg for the Booster Plug and almost +11%mpg for the Accelerator Module, (that's a total of 5,400 miles).

The MPG increase is a result of upshifting sooner as a result of improved acceleration according to the Accelerator Module manufacturer and therefore running a lower average rpm overall, (can't say I complete understand that to be honest).

I will be asking Santa to buy me the Accelerator Module for Christmas! [lol]

Here are the links to both manufacturers:

http://www.boosterplug.com/shop/frontpage.html

http://www.sol2.be/Performance/ENG/Home/index.html

 

Thanks Geoff, that confirms what I already thought, the only thing needed is the resistor, everything else is just to give the impression that product has more to offer as the cheaper solutions. Making one yourself should give the same result.

 

tweaking iat sensor directly produce better results...
have a look to my guide i wrote after i developed it
(i'm only an entusiast, i don't sell anything)

http://digilander.libero.it/belinassu/IAT.pdf

the document is in italian, if you doesn't understand it u need a tranlater, but immages and graphs are simply to unserstand even without a translation...
[]

a simple resistor works only in a precise temperature window...
u need the correct NTC to work in all climatic conditions in the best way.

 

I'm sure you are correct but what I don't know about electronics would fill a Football Stadium! [lol]

I'm just shocked that something seemingly very simple can have as dramatic an effect as confirmed by a VERY skeptical magazine that I have trusted for years.

Have you seen a 10% improvement in fuel efficiency with your solution?

 

i noticed same consumtpion driving faster...
but a friend that use my mod confirmed better consumtion (24km/l instead of 23km/l)

torque improvement let me drive with 6th gear even at 2000rpm
so consumtion matbe is better...

now i get rid of this mod because i remapped directly the bosch ecu changing dramatically the engine behaviour...
if u don't plan to rechip your ecu (+8cv in my case)
IAT mod is the best way to improve engine performances with a cheap trick...

 

you wanna translate that to 'english'?

 

i apologize for my poor english...
i mean that consumption with iat mod is similar to original bike
and it's a good mod even if a ECU mod is a better choice

 

Don't apologise for using a foreign language .... you're a bloody genius .. genio sanguinosa[][]

I translated and did some text editing, there's a pdf I've just done when I can work out how to post it ....

Here http://freepdfhosting.com/6d371e8540.pdf

A stoichiometric amount or stoichiometric ratio of a reagent is the optimum amount or ratio where, assuming that the reaction proceeds to completion, where all of the reagent is consumed, there is no deficiency of the reagent plus there is no excess of the reagent. .... you'll need to know that for the article to make sense

Thank You Andrea .... molte grazie

 

Got the Accelerator Module for Christmas.

Works exactly as advertised...not enough time with it to gauge any change in fuel consumption but for us electrically challenged types it's an easy plug and play upgrade that definitely improves throttle response and also allows smoother upshifts.

Here's a PDF of the Motorcycle Consumer News review:

http://www.sol2.be/Visibility/Images/MCN_1312.pdf

 

thankyou for your translation
i hope to get the time to finish the job on reflashing ecu after camshaft changing and airbox mod...
maybe original 65hp will grow up to 95hp....[]

 

Did not mean to offend anyone. It just that this "mod" seems to be not what the MCN magazine claims. There are engineers over at ADV rider that seem to know that there is no way that fuel consumption can be reduced with these modules. I am only interested in gaining 10% fuel economy to stretch the range on the F800 a bit. A bit more power on this bike means nothing to me. I did not buy it for the power.. It will always be limited there and I'm fine with that..