I'm using the Accelerator module now for several years, first on my R1100RT and now on the F800GT. I can confirm the findings of MCN: engine picks up better at low rpm, is running smoother. For the R1100RT this module was really needed to eliminate the famous "KFR" of this boxer engine. At the F800GT it is just more fun []!
I have measured no influence on fuel economy, not better, not worse.
It is a cheap modification and extremely easy to install!

 

I didn't post the pdf as a 'response' montanaman, I'd nearly done it anyway, I like his simple way of just connecting resistors up in series was then measuring the change

Possibly increased mpg that MCN got was by riding the same way, not taking advantage of the better pick

I find the biggest difference that the f800 has to my other (carbed) bikes is that the throttle doesn't always feel 'connected' when you try to accelerate below 3000

FrankV .. so it really does take away that hole in throttle response then?

 

Which hole ? [][]

 

fuel consumption is better if you drive with hi gear using increased torque...
if you drive using increased power at lower gear consumption is worse, but you'll fell better []

actually consumption is similar to original in normal use...

 

I've saved Thumper710's pdf for future reference and have added it as an attachment.

Thanks Thumper710 and most of all belinassu!

 

After the BMW dealers spent 5 & 1/2 hrs on it, total fuel strip including drain the tank and try another pump, 4 test rides and it still cuts out, I fitted an Accelerator basic unit to my stalling ST ..... it stopped stalling, 2 weeks a 600 miles later it runs perfectly and mpg has risen ......

For what they cost it was a bargain, thoroughly recommend it ..... pity BMW don't fit them, an admission of failure if they did maybe?

 

The reported success of the Accelerator Module is interesting, given the arguments elsewhere that the Bosch ECU adapts its long term fuel trim to compensate after a few tens of kilometres. I fitted one to my ST, only because it was relatively cheap compared with the Boosterplug, and I have experienced rare occasions of stalling. It seemed to make no difference top my bike, but I loaned it to a mate with an R1200R and he says it has transformed the low rev running of the bike (the improvement persists).

A more elegant solution is the AF-XIED (http://sales.nightrider.com/AF-XIED-for-BMW_p_54.html) which intervenes between the O2 sensor and the ECU, telling the ECU the mixture is leaner than it really is (by emulating a modified O2 sensor reading). This allows the user to modify the AFR across the range. Search Advrider forum for lengthy discussion on the matter.

I'm still not convinced either way. Yes, the AF-XIED is an elegant device that I believe works as stated. Whether the Accelerator module is a dud as implied in the Advrider forum, well the anecdotal evidence doesn't support this theory, so maybe there's something else going on, e.g. in the transition between off and on, that the Advrider guys aren't yet aware of.

 

it is not so simple to fool the iat sensor to gain an effective good behaviour of our rotax engine.
i did several trial based on re-calculated effect of different values of NTC on some excel documents...
i built some modified IAT for some friend with F800GS-R-S-ST and F650GS .
some of them having boosterplug or accelerator module or some other cheaper clone...
they told me my modified IAT works better, and the engine performs better...
it's important to use the correct kind/value of NTC for the bike and the setup (exhaust, air filter and so on..)
but in commercial plugs this job isn't done, they sell a version for all and this way of tweaking doesn't optimize the trick.
So lambda sensor will cut any wrong signal from iat cutting performances in the same way...
Any mod on iat sensor give something but only working in the same way of the original sensor ecu could manage this signaling properly.
I prefer to do not tweak lambda sensor, so the only way to do a good job is to modify the software parameter inside ecu BMSK.
Infact torque and power increase significantly even if reprogramming gas engine usually dont lead to as great increase as on a turbo engine...

excuse me for my poor english

 

I am running both an Accelerator Module and the AF-XiED on my F800gs. The Accelerator Module has been on the bike for several years, mainly in an attempt to deal with a low speed abrupt throttle syndrome, while riding off road. I thought it worked OK at the time and seemed to be working 2+ years later.

I read the threads on ADV dealing with the AF-XiED and had a lot questions about the "Adaption" process. How does changing the oxygen sensor signal, which can only occur in closed loop, affect open loop map values?

I bought one and added it to the bike along with the Accelerator Module. I noticed an increase in low and mid rpm torque right from the start. I not sure how it did that, as I was riding in open loop with little time for adaption. I have about 1,200 miles on it. I don't claim it makes more power than it did when first installed, but the engine has gotten smoother and the power increase has widened some what to include a broader rpm range.

Install time is so short you can almost do back to back testing.

Right now I am testing the above with a 17 tooth sprocket, as I thought with my new found power, it would pull the gearing well. About 300 miles with that set up and it seems to confirm what I hoped.

Mileage hasn't suffered. I can still ride Fire roads. Less vibration, Not gearing for the hard core.

 

accelerator uses wrong NTC...
infact who shifted from accelator (or boosterplug) to my iat mod noticed better engine behaviour...
anyway on s-st series the BMSK iat management don't allow the same kind of gain as on the GS serie, but it's a good point to start from.
try with about 15k ntc with about 4500 beta value (this value is mainly important than ohm value to achieve a good work result)

 

Thanks for the quick reply. I haven't found a circuit diagram for your mod here, so can you tell me if the NTC you recommend is connected in parallel with the stock one, or does it just replace it? Also, is a resistor (in parallel or series?) required to modify the response as for the Accelerator module and similar devices?

Thanks,

Fred

 

no resistors or other correcton, only the right ntc should be used IMHO
u shall replace the original sensor with the correct NTC
and make it waterproof if it have not an epoxy coat (wet affect behaviour of ntc curve response)

 

Thanks. I intend to get a secondhand sensor body to experiment on. Fred

 

Fitted an accelerator module 2 weeks age( thanks Marc!!, delivered in 4 days!!) massive difference low down, really smooth even with baffle out on the remus, and increased mpg!!! Happy??? Very!!!!

 

any tweak u fit on a iat sensor works, but only a good tweak achieve the max score (power, torque mileage, throttle response etc..)
in the same way as any food u put in your mounth avoid starving, but with different grade of satisfaction... []

 

Very interesting thread. Thanks to Avboden and Belinassu for the information... I just bought a new GS and I've been deciding on which solution is best. I've got an electronics background and I appreciate the "geek over and out" DIY approach... I read Belinassu's document/translation and it sounds great.

Belinassu, can you provide the proper NTC temperature detector resistance and beta? Avboden, I'm working with a limited internet access here - I presume from the text that the 56k-Ohm resistor is in parallel to the NTC temperature device?

Cheers and thanks in advance!

 

...i wrote it a few post above in this page...[8)]

 

Belinassu, forgive me, "I am just thinking aloud."

From what I understand about thermistors is that they are classified at the resistance they have at 25 degrees C. So a 15k Ohm NTC thermistor is 15,000 Ohms at 25 deg C.

I reviewed your document and what I believe is the resistance vs. temperature chart for the stock IAT (though my Italian is terrible - however I used to date an Italian girl 20 years ago!). According to the chart, at 25 deg C, the IAT gives 5k Ohms of resistance. Now, if we wish to subtract 20 deg C (25-20 = 5 deg C) to enrich the fuel-to-air ratio during open loop acceleration/changing throttle position - we can approximate the curve on the IAT chart to give us approximately 15K Ohms. So, by that logic, you suggest simply replacing the stock IAT with a 15K Ohm NTC thermistor (which will give us the 5k Ohms resistance plus 10k Ohms enrichment adjustment at 25 deg C). The remainder of the curve should stay in balance with the stock curve according to the thermistor beta of 4500. All is clear now! Cheers!

 

you're right...[]

 

^^ the trouble is findind a suitable NTC thermistor with a beta of 4500! I'm familiar with industrial/HVAC thermistors that have a nice stainless 2" probe - but most are either 5k or 10k. I noticed on your threads that you used small ceramic/epoxied thermistors... where would you recommend finding the proper device?

I did go ahead and order the accelerator module just for shits and giggles - if not for anything else, it is convenient to get the EV-1 plugs, which I had little success finding online yesterday. I'm going to break the multimeter out when I get home and do some poking around myself! It will be easier with all of the ground-work done already! We've also have a calibrated temperature bath at work for probes... so I can take an accurate measurement of the resistance vs. temperature chart next time around! Really interesting stuff - if you're into that kind of thing! [][][lol]

Thanks again!

 

there are several online shop for this items... don't be shy []

 

Just chiming in with my recent purchase of a full priced booster plug. Fitted to my new F800 GT at 2400 km, the BP has delivered everything promised, I know you tech heads have figured out the pathway to Eco fitments and all power to you, however, I am at the mercy of info off the web and am totally happy with my results albeit expensive results. Time will tell but so far the BP has transformed my GT into a very tractable machine and the km's are mounting. Have fun.........

 

Quick question for those of you who have the Compact version of the Accelerator Module for the F800ST. Can anyone tell me the model number which should be a tag on the cable? I know someone who has one marked for the R1150 and its not clear if its incompatible with the F800ST.

 

R1150 usa a completely different iat sensor it measure about 2kohm at 25°C f800 sensor is about 5kohm at 25°C
so a good mod for 1150 won't work fine on f800 and vice versa

 

Thank you very much Belinassu.

Tom

 

Just got my boosterplug - I've got a thermowell calibrator at work, I'm going to map the resistance throughout the useable range in about two weeks!

 

belinassu,

I live in Marseille, France, not far from you. Can you tell me where you ordered the 15K Ohm NTC thermistor ? Do you have a catalog number as well? My f800ST has had the problem of the motor stalling. I believe this would solve this problem as well.
Grazie mille!
Roberto