Accelerator module, must do something?

[mspenz]

Stuck one on a year ago and forgot about it but decided to unplug it today to see if there was any difference! The bike now idles about 150rpm higher and....it seems to be more responsive especially from midrange up

It obviously does something???

 

[Ian J Hartley]

It does. It drops the air inlet temperature by a significant margin, which fools the motronic into thinking it's taking in colder air. I think the motronic enriches the fuel charge slightly to compensate in the open loop range.

I can't remember the exact figures, but when I measured the air temp value with the GS911. Without the accelerator module the air temp was reading normal ambient temp say 21degC When the module was fitted the temp dropped to a value significantly below freezing.

Colder air is more denser than warm air, so to maintain the same fuel to air ratio the motronic would need to pump more fuel. This only works in the open loop, as the Lambda probe will cut back the fuel in the closed loop to maintain the correct emissions value. Irrespective of the air inlet temp.

Anyway I think that's how it works, I'm sure someone will be along in a minute to correct me if I'm wrong.

I think in your case the module may have been over fuelling, in the mid range, which could be why without it you have seen Improovements.


Ian

 

[Ian J Hartley]

Just checked the air temp with the GS911.

Ambient air temp 20degC without accelerator module

ambient air temp -7degC with accelerator module.

So a 27deg difference which is a lot.

Ian

 

[mspenz]

Thanks Ian, interesting information. So do you run with or without?

Mike.

 

[Ian J Hartley]

I run without it. I was a little concerned that over the long term that it might cause damage to the engine.

It only gave me a small boost in performance, but the fuel economy was down slightly. I chose the fuel economy over performance because at the end of the day the standard bike without modification, can beat the pants off a lot of other bikes out there.

Ian

 

[mspenz]

My front wheel was very light and 'skipping' when accelerating hard yesterday, never done that before so the module will stay unplugged for the time being. Cheers

 

[NCR900]

I think one factor to consider is whether you have a de-cat exhaust (eg Remus Y piece). There are two modules offered, for use with and without a cat. I think there's likely to be more benefit when fitted with a de-restricted exhaust. I've just ordered one as my new(er) GS is a twin spark, and the BB Power chip I had fitted to the Motronic on my older single spark GS won't fit (s**t!). The BB chip worked superbly with the Remus exhaust, smoother running, more power, and better fuel economy. Not cheap (about £280 from Motorworks), but really good, so I've ordered an accelerator module for the twin spark to see if that improves matters without spending hundreds. Unless anyone knows a source of a decent 'power' chip for the twin spark at a more affordable price????