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Do I Need a MAP Sensor?
scootz - 8/11/11 at 07:10 PM

I've been going through all the sensors that the BMW bike engine came with and I'm surprised there's no MAP sensor... just an Air Temp Sensor in the airbox.

I'll be bastardizing the OE airbox to suit my frame... is it worth adding a MAP sensor?


MakeEverything - 8/11/11 at 07:17 PM

Depends if you have anything to plug it into!


theduck - 8/11/11 at 07:22 PM

What BMW is it? Both of mine have had MAF sensors bolted to the airbox.


scootz - 8/11/11 at 07:26 PM

quote:
Originally posted by MakeEverything
Depends if you have anything to plug it into!


Yes... I do (or rather, I will!).


scootz - 8/11/11 at 07:27 PM

quote:
Originally posted by theduck
What BMW is it? Both of mine have had MAF sensors bolted to the airbox.


2009 HP2 Sport... it's just the air temp sensor in my airbox.


matt_gsxr - 8/11/11 at 07:31 PM

What ECU are you using?


scootz - 8/11/11 at 07:36 PM

Most likely a DTA S80.

[Edited on 8/11/11 by scootz]


T66 - 8/11/11 at 07:50 PM

If the BM has an airflow meter no map sensor is needed, if theres nowt in between the air filter and the throttle body measuring whats coming in, then there will be a map sensor or the other way is using the throttle position. Theres another way of measuring and I cannot recall how it works Scott. (alpha N)


Is there a sensor plug on the throttle spindle ?


If your going to use a DTA - you can use map as load or throttle , no doubt the mocal will do the same, so it might not matter at the minute until you decide what setup etc.


When you coming doon the toon ?


scootz - 8/11/11 at 07:55 PM

Was just thinking about tootling down to see the Fiat... will keep you posted!

No MAF sensor on the bike... just the Airbox Air Temp, Throttle Pot, Idle Actuators and Lambda's.



matt_gsxr - 8/11/11 at 07:56 PM

You BMW engine and ECU's are alien to me.

So, thinking aloud. No MAP sensor, and no MAF. Therefore the stock ECU must be running alpha-N?


My guess is that the MAP signal will be pretty lumpy, but when the guy tuning it wants to use the signal from the MAP it will be better for him to see its lumpy than waste time discussing it. It might be that a MAP signal is useful at low engine speeds.


If it were me I'd run the stock BMW ECU and not bother with a MAP sensor.


matt_gsxr - 8/11/11 at 07:59 PM

quote:
Originally posted by scootz
Was just thinking about tootling down to see the Fiat... will keep you posted!

No MAF sensor on the bike... just the Airbox Air Temp, Throttle Pot, Idle Actuators and Lambda's.





Having seen that I'd definitely be running BMW management. If it has 2 lambda probes and 2 det probes then it must have some intelligence and so surely it will deal with the small changes from a modified exhaust.


scootz - 8/11/11 at 08:15 PM

Thanks Matt. Unfortunately the BMS-K ECU is linked to the bikes 2D Dash via can-bus and is notorious for throwing hissy fits when a component is missing (and I can't afford to buy the lot).


T66 - 8/11/11 at 08:23 PM

Like Matt says - will be worth giving it a go using the beemer ecu first, if your not planning anything else other than an exhaust change , which in reality isnt going to be much more/less than the bike one. Is everything else staying stock ?


It doesnt look like the BM is measuring the air into it, so is using throttle position & rpm to manage the fuel/ignition


Without getting my book out alpha n is - A for throttle angle & N is rpm - best go check now methinks.





Just read your last post - How does that price compare with a DTA ?

[Edited on 8/11/11 by T66]


theduck - 8/11/11 at 08:29 PM

Oops thought you were talking BMW cars not bike...


scootz - 8/11/11 at 08:52 PM

The only second hand BMW ECU / lockset that I can find is £900... £2k with with the dash (which I suspect I would need to have any chance of making the ECU work).

I think a DTA S80 and a Race Technology dash will do me!

[Edited on 8/11/11 by scootz]


T66 - 8/11/11 at 08:59 PM

Makes sense - and its still cheaper.


scootz - 8/11/11 at 09:09 PM

It should work out about £500 less to go aftermarket Ivo. Not a huge saving, but at least I know that the S80 / RT dash will work and that I will find someone to map it.


matt_gsxr - 8/11/11 at 09:50 PM

Understood. That is a bit of a pain for you.

My guess is that you won't end up being able to use all those sensors with after market ECU. I guess it just means you have to make sure you always use good petrol, or accept slightly lower tune. But what you say does make sense.

Shame you can't get the stock ECU hacked.


scootz - 8/11/11 at 10:01 PM

It would be great to get the use of all the sensors, but I guess I can live without the Cylinder Temp and Knock sensors (the S80 allows for two Lambdas).

I guess I could hook the cylinder temp up to a spare dash channel just to keep an eye on things and I can use one of the Phormula Knock Sensor kits to map it then monitor it.


nz_climber - 9/11/11 at 04:11 AM

Is it possible the ECU has a built in MAP sensor? I know some after market ecu's do and just have a vacuum line going to the ecu along with all the wires.


scootz - 9/11/11 at 10:35 AM

Could do... I've not seen one of the BMS-K's in the flesh.