Guys,

There is am available plug and play unit that goes onto the Mass Air Flow. it gives the car an additional 40hp. they plug into the mass air flow, and it foosl the ecu into giving more power.

they were popular when bmw 335's came out. i know for a fact that these are really bad for our cars, but i dont know the actual reasons why.

can any of you smart guys explain to me why these plug and play devices are bad ?

 

Its bad because you want one! On our cars it connected to the map sensor not the maf. on the 350z and other cars it did the same and you had a port that you could hook up to a laptop and do some tuning Think they are call split second box?? It is a bandaid and with the right tool for the job now available why roll the dice?

 

Being around this board for as long as you have you should know better.. thats totally newbie question 101.. lol

 

are you guys nuts ?
i am debating this subject on a another forum. i know its bad, but i need to prove why. meaning, i need technical data.
I have a UMW tune on my car (k24s, 5 bar etc etc) , and it holds 1.2 bar on 93 all day. I need to explain to the members why the split box is bad.

 

this is getting really funny now because the other forum thinks these split boxes are good because i havent supported them with data as to why theyre un safe, but you guys are reprimanding me because you actually think i secretly want a split box... im cracking up here

 

Tricking the ECU into incorrect MAP values sounds like a bad idea to me. Especially on a forced injection car where the pressure is key to engine performance and safety.

 

MAF and MAP clamping - that some O.G euro-ricer methods.

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Euro ricer? Never heard of such thing...

 

It overrides the sensor from sending true values. the safety's in the uce are overrode too

 

I would think there would be long term side effects. I am not even close to being an expert - but I would think if it is adjusting timing and fuel richness based on the airflow it is receiving, but in reality something different is coming in - then you could basically be getting too rich or lean fuel all the time as well as pre-detonation due to timing not being ideal for the fuel mixture.

ECU tunes are taking real input data and adjust the engine operation accordingly. Whether factory or not - the ECU must take inputs and adjust engine operation accordingly. Screwing with the inputs by altering the data - sounds pretty scary.

 

I'm thinking this adds power by making the engine run leaner. Essentially telling the ECU there is less air going in than the sensor actually sees. This may make more power, but is a super cheesy way to do this.

As someone said, why not get a real tune that runs more boost, closely controls A/F mixtures and timing and leaves all safety systems intact?

 

I think you all need to read into the data more. The cars in question are primarily the new 335i BMW with a considerably more advanced ECU (presumably) than our 8 + year old cars. From what I recall, it raises boost, but does not affect the ECU's ability to adjust timing and fuel accordingly. There are many 335's running around with this type of tune for a long time now with no issues. While it may not be so easy with our cars, it has been proven to produce reliable power gains in those cars.