Supercharging BMW E90 N46B20 320i 4cyl

[SlavPala4a]

http://www.e90post.com/forums/showth...=supercharging
This is a link to my thread. Please spend several minutes to catch up on my idea because I could really benefit from the brains inside this forum...
The great issue know is on theory how I could manage to fool the original MAP sensor not going in limp mode after sensing boost.
I have just bought MF2 powerful driver and I would also need all kind of advice for additional injector/s setup.
I tried to search something for driving fuel injectors by MF2 but I didn't find even one thread.....strange...
PLEASE LET'S DO SOME TALKING!

[Richard L]

I read your link.

I saw your four- injector assembly (very nice bu BTW, wouldn't it be easier to have them at each runner for better fuel distribution?

[SlavPala4a]

I could buy a spare Intake Manifold and install the injector bosses right at the top of every intake pipe (if something is not well enough or the setup just do not work, I could easily just change the manifold and return back to the original NON moded one). This will make the setup sequential but could you be more detailing on the part: "at each runner". Do you mean I have a 4T engine so every injector sprays individually for every Tact? How could that be adopted via my gadgets and if you could give me a visual example I would be thrilled to see it!

[SlavPala4a]

I am new in the whole tunning field based on practice. I am reading a lot past several years but the theory is "fake" without an actual implementing in the practice.
So just generally speaking, do you think that I could do the job leaving the Engine management to the original ECU until I boost up and from this point upwards tune the proper AFR via MF2 and WaterInj?
Again, let's say my original map is 1Bar...if it is left in the OEM place, will it sens pressure above 1BAR? Will it inform the ECU that something is abnormal?
How should I trick the OEM Map to sens values like original until boost and after that just to feed the ECU with the maximum voltage related to 14.7psi absolute pressure(or theoretically speaking the biggest value that a NA engine with 100% VE could ever reach)?
Many questions...but that is the idea to share

[Richard L]

I think the MF2 can take over from 1 atoms upwards.

There are several ways to stop the OE ECU seeing the boost pressure.
1. By ECU reflash (you need a tool)
2. By putting a MAP sensor clamp. ie, it limits the MAP sensor signal from going above a preset voltage.

I think the second method is easier to do.

I have also notice that you are going to use a PPS system (progressive pump speed) for methanol injection.... few comments below:
1. The PPS system do not have enough dynamic range to cover a supercharged engine. a 50-250psi (pressure change) only give a flow range of 1: x2.3
2. Supercharge has very fast load change compared to a turbocharger. the PPS system is too slow to react to an instant throttle change dus to the rotating mass of the pump motor
3. The meth flow is not linear to pressure change
4. PPS system without an inline valve will dribble after switching off due to the pump running on.

[SlavPala4a]

The idea of my project is not to mess too much with the OEM equipment - if possible NOT at all.
Could you be again more specific on the MAP clamp...should I just search it in Google or? It is probably made with a bunch of resistors, isn't it?

[SlavPala4a]

Here is a picture of the manifold that is used with my engine:

[Richard L]

A good voltage clamp is more involved than a few resistor. Example below:

1 Zener diode based map clamp:
It a low cost solution, a 4.7V zener will clamp any voltage above 4,7V but it is a very soft clamp, ie, it will start clamping from 4... 4.2 .... 4.5V etc. This will effect affect the MAP sensor voltage and your fueling will not be as accurately above 4V.

2. Active voltage clamp:
Using integrated circuit or chip to allow a very sharp and accurate point, normally use ajustable betweem 4.3-5V. Aquamist makes those devices for many companies but not advertised as our normal range.

[SlavPala4a]

Do you think that I should buy a 2Bar Map, from Sierra RS Cos for instance, or I should keep the fuel map 2D for simplicity. In the manual is written that If I am using a supercharger the graphic has steady increasing slope, without any major peaks or drops, so the 2D map will do the trick well enough?
I do NOT have a Throttle Body(TB) that really works as it is supposed. In the Tech Info by BMW is written that my TB will act only if the valvetronic system fails. In a normal condition it will be half opened at idle and fully opened onwards.
I will try to film this statement when I go back home for the holidays.

[Richard L]

I saw the picture of your enigne, where is the Supercharge going to be installed? Are yo going to modified the manifold and runners?

Most of customers (tuning shop and turbno kit manufactures) uses an independent MAP sensor on the MF2 and purt a voltage clamp on the OE MAP sensor.

It will work on RPM only (boost triggered) but it is worth using the full 3D capability of the MF2. A two bar-map sensor is not too expensive, but the result of a 3D fueling system is more refined. Judging the amount of work you need to do get the supercharger to work, it is not worth cutting cost in this.