Turbo Chip to keep Motronic ECU

[crazymonk]

Hi, I've got a 1989 convertible with a 2.0L m20 engine, i'm not keeping the engine for that long so I've got a really cheap turbo conversion on it now. It's all done in terms of that I've got all the parts, about half way done with fitting, and I've already done an M30 afm conversion and I've got bigger injectors as well with the 325 throttle body. It's come together quite well but I want to run the standard ecu, I'm not looking for huge power, it's all been just a bit of fun, and I won't be running very high boost, but does anyone do or have for sale a turbo chip? and do I actually need the chip? Also would the system work better with the lambda system connected up? I've got the parts but I'm not sure if it would help or not?

[goosiegander]

Best Person to call about a motronic map/chip for your application is Ant at A-tech 01959 534718,

[DmcL]

yes it can be done and plenty of people run reliable turbo setups on M20's with merely a chip made up to suit.

in my experience from what ive seen looking at standard 2.0 and 2.5 files there isnt a great difference between them. the 2.0 file has a hair less fuelling in areas and a hair less ignition advance in areas but a 2.5 chip would run a 2.0 just fine and vice versa.

as for tuned files there would probably be a little more of a difference between 2.0 and 2.5 files tho still not a huge amount. many people sell chips tuned for a 2.5 but advertised as fitting both the 2.0 and 2.5 so not a great deal of difference between them.

im planning a turbo conversion in future and im basically in the opposite situation.. i have the tune sorted (well a starting point anyway) and need the apropriate parts to build the kit. id also have to agree with goosie and say Ant is definately ur man.. im not a trader here and i wouldnt dupe my turbo file anyway as its a direct copy of a name brand file i got from a fellow ECU tuning nutter for educational purposes and to compare with my own stuff.

i will tell u that the tune i have is setup for 7-8psi and with 24lb injectors. that should give u an idea of a basic setup. im sure Gunni will be along at some point and give some better info on boosting an M20, specifically how much boost they will typically take before needing uprated parts, ARP studs, etc, etc. as i think hes done a good few. i havent messed with any boosted M20's yet but i dabble in tuning the stock motronic management so thats all i can really tell u about myself.

also if u are still using the 320i's 2.5 bar fuel pressure regulator now would be a good time to bin it and fit a 3.0 bar regulator from a 325i. a better fuel pump may also be in order.. i had no problem running 19lb injectors on my 325i before i fit a walbro 255lph pump but i personally wouldnt be trusting my OEM pump for anything past 19lb injectors at 3.0 bar fuel pressure.

[Gunni]

As the goal with a ecu is control fuel and ignition it´s primary requirement is to measure fuel and ignition accurately.

I find it funny that tuners of BMW ecu´s run WOT maps. They don´t work on boosted cars. They just DONT.

I´d run a MAP sensor cause it´s the best way to measure air pressure and it has no flow limit.
so as long as your injectors can handle the flow requirements and your ignition coil can handle the spark intensity required to get the burn going well then that is what is important.

MAF conversions are fine for "kits" as they are supposed to be vehicle independent.

[BONNARSKI]

I read somewhere that it's possible to wire a map sensor into the standard Motronic inplace of the AFM, is this true and if so how is it done?

[DmcL]

about to try and get a 1 bar GM map sensor working with it soon so ill let u know how it goes. looking like it wont be too far off what had to be done to run the MAF but well see.

[DmcL]

picked up 2 GM 1 bar (039) MAP sensors. also picked up a Toyota/Denso 1 bar MAP sensor (denso# 100798-2754, toyota# 89420-20250).

with no vacuum applied to either the GM sensor outputs 4.7v from a 5v input and the Denso sensor outputs 3.55v from a 5v input. based on this the GM sensor looks like the easiest to potentially get working with a custom tune as the standard M20 AFM outputs up to about 5v and so does the GM 1 bar MAP sensor.

i also applied varying levels of vacuum to both sensors with the output of one connected to the + of my multimeter and the output of the other connected to the - of my multimeter. they start out with about 1.2v of difference between them with no vacuum but as vacuum increases the difference in output shrinks and eventually goes into the negative slightly. they both seem like they could be used im just not sure about that 3.5v output under no load from the Denso sensor.. dont know if i could work around not having a near full 0-5v range of output or not.