Jonas Olhssons BMW 1602
News
2007-08-20
We had our first tuning session with the car on the road tonight. As I expected the low load was pretty much impossible to get right with the basic Speed-Density approach and I can't use Alpha-N either because of the fact that this engine uses a turbo. It's the range 2000-4000 rpm that is especially hard. One can tune the VE map to work driving up hill, going down hill the same load site is used which makes it run pig rich. If it wasn't for the CDI ignition box we would've fouled a few plugs.
Any suggestions to a better approach to tune the low load with the feature set we got now ?
2007-08-03
Engine has been started, we had to add the R30 pull-up resistor because it was not mounted (I assembled and built this system myself) but after that the trigger worked. MAP is steady, about 85 kPa @ 1500 rpm idle. As expected this engine needs lambda 0.85 (or at least below 0.90) to idle properly. This engine could _really_ use mappable fuel injection angle to get a reasonable idle and low load quality, or at least development should be pushed towards Alpha-N with pressure compensation.
The engine was only warmed up today and an oil pressure problem appeared that must be resolved before any more is learned.
Engine specification
- BMW M10, 2.0 litre crank, stock rods and Mahle forged pistons
- Schrick cam shaft (300+ degrees duration)
- Individual Throttle Bodies (50 mm)
- Ford Motorsport 1600 cc fuel injectors, 5 Ohm impedance
- Run in saturated mode with no power resistors and a 30 V TS diode on the flyback wire
- Stock distributor with heavy duty coil and MSD 6A CDI box
- Honeywell GT1 Hall-sensor on crank (and eventually cam)
- I am interested to see how you do with the 1600cc injectors, when you have it running good I'd like to see the injector settings if you wish to share. I have a subpage for injector settings here: MembersPage/KevinBlack/InjectorSpecDatabase
- I will share the settings, but the parameters are _very_ hard to find since the VEMS firmware currently lacks the vital timed fuel injection function. Without that it is not possible to get good enough idle quality to get repeateable and discernable results. We will not focus much time to get good idle quality on this engine due to this.
MembersPage/PhatBob Just a few questions...
When are you injecting? It sounds like you're injecting when the inlet valves are open.
What PWs do you see at idle?
Why are you not running power resistors?
What is your req_fuel and VE values at idle?
Why are you using such huge injectors on such a small NA engine?