BMW 3 series E21 Turbo



After blowing headgasket and radiator at extreme boost and advance (mean 50deg at 2+bars), the car has been rebuilt with normal (8-9:1) compression instead of ~6.5.

Now it's making power at normal advance values of 15-20degs.

It was working fine for a few months of normal usage, but a few weeks ago one of the injector drivers blown. (Always on)

I've checked wiring, found nothing strange and remapped this injector channel to a free output, now it's running fine again.


Car is started and barely tuned with firmware 1.1.18

Boost pressure is 1.2 bars.

The whole ignition table is strange, car NEEDS very large values, e.g. 40 degrees at boost.. I suspect that timing is incorrect. - I have the same things on some cars that i've made, did't know why. Although the cars works good. But strange.-FERO

(However I strobed it at idle and seemed correct to the mark)



Project goals

- 300+ peak BHP

- reasonable daily driver

General hardware

- M10B20 (2000ccm) 4cyl 8v engine

- T3/T4 hybrid turbo, external wastegate

- big FMIC

ECU-related hardware

- custom 60-2 trigger wheel setup with VR sensor, missing tooth is 120 degrees BTDC (copied from M40 engine, the source of the wheel)

- 72lbs low imp injectors

- later motronic IAC valve instead of old mechanical one

- big throttle body with TPS potmeter. (from M50 2.5 24V)

- webshop IAT install with epoxy

- Ignition coil block from later M44 engines. see MembersPage/GergelyLezsak/MFortyFourIgnition

- EGT sensor bung in cyl4 exhaust runner

- WBO2 sensor bung in exhaust after turbo


4 x Power-resistor (6R8,50W) = 5888HUF

1 x EconoSeal?36-Wire side () = 4195HUF

2 x Sealed sensor connector () = 2984HUF

pincount 2

Sex pair

1 x K-thermocouple connector (K) = 3190HUF

mounting-style flying loom

Sex pair

1 x Wideband connector () = 2186HUF

With wire without wires

1 x Wideband O2 sensor (LSU4) = 19519HUF

1 x EGT sensor (K-type) (2x90mm) = 16249HUF

Size 6mm

1 x LCD4x20 (LCD4x20) = 5949HUF

Color green

1 x Econoseal18-Wire side () = 2487HUF

1 x Assembled v3.3 controller (v3.3) = 142353HUF

ignition driver 6+2

secondary_trigger HALL

primary_trigger VR

PowerFlyback? no

mounting-style no-screws

MAP connection 400kPa onboard (6/4mm pneumatic)

Knock and EGT yes

LCD and PS2 yes

1-wire interface no