MembersPage/RxEightRubenThirtySix (2015-11-23 13:05:27)

Ruben's Mazda rotary RX-8 engine in MX-5 track only car:

Engine 13B 2 rotor,

2 Rotor, 2 plugs per rotor, leading/trailing arrangement

6 high Z injectors, 3 per rotor, 2 banks 1 bank 2 primary injectors, 1 bank with 4 secondary injectors staged on rpm/load

4 active coils (LS2 truck coils, 5v TTL singal required)

wheel speed not required

minimum 3 PFET outputs required: 3 solenoids to control intake manifold/ports based on rpm

relay output for cooling fan and fuel pump would also be nice

Single Wideband required, preferred LSU4.9

Dual EGT inputs required (1 per rotor)

Fueling algorithm: preferred alpha-N with realtime barometric pressure correction based on airbox pressure (to eliminate influence on fueling in case of clogged airfilter, ram air, etc)


How much analog inputs are left over?

The rest seems nothing special.


Triggerwheel: stock RX-8 wheel, often called 36-2-2-2, picture of wheel: 55065-viability-megasquirt-application-fi-renesis-rx-8-trigger-wheel.jpg

Can you tell me which VEMS ECU / Round options I need?

Most rotaries installed before were HALL / HALL type,


I read nothing but good about the VEMS ecu and now my 2 specifik questions are:

>-will it work with the 36-2-2-2 wheel?

yes, supported without sectrig, or with sectrig.

> -Will trailing ignition work, if yes, does it have a rpm/load map just like normal ign timing to specify either absolute angle or better, split angle.

Most often 24 tooth wheel is used for rotary + trailing spark.

But 36-2-2-2 should also work. (with the 128 (0x80) in reftooth method, we'll recommend and benchtest config when you publish output wiring plans).


Data output to race technology Dash2 required (serial)

AIM stream is sent via serial port (if enabled).

"race technology Dash" previously sold interface for "VEMS" that simply did not work (Race-tech did not test it), at least not without fw update available later after users nudging.

Later they provided fw update on request. Version of "race technology Dash" should be preferred that uses

interface/fw AIM serial stream on the input (possibly the Motec fw version ?).


I would like to buy a VEMS ECU.

Actually the car has ran fine for 3 years with a kdfi v1.3, which died for no reason (crappy multilayer PCB), I ordered a new kdfi v1.4 but this unit is even faultier when new and there is no support at all. therefore I am sick an tired of k-data and kdfi and I want now a decent ecu where there is support in case needed.