evo 8 ecu question that hasn't been asked?

[bcjjones]

I searched and found nothing about this question at all. I found ignition timing but not mechanic.

With running an evo 8 ecu, shouldn't the mechanical timing be switch with the ignition timing? As in the timing should be set with the number four cylinder at TDC instead of the number one? Since the number four cylinder is now the number one with the evo 8 ecu?

 

[LIV4PSI]

Cylinders one and four rotate together. If one of them is at TDC, then so is the other one. Unless I'm misunderstanding something

 

[bcjjones]

But they don't fire at the same time correct?

 

[vr4play]

They do because these cars are wastespark.

 

[fuel]

Cylinder one is still always at the timing belt end of the engine. In the VR-4 from looking left to right across the engine bay the cylinders are ordered 4 3 2 1 while on the Evo 4-10 the cylinders are ordered 1 2 3 4. The engine in the VR-4 and Evo rotate the same way (clockwise) so there is no difference in firing order or pattern, the engine is simply spun 180deg in the engine bay and the sides of the intake/exhaust swapped on the cylinder head. Also as above as far as ignition goes, cylinders 1 & 4 share the same coil (on both VR-4 and Evo) and they spark at the same time despite only one of the cylinders actually being on the ignition/power stroke of the cycle. I'm sure the fuel injection is also batch fired rather than sequential injection too.

 

[gtluke]

Pretty sure it's batch fire too, these aren't real modern machines like an 1986 mustang with sequential fuel injection /ubbthreads/images/graemlins/wink.gif

Most if not all 4cyls are flat crank, so cyl 1 and 4 and 2 and 3 run at the same exact time. Which is why it's like impossible to put the plug wires wrong on our cars. 1 coil goes to outside cyl, 1 coil goes to inside. If you f*** that up, swap the inside with the outside and you're done. Or rotate the CAS 180deg

 

[vr4play]

I think the fuel injection is sequential as in DSMLINK you can adjust individual deadtime on the injectors.

 

[gtluke]

The ECU has individual injector drivers. I think a lot of cars do SFI at idle and then batch at higher rpm's. Because really it doesn't matter.

 

[bcjjones]

But the injector only fires on TDC for the compression stroke correct? It does not fire on the exhaust stroke. So I would still need to find TDC on the compression stroke?

So correct me if I'm wrong again, but the evo 8 ecu is going to fire the number four injector as the number one injector. So if I time it as if I was using a stock ecu and use the number one cylinder to do so...wouldmt the evo 8 ecu be firing the injector on the number four cylinder instead of the number one?

 

[fuel]

^^ no because cylinder #1 on a VR-4 is still cylinder #1 on an Evo. As I said, cylinder #1 is at the timing belt side of the engine and the only difference is the engines are literally lifted up out of the engine bay and turned 180deg when fitted to an Evo - the engine still spins the same clockwise direction and the firing order is still the same.

 

[jepherz]

You're over-thinking it. As long as you wired cylinder 1 injector up to the cylinder 1 injector on the evo ecu as listed in the wiring tables, you're good to go. The only thing that had to be compensated for on the swap was wiring the crank sensor wire up to the cam sensor instead since our engines don't have a crank sensor.

 

[fuel]

^^ they do have a crank sensor - it's built in to the cam sensor housing as there are two wheels and two sensors. The Evo motors just run the cam and crank sensors separately and the timing adjustment is done entirely by the ECU, whereas the VR-4/1G/2G etc CAS does both crank and cam position and you can manually adjust the timing (in addition to the ECU adjusting the timing).

 

[LIV4PSI]

Wrong Fuel. 2g's have a separate crank sensor

 

[fuel]

My bad. I've never seen a 2G in my life and just assumed they ran the single CAS system like the Evo1-3 7-bolts did, although the 95+ RVRs with the 7-bolt ran separate cam/crank sensors.