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Help with building your Speeduino, installing it, getting it to run etc.
By dazq
#46024
You should read up on how OEM go about shutting down cylinders for economy, it's a bit more involved than just stoping fuel!

You don't need to stop the spark, firing into a dry cylinder won't cause any harm or loss.

You need to find a way to decompress that cyl else you will lose all your savings in pumping loses
By Modified 3 cylinder
#46028
theonewithin wrote:
Sat Oct 24, 2020 4:07 am
Why would you want to do that though???

As you only have a single injector you will struggle to make it work effectively.

You would need all your offsets and corrections for Injector to be 100% perfect.

Could you explain what it is you are actually aiming for?

WHY do you want to shut down 1 cylinder?
I have a 3 cylinder engine that I want to turn into a running 2 cylinder engine. I will ony need 2 cylinders for my project car, I'm looking at doing.
By Modified 3 cylinder
#46029
dazq wrote:
Sat Oct 24, 2020 6:52 am
You should read up on how OEM go about shutting down cylinders for economy, it's a bit more involved than just stoping fuel!

You don't need to stop the spark, firing into a dry cylinder won't cause any harm or loss.

You need to find a way to decompress that cyl else you will lose all your savings in pumping loses
Thank you for your response.

I have researched how chevy did their v8 down to 4 cylinders during certain driving condition. That is what made me start thinking about doing this project.

Your right, the spark would not be as important. My current car, during deceleration and DFCO occurs. Spark continues and only fuel is cut off. There is no issue with spark occuring during that time.

I have already thought about the cylinder and valve train issues. I have a plan for that, not 100% sure if it will work, but
if i can't get the fuel issue worked out, the engine issue won't matter. This is herdle that I currently at.

I could always use carbs on it, but then I would loose control over the fuel system.
By LAV1000
#46030
Don't know if this is easy to achieve.
Use 2 fuel tables.
1 for running on 3 cilinders.
2 for running on 2 cilinders.
And then use a input to switch between the tables.

But you stil need a valve train modification to shut a cilinder off.
By Modified 3 cylinder
#46031
I need to clear something up, i only want to run 2 of the 3 cylinders . That's why I was wanting info on eliminating spark and fuel to one of the cylinders.
By theonewithin
#46035
You don't need to eliminate anything then.

Just set it up as a 2 cylinder engine.

Job done.

Or maybe explain exactly what it is you are actually attempting to do?

What is the end outcome you are after?
By Modified 3 cylinder
#46036
theonewithin wrote:
Sun Oct 25, 2020 1:27 am
You don't need to eliminate anything then.

Just set it up as a 2 cylinder engine.

Job done.

Or maybe explain exactly what it is you are actually attempting to do?

What is the end outcome you are after?
Wish it was that easy. The 3 cylinder engine, has a piston on TDC every 240 degrees. A 2 cylinder engine would have a piston on TDC every 360 degrees. The spark and fuel would not be timed correctly.

I have stated what I want to do. I have a 3 cylinder engine, the firing order is 1-3-2. I want to try and change the speeduino code so the #2 cylinder has no signal to the injector, while cranking or running. As stated before the spark would not matter if it occurs or not.

I get the fact that this is a unusual project that doesn't seem normal and it isn't.
This is the only way I can put an engine with less displacement in the car.
By theonewithin
#46037
This is easy...

As I already said run it as a 2 cylinder engine.

You can choose oddfire and enter any weird firing timing you need.

You will have to get rid of the intake for the cylinder you are not using though. No way around that.

There is no other possible way of doing this without removing the cylinder not in use's intake from the remaining cylinders as it will scavenge intake charge from the others.


WHY do you need to disable 1 cylinder though?

You still haven't said why you are doing this.

What is the end result you are actually aiming for?

Are you limited because of racing requirements?

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