Author Topic: Simple trigger setup  (Read 8073 times)

Offline AMGmercedes

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Simple trigger setup
« on: May 18, 2010, 10:18:17 pm »
I'm using 1.0.73 and wondering how to setup the fuel injectors. I'm using one gt101 with 2 bolts on the dampener and the stock distributor (simple trigger). The motor is a 4 cyl. Should this be batch fired, as in all the injectors at once, or semi sequentially? If it's batch fired do I set the banks to alternate during cranking?   

Offline mattias

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Re: Simple trigger setup
« Reply #1 on: May 18, 2010, 10:37:51 pm »
Regardless of the setup you can (and should) setup the injectors to fire sequentially. If you have cam sync or not is of no relevance, you still get the advantage of lower fuel pulsation problems in the fuel rail and a lower peak electrical load.

I repeat, you don't need cam sync to run the injectors sequentially.

The reason why there is a choice to fire the injectors simultaneously or alternating while cranking is simply because most engines start faster if you spray with all injectors, the intake is dry of fuel and you want to increase the chance that every intake stroke brings in some fuel to the cylinder. Once every 2 revolutions at those low rpms is a long time to wait for fuel.
« Last Edit: May 18, 2010, 10:39:31 pm by mattias »

Offline AMGmercedes

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Re: Simple trigger setup
« Reply #2 on: May 19, 2010, 04:45:59 am »
Thanks! So sequential it is. I'll see how it does on alternate firing while cranking.

So I have my req fuel figured out at 9.82, which I then halved to 4.91 and I'll double the VE amounts. I have a msq file from someone with a similar setup, but I'm only going to use the spark table and lambda from that. What's the best way to start setting up the VE table, as in what values to start with?

Also I've played around with the cranking/warmup window a bit and the car won't really start without about 10% throttle. With 10% throttle it starts up quickly and climbs to ~1,600rpm smoothly over a few seconds then stumbles, drops to 500, stumbles for a few seconds and dies. What are some good general numbers to start with in the cranking/afterstart/warmup page?

Offline mattias

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Re: Simple trigger setup
« Reply #3 on: May 19, 2010, 09:08:50 am »
I encourage you to put that question in your own project thread.

Use  the correct req fuel, that will work better with the newer firmwares which you'll likely end up with. Aside from trigger, injector and ignition output tables you could use my config and start your engine.

Offline z0tya

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Re: Simple trigger setup
« Reply #4 on: May 20, 2010, 01:51:30 pm »
Regardless of the setup you can (and should) setup the injectors to fire sequentially. If you have cam sync or not is of no relevance, you still get the advantage of lower fuel pulsation problems in the fuel rail and a lower peak electrical load.

I repeat, you don't need cam sync to run the injectors sequentially.

The reason why there is a choice to fire the injectors simultaneously or alternating while cranking is simply because most engines start faster if you spray with all injectors, the intake is dry of fuel and you want to increase the chance that every intake stroke brings in some fuel to the cylinder. Once every 2 revolutions at those low rpms is a long time to wait for fuel.

Can I modify the cranking enrichment in 1.1.74 or cranking pulsewidth in 1.1.27, if i want to go from individually to simultaneously (1.1.74), from alternate to all banks (1.1.27)?

Thx

Offline mattias

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Re: Simple trigger setup
« Reply #5 on: May 20, 2010, 05:12:09 pm »
I find that just changing the "crank VE %" is enough.

I tried both methods on my M20 (config in my signature) and while the effective pulsewidth is the same, i.e. the total amount of fuel injected during a 4-stroke cycle is the same with both methods - firing simultaneously will be more effective in getting the fuel in while cranking which results in having to use a lower "crank VE %" than you would use with sequential injection during cranking.

If you don't lower it when changing from sequential injection to simultaneous injection you will probably soak/flood the engine in some situations. I went from 70% to 50% to solve that problem, and it starts faster every time.