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Old 10-16-2009, 05:05 AM   #1
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Question Sequential ign OR sequential inj?

I want to do some research (and make a sperate thread about that - so that the DIYPNP thread doesn't go to crowded with side-topics) bacause it seems the DIYPNP has to less I/O ports (until there is a I/O extender board) to go sequential ign AND sequential inj and run boost/fans etc.

So I have to skip on ign or inj - what would anyone recommend (and why).

Any help appreciated!
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Old 10-16-2009, 05:35 AM   #2
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Injection with out a doubt. Smoother, better MPG, leaner idle AFR's, infact leaner all over non boost areas.

Ignition will allow you to run a stronger spark, which is great if your running high boost, but if not....
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Old 10-16-2009, 10:52 AM   #3
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Wasted spark with sequential injection would be better than COP and 2 channel fuel.

Ken
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Old 10-16-2009, 11:13 AM   #4
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O.K. so it will be sequential injection first then...
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Old 10-16-2009, 11:46 AM   #5
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I see both as a waste since I'm in boost like 90% of the time.
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Old 10-16-2009, 02:02 PM   #6
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Not sure if sequential has much benefit either. Better mpg is very doubtful, marginal at best. Maybe if startup is better with it, I'd consider it (startup is a bitch on a 99 on stock sensors).
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Old 10-16-2009, 04:41 PM   #7
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Sequential can give much better low-load tunability, and much better throttle response tunability.

For example, with sequential you get all the benefits of running 4 squirts per cycle (mainly throttle response) with none of the disadvantages (low PW tunability issues at low load fighting with opening time, and if your injectors are sized just large enough for the fuel requirements, you won't be pushed over the edge of safe duty cycle at high load).

You also get to set the injection timing to squirt at the optimal time. This can lead to better fuel vaporization which means you don't need as much fuel to run well. This lets you pull some fuel in the idle and cruise areas, and can improve fuel economy significantly (depending on how far off the timing is in the first place).

Finally, using wall-wetting accel algorithms is much easier with sequential, and wall wetting accel algorithms produce better fuel economy and drivability as well (I'll have to dig around for my "well tuned" EAE example... it shows a car I tuned autocrossing. The driver is usuing the throttle as an on-off switch, and AFR is almost flat instead of having the usual spikes and dips that are associated with accel and decel).

No, sequential will not help max power, but it will help a lot in drivability and tunability.

Ken
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Old 10-16-2009, 04:46 PM   #8
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this may be something for me to tackle in the future. subbed.
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Old 10-17-2009, 04:55 AM   #9
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Hi Ken,

thanks for the explanation. I haven't even tried to tune the EAE up to now, because this seemed really complicated to me with all those variables to change...

Is there an "easy" explanation? The thread at msextra is extremely big and not so easy to pull put the important information...

Greets
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Old 10-17-2009, 10:07 AM   #10
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There is a relatively easy explanation in the ms2/extra manual. To really tune it you have to be able to really grasp what is going on in your engine though.

EAE lets you tune just how much fuel the MS thinks is going into and out of the fuel puddle. In cases where you go lean, it is because the MS thinks more fuel is coming from the puddle (or less going into it) than there really is, so you tune accordingly. If you go rich it is the opposite. You just have to follow the manual looking at each situation and tuning for it. It is a bit harder to tune for most people than regular AE, but tuned properly (with a very slight amount of normal AE for the quick blips) it can really help drivability. Generally the car will drive as well as or better than OEM, and hold the AFR almost completely stable.

Ken
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