hairbrained EFI idea...

[CobraSix]

Don't anyone steal my idea...okay...so steal it...I just want royalties

Anyways, what about a EFI set up from a 99+ 3.8 V-6 mustang? Its an old pushrod engine, so only 2 valves per cylinder. Similar in size to a 200/250.

I was looking at my wife's mustang and that's how I got the idea. It is a 3.8L mustang. Makes about 197 BHP stock. That kind of power would be real nice in a 65 mustang. It's decent in a 99 (which is about 400lbs heavier then our 65). It is a crank triggered ignition, no conventional dizzy, just a solid state distributor block. obvious 6 injectors.

I was thinking this set up would work great on an Aussie head. make an adaptor for a Throttle body for the end of the intake. Before the throttle body (preferably on the other end of the car or low away from the exhaust, put the intake and MAF meter. Tap the intake manifold right before the head for the fuel injectors. Run a couple of O2 sensors from the exhaust, who cares about the check engine light caused by no cat (if it would even set it off). Hook everything up to the 99 mustang computer.

Other items needed, the crank trigger (or other crank trigger from like MSD) and sensor, the distributor. May have to custom make wires, that would depend on how you set up the distributor.

Think it would work?

Heck, you may be able to butcher the log head up enough to make it work pretty good, especially with mods such as the Offy cuts.

Slade

 

[MustangSix]

If you took the system intact and adapted the distributor, it would probably run ok. You are probably inside the parameters of the ECU as long as you stay close to stock. The wiring is not that complex and you could probably make the hardware fit.

The problem is tuning. The Ford ECU requires a special interface to change the way it operates and is not as "hackable" as the GM ECU. If it sees a condition that doesn't match a predefined mapping, it may go into "limp home" mode.

With all the aftermarket stuff available and with the advent of Megasquirt, I'm not sure it makes a lot of sense to try and adapt a dedicated ECU to a non-stock engine anymore, even for cost reasons.

 

[CobraSix]

I keep forgetting about MegaSquirt...shame on me.

Slade

 

[weeds]

 

[CobraSix]

though after reading, the it seems that Megasquirt can only do 2 banks and can not do real port injection. Maybe I missed something there.

Slade

 

[Anonymous]

It can do batch fire port fuel injection or it can do a tbi style. Your choice.


-=Whittey=-

 

[CobraSix]

Yeah., batch fire does half of the injectors at once.

Maybe I don't understand enough about EFI, but it seems that batch fire wouldn't be as good as true sequential port injection.

Slade

 

[Anonymous]

A GM engineer I chatted with once at eng-tips said sequential pretty much only helps smooth the idle and gain a very small amount of torque below peak. It also helps with emissions. Interestingly enough, he also said that their engineers were firing the injector (that was my main question, injection timing) at the back of a closed valve for good power...


-=Whittey=-

 

[addo]

Why was that? Did it cool the valves?

 

[CobraSix]

So there doesn't seem to be a big advantage of Seq. Port injection over throttle body injection?

It just seems to me that fuel sitting there would start to fall out of suspension, so what would be the real advantage of EFI? Better fuel atomization and a feedback loop from the O2 sensor helping set the fuel?

Slade

 

[Anonymous]

Why was that? Did it cool the valves?

I believe he said it was increased atomization. That conversation was a while ago, though.


-=Whittey=-

 

[weeds]

Some of the following is me thinking out loud. So, of course, if there any errors in the thoughts, please correct them.

I have read that TBI and TPI (GM terms here, it was a GM system I was investigating) really do not differ much in terms of power and economy. TBI has an advantage in low end torque, and TPI has the advantage in top end. But the engines for each are built differently, so that statement compares apples and oranges. So, given the simplicity of the TBI, I would go that route. Especially if you drop it on a log head.

If you install one O2 sensor, which is how MS operates IIRC, it averages the cylinders. Given the airflow characteristics of the turd and a port injection system, then #1 & 6 would be rich, #2 & 5 would be about stoich, and #3 & 4 would be lean. Install a TBI, where the air & fuel are mixed at the throttle body, my gut tells me that the A/F would be a little better balanced. But then again, I had fruit loops for breakfast this morning. On an Aussie head with a more airflow, then the variations in A/F should tighten up a bit.

With a sequential system, the timing of the fuel shot gets more critical and the complexity of the system goes up significantly. Instead of one or two drivers, you have 6. And each shot has to be timed to the crank position. And advanced for variations in RPM.

Me, I'm heading for a throttle body type system. Eventually.

 

[CobraSix]

I guess since the firing order of the 200 rotates front part of engine with back part of engine, you can set it up with 2 injectors (thinking on an Aussie 250 2V head), one on each side of the normal carb mounting spot, and you just have the firing patter on the sequential part to fire half of the injectors at once (megas can do that).

since the firing pattern is 1-5-3-6-2-4, then the sequental that MS is capable would work if you put the 2 injectors before the runners divide.

Is there another option for Multi Port? Would the car run well is you ran 6 injectors to run on the batch setting (all firing at the same time) but run smaller injectors so that by the time you get 6 firings of one injector, you have enough for 1 cylinder? I would guess that may give some start up problems, but don't know if it would be noticable about since the car would still have all the fuel needed within .5 seconds.

Or maybe do the 2 stage sequential it has, running 6 injectors, at 1/3 size. Just making sure that the injectors are firing when the cylinder is on the intake stroke. basically make a bank of three injectors with 1-3-2 and another with 5-6-4. Have the 1-3-2 bank fire, then the 5-6-4 fire, then the 1-3-2 fire, etc. basically, this would be similar to putting two larger injectors before the runners as mentioned before. Just you'll have better fuel atomization with the smaller injectors and closer to the cylinders.

Personally, I would think the second Multiport option would be better then the first one.

Slade

 

[twentyover]

What would happen if you moved the two injectors off the throttle body and placed themin the manifold between 2-3 and 4-5 similiar to a tpi system. Simple to use the factor TB w/ TPS to assist w/ signalling ecu.

Maybe a simple way to get better mixture distribution than with a tru tbi

 

[CobraSix]

Basically, that was what I was trying to describe for the second option.

You said it much better.

Slade

 

[Anonymous]

tbi isnt as good as dpi (direct port injection)
all the cylinders get uneaven fuel mixtures.

dpi is a more precisely fueled setup.

to be honest i would strongly advise to go a delco set up (gm)

i am running one here on my ea.
the delco can be re-configured in anyway u like.

mine is firing the injectors batch fired (153-624) running a single distribitor. as its a factory based ecu they have all the good sh!t such as idle control and closed loop, on some delco ecu's they even have spare outputs. in my veiw they are close to a motec ecu for perfomance.

best thing is that they are cheap.

cheers.joe.

 

[CobraSix]

So, maybe batch fire with 6 injectors would probably be the best way. I kept thinking about the fuel hanging in suspension, but even at 600 RPM, the longest the first burst of fuel would be sitting with batch fire with 6 injectors would be 1/10 of a second.

SLade

 

[twentyover]

I remember the article
http://www.slantsix.org/articles/dibias ... ersion.htm on the slant six board- DeBasie I think was his name-

That's kind of the way I'm heading with the induction on the MGC. I'm tring to come up with a set of European manifolds or, if necessary, i'll sacrifice the downton replica manifolds and weld bungs on for injectors.

While I really like SU's, I like the car to start and drive easily better.

The aformention suggest a MAF system- may be easire to adapt than a speed density system for weird applications

 

[MustangSix]

There is very little difference between the performance of SEFI or Batch fire except in terms of emissions and fuel economy. SEFI just allows a slightly finer fuel control at lower speeds. At above 3000 rpm or so, there is little difference between the two because of the duration of the pulse.

For a better explanation, check out http://www.sdsefi.com/techseq.htm

 

[CobraSix]

yeah, the more I read, the more i realize there is not much difference between batch firing and Sequential. But, if I batch fire 1-3-2 and 5-6-4 as groups, I'll still either need a crank sensor or just fire them all as one batch as opposed to 2 batches. Since it really doesn't make a difference, I supposed 6 smaller injectors batch firing together will work pretty good.

Slade