Cheap, simple, non-factory FI solution, parts, etc..., Type IV - This oughta be fun... Options

[Rick_Eberle]

Spell it out for me. Does a vacuum line have to be plumbed to the MS ECU then?

Exactly.

Which is why I think McMark likes the MicroSquirt. The MegaSquirt would need to be installed in the engine bay so the vacuum line isn't too long. The MicroSquirt can be more remote if desired.

-Josh2

That is more like it...I did not know that.
I would go for the microsquirt in that case...you can get the ECU inside the passenger compartment to keep it safe and dry.

Rich

No, Megasquirt does NOT go in the engine bay. You run a vac line to it. In my case, the ECU is in the console under the dash, and the vac line runs as part of the wiring loom for it. The length of the line makes very little difference.

[Rotary'14]

Spell it out for me. Does a vacuum line have to be plumbed to the MS ECU then?

Exactly.

Which is why I think McMark likes the MicroSquirt. The MegaSquirt would need to be installed in the engine bay so the vacuum line isn't too long. The MicroSquirt can be more remote if desired.

-Josh2

Just some FYI,, you can add a remote MAP sensor to the MegaSquirts,, any one of them. If you do add an additional one, the barometeric correction can be constantly monitored with the onboard MAP. vs Barometeric correction only on key on, one time. Ive read that a really long vac line does not cause a significant delay in your MAP signal.

-Rob

[Gint]

Excellent... thanks!

Wait till you see what I have for a question tomorrow. (IMG:style_emoticons/default/wink.gif)

I found this to be a helpful explanation of Alpha-N
http://www.bayareamotorsport.com/alphan.html

[McMark]

I also like the MicroSquirt because it's sealed as well, so it can go in the engine bay.

[Gint]

New questions generated from yesterday's dicsussion:

• Does anyone have any pics of a MS1 module built up? And in particular the vacuum port for the MAP sensor?
• Can MS1 receive an input rpm signal from say, a Mallory or any other ignition that it's not controlling?

Today's theme is injectors. Low impedance, high, which is which, preferred, etc...? And if memory serves me, D-Jet are low impedance, yes? Are all of the stock 914 injectors low impedance (or high if I have this backwards)?

TIA (IMG:style_emoticons/default/wavey.gif)

[jhadler]

New questions generated from yesterday's dicsussion:

• Does anyone have any pics of a MS1 module built up? And in particular the vacuum port for the MAP sensor?
• Can MS1 receive an input rpm signal from say, a Mallory or any other ignition that it's not controlling?

Today's theme is injectors. Low impedance, high, which is which, preferred, etc...? And if memory serves me, D-Jet are low impedance, yes? Are all of the stock 914 injectors low impedance (or high if I have this backwards)?

TIA (IMG:style_emoticons/default/wavey.gif)

Gint,

I think a whole lot of questions can be answered at diyautotune.com

They've certainly got pictures that will show you what and where the vacuum port is.

-Josh2

[McMark]

You can see the little black vacuum port in the foreground. This is not the only layout, so there are some that don't look exactly like this. But this gives you an idea of how it work.

MS can get a signal from a Mallory or other ignition system, but it's a DIRTY signal. I was absolutely blown away when I saw a crank fire signal compared to all the nasty tach signals I had been used to. People are using tach signals to 'feed' their MS and it works. I wouldn't recommend it to anyone since it's just another source of possible hiccups and headaches. And crank fire is so easy to do.

All stock 914 injectors are low impedance. All modern FI systems require high impedance. You can 'tweak' the stock injectors to work by installing a resistor pack inline with the injectors to 'fake it'. Which works fine, but I don't like having that extra piece of electronics hanging out somewhere. The resistors get quite hot. I have a source for high impedance injectors that fit stock manifolds, but they're well out of your initial budget.

[Gint]

Gint,

I think a whole lot of questions can be answered at diyautotune.com

They've certainly got pictures that will show you what and where the vacuum port is.

-Josh2

I sure that's probably true. But where's the fun in that. (IMG:style_emoticons/default/smile.gif) I'd rather chat it up with my pals here. And I'll bet there are a good number of people here on World with more than a casual interest in this thread.

I appreciate the feedback guys. Maybe we'll get a EEType ((IMG:style_emoticons/default/laugh.gif) EE, ET, Etype) to tell us how the standard tach signal could be filtered and cleaned up a little. It may even be pretty easy.

This post has been edited by Gint: Jun 17 2009, 07:07 AM

[McMark]

Maybe we'll get a EE to tell us how the standard tach signal could be filtered and cleaned up a little.

(IMG:style_emoticons/default/lol2.gif) Jeff Keyzer was who pushed me to go crank fire. I'll send him a PM and try and get him in on this chat.

[Gint]

Maybe we'll get a EE to tell us how the standard tach signal could be filtered and cleaned up a little.

(IMG:style_emoticons/default/lol2.gif) Jeff Keyzer was who pushed me to go crank fire. I'll send him a PM and try and get him in on this chat.

Perfect... (IMG:style_emoticons/default/beerchug.gif)

[mightyohm]

Mark summoned me so here's my $0.02!

As Mark and I found out, MICROsquirt was not made to accept a straight coil trigger signal on the tach input. We ran into a lot of problems with this, including actual physical damage of the Microsquirt due to the high voltage pulses that are present on the "low voltage" side of the coil (the primary). After messing with various resistors, capacitors, and other stuff for a week, we gave up, and that's why Mark is now an advocate of crankfire ignition.

MEGAsquirt, on the other hand, supposedly can handle a tach signal directly. However, I don't recommend it for a couple reasons:

1. You are introducing a bunch of electrical noise to the Megasquirt by plumbing a very noisy ignition coil primary wire into the MS box. From reading the MS forums this can be problematic.
2. It is very clear that the MS community in general has moved away from direct coil triggering, probably because of #1. That isn't to say you can't make it work, just that you are going against the technical evolution of the MS FI system. It seems like everyone is using crankfire now.

My Megasquirt setup, which has been running flawlessly for over 4 years now, uses a setup that avoids a lot of the problems with direct coil triggering, but without using crankfire. I added an MSD ignition to the car, and I trigger the Megasquirt off of the 12V tach output terminal on the MSD. The MSD tach output signal is very clean and free of a lot of the ignition noise you get by hooking directly to the coil. This allows me to get a good tach signal without resorting to crankfire. I am essentially using the MSD as a buffer for the tach signal, plus I get the benefits of CDI as a side benefit.

You could probably use another brand or model CDI style ignition as long as it has a tach output pin like the MSD.

That's not to say that we couldn't come up with a circuit that would be cheaper than the MSD and accomplish the same buffering effect, but in my case it was the easiest option since it uses off the shelf parts.

Hope this helps...

[jmill]

I'm loving this thread. (IMG:style_emoticons/default/piratenanner.gif)

The only reason I'm not jumping into FI is that it's my understanding that MAP and MAF limits you to one intake and your cam profile. Alpha N seems ideal for big cams and multiple intakes but you need to program everything off of a TPS. Is there an easy way to run a crazy cam and multiple throttle bodies without being a fuel programing wizard?

[underthetire]

Again, forget the MS1. Go MS2. If you plan on using stock injectors, the price of the large resistors required on the MS1 to raise the impedance will offset the cost. As far as the direct coil hookup, mine works ok, but I do think there is noise in the tach line. I am currently changing to a shielded cable for this which should eliminate the noise until I can pull the engine to do my crank trigger. I run my MS2 in the engine bay, but I don't drive it in the rain. A plastic cover would be nice to protect it however.

[mightyohm]

You can do it with Megasquirt, and people do. There are lots of ways to deal with big cams, and it all comes down to how much time you are willing to spend learning about EFI and playing with all of the settings.

I have experience running what I consider to be a pretty wild cam (70-90kpa vacuum at idle), and the only side effect was a choppy, unruly idle. Drivability above idle was fine. This was with the same MS setup I have run on a stock 1.7 and a mild cam 2056.

[underthetire]

Multiple throttle bodies no problem, just one TPS though. You would need to make sure the opening and closing are in sync. I don't see a big problem with a crazy cam myself. You set up base and max vacuum anyway. A wideband o2 sensor would make fuel programming very easy I would think.

[jhadler]

I'm loving this thread. (IMG:style_emoticons/default/piratenanner.gif)

The only reason I'm not jumping into FI is that it's my understanding that MAP and MAF limits you to one intake and your cam profile. Alpha N seems ideal for big cams and multiple intakes but you need to program everything off of a TPS. Is there an easy way to run a crazy cam and multiple throttle bodies without being a fuel programing wizard?

I think with multiple intakes, as long as you run some form of vacuum plenum, and it doesn't have to be large, the MAP sensor can read from there. Then you're getting the average from the multiple intakes.

If you're running ITB's, drill and tap the manifolds if the throttles don't already have vacuum ports, and connect them all to a vacuum plenum or reservoir.

Granted, I've not done this, but it seems like it would work. Or... Am I way off base here?

-Josh2

[Gint]

Mark summoned me so here's my $0.02!

As Mark and I found out, MICROsquirt was not made to accept a straight coil trigger signal on the tach input. We ran into a lot of problems with this, including actual physical damage of the Microsquirt due to the high voltage pulses that are present on the "low voltage" side of the coil (the primary). After messing with various resistors, capacitors, and other stuff for a week, we gave up, and that's why Mark is now an advocate of crankfire ignition.

MEGAsquirt, on the other hand, supposedly can handle a tach signal directly. However, I don't recommend it for a couple reasons:

1. You are introducing a bunch of electrical noise to the Megasquirt by plumbing a very noisy ignition coil primary wire into the MS box. From reading the MS forums this can be problematic.
2. It is very clear that the MS community in general has moved away from direct coil triggering, probably because of #1. That isn't to say you can't make it work, just that you are going against the technical evolution of the MS FI system. It seems like everyone is using crankfire now.

My Megasquirt setup, which has been running flawlessly for over 4 years now, uses a setup that avoids a lot of the problems with direct coil triggering, but without using crankfire. I added an MSD ignition to the car, and I trigger the Megasquirt off of the 12V tach output terminal on the MSD. The MSD tach output signal is very clean and free of a lot of the ignition noise you get by hooking directly to the coil. This allows me to get a good tach signal without resorting to crankfire. I am essentially using the MSD as a buffer for the tach signal, plus I get the benefits of CDI as a side benefit.

You could probably use another brand or model CDI style ignition as long as it has a tach output pin like the MSD.

That's not to say that we couldn't come up with a circuit that would be cheaper than the MSD and accomplish the same buffering effect, but in my case it was the easiest option since it uses off the shelf parts.

Hope this helps...

Hiya Jeff (IMG:style_emoticons/default/wavey.gif) It certainly does help. Thanks!
(IMG:style_emoticons/default/idea.gif)
Can I use my MSD6AL with my current Mallory dizzy?

[mightyohm]

Gint - Yup, that's the same setup that I have!

[Gint]

(IMG:style_emoticons/default/cheer.gif)

[Rotary'14]

Again, forget the MS1. Go MS2. If you plan on using stock injectors, the price of the large resistors required on the MS1 to raise the impedance will offset the cost. As far as the direct coil hookup, mine works ok, but I do think there is noise in the tach line. I am currently changing to a shielded cable for this which should eliminate the noise until I can pull the engine to do my crank trigger. I run my MS2 in the engine bay, but I don't drive it in the rain. A plastic cover would be nice to protect it however.

I got my resistor pack from an 86-88 Mazda RX-7,, I believe many manufacturers used the cheaper priced low resistance injectors in practically every car made from 84~92. If you find a 4 cylinder,, the resistor pack is perfect for what we want to do, and these resistor packs were designed for this application, so the heat should not affect them.

As far as ignition noise,,,,
I'm not sure of this,, but couldn't one use the signal of a pertronix for an rpm input to the MS? I'm not sure of this so take with a large grain of salt. It would be a cheaper alternative to using an MSD box if it works.

-Rob