megasquirt

Send a PM to Dr.Fiero he built a mega-squirt system for a Turbo V6 Fiero.  Although it worked, I think he eventually gave up on it and went back to the stock ECM with a modified chip, then installed an ignition box that had boost retard and added a rising rate fuel pressure regulator.

         The Mega Squirt idea is cool, but in most cases way over the top for what anyone needs.  The OEM computers on GM cars are actually fairly well designed. The most that is needed is to upgrade to a newer model ECM.  In the case of the Fiero V6 just going to the 7730 ECM is a huge improvement.

      As to the 4.9 I have a stock ECM with a heavily modified chip that works amazingly well.  

itb? Injected throttle body???

If so, I'd use the ecm from a 93-95 chev truck. They are very hacked at 3rd gen camaros, as some camaros shared the ecm.

I like megasquirt, but the gmecms are VERY reliable, proven etc. You just need a few more tools, like an ostrich (moates.com) to tune them, or a prom burner, etc.

If I didn't have the prom burner already there's no question I'd have done megasquirt. I'd only do it for a radical engine change though, like turbo, new style manifold etc, not just to tweak a standard engine.


Chay

AWESOME. That's like an F1 car's induction then.

No i would not need anything special (Megasquirt) if i could get the volume
of each port from valve to throttle blades the same as stock, otherwise there
would be more or less air to suck at idle and it would run lean or rich. At
least thats what i understand.

I think you are headed for trouble. I guess the idea behind single stack is to increase the flow. The tradeoff is that you don't have a plenum to moderate the flow changes. In other words, I think accel enrichment will be very tricky to program.

1) You will still need a single iac valve for the engine. If you try to adjust each throttle valve for idle (IE: Crack them a bit) you will have a bitch of a time tuning them, linkages etc. I had a three carb mercury outboard once and I think tuning a piano would be easier. If you have multiple iac's they very easily could end up fighting each other.

2) Unless you have individual metering (IE: 8 megasquirt systems) I don't see the advantage, except for better flow of course. Each cylinder will be individual. I would guess the F1's use individual tuning to maximize each cylinder.

It may work. It will be a lot of work.


Chay

I guess this is an idea to get around a high rpm restricitive intake? I remember the 4.x guys like the Allante intake, but singles would likely be better for top end. The bottom end may suffer a bit, but I've read it has lots there anyway.

It may be worth the while then.

If the iac's are per cylinder, and small it should work. If they are all the size of the stock size, it will be like moving 8 steps at once. Also, there is the question whether the megasquirt iac driver circuits can handle the low impedance of 8 parallel IACs.

It's not necessary to tune uniqely, but it would give you the max advantage, that's all I'm saying.

I still think getting the linkages to work might be a bit of a nightmare. I had a hard enought time synching 2 tb's.

Chay

Why not just add a tube under each plate, all coming back to a common point.  Then have a valve that feeds to open air.  The valve of course being your IAC stepper motor.

Problem solved.

Dr.Fiero wrote: Why not just add a tube under each plate, all coming back to a common point.  Then have a valve that feeds to open air.  The valve of course being your IAC stepper motor. Problem solved.

...My goodness. It's so crazy it just might work!

I am humbled at how simple a solution that is.

In all honesty, I never even looked at the video.

Still think getting 8 vac lines to self balance would be easier than
getting 8 linkages all to move at the same level. But.... To each their
own.

Just scored a free 4.9 and free intake manifold, fabrication thoughts will start
soon.