Megasquirt?

[newaccorddriver]

Don't tell me how good it is. Give me pros as well as cons. I hear the B16 intake gives a little more top end HP at the expense of some low end torque. I'd like to know how true this is, especially if someone else is doing all the dirty work.
That sucks. Who was the culprit, what done stole yur week end?
What is the purpose for removing the slings from your dizzy?

comparing the HEI to the GM DIS or ford EDIS, i think the best part of the HEI is that it uses the sensors that are already on our cars. it requires very little work to actually get it to work, and no fabrication work. i havent researched the gm DIS or ford EDIS, but i believe they both use a wasted spark system, so the voltage on each of those sparks is split in half whereas with the HEI, you get one powerful spark each time.

the main reason why im going HEI is because its cosmetically 'in place'. the only thing i have to do is remove the weights, and lock the shafts together which is alot easier then modifying my car with a crank trigger which both the GM DIS and ford EDIS needs. i know ive got my crank pulley modded for EDIS already, and its easier to setup, but i wanna do HEI to 'inspire' people to do the same thing. its easier to get people to take apart their distributor then to take out their crank pulley, order a trigger wheel, and to have it machined on and welded.

as far as the B16 intake manifold goes, it gives you a better top end at the expense of the low end. for what im using this car for, its not a problem. although i havent actually ran the motor yet, i think its a little exaggerated. when we speed up in traffic, its our feet that control how fast we accelerate. when it comes to the drag strip, our feet are planted to the floor anyways, so we could use the better top end anyways.


i got robbed of my weekend because we 'needed' a sunday shift which i believe is totally BS. my foreman is on a temporary power trip since nobody really wanted to work on the weekend, so he dragged 5 of us into his office and tore us up new assholes. what he failed to realize is that ive been working for a different department for the past week or so, so obviously there was no work for me or anybody that helped me to do

[mikes87lude]

.......the best part of the HEI is that it uses the sensors that are already on our cars, it requires very little work to actually get it to work, and no fabrication work...

....the main reason why im going HEI is because its cosmetically 'in place'.....

So, if you set up our dizzy to look as moch as possable as a HEI dizzy it should work. As far as the internal parts are concerned?

... i havent researched the gm DIS or ford EDIS, but i believe they both use a wasted spark system......

Correct.

....but i wanna do HEI to 'inspire' people to do the same thing.....

You make a stron argument for HEI. It would be much more simple to slightly modify an existing dizzy, and wire up an HEI module. MS instruction manual even tells you how to wire it up.

....i got robbed of my weekend because we 'needed' a sunday shift which i believe is totally BS...there was no work for me or anybody that helped me to do

Sucks to loose a sunday, but overtime is always good when payday comes around.

[cygnus x-1]

I've decided to take the plunge into FI so I've been thinking about how to do the ignition. Using the stock distributor plus an HEI module seems like a good idea but one thing is bothering me. I'm not sure that the rotor is wide enough to allow for enough advance without actually advancing the rotor itself. The mechanical part of the advance actually changes the position of the rotor with respect to the cam. If the mechanical advance is disabled the rotor will then be fixed relative to the cam and I'm not sure the rotor will be lined up with each plug terminal soon enough to get the full advance at higher RPMs.
I was curious about the newer electronic distributors so today I went and pulled one from a '90 Integra. As I expected the rotor is much wider than on A20 distributors. So I wonder, has anyone actually tried using an A20 distributor with MS?

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[newaccorddriver]

im not fully aware of how the timing advance/retard works on a car, so i shouldnt get into this too much and lead people the wrong way. my arguement would be how much actual advance we truly need on a car that goes upto around 8000rpm realistically. our rotors might not be that wide, but i think its a fare amount of space and possibly advance we can get from it. we can also set our base timing on megasquirt as well, so that adds a bunch of advance already.


i guess whoever gets to it first, will be the first to try it out/suceed

worst comes to worst, we can probably salvage the TDC or cylinder sensor on our distributors and somehow run EDIS or GM DIS on it.

[cygnus x-1]

What I'm trying to say is that by locking the mechanical advance part of the distributor down, you limit the amount of advance that the distributor can handle because the rotor has not yet gotten close enough to the terminal to allow the spark to the plug wire. Regardless of the timing of the coil firing, the rotor has to line up with each terminal at the right time to get the spark energy to the plugs at the right time. I'm concerned that the amount of usable advance will be severely limited compared to stock.



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[newaccorddriver]

have you tried fitting the integra rotor onto the accord distributor?

[cygnus x-1]

have you tried fitting the integra rotor onto the accord distributor?

No, but that very thought occurred to me later on. From what I remember of the integra rotor is larger in diameter so I'm betting it wouldn't fit. But you're on the right track. Another possibility is to lock out the mechanical advance such that the rotor is already advanced somewhat to begin with. In a sense you fix some amount of static advance so that you don't need as much adjustable range. This could also be done just by rotating the whole distributor as well.

Does anyone know what the spark duration time is for A20 ignitions?

EDIT: First I said "dwell" but what I actually meant was "spark duration".

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[newaccorddriver]

No, but that very thought occurred to me later on. From what I remember of the integra rotor is larger in diameter so I'm betting it wouldn't fit. But you're on the right track. Another possibility is to lock out the mechanical advance such that the rotor is already advanced somewhat to begin with. In a sense you fix some amount of static advance so that you don't need as much adjustable range. This could also be done just by rotating the whole distributor as well.

Does anyone know what the spark duration time is for A20 ignitions?

EDIT: First I said "dwell" but what I actually meant was "spark duration".

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the beauty of MS is that with the HEI module, you gotta set the base timing, and you need to set it at a certain degree, but from there, i believe you can also set the offset to advance it even more. the only concern with that is that it might be advanced a bit too much at certain points of the map. if we have a base advance of 10 on a stock setting, and we make it 20 degrees instead, there are some parts of the map that might be getting too much advance.

im going to the junkyard on friday, ill see if they have any integra distributors to test fit and compare

[cygnus x-1]

I measured the rotor on my spare A20 distributor, and it equates to about 35 degrees of rotation. So this means that the rotor is lined up with each terminal for 35 degrees of rotation. So there will be at the very most 35 degrees of timing adjustment for MS to play with. At high RPMs it could be even less because of the time required for spark duration and how fast the rotor passes by the terminal. If the coil fires too late the rotor may have mostly passed by the terminal already and the full spark energy won't be conducted to the plugs. Now I'm not sure how much advance range we really need, so it might not be as big a deal as I'm thinking.

As for other rotors, as long as they fit the shaft and everything lines up ok they could be used. Wouldn't have to be an Integra rotor either, anthing would work.

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[cygnus x-1]

I journeyed out to the boneyard today to grab some fuel lines (stupid Ford fuel pump uses these fittings that seem to cost a fortune) and to check out distributors. The 4g Accords and the 90 Integra appear to use the same distributor. I checked out the rotor and it's not compatible with the A20 distributors. I also test fit a 4g Accord dristributor to an A20. It fits but it's really tight because the 4g distributors are huge.
Then I discovered something interesting. 3g fuel injected Preludes also use electronic advance, and the distributors are the same size as the A20 distributors. They have 3 mounting ears and they don't quite line up with the A20 mounting holes but they're pretty close. So I bought one to play with. Now I just need to order the MS.

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[cygnus x-1]

Just a quickie update. I'm nearly finished with the MS conversion. I decided to give up on distributors in general and went with the FORD crank triggered EDIS setup. I'll post more when I get home from work.

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[cygnus x-1]

To back track a bit, I messed around with the 3g Prelude distributor and decided that it's really no better than any of the other distributors as far as modification for electronic control is concerned. It's setup for direct electronic control but you still have to deal with mounting it.

So in the end you will have to do some modifications, whether it be to the distributor or to the crank pulley. So I decided that the EDIS system is really the best solution despite the higher level of modification difficulty. I have a lathe though so it really wasn't that bad. I also don't have AC or PS so that made it even easier.

I have a thread over on PP with more info and pictures:

http://www.preludepower.com/forums/s...d.php?t=268263

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[MessyHonda]

did you mess with a 4th gen accord dizzy also?

[cygnus x-1]

I played around some with a couple F22 distributors at the junkyard. The problem with those is that they are huge and clearance with the thermostat housing is an issue. It could be done but would be very tight. If you really wanted to stick with a distributor I think a 3g Prelude one would be easier since its the same size as the 3g Accord ones. And 3g 'ludes are still somewhat common.

For the trouble though I still think EDIS is the way to go. I just got the car running last night and let me say, the capability of the Megasquirt with EDIS is unbelievable. You can tweak ignition timing and AFR at any RPM and manifold pressure; WHILE IT'S RUNNING! And see and hear the effect on the engine immediately. Incredible. Almost scary.

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[MessyHonda]

I played around some with a couple F22 distributors at the junkyard. The problem with those is that they are huge and clearance with the thermostat housing is an issue. It could be done but would be very tight. If you really wanted to stick with a distributor I think a 3g Prelude one would be easier since its the same size as the 3g Accord ones. And 3g 'ludes are still somewhat common.

For the trouble though I still think EDIS is the way to go. I just got the car running last night and let me say, the capability of the Megasquirt with EDIS is unbelievable. You can tweak ignition timing and AFR at any RPM and manifold pressure; WHILE IT'S RUNNING! And see and hear the effect on the engine immediately. Incredible. Almost scary.

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ok get in a box and come over to do the same set up on my car....i saw the pics over at PP...and its crazy.