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1966-2013
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I could mess around with the AFM spring and tell you guys how much you are actually affecting it with so many clicks of the spring tension. (Air/Fuel ratio)
If the stock ECU is in use, the answer to that is 'none' except at idle or WFO, when in open loop, or if you go way to far with spring adjustment, which will kick it back to default open loop as it won't be able to control things in closed loop, so will revert.


@pillowmeto:

I presume you're familiar with dealing with a vacuum balance chamber for use with a MAP sensor then? (the sensor really, really doesn't like that pulsation/surging that occurs when all the intake runners can't be tapped)

Coil packs? So you'll be using a Hall sensor or the like to trigger, or have you something else in mind?

As you say you're used to the motec, and realistically most all of the systems operate in some simular fashion, (measure manifold pressure, measure air and water temperature, known values for injector flow plugged in by some means, proper fuel pressure, crunch numbers, squirt fuel), is there any reason to think you could get close using numbers you already know to start with?

I'm not talking exact obviously, but a decent close start to work off, or at least get it to fire up quicker than a hunt and seek type method.
 

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Discussion Starter #22
Yeah, I will have to build a little stabilzation chamber and possibly a fuel filter inline.

I am looking at using a spica pulley w/ one gear milled off, but am also looking at a toothed wheel.

I should be able to come up with some numbers that will get her to run, and once she runs the 02 sensor lets you fill the list pretty fast, and megaasquirt can learn an engine by using the 02 sensor, it can fill the tables.

The motec uses the same types of sensors but ti is worlds beyod these with 48x24 fuel tables for more than a few sensors, ,you can have a table for just about anything.
 

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I dunno if you've got a chamber size in mind, but I constructed one that is 1 1/4" diameter by 11 1/4" long that lays just nice between the TB's and the water passage on the type manifold you're planning on using.

It'll pull 11 some inches of vac at idle and spans from -4 to around -17 depending on what you're doing with the loud pedal.

I did half consider one of those 'vacuum balls' you see in older Fords that has the diaphram in them to soften pulses, but this seems to be working fine.

Learning and self programming form the O2 sensor.

That sounds hip, but how does it deal with situations that would normally be open loop?

Will it allow for the much richer mixture that real power requires?
 

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Discussion Starter #24
the way it works is you drive the car with it preset in this learning mode and the O2 sensor reading is used to adjust the fuel tables, but I don't think it can adjust the throttle position tables. You drive nice and easy without any sudden pedal movements and it saves what it thinks should be the right values, and also saves the telemetry. When you get home you figure out how long of a lag the O2 sensor has, and just adjust the telemetry for the lag, and the fuel tables will recalibrate.

Obviously this will not be anywhere near perfect, but if your sensors are all working, and you can get the car to idle, then shortly there after you have something that will let it run.

also megasquirt is just so darn cheap

There is also a small handheld controller that can adjust the fuel tables similar to SDS.
 

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Be careful with MS's autotune feature, it has a few bugs regarding unburnt fuel at detonation and causing a richening loop until the pistons melt... It's very easy to get a Spider idling.. These engines are beasts and take just about whatever you'll offer.
 

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I can give you a template for the TPS mounting bracket. You will need a variable TPS, if you haven't put one in already. If you have a local junk yard, try to pull the throttle position device from a Volvo 850. The stock one is only a switch and will not work. And once you take out the stock one, you'll need to figure out a switch for the ignition ECU.. There are a few decisions to be made with these cars.
 

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I use a 5K linier potentiometer with a double pole double throw toggle switch. You tap into the coolant sensor with a series conection, and you can go back to the stock value with the flip of the switch. This way you change the "DUTY cycle" of the injector and get all the fuel you could ever want without raising the fuel pressure. Works great on L-Jet race cars and modified street..........also turbo applications! Dial in the mix you want under boost and turn it on with a Hobs switch. I sell these and you can see them at www.rmlautomotive.com.
Ric Lovecchio
 

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I sell essentially the same thing and use it on my supercharged Alfa (mine is more expensive, complex, and doesn't look nearly as cool). It works pretty well, combined with larger injectors it enables stock L-Jet to handle 10 pounds of boost while still keeping the mixture in an acceptable (but far from perfect) range most of the time. A switch to activate it at a certain point in the RPM range is pretty important or the engine will run way to rich at low rpm.
 

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Discussion Starter #30
I an using Spica throttle bodies and have not decided on a TPS yet. I need to take car of a few things before that step. I am looking at possibly using a universal potentiometer from digikey, or else ill steal something that looks good from a junkyard. I am also boring the Spica throttle bodies larger.

I thought of building a circuit that would add fuel to the Ljet system, increase signal from AFM during rapid throttle changes via TPS added to throttle, but megasquirt just makes more sense to me. I really do hate the warm up circuit on the Ljet.

I remember someone has designed as small handheld device that can manipulate the fuel tables in megasquirt, I think it was on the BB.
 

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It is nice to ditch the CSI and put a nice 2.5" intake pipe where anybody would expect the AFM to be. If you are picking up a TPS at the junkyard, just don't get any that look the same as the stock L-jet one, but it's easier to get one that already accepts a D-shaft. And also, when you get to it:
93+ Volvo 850
-bosch #0280 122 001
-needs reclocking
93 Volvo 240
-bosch #0280 122 001
-lh3.1
-htf, but ideal
92-98 Volvo 960
-bosch #0280 122 001
-needs reclocking
90's Infinity v6
-JECS #A22 625 921
-needs reclocking
91-93 Saab 900 n/a
-bosch #0280 120 300
-lh2.4.2
-needs reclocking
91-93 Saab 9000 n/a
-lh2.4.2
-double check on 16v n/a
-needs reclocking
94+ Saab 4cyl
-bosch #0820 122 004
-trionic
-needs reclocking
-may also include 6cyl

A little harder to find, since the cars are rather new for a normal junkyard (sadly, at least around here).
 

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I need to add a TPs to my spica too. I grabed a TPS pot off a BMW in the junkyard. I just need to ground the shaft some. but I would say use a car TPS it just looks better when done. and they use common Jr. timmer connectors. and they jusy slide on a D shaft. I have thought of also boring them out some. and using a thicker 8mm shaft that is used on everything now so it would fit the normal TPS better then the 7mm shaft. also tap and fit a nipple in the center and mill a notch so I have MAP for idle/low RPM. then go to alpha-N over x RPM where the MAP readings get bad do to venturi effect.
 

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I need to add a TPs to my spica too. I grabed a TPS pot off a BMW in the junkyard. I just need to ground the shaft some. but I would say use a car TPS it just looks better when done. and they use common Jr. timmer connectors. and they jusy slide on a D shaft. I have thought of also boring them out some. and using a thicker 8mm shaft that is used on everything now so it would fit the normal TPS better then the 7mm shaft. also tap and fit a nipple in the center and mill a notch so I have MAP for idle/low RPM. then go to alpha-N over x RPM where the MAP readings get bad do to venturi effect.
BMW used a lot of switch style TPS's. Have you checked yours with a multimeter?
 

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no it is a pot type is is much smaller then the switch type.when I go looking at the junk yard only 1 out of say 20 have a pot.
this is one I found before I used on the Verde
I think it came off a vovo
http://www.alfabb.com/bb/forums/showpost.php?p=248100&postcount=55
the BMW seems to be even smaller but I think the mounts are the same just the plastic is a bit smaller.
 

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It's not so big if you browse on your cellphone :(

The actual size is perfect. It's even smaller than mine and I would love to get this kind.
 
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