12a/13b hybrid
05-30-14, 12:57 PM
#1
12a/13b hybrid
Using 12a irons with 13b gsl-se housing: I know it is a well known build and I don't want to waste anyone's time but I can't find a definative post discussing it?
Can anyone help me out with a good build thread for this?
I have a gsl-se track car and want to rebuild the motor with ported 12a irons.
My main question is I want to maintain the stock EFI. Does anyone have any experience with this? Will I need to get one of those quasi fuel management system units that bump up the signal to the ecu?
Like I said, I have searched but haven't found too much solid information on the 12a/a3b hybrid build.
Can anyone help me out with a good build thread for this?
I have a gsl-se track car and want to rebuild the motor with ported 12a irons.
My main question is I want to maintain the stock EFI. Does anyone have any experience with this? Will I need to get one of those quasi fuel management system units that bump up the signal to the ecu?
Like I said, I have searched but haven't found too much solid information on the 12a/a3b hybrid build.
05-30-14, 02:30 PM
#2
You want to keep the stock EFI? Really? Well I would go ahead and build the hybrid you;re talking about. Then I'd get the RB 4 port lower manifold for weber/dellorto and bolt the stock GSL-SE upper manifold to it. This lets you keep the stock manifolding and TB, and the stock injector rail.
I don't know what a quasi fuel whatever it is.
You would be better off, if wanting to stay with EFI, to get a stand alone EFI computer like a MegaSquirt and do a lot of research to find out what sounds like the best combination of parts for you. Like either sticking with the 6 port layout, or the 4 port hybrid. Then which manifolds, TB, ITBs etc.
I personally prefer carbs so this is the last you'll be hearing about this subject from me. I do like engine builds though. If you have a specific sideplate question or whatever, I can still help with that.
I don't know what a quasi fuel whatever it is.
You would be better off, if wanting to stay with EFI, to get a stand alone EFI computer like a MegaSquirt and do a lot of research to find out what sounds like the best combination of parts for you. Like either sticking with the 6 port layout, or the 4 port hybrid. Then which manifolds, TB, ITBs etc.
I personally prefer carbs so this is the last you'll be hearing about this subject from me. I do like engine builds though. If you have a specific sideplate question or whatever, I can still help with that.
05-30-14, 08:46 PM
#3
Old [Sch|F]ool
I don't see why the -SE's stock injection would care either way. It's AFM based and just spits out as much fuel as the measured amount of air wants. So go for it.
When I made an EFI 4-port 13B by putting 12A end housings and GSL-SE center housing together in one engine, I used a Racing Beat manifold. I figured that making the injectors' air bleeds functional would be a Good Thing, so using a GSL-SE gasket as a template, I used my Dremel to cut a slot, then drilled a hole in the center of the slot, then an intersecting hole that I pressed a piece of 1/4" brake line into. Basically I just duplicated the injection manifold's air bleed passages. The hose gets routed to filtered air upstream of the throttle body.
Of course, I got no PICTURES of this process.. but you can see the chunk of tubing sticking up in the manifold here:
When I made an EFI 4-port 13B by putting 12A end housings and GSL-SE center housing together in one engine, I used a Racing Beat manifold. I figured that making the injectors' air bleeds functional would be a Good Thing, so using a GSL-SE gasket as a template, I used my Dremel to cut a slot, then drilled a hole in the center of the slot, then an intersecting hole that I pressed a piece of 1/4" brake line into. Basically I just duplicated the injection manifold's air bleed passages. The hose gets routed to filtered air upstream of the throttle body.
Of course, I got no PICTURES of this process.. but you can see the chunk of tubing sticking up in the manifold here:
05-31-14, 08:19 AM
#4
I don't see why the -SE's stock injection would care either way. It's AFM based and just spits out as much fuel as the measured amount of air wants. So go for it.
When I made an EFI 4-port 13B by putting 12A end housings and GSL-SE center housing together in one engine, I used a Racing Beat manifold. I figured that making the injectors' air bleeds functional would be a Good Thing, so using a GSL-SE gasket as a template, I used my Dremel to cut a slot, then drilled a hole in the center of the slot, then an intersecting hole that I pressed a piece of 1/4" brake line into. Basically I just duplicated the injection manifold's air bleed passages. The hose gets routed to filtered air upstream of the throttle body.
Of course, I got no PICTURES of this process.. but you can see the chunk of tubing sticking up in the manifold here:
When I made an EFI 4-port 13B by putting 12A end housings and GSL-SE center housing together in one engine, I used a Racing Beat manifold. I figured that making the injectors' air bleeds functional would be a Good Thing, so using a GSL-SE gasket as a template, I used my Dremel to cut a slot, then drilled a hole in the center of the slot, then an intersecting hole that I pressed a piece of 1/4" brake line into. Basically I just duplicated the injection manifold's air bleed passages. The hose gets routed to filtered air upstream of the throttle body.
Of course, I got no PICTURES of this process.. but you can see the chunk of tubing sticking up in the manifold here:
My only concern with the AFM was that perhaps a ported 4 port motor would need more fuel per incremental opening of the "door". Annnnyway. Air coming in is air coming in so I guess it doesn't matter.
05-31-14, 01:37 PM
#5
Old [Sch|F]ool
Yep, air coming in is air coming in so it doesn't matter. That is the beauty of actually measuring the air instead of making a calculated guess.
I have MS because it was easier than installing the complete GSL-SE fuel injection system. When I did my original install in 2008 or something, I was putting a GSL-SE engine into my GSL, and actually did have the computer/wiring/AFM/etc. But I figured that standalone was simpler and gave me more options in the future so the GSL-SE electronics went into a box.
That was the first of (counts on fingers) six different engines, not counting rebuilds or reports, ranging from that first stock GSL-SE engine out to a peripheral port 12A, all with the same ECU installation and wiring harness... so I guess my foresight was validated
And all engines wanted more or less the same air/fuel ratio under full load, which is still going to be leaner than what the OEMs give an engine because the OEMs (especially Mazda rotary tuning) run pig-rich in order to protect the catalysts. The only real tuning difference air/fuel ratio wise is that the more port an engine has, the less it will like running lean under cruise conditions.
I have MS because it was easier than installing the complete GSL-SE fuel injection system. When I did my original install in 2008 or something, I was putting a GSL-SE engine into my GSL, and actually did have the computer/wiring/AFM/etc. But I figured that standalone was simpler and gave me more options in the future so the GSL-SE electronics went into a box.
That was the first of (counts on fingers) six different engines, not counting rebuilds or reports, ranging from that first stock GSL-SE engine out to a peripheral port 12A, all with the same ECU installation and wiring harness... so I guess my foresight was validated
And all engines wanted more or less the same air/fuel ratio under full load, which is still going to be leaner than what the OEMs give an engine because the OEMs (especially Mazda rotary tuning) run pig-rich in order to protect the catalysts. The only real tuning difference air/fuel ratio wise is that the more port an engine has, the less it will like running lean under cruise conditions.
06-01-14, 02:05 PM
#6
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yeah the GSL-SE stuff should do ok, idle is adjustable and 1100-3500rpms it runs from the 02 sensor, so it can correct itself, to an extent.
at WOT you will be power limited, as it'll run out of injector, 2x680 will only support so much power.
if you need it, the GSL-SE AFM is actually fairly adjustable. mark the starting points, but you can adjust the tension on the flapper door, the amount if air that bypasses at idle, and there is also an adjustable stop at the fully open position.
at WOT you will be power limited, as it'll run out of injector, 2x680 will only support so much power.
if you need it, the GSL-SE AFM is actually fairly adjustable. mark the starting points, but you can adjust the tension on the flapper door, the amount if air that bypasses at idle, and there is also an adjustable stop at the fully open position.
06-01-14, 02:51 PM
#7
yeah the GSL-SE stuff should do ok, idle is adjustable and 1100-3500rpms it runs from the 02 sensor, so it can correct itself, to an extent.
at WOT you will be power limited, as it'll run out of injector, 2x680 will only support so much power.
if you need it, the GSL-SE AFM is actually fairly adjustable. mark the starting points, but you can adjust the tension on the flapper door, the amount if air that bypasses at idle, and there is also an adjustable stop at the fully open position.
at WOT you will be power limited, as it'll run out of injector, 2x680 will only support so much power.
if you need it, the GSL-SE AFM is actually fairly adjustable. mark the starting points, but you can adjust the tension on the flapper door, the amount if air that bypasses at idle, and there is also an adjustable stop at the fully open position.
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06-01-14, 04:55 PM
#8
Old [Sch|F]ool
For what it's worth, the injectors go static at roughly 210-215hp on a street port, about 230hp on a bridge port (better BSFC). I've tagged that limit on a large street port 13BT (nonturbo) and it's my current limiting factor on the bridge port.
I do not know if the GSL-SE computer will allow the injectors to go static or if it has some kind of internal cutoff.
I do not know if the GSL-SE computer will allow the injectors to go static or if it has some kind of internal cutoff.
06-01-14, 05:16 PM
#9
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a newer car just doesn't let you rev as high when its cold...
06-01-14, 06:54 PM
#10
Old [Sch|F]ool
So you can adjust the max duty cycle with a trim pot on the coolant temp sender, and then adjust the airflow meter flapper spring for the proper amount of fuel, which would require making the spring stronger not weaker.
I'm thinking of the airflow meter spring like control pressure on CIS, the control pressure determines how much air the flapper can measure, which you want to coincide with how much air the engine can use.
On the other hand, I just tweak all this stuff with the laptop, it's simpler after a while. And there's a strong chance that one of my CIS cars will sprout a pair of DCOEs because it's been a long time since I've had a carbureted car and that would be kinda neat to have again.
Also, there's a strong chance that you wouldn't have to tweak anything at all.
I'm thinking of the airflow meter spring like control pressure on CIS, the control pressure determines how much air the flapper can measure, which you want to coincide with how much air the engine can use.
On the other hand, I just tweak all this stuff with the laptop, it's simpler after a while. And there's a strong chance that one of my CIS cars will sprout a pair of DCOEs because it's been a long time since I've had a carbureted car and that would be kinda neat to have again.
Also, there's a strong chance that you wouldn't have to tweak anything at all.
06-01-14, 07:29 PM
#11
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yeah exactly stiffer AFM spring = higher airflow reading.
carbed cars are kind of fun, except for having to order parts instead of hitting a key, they are quicker to tune, cause theres less to do... and they look cool.
carbed cars are kind of fun, except for having to order parts instead of hitting a key, they are quicker to tune, cause theres less to do... and they look cool.
06-02-14, 12:26 PM
#12
The stiffer spring thing I am not quite getting though. The way I am thinking about it right now is (less other variables like coolant temp) the AFM flap is like a "trigger" for the injectors right, so as it open more, more fuel goes in. It would seem to me a lighter spring would yield more fuel? The easier it is for the flap to open the more quickly the ecu ramps up the injectors. What am I missing?
So let's say the flap is dead center of it's range of motion and for simplicity sake let's say this corelates to the injectors being at 50% duty. Why would the spring tension change the amount of fuel going being used? As we said before isn't air going in air going in?
As for carbs... I was born in 1985... carborators seem infanitely more complex to me than computers
06-02-14, 01:17 PM
#13
Old [Sch|F]ool
This is a great conversation!
The stiffer spring thing I am not quite getting though. The way I am thinking about it right now is (less other variables like coolant temp) the AFM flap is like a "trigger" for the injectors right, so as it open more, more fuel goes in. It would seem to me a lighter spring would yield more fuel? The easier it is for the flap to open the more quickly the ecu ramps up the injectors. What am I missing?
The stiffer spring thing I am not quite getting though. The way I am thinking about it right now is (less other variables like coolant temp) the AFM flap is like a "trigger" for the injectors right, so as it open more, more fuel goes in. It would seem to me a lighter spring would yield more fuel? The easier it is for the flap to open the more quickly the ecu ramps up the injectors. What am I missing?
The thing to think about is, when the flapper is wide open, it is no longer metering air. If the engine can pull more air than that, then you're no longer measuring how much air is going in. So IF you get into a situation where you run out of range, then you have to stiffen the spring so that it takes more airflow to max out the flapper. This is all independent of mixture tweaking - first you have to ensure that you're going to be able to measure across the engine's whole range, then you can start worrying about what the computer is doing with that information.
But that is all getting ahead of ourselves. In all likelihood you won't have to mess with a thing.
06-02-14, 01:25 PM
#14
That is assuming that you need a richer mixture (which you may very well NOT - the guys stuck running stock FC computers have to work hard to pull fuel AWAY, not add more).
The thing to think about is, when the flapper is wide open, it is no longer metering air. If the engine can pull more air than that, then you're no longer measuring how much air is going in. So IF you get into a situation where you run out of range, then you have to stiffen the spring so that it takes more airflow to max out the flapper. This is all independent of mixture tweaking - first you have to ensure that you're going to be able to measure across the engine's whole range, then you can start worrying about what the computer is doing with that information.
But that is all getting ahead of ourselves. In all likelihood you won't have to mess with a thing.
The thing to think about is, when the flapper is wide open, it is no longer metering air. If the engine can pull more air than that, then you're no longer measuring how much air is going in. So IF you get into a situation where you run out of range, then you have to stiffen the spring so that it takes more airflow to max out the flapper. This is all independent of mixture tweaking - first you have to ensure that you're going to be able to measure across the engine's whole range, then you can start worrying about what the computer is doing with that information.
But that is all getting ahead of ourselves. In all likelihood you won't have to mess with a thing.
Bottom line being, basically any modifications I do to get better flow through the motor will most likely never be enough that it starts to lean out due to the stock AFM.
06-02-14, 01:31 PM
#15
Old [Sch|F]ool
It's possible, don't get me wrong. Maybe not possible with the stock GSL-SE intake manifold (I never made more than ~180hp through mine, although I wasn't going for max effort) or maybe you will be able to get right on up there but squeaking just past the edge of the envelope isn't going to hurt.
06-02-14, 05:16 PM
#16
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i found that the AFM was actually 100% open at around 5,000rpm, although its adjustable, so i was actually able to get it to run right with the AFM open to 105%*. there is a stopper on the AFM door that is adjustable....
however the real problem is that the ecu doesn't drive the injectors very hard, so PJ is making like 50hp more than i was, on the same injectors/pump.
makes a good case for a standalone, except that the GSL-SE ecu is easy enough to tweak, and runs really nicely. it is also sometimes more satisfying to get something like this to run on a stock ecu, than it would be to just go standalone.
*the GSL-SE AFM is weird, but happily its weird in our favor. so an FC AFM is 0-5v, with 0 being 100% open. this sucks because you can't go any further than 0. the GSL-SE AFM is a 0-12v device, with 12v being WOT, and as such you CAN go higher than 12v.
the GSL-SE primitiveness also works for us here, as its not really a "computer" it just plugs the AFM voltage into its calculation and comes up with a duty cycle, it doesn't seem to have a voltage range.
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