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i was told by a random source, that there would be an AFM delete coming out soon. is this true? when can we expect it?
also, would it do something, like use the GM 3bar map sensor? (which would be very cool)
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This is the main mod I really want to see go live. Being able to use a 3 bar MAP would literally make my year.
When this finally comes out, will this be a software update or a whole new stage?
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88 Black Turbo II - 150 rwhp @ 7500 rpm - Corksport 80mm DP, Corksport 80mm MP, HKS SSQV, S5 turbo upgrade, FCD
Coming soon - Standalone and a LOT more boost and fuel. To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
91 Blue CRX - Beater
94 Green Corolla Station Wagon - Absolute Race Car
I've installed one on my buddies dsm, the spool gains were pretty dramatic. Unfortunately the early MAF translator was model specific. Their newest model, the MAF Translator pro claims to be applicable to all cars using a MAF sensor.
Here is a link to a description of it's capabilities. http://www.maftpro.com/tproinfo.shtml
I was wondering if some of its features could be incorporated into a future release of the Rtek.
The features I would like to see would be; After Start Correction- Sets enrichment level for the first few minutes after starting. I think this would help all of us who don't run the BAC and AWS systems anymore. Even better would be an adjustable coolant temperature correction map for fuel WOT AFR Tracking This automatically adjust fuel trim based off a wide band input at WOT. (Very cool but probably not necessary).
There were a couple other cool features, but the adjustibility in terms of fuel and timing don't compare to the Rtek. It's only $399 though, not a bad price for the features. If could find one used, which I highly doubt, I would consider using it until the AFM delete comes out. I'm still hoping the AFM delete will come out this summer.
I've installed one on my buddies dsm, the spool gains were pretty dramatic. Unfortunately the early MAF translator was model specific. Their newest model, the MAF Translator pro claims to be applicable to all cars using a MAF sensor.
Here is a link to a description of it's capabilities. http://www.maftpro.com/tproinfo.shtml
I was wondering if some of its features could be incorporated into a future release of the Rtek.
The features I would like to see would be; After Start Correction- Sets enrichment level for the first few minutes after starting. I think this would help all of us who don't run the BAC and AWS systems anymore. Even better would be an adjustable coolant temperature correction map for fuel WOT AFR Tracking This automatically adjust fuel trim based off a wide band input at WOT. (Very cool but probably not necessary).
There were a couple other cool features, but the adjustibility in terms of fuel and timing don't compare to the Rtek. It's only $399 though, not a bad price for the features. If could find one used, which I highly doubt, I would consider using it until the AFM delete comes out. I'm still hoping the AFM delete will come out this summer.
so are there systems plug and play? or what kind of wiring and setup needs to be done...
well, i talked with mike through email and he said that the AFM removal for the na and turbos are about an estimated 6 months from going into production. they are still testing tweaks and what not. this is one of the conversations:
Quote:
There are two types of systems ECUs use to calculate fuel. One is mass air (like the RX7s) and the other is speed density (like most hondas).
Mass air systems measure the volume of the air coming in directly. It knows airflow (from the AFM sensor), and it knows temperature (from the intake temp sensor), as well as the barometric pressure, so it can calcualte the mass of the air. With the mass, it can calculate how much fuel to mix with it.
Speed density systems dont measure the airflow directly. The ECU does an extra step. In order to get the airflow, it uses the theoretical airflow for a given RPM eliminating the need for an airflow meter. An engine is just an air pump. At x RPM, it will move Y volume of air. The ECU is programmed with this lookup table (throttle position is also a factor) that tells it the airflow for a given RPM and throttle position. So now that it has looked up the airflow for a particular RPM, it reads the density from the MAP sensor and the temperature from the temp sensor. With that it can calculate the mass of the air, and therefore how much fuel to mix with it.
The downside to the speed density system is that the airflow lookup table is fixed. So if you change the efficiency of how the engine breathes (like adding an intake, exhaust or doing a port, all of which stuffs more air into the chamber for a given RPM) the ECU has no way to compenstate because it simply doesnt know that while the density of the air hasn't changed, the volume of air has.. With a mass air system, the airflow meter would see this change in volume and the ECU would comensate. So speed density systems are harder to tune as they are less forgiving to changes, but you get the benifit of no restrictive airflow meter.
i suppose i am more willing to stay with the AFM on for now... until i resolve on a method to save money on getting an MAF sensor and translator.
unless digital tuning is going to sell bundle kit:
Wouldn't the restriction be less of a problem if you were boosting through it?
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Money = Power
Rotaries are like a bad relationship, they piss you off so much you don't want anything to do with them, then they run so good you would never want to do without them.
Wouldn't the restriction be less of a problem if you were boosting through it?
wouldnt that be the intial set-up that we are stuck at, or is it just before the TB... and i dont know but i have a feeling this has been covered before. all i'm thinking is that its restrictive, and something about teh air going in.
yeah it would be after the IC and before the TB. It seems like it would work to me , or at least be made to work easier. Im going to have to go back to my fluid dynamics and analyze it but intuitively it seems right? Does anyone have more knowledge on this issue?
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Money = Power
Rotaries are like a bad relationship, they piss you off so much you don't want anything to do with them, then they run so good you would never want to do without them.
In order for the ECU to calculate how much fuel to inject, it needs to know the mass of air entering the combustion chamber.
mass = volume * density.
In the stock setup, the barn door type AFM measures air velocity. Velocity alone doesn't tell us mass. But velocity through a hole with a known area can be used to calculate volume.
So now we need density. In the stock "pull through" setup, the density (pressure) of the air being pulled in is, well, atmospheric pressure. One end of the AFM is open to the atmosphere so the air inside is at 1 atmosphere. That is why there is a barometric pressure sensor, to measure the atmospheric pressure, and now we have the density of the air. Along with the volume, we can calculate mass, and do our fuel calculations.
Now move that AFM to after the turbo.
The turbo takes air and compresses it. So for example, 1 cubic foot of air at sea level pressure is sucked in and pressurized so now only occupies 1/2 cubic foot and is at 14.7 PSI. (I dont know if those number are correct, but just for illustration)
Note that an engine always moves the same volume of air for a given RPM (as measured at the intake port). Mechanically, it has to move the same volume of air as it's displacement. The density of that air is what changes depending on throttle position and boost. Thats what changes the volume of air as measured at the air filter.
So if you had a 1 cylinder ( 4 stroke) 1 liter engine at 1000 RPM you would move 500 liters per minute at atmospheric pressure. (1000rpm/2 (4 stroke) *1 liter per revolution= 500 liters/min) If you pressurized the air to 1 BAR, you double the air density. So the engine is still moving 500 liters per minute (as measured after the turbo), but the air is under pressure. Before the turbo, you doubled the velocity of that incoming air because you have to move twice the mass of air in the same time period.
With that said, if you move the AFM from before the turbo to after the turbo, for a given engine condition, the velocity of the air after the turbo actually slows down because that same volume of air is now under pressure and simply takes up less room when its under pressure, so there is no need to move it as quickly.
So with the AFM after the turbo, it is now reading less air velocity than it would if it were before the turbo.
But thats only half of the problem....what about the density?
The barometric pressure sensor can no longer read the pressure of the air being measured in the AFM. It still thinks the air being measured is at atmospheric pressure. It has no idea what pressure the air is actually at. If the air is at 14.7PSI, and the ECU thinks the air is at sea level, the mass it will calculate is 1/2 the actual mass of air entering the engine, and will fuel accordingly. This will of course end up in a massive lean condition.
So between the incorrect velocity due to the increased density and not knowing the pressure, it is impossible for the ECU to calculate the proper fuel mixture with any sort of accuracy. This is why its very not recommended.
Last edited by turbo2ltr; 08-28-08 at 06:19 PM.
Reason: corrected my horrible math
Rotaries are like a bad relationship, they piss you off so much you don't want anything to do with them, then they run so good you would never want to do without them.
knowing the instant pressure of the air, the instant density, and the instant cross sectional area of the afm, couldn't we find the velocity and flow rate?
I'm not trying to question anyones knowledge, I just want to fully understand this.
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Money = Power
Rotaries are like a bad relationship, they piss you off so much you don't want anything to do with them, then they run so good you would never want to do without them.
You probably could. The biggest obstacle would be simply validating the system as a whole in the new configuration. You're making major changes to the way the ECU was designed to work. I didnt mention anything about temperature, but it also plays a large role in calculating density.
The missing key to moving the AFM to a blow through is the ECU knowing the pressure of the air inside the AFM. And the AFMs velocity to volume calibration in relation to fueling.
so if we could measure the pressure and temperature we could know the new air density and from there we could make a ( i would assume) simple logic circuit that would convert that info to something similar to what the ecu received before.
__________________
Money = Power
Rotaries are like a bad relationship, they piss you off so much you don't want anything to do with them, then they run so good you would never want to do without them.
In oversimplified theory, yes. Though I'd be more inclined to modify the software than to create additional hardware. The hardware is already there, it just needs a program to properly use it in the new way.
And no, we have no plans to do this...the AFM delete will be better than this idea.
Oh I didn't think you did plan on doing it the way I was thinking, im sure you already thought about this, and no doubt the AFM delete will be way better (trust me I will be first in line to get mine). Thanks for brainstorming that with me!!!
__________________
Money = Power
Rotaries are like a bad relationship, they piss you off so much you don't want anything to do with them, then they run so good you would never want to do without them.
just a tid bit of information, i recently switched to a haltech (map based), and the main difference i noticed is the AFRs are a LOT smoother in boost. I was never able to get very steady AFRs with the rtek, it would always fluctuate by about half an AFR. I suppose the AFM flapper does not stay very steady under high airflow
just saying there are big advantages to hte AMF delete, especially when pushing the limits of our stock AFM
turbo2ltr, how much control do you have over the ecu programming? the above discussion seems to be over-complicated to me, unless you are talking about the difficulty of trying to recreate the "stock" fuel lookup table using a map-based system. Its seems to me map-based would simplify things, since you have less inputs (rpm, map, air temp, coolant temp). isnt it just a 2-D lookup table, then multiply by the temp correction tables?
What we are working on is a speed density system, not a blow through AFM system like we were just talking about. The blow through would be more complicated than it's worth with little in return.
So the AFM delete will do just that.. eliminate the AFM and use the existing sensors for calculations.. It may be required or optional to change the sensor to a 3 bar. Not sure at this point. We are woking on the NA first (simpler) which I think will be fine with the stock MAP. Henrik has a basic drivable prototype but still needs some refinement.
What we are working on is a speed density system, not a blow through AFM system like we were just talking about. The blow through would be more complicated than it's worth with little in return.
So the AFM delete will do just that.. eliminate the AFM and use the existing sensors for calculations.. It may be required or optional to change the sensor to a 3 bar. Not sure at this point. We are woking on the NA first (simpler) which I think will be fine with the stock MAP. Henrik has a basic drivable prototype but still needs some refinement.
If you need someone to prototype a Turbo II system, let me know. I'll gladly get down and dirty... as long as i can throw that MAF as far away as possible.
Hell, I'll even pay the full price to test it out.
__________________
88 Black Turbo II - 150 rwhp @ 7500 rpm - Corksport 80mm DP, Corksport 80mm MP, HKS SSQV, S5 turbo upgrade, FCD
Coming soon - Standalone and a LOT more boost and fuel. To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
91 Blue CRX - Beater
94 Green Corolla Station Wagon - Absolute Race Car
If you need someone to prototype a Turbo II system, let me know. I'll gladly get down and dirty... as long as i can throw that MAF as far away as possible.
Hell, I'll even pay the full price to test it out.
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