Open ECU rule and CIS

BlueStreak

BlueStreak

New member
"The engine management computer may be altered or replaced. A throttle position sensor and its wiring may be added or replaced. A MAP sensor and its wiring may be added. Other existing sensors, excluding the stock air metering device, may be substituted for equivalent units."

My intent starting this thread is for us CIS guys to bounce around some ideas on how best to take advantage of the ECU rule.

A couple of points to consider:
True or False: CIS is a mechanical computer.
True or False: The new rule doesn't clarify mechanical vs. electrical.

So, IF CIS is a mechanical computer, where does the customization potential end? The fuel distributor is the mechanical computer. Is it legal to replace it with a home made unit?

Under the new rule, wouldn't updating CIS to CIS-E suddenly become legal? If so, would it be worth it?

An interesting page about the different CIS systems - done by a turbo guy, but still interesting:

http://home.comcast.net/~vwmikelvw/Tech/cise/cise.htmhttp://home.comcast.net/~vwmikelvw/Tech/cise/cise.htm

and another educational basic CIS explanation:

http://home.hiwaay.net/~langford/CIS.html

um, what was the saying, wheee :eclipsee_steering:
 
True or False: CIS is a mechanical computer.
True or False: The new rule doesn't clarify mechanical vs. electrical.[/b]
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"Yes" on both counts.

Some things to try:
- Reshaping the fuel rod to cater the fuel flow to airflow;
- Reshaping the flapper valve to cater flapper movement to airflow;
- Reshaping the bowl to cater airflow.

It's not going to be anywhere near as easy as ECU tuning; in fact, it's going to be a lot of work. But, it can be done. In fact, I seem to recall someone in the 80's (was it the Hacker Brothers? Maybe Archer Brothers?) reshaping the pins in Showroom Stock (cheating in Showroom Stock??? Horrors!) Ask around in various ex-old-guard-SS V-dub circles, I'm sure there's a lot to learn...
 
The flapper valve and bowl are integral to the mass air flow sensor of the CIS system. Thus they cannot be modified.

While we are at it, would you also suggest that a carburetor is a mechanical computer?
 
Chris, loosely speaking I'll give you that the bowl is a part of the air intake restriction (VERY loosely interpreted as a MAF, but as lose as a Vegas who...never mind..) But the flapper is part of the fuel system, affected by the air system and interfacing with the fuel pin to "meter" (whee...!!!) the fuel to the lines.

Now from your post on the Fastrack topic:

No way no how that plate can be modified or removed under current, or 2008 IT rules.

Now - you CAN use whatever computer you want to alter the resulting fuel flow from the system. Maybe control the differential pressure regulator of a CIS-E system to get optimum fueling in all conditions. I don't know CIS basic well enough to know if/what you could change controls wise...beyond the adjustable warmup regulator trick.[/b]
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Ok, so you're saying you cannot modify or even affect the flapper...but that's what the control pressure does! The control pressure resists the upwards movement of the pin (otherwise it would shoot upwards uncontrollably); since the pin pushes down on the flapper, aren't you modifying the action of the flapper (and thus the "air fuel meter") but modifying the control pressure?

Isn't this fun? It's destined to get even better, I'd wager...
 
It's fun, but your wrong :P

Those components ARE a mass airflow sensor. Regardless of how they communicate with the fuel system (in this case mechanically), you can't modify the mass air flow sensor.

I didn't say you couldn't affect it, but you can't change it. You are allowed to modify fuel pressure already.
 
While we are at it, would you also suggest that a carburetor is a mechanical computer?
[/b]
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I think you just did :blink:

Seriously - someone (not me) WILL take it to that point. You can yank the fuel metering out of a carburetor, stick an injector (or four) in it, add a megasquirt, and voila, you'd be taking maximum advantage of the new ECU rule. Would it get protested? Uh, it better, because that's certainly not the spirit of the new rule, but I doubt CIS mods are either, and here I am looking for anything I can find for us CIS guys.

Back to my CIS questions,
I see your point on the bowl/flapper, but I can see this one easily winding up "in court".

Maybe it's time to scrap my CIS car and build a Megasquirt equipped A3 dub.

Maybe, with this rule, I can make the ITC New Beetle competitive!
 
It's fun, but your wrong :P[/b]
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And you're saying that the part that apparently "senses" the airflow - the flapper - cannot be modified in any way, presumably because it's a restriction to airflow, but yet you're saying that I can zero out the control pressure to a point where the flapper never even moves downwards (maybe not even at idle!) allowing a massive amount of airflow far above what the original design expected, and compromise that with a massively reshaped fuel distributor pin, but that's all right?

Ooookaaay....

But you are correct: this is gonna get real fun over the next few years. And what's even better? No one's ever gonna protest squat...
 
That is an interesting conversation peice, but since you do need to use that MAF to control your fuel flow, making it stick open might not return the best AFR. Maybe there is another way to control the fuel within the fuel distributor that I am not seeing on the CIS basic car, but that thing just won't run the way you described it.

EDIT - even with the massively reshaped fuel distributor pin, you need to allow enough motion to have a flapper position repeatable vs. airflow, and to allow enough 'resolution' in fueling to work for the racing rev range. Who knows maybe it could work. It would take a crap load of development.
 
- Zero the control pressure. Flapper valve and fuel distributor pin go all the way vertically, maximizing airflow through the 'box and minimizing fuel flow restriction through the distributor and out to the injectors;
- Add a TPS and MAP;
- Add an ECU (ECUs and wiring are free) that takes in MAP, RPM, and TPS and controls the fuel system pressure based on a mapping of load versus RPM. Fuel flow changes with system pressure.
- If you're concerned about over-fueling, add in some limited control over the "control pressure" to limit the amount of fuel as desired, and cut off the bottom of the pin so that it never contacts the flapper valve (which would reduce airflow) and have the pin location opposed by a very light spring with a nut on the bottom (but don't touch the Holy Flapper "MAF"!)

Alternatively, given that the so-called "MAF" is now non-operational, simply remove the fuel control pin entirely, use the above fueling system, and delete the boot between the "MAF" and throttle body (rules specifically state you can remove them), maximize the airflow, and go to a complete TPS/MAP/RPM mapping system that adjusts fuel based on fuel system pressure (noting the ability to control fuel as described above.)

Once you start opening gaping holes in the rules, all it takes is a little creativity to begat a monster... - GA
 
Nice.

I expect the intake piping words to be correctd soon to get rid of the 'boot deletion' option, but I would protest that under the current rule anyway.

This is all well and good, but it is a lot harder to execute than to think up. We have been thinking long and hard about CIS based solutions for a production car I crew with for a few years, where a whole lot more goes than even this brave new IT world.
 
wow where have i been? Am I getting it right that we can now goto a standalone system for 2008???
 
I was following Greg's idea perfectly until I saw this:

"On cars so equipped, the air metering/measuring device (i.e. air flow meter, air mass meter, MAF) must be operational and shall not be modified."

Doesn't that throw your plan out the window?
 
not sure... There are a few systems that would allow a MAF, but there are a couple other aspects that need to be researched before it could be done.
 
OK, now that I am putting together my list of what I want to do the car over the winter, did I read this whole discussion topic correctly......that the ECU is completely open now?? Can someone, in a clear and easy to understand way, describe what happened in the GCR concerning this? I have an OBD I 1994 Golf and it used to be that I could work on the chip inside the existing housing of the ECU, but could not change any part of the wiring etc, correct? Now, if I have waded through the various posts correctly, we can do whatever we want to the computer management system of the car? Am I oversimplifying?

help........and didn't mean to hijack THIS thread, just trying to not start another multi-page deal.

thanks,

Tim M
 
The point is, Chris - despite my over-reaching - it's a brave new world out there. "Thinking outside the box" is - literally - approved, encouraged, rewarded.

Thinking further, where does it say the "computer" (the fuel distributor) even has to stay on the "MAF" box? Relocate it entirely and have your way with it. Hell, you can even "modify" or "substitute" it such that you have an electrical feedback solenoid moving the pin instead of the flapper. The added ECU - with feedback from the new TPS, MAP, and RPM - controls its position within the fuel distributor.

The possibilities are seemingly endless.

"...MAF) must be operational and shall not be modified."

Doesn't that throw your plan out the window?[/b]
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Nope. As Chris noted, I'm sure the ITAC is furiously re-writing rules as we speak (and should be thanking me that I'm saying this stuff publicly and not simply doing it) but if you removed that boot, the "MAF" is still operational, and responds to air flowing through it; I just simply choose not to run air through it.


Am I oversimplifying?[/b]
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Nope. Grab the new Fastrack, Tim: ECUs are free, wiring in the engine compartment is free, and you can add TPS and MAP sensors.

Like I said: brave new world. - GA
 
Correctamundo. ECU rules in 2008 are more free than they were in 2007. You used to have to jam a standalone into the stock ecu box, and mate the stock wiring harness to it. Now you can run any ecu you like, can make a harness so it will work right and can add a MAP and TPS if your car does not have one (or use alternates if it does have). Still must use stock fuel injection components (unless otherwise allowed to change, such as fuel pressure regulator), and still must pull air through the stock air measuring device - regardless of how well a job Greg has done shredding the words there, that's what the rule is meant to say, now they just need to make the words more 'durable'.

So A2 and A3 Golfs now can run programmable engine management more easily than you could last year.

While this thinking outside the box is fun, the reality is that our cars are not fuel limited, and the reality is that the CIS mass airflow sensor is not a 'choke' in the system. You can put whatever management you want on these things, and the cam will still be a conservative profile, and the head will still flow a certain amount of air. I looked at the new rule and thought I would take advantage of it to replace all my old, scary looking CIS-E stuff with new, more easily obtained Digifant components and run a Megasquirt or SDS system, more for reliability sake than anything. However, instead I am letting other A2 racers do that, and looking for deals on spares for my CIS-E system. I really don't believe that I am giving up any power potential to a standalone car at this point. Of course if I learn this year that this is not true, I will certainly change course, but until that point I see no reason to change.
 
Greg,

You've covered most of what I've been noodling on w.r.t. this one. I suspect that we'll shortly see a change in the rule wording that all air entering the engine must pass through said MAF/AFM/etc. Even so, I think that with enough development, what you have proposed could be made to work. It would be an interesting exercise to see just how much of a gain could be made.

I also see some somewhat easier (and probably much less costly) alternatives. Swap the fuel distributor, err, 'computer' out for one that flows more fuel. Say one from a 944 or a Volvo. Or just modify the existing one to meet the specs of the higher flowing one. That's probably where you'll see anybody that's interested in tweaking one of these cars going.

You would think after all that's gone on w/ rules over the past few years, that they would have figured out how to write them by now so that they actually addressed the desired issue.
 
But Bill, with these IT engines, the stock stuff can support something like 50% more power than any of us will make. Why bother switching over to a Volvo component? It would be a tough swap, as you would have to retain the VW mass air flow sensor, and mate it to the Volvo fuel distributor, and hope the calibration is right, or make it right with a bunch of development. It would be interesting to see an A1 racer throw some pressure sensors on the filter side and intake boot side of the MAF (basically put a few vacuum gauges there) and make some full throttle, or dyno runs to measure the pressure drop. My money says it is not a lot, and this is much ado about nothing.

To be honest I think those of us with CIS-E have had a gift in the rules for years because it is SO easy to get the fueling right for race conditions. This updated rule probably takes some of that advantage away. It is easy enough and works well enough that this is how the fueling was accomplished to reach the podium the last three years in GP, even though we had the leeway to do so much more in that class (of course now we are searching for alternative solutions, because if we move it up to F, it should bump into the limits of the CIS/CIS-E systems power potential in order to be competitive).
 
OK, now that I am putting together my list of what I want to do the car over the winter, did I read this whole discussion topic correctly......that the ECU is completely open now?? Can someone, in a clear and easy to understand way, describe what happened in the GCR concerning this? I have an OBD I 1994 Golf and it used to be that I could work on the chip inside the existing housing of the ECU, but could not change any part of the wiring etc, correct? Now, if I have waded through the various posts correctly, we can do whatever we want to the computer management system of the car? Am I oversimplifying?

help........and didn't mean to hijack THIS thread, just trying to not start another multi-page deal.

thanks,

Tim M
[/b]
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Tim,
You read it correctly. You can do what ever you'd like to your computer system...even run the whole thing on bird poop...just so long as you have your washer bottle you're good!!


Sorry I just could stop myself...

R
 
But Bill, with these IT engines, the stock stuff can support something like 50% more power than any of us will make. Why bother switching over to a Volvo component? It would be a tough swap, as you would have to retain the VW mass air flow sensor, and mate it to the Volvo fuel distributor, and hope the calibration is right, or make it right with a bunch of development. It would be interesting to see an A1 racer throw some pressure sensors on the filter side and intake boot side of the MAF (basically put a few vacuum gauges there) and make some full throttle, or dyno runs to measure the pressure drop. My money says it is not a lot, and this is much ado about nothing.

To be honest I think those of us with CIS-E have had a gift in the rules for years because it is SO easy to get the fueling right for race conditions. This updated rule probably takes some of that advantage away. It is easy enough and works well enough that this is how the fueling was accomplished to reach the podium the last three years in GP, even though we had the leeway to do so much more in that class (of course now we are searching for alternative solutions, because if we move it up to F, it should bump into the limits of the CIS/CIS-E systems power potential in order to be competitive).
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That's interesting Chris, because several of the strong proponents of this new rule said that it didn't allow anyone to do anything new, that they couldn't do under the old rule. But hey, what do I know, I couldn't see the similarities between running a stock harness and sensors w/ an open harness and added sensors.

I am inclined to agree w/ you though, I don't know how much gain anyone would see w/ a modified CIS system. The limiting factor is the intake, can and the throttle body. You may see better mid-range performance (that whole 'area under the curve' thing), but you're not going to find 5-10 hp in it.

And there's really no incentive for anyone running an A1 to throw mad amounts of money at this, because those cars will never be able to run with a full-boogie A3. Look how many new ones came out of the woodwork when they dropped the weight.
 
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