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ELECTRONIC CIS fueling & BOOST control

Hello

Few peoples here suggested to me to make a thread about my setup. Happy to share my small experience with you…

Just hope you will forgive my French touch English…

Prior to start this thread, I would like to thank Keith ( well-known here as 911ST). Actually he introduced the base of AIC idea to me….He was very patient with me and we exchanged many though by email. From this AIC base, from some thread here, I’ve got some additional idea and I built the following setup.

I own a 964 C2T 3.3 (1991). As many of these car( about 82 k miles), although a good maintenance, the engine suffered of several oil leak. Early this year, I took the decision to make a complete engine rebuild . So I brought my car to my favourite workshop here. (thanks to MJ TECHNIC FRANCE). In fact , as my idea was to lightly upgrade the performance of my car, we didn’t take any risk In order to do the right job and reliable car, we have changed many parts …


During engine rebuild...

In the mean time I sourced a pair of second hand X33 camshafts ( which are SC cams actually). The X33 option is known to increase the power from 320 HP to 355 HP on the stock car. These cams has been installed on my car and timed to 1mm. As the factory did with the X33 option, I polished intake and exhaust ports on each cylinder heads.



X33 ( SC) camshaft


Lastly, the air injection circuitry has been removed and the catalyst exhaust has been replaced by a direct tube. ( followed by a Dansk muffler).

As to the performance improvement, my goal was to keep the original “philosophy” of this car and to get enhanced road/ street performance. So my car is still close to stock version since I kept the original CIS , the headers, K27-7200 turbo , ignition and so on….

I just added the “electronic boost control function and previously mentioned modification to increase the power. In this way and thanks to the community , I knew the CIS limits would have appear quickly if the averaged boost exceed 0.9 bar ( sorry I am not used with the PSI ) .So I knew I should also optimize my CIS to get suitable results. My first idea was to use a separated electronic boost controller and to install a DIGITAL WUR . However, when Keith introduced the AIC Split second to me , when I saw it has 2 channels , I thought it would be very nice to combine 2 devices into a single box , a very affordable and user friendly controller.....

As I wanted to get a safe and reliable tuning, I bought an INNOVATE measurement system. ( data logger + map sensor + wo2 sensor + egt sensor ). (It works very well but I have to complain about the poor customer service…. )

In order to let you know more, here is the diagram of the fuelling and boost controlling system.




Actually the system use an AIC SPLIT SECOND controller. This very affordable controller has 2 injectors outputs with 2 distinct maps ( each output has it map). It also includes a manifold pressure sensor and maps are made according RPM / MAP.



SPLIT SECOND AIC CONTROLLER


The first channel is connected to a frequency valve ( Andial fueller plumbing) . As known by many here, the purpose of the frequency valve ( with it own map) is to trigger ( PWM / DUTY CYCLE) the so called PRESSURE CONTROL (PC) . In this setup, the WUR is not removed and the frequency valve operate on the PC in parallel.


FREQUENCY VALVE ( taken from ANDIAL KIT / ref BOSCH 0280150945)

The second channel ( with it own map) of the AIC is connected to an AEM boost pressure 3 ways electrical valve. This boost valve is basically plumbed to act on the top pressure of the wastegate. Here also, this electrical valve is supplied with PWM / DUTY CYCLE signal. As there is no PID device inside the controller, the map must be programmed in a special way . However, one advantage of this system is to allow a very friendly RPM mapping ( that’s true that a 250 RPM scale instead of 500 RPM would be helpful for the boost controlling function …anyway, it is a good toy !)


AEM 3 ways electrical boost valve

As you can see on the diagram, there is also an electrical valve between the manifold pressure output and the manifold pressure input of the WUR. In fact I installed this valve in order to allow me to return to original WUR setup. At beginning this was useful to discover the original behaviour of the CIS. ( and to make measurement with the datalogger) Now this valve stay closed all the time …I could simply cut the boost enrichment line but I prefer to keep it wired in case of problem. Unlike the famous adjustable WUR setup, this electrical valve is not triggered by an RPM switch (there is no need)


ELECTRICAL VALVE ( WUR line boost enabling / disabling )
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Old 06-26-2009, 02:35 PM
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here is few pictures of my setup



Before assembly.... The mini pc is always in my car. ( very convenient to program AIC software and to make dataloging )



I designed a special gauge holder ( 3D prototyping)



AFR and MAP gauge / SPLIT SECOND controller.... some will recognize the Andial aluminium plate I transformed and used



Electronic devices are located under the passenger seat





Wide band O2 sensor controller



Wide band O2 sensor location



AIC software ( 2 channel / 2 maps )
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Old 06-26-2009, 02:47 PM
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Good man, Thierry! Thanks for taking the time to translate for the rest of us language-challenged people.
Very impressive.
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Old 06-26-2009, 03:19 PM
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The way the oxygen sensor wire is bent and going through the engine tin in this picture is gonna bite you in the future.

While the corrugated sheilding on bosch wideband sensors is flexible when they are new, after a bunch of heat cycles they become very stiff and totally nonflexable and you won't be able to unscrew that oxygen sensor without breaking the wire insulation.
I know from experinece...

You may as well buy another oxygen sensor now so you have one for the day that happens... ebay and amazon are the cheapest source.
Old 06-26-2009, 05:10 PM
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You have skills my friend!

Impressive.
Old 06-26-2009, 08:08 PM
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So do you have control over you AFR's by rpm and load up to the limit of the fuel head?

And can you control boost level at different rpm levels so you can taper it back as you start to run out of fuel?
Old 06-26-2009, 08:11 PM
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Quote:
Originally Posted by 911st View Post
You have skills my friend!

Impressive.
I must return the compliment to you !!!! Your skills is in this setup too !!! You are very smart with strong knowledge about our 930 - 964 turbo car.

Yes of course, I am able to "play" with some parameters and to measure the result on the datalogger...
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Old 06-27-2009, 04:23 AM
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Good man, Thierry! Thanks for taking the time to translate for the rest of us language-challenged people.
Very impressive.

Thank you dear Mark ... just hope I do not write too much mistake !
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Old 06-27-2009, 04:25 AM
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Here is the 1st measurement I made with my system

The AIC devices wasn't started. So we would say this is something like the stock measurement. However you have to consider my SC cams , Catalyst bypass straight tube.





There is nothing new into this measurement. As describded by many in this community, we can perfectly see the bahavior of the CIS. It is a bit too fat in the mid ( AFR 10.8 ) and it becomes too lean on top end. (12.8 )

As to the boost pressure, the progressive drop is certainly due to the wastegate. Actually the valve guide is worn and some exhaust gaz go through . Then, this additionnal pressure false the wastegate boost pressure signal. On this curve the maximum boost is 0.95 b and it drops to 0.8 at high rev.

The lambda regulation works very well and the AFR is closed to 14.2 at low RPM
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Old 06-27-2009, 04:48 AM
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here is the 2 nd measurement

The AIC device is connected . As the WUR boost line is still activated, The AIC controller was programmed to act between 4500 to 6000 rpm only...
I made 2 very simple maps in order to stabilize the boost level ( no adding boost beyond 6000...) and to get more fuel on top end . ( about 40% duty cycle on the frequency valve).




The boost level is correctly achieved. ( about 1 bar until 6000 RPM). As mentionned I do not maintain any boost gain above 6000 RPM. ( so it drop suddenly ) .

However , the fuelling is not correct and it is too lean above 4800 rpm ( almost 13 ) . (We can noticed the AFR comes back to 12.5 while the boost decrease above 6000 RPM) .
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Old 06-27-2009, 07:10 AM
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Here is the 3rd measurement

As seen as before, it is too lean above 4800 RPM. I could even doubt the frequency valve works correctly

So I dialed 40% frequency valve duty cycle between 2000 and 4500 RPM and I pushed it to it maximum ( 80%) between 5000 RPM to 6500 RPM





In order to compare, I did the run in the same place . I fitted the scale and pictures using picture software.... This is for comparison purpose only.

As can be seen, the fuelling is improved in the low mid can. The AFR drop to real low value (9.5 around 3500 RPM). The mid high are a little bit improved (about - 0.5 on AFR) However it's still too lean. The frequency valve with it controller setup works correctly. But I hit a wall....can not get more fuel.
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Old 06-27-2009, 08:12 AM
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Quote:
Originally Posted by JFairman View Post
The way the oxygen sensor wire is bent and going through the engine tin in this picture is gonna bite you in the future.

While the corrugated sheilding on bosch wideband sensors is flexible when they are new, after a bunch of heat cycles they become very stiff and totally nonflexable and you won't be able to unscrew that oxygen sensor without breaking the wire insulation.
I know from experinece...

You may as well buy another oxygen sensor now so you have one for the day that happens... ebay and amazon are the cheapest source.

Thanks for your input

Actually, I left some extra lenght of this wire in the upper engine bay. I did recently a recalibration, I just pull the cable prior to unscrew the sensor. At present time, no problem. However I believe your experience and the fact that it will become harder with past time.

Good suggestion from you to buy another one and to keep it for futur.
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Old 06-27-2009, 08:43 AM
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Quote:
Originally Posted by Thierry25 View Post
Hello

Few peoples here suggested to me to make a thread about my setup. Happy to share my small experience with you…
..................................
As you can see on the diagram, there is also an electrical valve between the manifold pressure output and the manifold pressure input of the WUR. In fact I installed this valve in order to allow me to return to original WUR setup. At beginning this was useful to discover the original behaviour of the CIS. ( and to make measurement with the datalogger) Now this valve stay closed all the time …I could simply cut the boost enrichment line but I prefer to keep it wired in case of problem. Unlike the famous adjustable WUR setup, this electrical valve is not triggered by an RPM switch (there is no need)


ELECTRICAL VALVE ( WUR line boost enabling / disabling )
Thierry,
Very impressive. I do have one question. Why disable the MAP sensor line to the stock WUR?
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Old 06-27-2009, 09:03 AM
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Thierry,
Very impressive. I do have one question. Why disable the MAP sensor line to the stock WUR?

Dave, thanks fo your input

Good question actually !

Not easy to find my words sometime

In fact, this is because there is no need to use the boost "enrichment" function from the WUR in this setup. As there is a MAP sensor and complete map on the AIC device, the " boost enrichment function" can be done by the AIC + frequency valve. In other words , with this setup , the WUR is still used to provide the correct CP at starting (cold 2.9 bar) and during running ( Warm 4.5 bar) . But the WUR is no more used to handle the pressure control on boost. Thank to it map, the AIC controller + frequency valve can handle the pressure control on the complete RPM range . The WUR provide stable 4.5 b of PC..... the AIC+ freq valve can drop this PC at any requested value under 4.5 b ... (it can even drop the PC to 1.2 bar at 90% of duty cycle …I made the measurement )

As known by many here, the enrichment device of the WUR provides too rich mixture in the mid RPM ( just when the boost pressure occurs ). To cancel this fat mid, many members here are using an RPM activated switch ( often combined with BL adjustable WUR) to disable the WUR boost line below an RPM point ( 3500 -4500 RPM). ( the boost line is activated above this point only) The reason I disable the WUR boost line on this setup is somewhere very near...
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Old 06-27-2009, 09:38 AM
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Quote:
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here is the 2 nd measurement






However , the fuelling is not correct and it is too lean above 4800 rpm ( almost 13 ) . (We can noticed the AFR comes back to 12.5 while the boost decrease above 6000 RPM) .

As can be seen previously, the mixture was a bit too lean ( let's say 12.8) at high RPM under 1b of boost. Although the big decrease of the control pressure , the Kjet was not able to provide richer mixture.

Prior to do something else, I verified the fuel supply system.

As specified in the Porsche workshop manual:

- I controlled the fuel system pressure ....and measured 7 bars ( so I thought no problem on this)

- I verified the fuel flow : I've got about 1.7 liters/ 30 sec . Porsche recommend 1.5L/30sec at least. So the flow was in the tolerance...

- I verified the control pressure under warm condition : Measured 4.5 bar ....which is exactly the correct value. By this opportunity, I either tested the AIC +frequency valve working. The CP was decreased to 1.2 bar under 90% duty cycle.


At that time, Keith suggested to me to " play" with the lambda frequency valve instead to play my AIC frequency valve. According to him I could maybe get more fuel by playing. As described into the Porsche manual , the enrichment device ( which is under the driver seat) triggers the lambda frequency valve to stable 50% duty cycle while the throttle exceed 66°. It also increase this duty cycle to 75% during 0.5 second while the throttle moves from 0° to 7° and from 6° to 66°...( This is for acceleration enrichment purpose only) . So I look into the Porsche diagram if it could be possible to get 75% enrichment all the time. Finally it was quite easy to do.
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Old 06-29-2009, 10:04 AM
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Thierry,

Just for fun, run two tests. Don't change your AIC settings, but run one with the MAP line hooked up to the WUR and one without. Just to see how the AFR looks at the highend.
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Old 06-29-2009, 01:03 PM
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If going from 50% to 75 % gets .5 point of added AFR, will going from 25% to 75% get a full point?

If so, could drive the Lambda valve at 25% and re-set the CO at the head.

To achieve / test for the lowest control pressure, run the factory enrichment at the same time as the Andial valve at a max duty-cycle.

Achieving the lowest control pressure dose not necessarily confirm that the metering pin has reached full travel. I took my metering assembly apart and found that I could detail it so the pin could travel further depending on the CO adjustment.

Beyond that, we may need to make mods that will ensure the metering plate will travel past its stall point and to full engagement to max fuel delivery.

Any more than that would require re-adjusting the springs around the internal orifices in the upper chamber to a higher rate and or bumping/shimming the system pressure. Assuming the fuel pump can support the higher SP and flow rates.

Some believe that modifying the metering pin slits can increase fuel delivery. I have not been convinced of this but only because I have not studied it.

Unbelievable initiative and motivation.

Cheers.
Old 06-29-2009, 08:52 PM
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Quote:
Originally Posted by 911st View Post
Achieving the lowest control pressure dose not necessarily confirm that the metering pin has reached full travel. I took my metering assembly apart and found that I could detail it so the pin could travel further depending on the CO adjustment.
Kind of what I was going for with the MAP line test.

Reduce the control pressures as low as possible and see what the 'real-world' results would be. If it doesn't add much at the highend, then more mods are needed, like you stated.

Curious minds want to know.
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Old 06-30-2009, 08:39 AM
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Good work so far Thierry.

I have a similar car , i have been runnuing similar set up for months and my car makes over 400 bhp at the wheels and have plenty fuel still in reserve!...so there is no reason why you shouldnt be getting enough fuel in there!

Check my thread out also for more info on adjusting meter head to flow match fuel to each cylinder,,i have mentioned approx fuel you should be getting versus a certain amount of time and at wide open throttle(meter plate wide open)

Meter head flow adjustment question??

I would check control pressure flow rate, this was 220ml per 1 minute in mine(line into wur,with pumps running only)
Test values are 160-240ml per 1 minute,,so best being somewhere in the upper limit!!

You could increase the pressure with adding a very small shim to the pressure valve in your metering head if you find you are not within the upper limit as mentioned above!..Pretty easy job to do and i would maybe start with only a shim of 0.25mm approx(0.010") then re-check and add more if need be!

If you were just to go ahead and add say 1mm+ and then only require to open frequency valve say 60% or so to acheive correct AFR curve throughout rev band, this would then be too high a pressure against the meter arm for no reason....I currenty have my frequency valve maximum opening at 80% so at this setting i still have a little fuel in reserve if need be!
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Old 06-30-2009, 09:47 AM
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stup,

I think everyone that runs CIS should read how you flow matched your injection. Poor flow matching is probably whey CIS has to run richer AFR's on boost and why we loose cylinders to lean burn even though we are running fat.


Quote:
Originally Posted by stup View Post

... then only require to open frequency valve say 60% or so to achieve correct AFR curve throughout rev band, this would then be too high a pressure against the meter arm for no reason....
If you are talking about the Lambda FV I do not believe that effects the metering arm pressure. It is intended to effect the pressure differential between the upper and lower chambers in the head to control how much flow can pass to the injector circuits.

The Control Pressure as he is manipulating with the Andial FV dose effect the metering arm pressure significantly.

By manipulating the CP with the Andial-FV, throttle response can be significantly improved. I used what I called a drop and catch strategy where the map cells that represented first drop in intake manifold pressure with acceleration, I drooped my CP like a rock to get the metering arm moving and move the AFR immediately to near 13-12.5 / 1. Then I would have to bring CP back to maintain my ideal AFR's.
Old 06-30-2009, 10:42 AM
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