Tuning CIS -using a wideband controller
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I've been using the LC-1 in my cabby for about 4 years now. The ability to tweak the Lambda switch point and adjusting the transfer rate is what makes it all worthwhile for me.:heart: For those of you who are try to race an old CIS car, one of these will help you make more power.
Basic with out Lambda, it would not work, though on a pure basic setup, you could manipulate the heating strip in the WUR.
From what I gather in this someone is writing about sending a signal to manipulate the frequency valve duty cycle (lambda valve), in order to regulate upper to lower fuel cahmber pressure. In theory it will work, applicationally, it will take a lot of trial and error, especially if you are dealing with a boosted application.
I know because I am, although I am doing it to a CIS-E platform (K-Jetronic), with the DPR, taking the Lambda's place and enhancing it with faster and finer response.
Though applicationally, my setup is a crude hodgepodge of a Hobb switch and playing with a fixed signal to effect the DPR (future plans are a MAP and TPS). All this while using my wideband as a "window" into the running conditions so I don't melt pistons.
From what I gather in this someone is writing about sending a signal to manipulate the frequency valve duty cycle (lambda valve), in order to regulate upper to lower fuel cahmber pressure. In theory it will work, applicationally, it will take a lot of trial and error, especially if you are dealing with a boosted application.
I know because I am, although I am doing it to a CIS-E platform (K-Jetronic), with the DPR, taking the Lambda's place and enhancing it with faster and finer response.
Though applicationally, my setup is a crude hodgepodge of a Hobb switch and playing with a fixed signal to effect the DPR (future plans are a MAP and TPS). All this while using my wideband as a "window" into the running conditions so I don't melt pistons.
CIS does a good job of holding the AFR that you set it to. The WB is a good way to see where the AFR is at and then adjust it. Unless you get close to the systems limits, a good functioning CIS is hard to beat for what it is.
When we swapped the 16V into the Scirocco (which had CIS-Lambda), that is what we did, as trying to feed the lambda controller the signal from the WB did nothing but make it go lean, no matter how we programmed the WB. We just disconnected the frequency valve's power and set the mixture with the 3mm allen and had solid AFR's from idle to redline.
When we swapped the 16V into the Scirocco (which had CIS-Lambda), that is what we did, as trying to feed the lambda controller the signal from the WB did nothing but make it go lean, no matter how we programmed the WB. We just disconnected the frequency valve's power and set the mixture with the 3mm allen and had solid AFR's from idle to redline.
That is because a signal to the lambda causes a lean duty cycle, as in IIRC, opening lower chamber flow, increasing the lower chamber pressure and restricting the flow that is allowed to be metered out the upper chamber ports.
Did you try switching the voltage?
That is what I am doing on the DPR, but in that the DPR is a magnetic coil that can accept positive and negative current, the lambda cannot as it is a valve that is switched on.
Did you try switching the voltage?
That is what I am doing on the DPR, but in that the DPR is a magnetic coil that can accept positive and negative current, the lambda cannot as it is a valve that is switched on.
We had the WB set up to output a NB signal in place of the NB O2 sensor. And yes, once the Frequency valve was unplugged, the system goes lean, then you just adjust the mixture screw to set the mixture(AFR) and that is pretty much where it stayed. We did have the WUR mounted up where the battery used to be, so as not to change the system pressure and therefore the the mixture.
The Lambda system has a controller (under the dash) along with the NB sensor along with the Frequency Valve on the Fuel Distributor.
The Lambda system has a controller (under the dash) along with the NB sensor along with the Frequency Valve on the Fuel Distributor.
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So the consensus is that these gauges are a more useful tool than dwell tuning? For setting a basic tune/diagnostic work is there a large advantage to the gauge? Thanks in advance, I am trying to justify buying the whole wideband setup when I could just buy a dwell meter. Thanks
Dwell meter can get you close to a good tune if you have a dyno or wide band read out. Other wide the dwell readings will get you factory AFR . Remember normal CIS -k jet (GTI) injection runs open look (not computer controlled) at wide open throttle not real fuel metering other than your basic dwell settings. With the wide band controller you are running closed loop all the time. (computer controlled all the time) The computer controls fairly accurately your AFR for WOT and non Wot driving.
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Does anyone have a good write up, or link to one on how to do all this? Or know if Scientific Rabbit still sells the harness kit for it? I'm building a CIS turbo frankenturd, and this would be perfect.
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This is the guts of the cis lambda controller. https://youtu.be/aE_tfbQPPqo
As you can see the problem is the cis lambda controller is slow to react, I assume this is on purpose so it doesn't overshoot the mixture requirements. Because of the reaction time simply switching o2 signals may not be the best solution especially for quick on/off throttle situations. How about feeding both o2 signals to the two separate cis lambda controllers and just switching the input of the frequency valve between the two cis lambda controllers outputs using the wot switch? I forsee no lag this way and would cost only another cis lambda controller box
As you can see the problem is the cis lambda controller is slow to react, I assume this is on purpose so it doesn't overshoot the mixture requirements. Because of the reaction time simply switching o2 signals may not be the best solution especially for quick on/off throttle situations. How about feeding both o2 signals to the two separate cis lambda controllers and just switching the input of the frequency valve between the two cis lambda controllers outputs using the wot switch? I forsee no lag this way and would cost only another cis lambda controller box
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Yeah, I had a friend who used the MTX-L out for CIS-E (KE Jetronic) and it didn't work all that well under WOT for reasons described above. We went a different path for CIS-E which I posted. Similar idea in terms of using an MTX-L but different in that we added some of our own electronics in there to control the DPR. I didn't think to see how to do that with plain CIS which might be simpler?
-e
-e
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Do you have any ideas for implementation on CIS-basic, with no frequency valve?Yeah, I had a friend who used the MTX-L out for CIS-E (KE Jetronic) and it didn't work all that well under WOT for reasons described above. We went a different path for CIS-E which I posted. Similar idea in terms of using an MTX-L but different in that we added some of our own electronics in there to control the DPR. I didn't think to see how to do that with plain CIS which might be simpler?
-e
But CIS basic does not have an O2 sensor. If you put an O2 sensor in the exhaust, adjusting it to that value does not really set the mixture right.
Read how a narrow band O2 sensor works and you will see, it only helps in a really narrow band. Certainly not good enough to adjust a fuel mixture.
http://www.enginebasics.com/EFI Tuning/AF Ratio Basics.html
Read how a narrow band O2 sensor works and you will see, it only helps in a really narrow band. Certainly not good enough to adjust a fuel mixture.
http://www.enginebasics.com/EFI Tuning/AF Ratio Basics.html
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wow... i haven't been back to vortex in a while so its kind of interesting seeing this CIS section.
My Lysholm supercharged Cabriolet has been in storage for years as well so i haven't played with CIS in a while and frankly am a bit rusty lol. Someday i'll get the new 2.0 8v with 42/35mm solid lifter valves in and have at it again.
When i was dyno tuning my Volvo 240 turbo CIS setup on it... i found i could not get the fuel i needed using the Volvo warm up regulator. i ended up adding an additional fuel circuit to directly drain control pressure with a frequency valve controlled by my VSAM setup. VSAM had load and duty cycle map which could be accessed using a laptop and the special software. Normally this fuel circuit would be closed, but under boost would open according to the duty cycle lookup point on the map.
i did a lot of injector testing... and was able to get top end fuel flow up to 420 cc per injector (per minute?). i think it was close to 100% more than the stockers.
i also found that after doing this that my new Bosch fuel pump was not supplying enough fuel at the top end... things were going lean. Ended up having to add a Boost-A-Pump to fix that problem (this was triggered only under boost).
The car ran perfectly well with CIS and the charger (and old video):
https://www.youtube.com/watch?v=J6EBPYnS_Qw
i ended up tuning things under boost to run around 12:1 afr... and of course off boost with the stock lambda valve in control dithering around 14.7 (all measured with a wide band).
Anyways just my $.02 now that i am back visiting the vortex.
My Lysholm supercharged Cabriolet has been in storage for years as well so i haven't played with CIS in a while and frankly am a bit rusty lol. Someday i'll get the new 2.0 8v with 42/35mm solid lifter valves in and have at it again.
When i was dyno tuning my Volvo 240 turbo CIS setup on it... i found i could not get the fuel i needed using the Volvo warm up regulator. i ended up adding an additional fuel circuit to directly drain control pressure with a frequency valve controlled by my VSAM setup. VSAM had load and duty cycle map which could be accessed using a laptop and the special software. Normally this fuel circuit would be closed, but under boost would open according to the duty cycle lookup point on the map.
i did a lot of injector testing... and was able to get top end fuel flow up to 420 cc per injector (per minute?). i think it was close to 100% more than the stockers.
i also found that after doing this that my new Bosch fuel pump was not supplying enough fuel at the top end... things were going lean. Ended up having to add a Boost-A-Pump to fix that problem (this was triggered only under boost).
The car ran perfectly well with CIS and the charger (and old video):
https://www.youtube.com/watch?v=J6EBPYnS_Qw
i ended up tuning things under boost to run around 12:1 afr... and of course off boost with the stock lambda valve in control dithering around 14.7 (all measured with a wide band).
Anyways just my $.02 now that i am back visiting the vortex.
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