# fuel enrichment... cis-l



## bmxguy (Sep 18, 2008)

is there any way to hook up a fuel enrichment switch on my 84 gti? i know you cant hook them up on basic, and everything i found in search is for cis-e. any help? if i can install one, a diagram would be sweet. 
TIA http://****************.com/smile/emthup.gif


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## WaterWheels (Aug 14, 2005)

No electronics that control the mixture, except for the O2 sensor but that system will not help, so no magic switches to enrich things. You can purchase a vacuum enrichment control pressure regulator for not too much. There is also at least one company that sells an electronic control pressure regulator which can be programed or adjusted, but it is $$$ if I remember. To be honest, I doubt 90% of the people who seek some form of CIS enrichment really don't need it, are you sure you do?


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## Glegor (Mar 31, 2008)

*Re: fuel enrichment... cis-l (bmxguy)*

does it run perfect already? its gonna run perfect before you start changing things.


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## Uberocco83 (Jul 15, 2008)

*Re: fuel enrichment... cis-l (bmxguy)*

There are a couple things.......... You can try different frequency valves that have different duty cycles, ie: something from a Saab or Volvo. You can also use an Innovate LC-1 wideband lambda controller in place of your stock O2 sensor to control the O2 input through a relay. At part throttle you set it so its like a stock simulation and at full throttle you can change it with the LC-1 so it enriches the mixture. Its very simple and Ive used it in a different way with cis-e with great results. http://forums.vwvortex.com/zerothread?id=4403069 ......check that one out, Wclark is a great guy. http://****************.com/smile/emthup.gif


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## WaterWheels (Aug 14, 2005)

*Re: fuel enrichment... cis-l (Uberocco83)*


_Quote, originally posted by *Uberocco83* »_You can try different frequency valves that have different duty cycles, ie: something from a Saab or Volvo. 

Although the cost of using the LC-1 may not be too high for most people, something like $200 plus a relay or two and some wiring stuff, it is still more than just doing a control pressure regulator up-grade and doing away with the Lambda system. Using the LC-1 has one draw back in that it requires both outputs and then it can no longer drive a gauge. I don't know if the LM-2 (or older LM-1) can handle more then two outputs, but that costs much more. But yes, there is almost always a way to do something if you have the cash collecting dust somewhere. Remember, Mr. Clarks auto is if I recall a single purpose auto, hill climbs or something, and using gadgets for other purposses to gain an edge is part of the cost of racing. Street drivers just don't have the extra cash or want to spend it for little gains if any for a street engine.
As I mentioned above, most people really do not need any "extra" enrichment. For some unknown reason it is often thought that "more fuel equals more power". Also many seem to believe that some minor modifications, mild camshafts, headers, port matching and such cause the engines fuel management system to require some help, both false in most cases. I can not think of a system, not talking carburators here now, that can not handle normal mild street type modifications or that can be pushed that very little extra with factory parts.
The statement about using different frequency valves sparks my curiosity. Just how would using say a Volvo or Saab frequency valve change things? Frequency valves are just open-closed valves driven by a control box, no?


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## salz2135 (Sep 18, 2006)

*Re: (WaterWheels)*


_Quote, originally posted by *WaterWheels* »_No electronics that control the mixture, except for the O2 sensor but that system will not help, so no magic switches to enrich things. You can purchase a vacuum enrichment control pressure regulator for not too much. There is also at least one company that sells an electronic control pressure regulator which can be programed or adjusted, but it is $$$ if I remember. To be honest, I doubt 90% of the people who seek some form of CIS enrichment really don't need it, are you sure you do?

I thought this is something that could be done by integrating a WOT switch to the CIS-L fueling system. The switch being activated should change the duty cycle at the frequency valve giving you a richer mixture under full throttle conditions. 
Isn't the theory that maximum power produced under slightly rich conditions, but at the expense of fuel economy? I thought this was the entire purpose behind introducing the full throttle circuit in the first place.



_Modified by salz2135 at 9:58 PM 3-11-2010_


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## WaterWheels (Aug 14, 2005)

*Re: (salz2135)*


_Quote, originally posted by *salz2135* »_I thought this is something that could be done by integrating a WOT switch to the CIS-L fueling system. The switch being activated should change the duty cycle at the frequency valve giving you a richer mixture under full throttle conditions. 
 
In factory form this is exactly how it works in basic terms. The WOT switch signals the control box which locks the frequency valve at something like 85% duty cycle (would have to check the exact value but that should be close). Under full throttle CIS-L is more or less CIS basic, the chamber pressure is fixed by the Lambda controler and the control pressure regulator is the sensor plates lifting limiter.

_Quote, originally posted by *salz2135* »_Isn't the theory that maximum power produced under slightly rich conditions, but at the expense of fuel economy? I thought this was the entire purpose behind introducing the full throttle circuit in the first place. 

Again I would say you are correct. This leads me to a question, did you have a counter comment, disagreement, wanted to clear something up, or other? Everythings fine I just don't understand where your leading, if in fact you were.


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## Uberocco83 (Jul 15, 2008)

*Re: fuel enrichment... cis-l (WaterWheels)*

How can it no longer drive a gauge? The LC-1 has an output for the gauge and an analog out for your O2 wire to the ecu. I am using mine in a street car with cis-e the same way WClark is in his hillclimb car. I use it in place of the stock O2 sensor so its like a normal O2 at part throttle and idle and at wot the relay clicks in and enriches to whatever lambda values are set in the program, which I cant remember right now what mine are at. $239 is not bad at all for me to tune something I invested a lot of time, effort and money into building even if it isnt a full out race monster.
I remember reading something about Collin(TT) using a Saab frequency valve on his high compression drag rabbit or maybe that was the entire fuel system......... Anyways, I thought maybe some other FV would have a different duty cycle like something from a turbo car. Ive never really played with cis-l much, I always ditched it for basic.


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## WaterWheels (Aug 14, 2005)

I don't know, I read and looked at his diagram some time back and re-read and looked again for this respose and the prior one, he has both outputs in use and the LC-1 only has 2. He has one being used for the relay/full throttle signal that he wants and the other is being used as a normal O2 sensor for the control box. That leaves none for a gauge, or have I missed something?
Yeah, I guess for some people $240 just to gain a little extra fuel is no big deal. In my book though, for a street car which really does not require any "extra" enrichment, or a very slight amount if it is really modified, it's a steep price to pay and could be put to better use. Believe me, I do know about cost vs. benefit and cost vs. return in race cars and street cars, been there, done that and paid for many many T-shirts.


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## ziddey (Apr 16, 2006)

*Re: (WaterWheels)*

How much can cis-l compensate? What if you set the mixture rich to the point that closed loop just brings it back to stoich? Then, set your WOT switch to cut lambda feedback, and the car goes open loop rich again. Would this be enough enrichment?
And for cold running open loop if it'd be too rich now, would there be a way to manipulate the CPR accordingly?


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## Uberocco83 (Jul 15, 2008)

*Re: (ziddey)*

Nope.
With them LM-1 or 2 you can do what WClark is doing with cis-e and because you arent using one of the two outputs for the gauge like the LC-1 you can use the hand held piece. Yes with the LC-1 you have to use one of the ouputs for the gauge. But you can just buy the LC-1 without the gauge and use it the way WClark and I are and monitor with your laptop. 
I built a 2.0 16v with a higher compression than stock, porting, larger intake manifold, header and cams for my street car. I didnt think that just slapping untuned cis-e on that would go over too well. I actually remember when I first got it running with out a fuel enrichment module I couldnt really floor it much because it would knock from being lean. It required much more fuel than stock and more resistance in the fuel enrichment module than anyone sells. This was also true for the aba/rd engine that I just got running with the same cis-e. However, I guess if you just had a stock 1.8 8v with no modifications what so ever then enrichment wouldnt really matter.


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## WaterWheels (Aug 14, 2005)

*Re: (Uberocco83)*


_Quote, originally posted by *Uberocco83* »_ Yes with the LC-1 you have to use one of the ouputs for the gauge. But you can just buy the LC-1 without the gauge and use it the way WClark and I are and monitor with your laptop. 

Sorry, my mistake I guess or your type-o. I thought I remembered in the other post where Mr. Clark discusses the setup you stating you had just recieved your LC-1 "with gauge". My fault I guess as it would be kind of dumb to spend the extra money for a gauge you wern't going to use. 

_Quote, originally posted by *Uberocco83* »_I built a 2.0 16v with a higher compression than stock, porting, larger intake manifold, header and cams for my street car. . . It required much more fuel than stock and more resistance in the fuel enrichment module than anyone sells. 

Although I love to talk shop with people, the above is just absurd at best. I know many people with engines which are really modified, not just some bolt on stuff, and are running just fine with CIS, CIS-L, CIS-E and Digifant II (yes Digi II). None of them have had to resort to drastic measures to find the correct mixtures. Yes, a bit of tweeking or some old racer tricks to get that little extra might be in use, but like I said above and often here and other places, 90% or more of the people do not need extra enrichment. I would even go so far as to say that a large percent are lower on power due to their "tuning" then they would be if they just left well enough alone.


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## Uberocco83 (Jul 15, 2008)

*Re: (WaterWheels)*

Im not arguing over this guys thread.........I simply tried to offer a suggestion to the guy that has actually worked very well for more than one person however absurd it is.


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## ds1919 (Oct 13, 2004)

*Re: (Uberocco83)*

the mkI GTI fuel enrichment device is tuned just right for the stock GTI. It does allow more fuel at WOT. Sometimes tho, a leaner mixture will gain more power, as more fuel at high RPMs will not burn all the way, creating lag. But a lean mixture can lead to excessive heat and thermal breakdown.
If you are doing boost, then yes more fuel would be desirable. But for NA stock rabbit GTI, you should have all the fuel you need from CIS. Too much fuel and the car wont perform well.


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