# CIS injector flow rates?



## Stephen Webb (Apr 12, 2001)

I am trying to find flow rates for CIS fuel injectors, but I am not having much luck.
(For instance from CIS-E motronic setups, Audi turbo setups, Porsche, etc etc.)
Ideally I would have access to a list of CIS fuel injectors, the amount of fuel they flow, and a part number. Most sites I have found so far deal with EFI components.
Any help would be appreciated.
Thanks
-Steve


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## Dieder (May 30, 2000)

*Re: CIS injector flow rates? (Stephen Webb)*

I am curious TTToo. Can they flow well enough for say.... 160 hp?


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## Stephen Webb (Apr 12, 2001)

*Re: CIS injector flow rates? (Dieder)*

quote:[HR][/HR]I am curious TTToo. Can they flow well enough for say.... 160 hp?[HR][/HR]​Well according to Darrll Vittone of Techtonics, the stock injection can support about 170 HP without modification.
I'm not going to be happy with 170, though. I hope to boost enough to get round 190 or so.
I've got a fuel distributor from a Volvo turbo, which is actually a 6 cylinder unit with two of the ports plugged. Now I'm trying to source injectors for this setup. I exchanged email with Gary Miller of Miller Fuel Injection, and he said:
"Look for the 017 suffix injectors, Bosch dealers can get them"
I just friggin wish I could figure out how much they flow, and what cars they came on, etc. etc.
-Steve


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## Dieder (May 30, 2000)

*Re: CIS injector flow rates? (Stephen Webb)*

Steve-
tell me more tell me more!
I was trying to figure out how to get more gas lines for my extra injecors. I got a turbo plan in the works.
Please fill me in on all this volvo fuel dist swapping info.
thanks


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## Stephen Webb (Apr 12, 2001)

*Re: CIS injector flow rates? (Dieder)*

quote:[HR][/HR]Steve-
tell me more tell me more!
I was trying to figure out how to get more gas lines for my extra injecors. I got a turbo plan in the works.
Please fill me in on all this volvo fuel dist swapping info.
thanks[HR][/HR]​You are in luck. (maybe) 
I have been doing research on this subject for several months now; I tend to dig in deep when I do research.
I will tell you all I know.
1. Volvo turbo fuel distributors are 6 cylinder units with two ports plugged off. There is MAYBE something else going on inside too, I don't know. (ie you my not just be able to grab a 6 cylinder unit and plug two of the ports yourself - but you may. Not sure)
2. The Volvo units are good for either 220 or 260 HP, depending on which one you have (I don't know how to tell them apart) The one I have will literally bolt into my factory airbox, but the flow plate is definitely larger.
3. The control pressure regulator (if you don't know what this is, ask) for the Volvo turbo (as well as Audi turbo models and many others) is a boost-sensitive unit. Under boost it will LOWER your control pressure, which causes MORE fuel to be injected for a given amount of air. I would consider this a must for a CIS turbo install. (In fact it's a pretty appealing part of CIS if you ask me). The important thing is that you have a full throttle switch in good working order. Otherwise your lambda system will try to bring you back to "stoich" mixture, wich it may or may not be able to do. In any event, without the switch you will run leaner than with it, so make sure you have one.
4. At least one person has used an Audi 5k fuel injection setup, running the fifth injector to a port in front of the throttle body. Sort of a weird mix of multi port injection and throttle body injection. But hey, if it works it works. These audi units are 6 cylinder units with one port plugged. I have heard that they can handle 280 HP or something (don't quote me on that). 
5. Someone somewhere was complaining about running lean under serious boost (volvo or Audi, I forget). They were looking for larger injectors, but were told to increase their system pressure. You can do this by shimming up the fuel pressure regulator that is built in to the CIS fuel distributor. It's a valve witha spring and some shims, I think less shims increases system pressure, but I don't know for sure.
6. If you don't have it, buy "Bosch fuel injection and engine management" by Charles O. Probst. It's a Robert Bently published book. Good stuff. It's good for a thorough understanding of the fuel system. The cove says "includes high performance tuning" which is a total load of boolsheet. It doesn't cover much of anything as far as perforance goes. BUT, you gain the knowledge you need.
I think I paid $40 for the book, I may be off on that, though.
I'm sure I know more, but I forget right now.
Ask if you have questions.
-Steve


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## Dieder (May 30, 2000)

*Re: CIS injector flow rates? (Stephen Webb)*

Steve, now I dont want you to go and do all my work but... what setup should I use? 
I have heard things about the Saab 900 fuel dist, and either the Saab turbo pressure regulator or the Audi turbo unit. Where exactly is it on a CIS-E car I know the CIS one is on the block. Which works best?
The 5 cyl distributor sounds perfect, I assume that actually has 6 lines coming off it. 5 injectors and 1 cold start. So I would have one line to hook up to an extra cold start valve in the intake and run a boost sensitive switch to it. Would having one of the lines closed execpt under boost cause the other injectors to run at a higher pressure, throwing things off? The origianl cold start valve remains the same right? I was even thinking of adding diffrent boost pressure switch to the cold start and the full throttle switch to kick another injector on at higher boost. 
And what exactly does the pressure control unit do? would I need the boost switches or will that do the job to send more fuel (with less pressure) to the existing injectors.
please tell me if I'm confused and have this all wrong.
I really need a visual diagram or a full explanation of the system, i guess its time to get the bosch book.


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## Stephen Webb (Apr 12, 2001)

*Re: CIS injector flow rates? (Dieder)*

First off, yes, the audi 5k setup does have 6 lines. 5 of them are "metered" fuel lines, and the 6th one is for the cold start valve. A setup with multiple cold start valves and switches to engage them under various conditions can be successful, but may not be necessary. 
I don't know what happens when you plug off the 5th injector line. I think you would hope that the other 4 injectors would spray 25% more to accomodate for the blocked injector. I say this because the fuel metering flap raises in proportion to the amount of airflow, and if it "allocates" a certain amount of fuel for 5 injectors, the same amount of fuel is needed if you only use 4 injectors.
Since you have CIS-E, you don't have a control pressure regulator. Instead you have the grey box on the side of your fuel distributor, which does basically the same thing, but is electronic. It's called the differential pressure regulator, and more or less takes the place of the control pressur eregulator and the frequency valve ("lambda valve" it's sometimes called). The problem is that I don't know much about a boost sensitive version of this setup. I believe there is some freely available circuit schematic / PCB layout that acts as an enrichment module for CIS-E, and you may be able to adapt it to react to MAP. If you are so inclined to take this project up, you might want to look into this part: Motorola MPX4250A. It's a pressure sensor that is designed for automotive use. It gives a linear response for 2 to 36 psia ranging from 0.1 - 4.9 volts or something like that. 
I believe the CIS-E fuel distributor has a manifold pressure controlled fuel pressure regulator into it, but I don't know what it does when it sees boost. 
Unfortunately (for you) I don't have CIS-E, so I haven't been doing much research for the CIS-E setup.
Good luck to you.
-Steve
edit: typo


[Modified by Stephen Webb, 5:20 AM 9-26-2001]


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## 89turbrio (Aug 31, 2001)

*Re: CIS injector flow rates? (Stephen Webb)*

http://****************.com/smile/emthup.gif awesome research! you should be an investigator. There's a guy who runs a hobbs switch to the cold start injector that says he pushs 220HP. I personally have a turbo and have microfueler enrichment. I have a short in my system- electrical wirin in the dash I think- but before this problem started, my lambda read first green light rich under 1 lb of boost and stayed there until the spring opened the wastegate at 7 psi.
I'm lookin to try to hobbs switch the lambda temperature enrichment switch to 1-4 lbs boost, (but I'm not sure where that is) This is as per the Callaway manual on fuel enrichment under boost.
Let me know how the set up works for you'all I'm always working towards more safe boost.


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## Tette (Jun 13, 2000)

*Re: CIS injector flow rates? (89turbrio)*

I have a complete audi 5k turbo CIS setup for sale. The system is good to ~250hp on the 5000 turbos. Email me if you are interested -> [email protected]
-tom


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## Rabbid Rabbit (May 1, 2000)

*Re: CIS injector flow rates? (Peter Tong)*

Any CIS injector can flow enough for up to like 400hp.(dont quote me on that) It all depends on the fuel distributor.(you can quote me on that!







)


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## Stephen Webb (Apr 12, 2001)

*Re: CIS injector flow rates? (Rabbid Rabbit)*

Nice info. Makes my life somewhat easier. 
So if I use my Volvo 240 turbo fuel distributor, and stock rabbit injectors, I can support 200 HP without needing to change injectors....right? 
If this is the case, I'd be right happy about things.








-Steve


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## Rabbid Rabbit (May 1, 2000)

*Re: CIS injector flow rates? (Stephen Webb)*

Right!


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## zaskar (Jan 17, 2000)

*Re: CIS injector flow rates? (Rabbid Rabbit)*

Another question for you guys, instead of starting a new topic im better asking here. you seems to know alot.
Ive done a 16 swap in a rabbit. I have put the injection system from the golf 2.0, with the motronic computer. but I had fit the motronic fuel system distributor on the driver side with a scirocco intake. now my problem is that I can' t use the motronic injector because they are not the same tread. 
if I put the rabbit injectors/line, it's gonna be OK ? I guess by what I've read. 
Zaskar


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## jpawl (Apr 12, 2000)

*Re: CIS injector flow rates? (zaskar)*

quote:[HR][/HR]Another question for you guys, instead of starting a new topic im better asking here. you seems to know alot.
Ive done a 16 swap in a rabbit. I have put the injection system from the golf 2.0, with the motronic computer. but I had fit the motronic fuel system distributor on the driver side with a scirocco intake. now my problem is that I can' t use the motronic injector because they are not the same tread. 
if I put the rabbit injectors/line, it's gonna be OK ? I guess by what I've read. 
Zaskar
[HR][/HR]​You can use the CIS-E lines from a S16V, use the CIS-E to Motronic adapter sold by http://www.parts4vws.com (Potterman), if you want to use your Motronic Injectors. I have seen 16V conversions using the CIS-E lines and CIS-E injectors as well within the Motronic set up....despite hearing that the Motronic Injectors flow more fuel? I thought it was up to the distributor? There must be some advantage to the Motronic Injector otherwise the VW engineers would not have made them when Motronic came out in 1990.
Thanks,
Jim


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## Peter Tong (Jun 17, 1999)

*Re: CIS injector flow rates? (Stephen Webb)*

Steven,
Whats the part number for your fuel distributor - I'll look up the flow per injector... the better way to do it is to lift the sensor plate all the way while grounding the lambda wire. Have the injectors discharging into a graduated container with a stopwatch.
FYI, the european style non lambda fuel distributors typically flow somewhat more...
PS: I probably should have gone with the simpler Volvo CIS - my Cabby has the downdraft Porsche 924 turbo CIS... would have saved myself a bit of installation/plumbing time.
Peter Tong
quote:[HR][/HR]Nice info. Makes my life somewhat easier. 
So if I use my Volvo 240 turbo fuel distributor, and stock rabbit injectors, I can support 200 HP without needing to change injectors....right? 
If this is the case, I'd be right happy about things.








-Steve
[HR][/HR]​


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## Butcher (Jan 31, 2001)

*Re: CIS injector flow rates? (Stephen Webb)*

<I don't know what happens when you plug off the 5th injector line. I think you would hope that the other 4 injectors would spray 25% more to accomodate for the blocked injector. I say this because the fuel metering flap raises in proportion to the amount of airflow, and if it "allocates" a certain amount of fuel for 5 injectors, the same amount of fuel is needed if you only use 4 injectors>
Sorry, WRONG answer. The fuel distributor has one opening for each injector. The openings are long slots in the bore of the control plunger. The more the openings are exposed the more fuel is sent to the injectors. If one is closed off that would not send more fuel to the other injectors. All it means is that that port would not flow any fuel. The fuel injectors do not regulate fuel at all. They just make the spray pattern. No metering is done by the injector [thats the job of the fuel distributor]. I do not know for certain but I would say the fuel distributors that have plugged lines are used because it would be cheaper to pull one off the Bosch shelf then to have one custom built for the application. I am not certain of this though.


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## Stephen Webb (Apr 12, 2001)

*Re: CIS injector flow rates? (Butcher)*

quote:[HR][/HR]<I don't know what happens when you plug off the 5th injector line. I think you would hope that the other 4 injectors would spray 25% more to accomodate for the blocked injector. I say this because the fuel metering flap raises in proportion to the amount of airflow, and if it "allocates" a certain amount of fuel for 5 injectors, the same amount of fuel is needed if you only use 4 injectors>
Sorry, WRONG answer. The fuel distributor has one opening for each injector.[HR][/HR]​Please read my posts before replying so strongly. 
I said "I think you would hope that the others would spray 25% more" because "the fuel metering flap raises in proportion to the airflow...so if it allocates a certain amount of fuel for 5 injectors, the same amount is needed if you only use 4 injectors"
I never said ANYTHING about what happens, just what NEEDS to happen if you want to run correctly.
-Steve


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## Andrew Stauffer (Oct 2, 2000)

*Re: CIS injector flow rates? (Stephen Webb)*

I think the answer ( I said "I think", I'm not sure) might lie in the fuel dist being cross drilled. 
The fuel plunger rises, exposing the metering slits. If fuel can flow, it does so. If it can't, it wont. That volume will be returned to the fuel tank via the return line without effecting the amount of fuel delivered to each respective injector. Some one tell me if they think I'm right thus far, this is definitely a work in progress. 
Now then, if the ports in the fuel distributor are cross drilled, the fuel from the metering slits WILL flow despite the fact that the port maybe blocked or closed. Take those spots on the Audi and Volvo fuel dist that DO NOT have fuel lines connected to them. If the plunger is feeding fuel to those lineless ports and they're crossdrilled to connect to the additional ports/fuel line attachment point, you'll receive more fuel, by volume, to each injector. More volume in a fixed area translates into higher pressures and in the world of CIS, that is how you get more fuel to flow out of the injectors. 
No idea if any of this is truly the way it works, but to me, it makes sense. Anyone else?


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