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Guest Message by DevFuse

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CIS Fuel Injection Conversion - Write-Up with Pictures!!

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39 replies to this topic

#1 Guest_OH Noah_*

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Posted 04 June 2003 - 01:31 PM

Well, here's a little write-up I did on my fuel injection conversion:

Please let me know if there are any problems with the links or if you think of something else I should put in there. I plan to expand the page anyways, so I'm open to suggestions.

Also, feel free to ask any questions you may have about my conversion, but PLEASE read through my write-up first. I may have your answer in there already.


#2 Guest_SubaruJunkie_*

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Posted 04 June 2003 - 03:02 PM


I went to the junk yard today to get a fan for my radiator, and while i was there i was like "well, i think OH Noah said the CIS injector came on a VW FOX"

So I walked to the VW Section, and I found about 5 or 6 of them with the complete F.I setups still in them. Wasnt 100% sure if it was the same thing, but now that I just saw your pictures i am convinced it is.

So, should I be the 1st to try this on a EA81? Will we still need to change out all the fuel lines on a Carbbed EA81 to larger diameter for this CIS setup??


#3 Guest_hodakarider_*

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Posted 04 June 2003 - 03:13 PM

I notice you didn't use the knock sensor setup. Any reason why?

#4 Guest_SubaruJunkie_*

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Posted 04 June 2003 - 03:20 PM

Anyone know if you can do this with a SPFI manifold and only 2 injectors??

Also, Noah... can you get a picture of the pump and fuel distributor assembly and label the fuel lines and which line goes to which injector (cyl 1, 2 etc).


#5 Guest_OH Noah_*

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Posted 04 June 2003 - 04:38 PM

<img src="http://www.fortunecity.com/silverstone/subaru/1/CIS/Top%20View%20After%20with%20Labels.JPG" style="border:0;"/>

I added a couple more pics to the gallery.

Brian, I think you've fallen under the common misconception that this is a sequential injection system. It makes absolutely no difference which fuel line is connected to which output from the fuel distributor. All four injectors are spraying continuously.

Otherwise, the #1 and #3 lines I used were from the VW Fox, and the #2 and #4 lines are the longest lines from two VW Rabbits.

As for the SPFI intake, it might be possible to mount the injectors at an angle for an EA81, but the best method would be to mount them directly into the heads like the EA81T. I'm pretty sure you'd have to use all four injectors to get the correct mixture.

As far as knock sensing ignition, I didn't have it available to me. Also, since I don't have a turbo yet, I didn't see the point in the added complication.

#6 Guest_SOOBME_*

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Posted 04 June 2003 - 05:04 PM

GREAT WRITE UP!!! I have been kicking the idea arownd for my EA81 engine for a while now. I'm thinking that the eazy way to do it is to take my heads off and take them to a good aluminum welder and have extra aluminum welded onto the tops of the intake runners on top of the heads. Then drill and tap into the new materail to mount the injectors. Turbo heads for an EA81 car are hard to come by.
Did I understand it right, U have the fule acumulator mounted right up by the fule pump and fule dis.?

#7 Guest_SubaruJunkie_*

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Posted 04 June 2003 - 05:04 PM

Ok... Its just alot easier to get my hands on a SPFI intake rather than a set of EA81T heads. Although I do have a lead on a set.


#8 Guest_SOOBME_*

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Posted 04 June 2003 - 05:12 PM

You could try making your'e oun intake, and build it with 2 injector mounts, 1 on each side of the runner at like a 45* angle pointing down @ the head. I don't know how well it would perform, but this is one idea I was thinking of using.

#9 Guest_thealleyboy_*

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Posted 04 June 2003 - 05:53 PM


Very nicely done!! I'm very impressed. I'm glad I live so close to you incase I want to attempt it myself {hint} {hint}.

You should see if Norm will be your official sponsor.:lol:

Gotta check it out up close in personal. What's your work schedule like these days?


#10 Guest_OH Noah_*

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Posted 04 June 2003 - 10:47 PM

John, you've got mail.

Brian, I'd like to do this to an EA81 too, and my plan is to JB Weld modified axle nuts onto the heads and use an SPFI intake to mount a throttle body. I had originally planned to just use an SPFI throttle body without the injector, but they have really tiny throttle plates.

Someone here said they have measurements that explain where the injector bosses are located on EA81T heads. With that info I'm hoping to be able to just drill the necessary holes in my carbed heads.

I just realized that there's a section missing from the write-up that I had planned to include. When I get time, I'm going to add a section about other engine possibilities. For instance, you can get 6 cylinder fuel distributors. I think CIS would be a great way to get an XT6 engine swap done. The biggest problem would be the ignition.

#11 Guest_SubaruJunkie_*

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Posted 04 June 2003 - 11:04 PM

Well hopefully here in a couple of weeks I should be able to get my hands on some EA81T heads.


#12 Guest_NoahDL88_*

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Posted 04 June 2003 - 11:29 PM

I need to get rid of the SPFI on my car and i don't want to get rid of the ease of fuel injection, I am converting to a EA-81 engine, so if anyone in the seattle area is doing this mod we should get to gether and guinea pig a car, i'm offering mine, and then we can bust out the rest real quick.

#13 Guest_RedLance_*

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Posted 05 June 2003 - 12:30 AM

All you guys/gals who are ditching your SPFI setups for CIS, can send me all the parts you take off. I've got several carbed EA-81's that I'd like to get fuel injected. I feel injection is way better then carberation, when done right. I've had to rebuild way to many Hitachi's, and webers are too expensive for me, and I don't want to mess with tuning them. So, if I could get hold of a couple SPFI systems, for little or nothing, I'd be a happy camper.


#14 Guest_tomrhere_*

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Posted 05 June 2003 - 01:55 AM

I meet Noah at the Butler, In. swap meet. This is one sweet set-up. Looks straight forward, and easy to do, for the mechanically inclined. The engine purred like a kitten, and I'm quite sure Noah has noticed an improvement in performance, if I've read his postings right. I like the look of the multi-port heads and spyder intake, myself. And I'm seriously considering it for my '82, maybe even the '86 down the road abit. Best thing about it is, no computer to mess with per se, plus you don't have to worry about which cylinder this injector hose was suppose to go to. I Like It!!!!! Good bit of engineering there Noah.......Tom

#15 Guest_Adam N.D.J._*

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Posted 05 June 2003 - 02:10 AM

I"m gonna go over to my VW buddies house tomarrow and pick up a couple of injectors, then pull some of my old heads outa storage (EA81's) and see how hard it would be to mount them in here. I don't think it would be too hard, specially if you know how to weld aluminum :P Hopefully I can get a camera to take pics of them, and many other things when I get done with them. I'll get back to ya'll on it. And lookin good Noah, it's funny that I was talking with Rich (the VW guy) that day before you posted about doing this to an EA81. Good bit of engineering there. Keep up the good work. Catch ya Laters.

#16 Guest_MilesFox_*

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Posted 05 June 2003 - 09:50 AM

I would like to see a tubo on that thar thang!

looks good, but looked better in person;)

since it already has turbo heads, that would work. but the poping would have to be made up. but you already know about the saab parts that fit

jooks like you got everyone to jump on the CIS bandwagon!

#17 Guest_OH Noah_*

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Posted 05 June 2003 - 10:30 PM

I'm really happy to see the interest in putting CIS on a EA81. That idea was actually what started this whole thing for me. The only reason I did the CIS swap to my EA82 was that I was having trouble with it, and had MPFI heads available. That meant that I could attempt this project with very little fabrication just to see if it'd work and to learn what sorts of problems there'd be. I'm very glad I did it this way.

Now for an update:

The car runs pretty well overall. I've still got my crappy 3spd Automatic in it, so it's kinda hard to judge power differences. It's also a little hard to stay objective about power gains since I have so much desire to feel that all my hard work resulted in more power. That said, I really do believe that I gained some power from this conversion. The most noticeable thing for me is that if I put the car into a situation that used to make it strain, it is now fully up to the task. It's still no speed demon, but at least it feels competent now.

I should also note that I'm having a small problem that I believe is robbing me of some power. My problem is most likely either coming from the way I hooked up my vacuum lines, or from the distributor. What's happening is that there is a very weak spot right when I come off of idle. Occasionally I'll get a little exhaust "pop" at this spot, especially right after the engine has been running at high RPM. I think I got a little too zealous in connecting up my PCV valve and charcoal cannister before I had fully tested the car. If neither of those turns out to be my problem, then it's pretty likely that I don't have my distributor hooked up right. I kinda guessed as to how the vacuum advance unit should be hooked up, and also guessed at what to set the timing at.

I'll be sure to let everyone know when I get this little bug fixed.

#18 Guest_SubaruJunkie_*

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Posted 05 June 2003 - 11:04 PM

Where is the air filter? Is there a way to stick a turbo on this thing? And if so, how would the ECU from the Fox like the fact that it is sucking in alot more air than stock?

Idea's are brewing!!! Ive been doing some searching on the net, and the CIS conversion seems to be popular with alot of people out there.

Did you go CIS or CIS-E??


#19 Guest_ShawnW_*

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Posted 05 June 2003 - 11:09 PM

Brian first paragraph on his page says its the E kind.

#20 Guest_SubaruJunkie_*

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Posted 05 June 2003 - 11:14 PM

thought so, i forgot and was too lazy to check :)


#21 Guest_OH Noah_*

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Posted 06 June 2003 - 09:56 AM

It's a little hard to see in the picture I posted above, but the fuel distributor is mounted on top of the air box. The filter is inside.

The turbo possibilities are another part of what convinced me to try this. Audi, Porsche, and Saab turbos all used to use CIS (specifically CIS-2). The four cylinder versions of CIS are supposed to be good for up to 175hp before running out of fuel.
I dare you to get 175hp out of an EA81!!

If you used a knock-sensing ignition or factory boost levels, then all you'd have to do is plumb the turbo in between the fuel distributor assembly and the throttle body. CIS is not too smart, so it would just see more air flow and respond with more fuel.

Many VW folks have put turbos on their cars, so there's some support out there for doing this.

As a sort of side note, CIS-E was also available on the 16 valve versions of the VW Jetta, Golf, and Scirocco, as well as some Audi 4000s.

I'm going to be adding a section to my write-up that covers what cars have what parts at the junkyard, so keep an eye out for it.

Brian, watch for me on ICQ (see my bio).

#22 Guest_SubaruJunkie_*

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Posted 06 June 2003 - 10:44 AM

Ive already added you. Add me if you'd like, 42432153.


#23 Guest_OH Noah_*

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Posted 06 June 2003 - 12:05 PM


I've added a page that shows the basic differences between versions of CIS.

<a href="http://www.fortunecity.com/silverstone/subaru/1/CIS/CIS%20Versions%20Table.htm" target="top">CIS Versions Table</a>

#24 Guest_hodakarider_*

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Posted 06 June 2003 - 04:56 PM

Hmm. The chart is a little simplified, I think? I might be wrong. (My 1985 Jetta Carat had CIS-E with knock sensor) Also, there were some key diferences in the air sensor plate assembly itself. With the proper components, and good setup, this system has actually supported 200hp with turbo, and (I think) 180 without. I've got a book somewhere that gives a nice guide for mixing and matching components and tuning.

#25 Guest_OH Noah_*

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Posted 07 June 2003 - 06:59 AM

Yeah, I just returned that book to the library a couple days ago.

I know that some of the CIS-Basic and CIS-2 fuel distributors had 60mm air plates, while others had 80mm plates, and some of the 80mm plate ones had a thinner rim. There are performance differences between these, but all I wanted to show in the table was which system came on what. So yes, I guess it's a little simplified.

Did your Jetta Carat really have CIS-E (with the aluminum fuel dist.)??
All the CIS Jettas I've ever seen had CIS-2, except 16 Valve and possibly GLI models. Maybe the Carat had the GLI engine?? I'll have to look closer the next time I'm at a junkyard.

The knock sensor is part of the ignition, so it's totally separate from CIS.

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