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Cis Question

3K views 24 replies 7 participants last post by  BennettVW 
#1 ·
Ok I picked up a 1989 Gti 16v. Just had some questions about it's fuel system

CIS-E, I believe it's called
Pro's, Con's? I'm trying to get some info how it works.
I've seen alot of people on vwvortex ditch it then some people don't.

I'm not planning On boosting it or Building, but I'd like to know, how, and if it's even possible. And if it is possible to what extent?
 
#3 ·
I'm not really wanting to boost do to it's going to be my DD for awhile and my wife would kill me if I boost another car right now lol, but what all do you need to do a digi 1 swap?
 
#4 ·
CIS-E can run boost, you will need to retard your base timing for ignition or get an MSD timing retard system. You would want to get a pressure switch to hook up to the intake manifold and wire it into the WOT switch wiring. You'll need to add extra fuel as well, you'll want to adjust the bas pressure for the DPR. There is instructions on doing it here.\\

http://forums.vwvortex.com/showthread.php?3070507

"Take the DPR from the car and place it in the palm of your hand in a folded-over shop rag. The rag is there to protect your skin in the event of flathead screwdriver slippage. Unscrew the brass flathead screw from the back of the DPR. The threads on this screw are amazingly fine. It is a marvel to me that such a screw could even be made. Remove the screw and KEEP TRACK OF THE COPPER WASHER. If you lose this washer, you will be looking for another DPR.

Behind this screw is a small allen head (VERY rarely this screw is actually a very small flathead) setscrew. This screw is what you adjust to power tune CIS-E. Just as with the idle mixture screw, small adjustments are significant, and just as with the idle screw, CW enriches. A good initial adjustment is 1/4 turn CW. Turn the screw, then re-tighten the flathead screw and reassemble the DPR to the metering head and reconnect the DPR along with the test harness. Don't go nuts tightening the screws that hold the DPR onto the metering head. They don't require that much torque and they may well be coming right back off after a brief test drive.

Fire up the engine. The idle mixture that you just set a few minutes ago will now be way rich. As always, wait for the O2 sensor to heat up before making any adjustments. Once the O2 sensor is warmed up, the idle current will drop substantially, possibly to zero. Make small CCW tweaks on the idle mixture screw until current is back to spec. Continue running engine until cooling fan has cycled once. Once engine is fully warm and idle mixture is set, take the car for a test drive with the test harness connected and routed into the car for a passenger to read while under low-load cruising and acceleration conditions.

On the test drive, you are looking for a nice rich 12:1 if possible AFR under WOT/boost and a middle of the road amperage to the DPR under light cruising throttle. When the system is near the end of its range of adjustment, cruising amperage to the DPR will become very low. At the point that the cruising amperage touches zero, the ECU will no longer be able to make lean-out adjustments to correct light-load mixtures. Adjusting the system beyond this will cause poor economy with negligible (if any) power increases.

Repeat the above DPR adjustment procedure as necessary with this caveat: DPR adjustments from this point can be VERY touchy, so no more than a 1/8 turn increment per adjustment is advisable. Each time you adjust the DPR, you re-start the engine, warm it up and set idle mixture again as described above before driving.

So far, I have found that 1/4 turn is all a stock engine needs to reach its full potential on CIS-E with a WOT switch. A 2L/big valve head/mild cam/good exhaust setup usually can take about 1/2 turn. A SUPER wild NA engine or turbo engine can use all the fuel it can get before the system can no longer adjust light load mixture--usually 3/4 turn. Beyond this, the system can usually no longer maintain a good stoich-ish mixture under light load."

more details in the thread obviously. The DPR is the part on the fuel distributor with the 2 wire connector, the 2 wire one is a potentiometer for the metering head position.

You can also turn it up some to make more power on the stock motor.

Before you mess with it though, make sure to find and fix all of the vacuum leaks, do a tune up, using ngk v power plugs. This includes all of the adjustments in the bentley for ignition timing, idle speed, co mixture etc. If you want a pdf copy of a bentley, i have one for a scirocco, it's the same engine so those things will be the same, although you have a ce2 wiring system so the wiring isnt the same going into the car's body harness.
 
#5 ·
A digi 1 swap would require finding a Corrado G60, getting the entire EFI system from it, including injector sleeves, and an aftermarket fuel rail with FPR adapter or aftermarket FPR. It would plug into your stock fuse panel.

I would go with megasquirt instead really. There is a lot to be gained with it. Especially since it's so easy to swap on bike throttle bodies in that case. The stock intake manifold is restrictive and can be cut down and hoses can be clamped on to fit them. Digi 1 would also require a custom burnt 16v chip to really run that motor right since the fuel and ignition requirements between the two motors are radically different and i believe the rev limit cuts way too early for a 16v as well.

If you wanted a stock efi, i'd really prefer doing an abf hybrid setup. Using a mk3 4 cylinder bottom end and management, with a 16v head swapped on. You can either run custom pistons on it, or run the sohc pistons and get really low compression, you also cant run aftermarket cams because there are no valve reliefs. There is also the option of replacing the aba rod bushings to early ones, and running stockk pistons from a 2.0 16v and getting approx 9:1 compression ratio, which is ok for na and still decent for boost as well. If you wanna do the swap you can research it online some more or i can answer some questions for you.

The stock CR is around 10.5:1 BTW, if you're thinking about boost, alot of people blow skirts off of stock pistons. Although a good efi and tune would help.
 
#6 ·
LOL I just got done reading that post

I'm going to stay away from the 16v/aba I've all ready built a 20v/aba before I liked it but, I'd like to keep the 16v the way it is motor wise

I've read that the CIS-E can only support to 160whp.
 
#7 ·
Also if i went megasquirt what one could I get away with
I,II,III, ect
 
#8 ·
Any of them will work. You just need one ignition input and one output, it's fairly simple, there is a guide on the small modification you need to do on diyautotune.
 
#9 ·
As far as max power goes, I've read before it's in the low 200s, as long as you adjust the DPR and all. Obviously you will have much better driveability with megasquirt, at least properly tuned.
 
#11 ·
Yeah, if you're going to stay NA 16v, my opinion for best bang for the buck as long as you're doing shit yourself.

Autotech Cams
Full Exhaust
Megasquirt
GSXR or similar throttle bodies
2l 16v block swap
 
#16 ·
My car ran fine on all mechanical CIS. Granted I never dynod it, I beat the brakes off of several new, more "advanced" cars.

CIS is fine if you know what you are doing and have the correct CIS setup. Collin from TT for example, went 12s in the 1/4 in a CIS 8v Rabbit.
 
#18 ·
Running high 12s in a car set up for drag racing with an insanely built engine by one of the pionering performance VW tuning companies really isint a testament for the mechanical fuel injection, rather the builder and engineering that went into his set up. I daily drove an 88 gti for three years on CIS with no issues from it. He asked about performance and boost, CIS isint optimal for either.
 
#19 ·
Well I know if I wanted to make power I'd go standalone. But really I was thinking make it healthy, Later on maybe work the head just a bit throw a small cam and exhaust, tweak the cis then just mate it up with a ridiculously Geared tranny< even if I every go boost i'll only push 8 pounds out of a small 16g just to make it routy and surprise the hell out of people stop light to stop light, I'm going to use another platform to go fast with.

Ignore my wife she's peggo and moody
 
#21 ·
I'm going to leave it a 1.8 for a good while, if not forever

Only way I'll be swapping the the bottom end is if I'm building it then I'll throw some rods and pistons and a nice bore and blah blah blah. But then again.. Fwd is going to kill me on speed so To go fast I want something Awd.
 
#22 ·
16V has dual downpipe stock in all chassis/engine sizes/management system.

Bennet has it right, it's obvious it has limitations, but I wouldn't upgrade unless i was going ITBs or forced induction, and he said he wasn't planning on boosting it.
 
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