# GX CIS



## taimaishu (Mar 2, 2009)

Anyone have any suggestions on CIS tuning for this motor/injection system?
I have a 1986 1.8 8v. The car is getting an autotech cam and sport springs. I also have the head from a 1987 GLI that i am putting on with the dual down pipe exhaust manifold and the dual down pipe into a high flow cat and 2.25 exhaust pipe. 
I don't want to have to upgrade to the CIS-E injection if I don't have too.


----------



## BSD (Jul 8, 2008)

I don't know how good you are with fiberglass.. but I cut a 3in hole in the side of my airbox.. and fiberglassed a tube that goes down into the fender where the charcoal canister used to be. 
I also removed A/C and P/S, Got a lightweight cam and intermediate gear, Drilled the little plug out of the CIS box and adjusted the CO2 mixture, raised ignition timing to 9 degrees, gasket matched intake and exhaust ports, lightweight flywheel, lower temp thermostat, ( raising ign timing and cam timing can will raise engine temperature ) definetly recommend an external oil cooler.. Theres more stuff.. but i'm at work and cant talk much more. LOL
CIS basic ( lambda ) is capable of like 170HP.. I doubt you will be making that much.. unless you go forced inducation.. I don't like CIS-E Actually.
I got a Volvo 240T Fuel distributor because I will be boosting soon.
Just my thoughts and opinions.
Steve-


----------



## taimaishu (Mar 2, 2009)

*Re: (BSD)*

Thanks. I have the Lamba CIS then?


----------



## BSD (Jul 8, 2008)

Yes you do.. you have the same exact engine I used to have.








Oh, and it seems cis Loves more spark..


----------



## taimaishu (Mar 2, 2009)

*Re: (BSD)*

I am planning to put a BMW coil in it. My Mechanic told me in will feel a lot different.
Can you put together a lit of what you put in the car? It will save me a lot of guess work. Manufacturers and why. 
Can you post some pics of the fiberglass work you are referring to? 
Thanks, 


_Modified by taimaishu at 6:54 PM 3-7-2009_


----------



## BSD (Jul 8, 2008)

I sure can bud, I can probably do all that tomorrow.
Steve-


----------



## taimaishu (Mar 2, 2009)

*Re: (BSD)*

Any help is appreciated. Take your time. 
Thanks again, 


_Modified by taimaishu at 7:32 PM 3-7-2009_


----------



## WaterWheels (Aug 14, 2005)

*Re: GX CIS (taimaishu)*

Swapping the head is a good start as the it is a bigger valave head and will help with cylinder filling. With that head and the exhaust, the camshaft will work much better. Drop the idea of using that BMW coil as it is a total waste of your time and money (bet the mechanic just happens to have an extra laying around he'll sell to ya). The GX engine is a low compression engine and it would be a real benefit to swap in a set of GTi (i.e. 10:1) pistons. Of course if money is real tight it might just make more sense to find a good used GTi engine? The fuel injection can handle/adjust to everything you are planning without making any changes, and you should not try unless you can monitor the mixture.


----------



## BSD (Jul 8, 2008)

Well said WW.
I swapped out my GX because of the lower compression... IMO, I reeeeally liked the way MSD has performed in my car.. I get amazing spark.
GTI's have higher compression and bigger valves.. I think only 85-87 standard cars had small valves??


----------



## taimaishu (Mar 2, 2009)

*Re: (BSD)*

The BMW coil provides more spark just like the MSD and it fits in the location of the original without modifying it.


----------



## Prairie (Aug 5, 2008)

Can one simply use a good set of used pistons out of a digifant block to get to 10:1???


----------



## bubba_vw (Dec 3, 2008)

*Re: (taimaishu)*

what year of BMW is for that coil??? I have a GX head on a GTI (HT) bottom end. makes a would of difference. Where should i put my timing and do it need to adjust the fuel for the higher compression??


----------



## WaterWheels (Aug 14, 2005)

*Re: (bubba_vw)*


_Quote, originally posted by *taimaishu* »_The BMW coil provides more spark just like the MSD and it fits in the location of the original without modifying it.

Yes it fits in the same holder, but so do hundreds of other coils non of which will do squat for the engine. 80% or more of the "High Performance" ignition parts and information are nothing but *HYPE*. Granted the 80% I stated was just a guess on my part but I bet I'm close. The VW ignition is a very good system and provides more than enough spark to satisfy your engines needs. Do you know the primary resistance of this BMW coil? Do you know the secondary resistance? Do you know just what the effects of the two would do spark wise? Do you know how much voltage is required to bridge the sparkplug gap of your engine? And just what would having 10K or 20K more volts do if the coil did provide that much more? OK, this coil I'm sure would be real cheap, but why bother? Spend the 10 dollars on a manual to learn about ignition system parts or for Internet time to search for information, it would be better spent.
As for the MSD ignition, you do gain a slight bit by using one, but it has zero to do with increased voltage.

_Quote, originally posted by *Prairie* »_Can one simply use a good set of used pistons out of a digifant block to get to 10:1???

Yes, but the cost could be higher then just finding a good used block. The pistons will need rings, bad idea to use old ones, and the block could require boring or de-glazing. Then there is the labor involved and the big question; "Do I replace the main and rod bearings while it is apart?". If you just want to take your time and play/learn then I would say do it, with a second block, and keep you current engine in the car until finish.

_Quote, originally posted by *bubba_vw* »_ I have a GX head on a GTI (HT) bottom end. makes a would of difference. Where should i put my timing and do it need to adjust the fuel for the higher compression??

Yes, I'm sure it did make a difference as you bumped up the static compression by one point, but the GX head is holding you back due to valve size. Timing would be the same as the factory setting for either engine, the GX or the HT and most other 1.8L 8v engines.


----------



## taimaishu (Mar 2, 2009)

*Re: (WaterWheels)*

Do you have any of the specs of the MSD? I have done this in a GLI 8V and it made a huge difference.


----------



## bubba_vw (Dec 3, 2008)

*Re: (WaterWheels)*

the only reason i put the GX head back on was that i needed to get the car back on the road. Is there that much of a difference between the to heads?? Right now the timing is off from stock.


----------



## salz2135 (Sep 18, 2006)

The intake valves on the GX cylinder head are 38mm vs. 40mm valves found on the "large valve" heads. 
The stock ignition timing for your setup would be at 6 degrees BTDC. 


_Modified by salz2135 at 6:30 PM 3-9-2009_


----------



## bubba_vw (Dec 3, 2008)

*Re: (salz2135)*

it will not run at 6 degrees. it pings going down the road and is with 92 in it. will having the GX head on the HT bottom end hurt the motor any??


----------



## taimaishu (Mar 2, 2009)

*Re: (bubba_vw)*

Start at stock timing and decide if you want more high end power or low end power. 
For higher rpm power retard the timing. For lower rpm power advance the timing. 
Start small and slowly increase it till you get it where you want it.
If you are going to play with it a lot, i.e. retard it for one course and advance it for another, it is worth the $100.00+ in the time it will save you.


----------



## salz2135 (Sep 18, 2006)

*Re: (bubba_vw)*

So, if it can't run at the stock setting, what do you have it set at? I'm running my ABA bottom/CIS head at 12 degrees BTDC for what it's worth. The ABA is a high compression block as well, but it still runs fine at stock 6 degrees base ignition timing.


----------



## bubba_vw (Dec 3, 2008)

*Re: (salz2135)*

i'm not sure. my guess is 12-15 degrees right now. i don't have a timing light


----------



## Holden McNeil (Jul 26, 2004)

*Re: (bubba_vw)*

woah.... wait a sec... Let's clear a few things up... CIS Basic doesn't have an O2 so it's actually a non-lambda setup and it also doesn't have a frequency valve. CIS-L a.k.a. CIS Lambda has an O2 sensor, freq valve, and the Jetronic "Lambda" box which controls the 02 loop. CIS-E, which that GX motor should have, has knock sensing ignition control and O2.


_Modified by Holden McNeil at 10:58 AM 3-11-2009_


----------



## Prairie (Aug 5, 2008)

My CIS-E '85 Jetta does not have a knock sensor. Aparently, the early ones did not??


----------



## WaterWheels (Aug 14, 2005)

*Re: (Holden McNeil)*


_Quote, originally posted by *Holden McNeil* »_ CIS-E, which that GX motor should have, has knock sensing ignition control and O2.


Not that it really matters at this point or for other reasons, but my information and research shows that that model could have one of three engines. The GX could come in one of two versions, I guess depending on just when it was made. Either a CIS w/Lambda or a very early CIS-e with no knock sensor ignition. The other would I guess come on something like the GL or GLi which would be the RD code engine with CIS-e and the knock sensor ignition. Could be wrong but that is what a few sources say.


----------



## Holden McNeil (Jul 26, 2004)

*Re: (WaterWheels)*


_Quote, originally posted by *WaterWheels* »_
Not that it really matters at this point or for other reasons, but my information and research shows that that model could have one of three engines. The GX could come in one of two versions, I guess depending on just when it was made. Either a CIS w/Lambda or a very early CIS-e with no knock sensor ignition. The other would I guess come on something like the GL or GLi which would be the RD code engine with CIS-e and the knock sensor ignition. Could be wrong but that is what a few sources say.

I've heard rumor of CIS-L on early MK2s but I've never seen one in the wild - It would definitely be cool if this is one of them! (OP please take pics







) I had an '85 GTI which definitely had CIS-E and is the desirable knock sensing ingnition setup IIRC.


----------



## bubba_vw (Dec 3, 2008)

*Re: (Holden McNeil)*

my GX didn't have a knock sensor, so im guessing it's a cis-L because it has an O2 sensor


----------



## Prairie (Aug 5, 2008)

Allow me to add that yes, there are CIS-L Mk II's out there. I own an original '86 Golf with CIS-L and my best friend has an '85 Mexican made Jetta with original CIS-L as well.
I also have an '85 Jetta with CIS-E minus any knock sensor......so, yes, ALL these variants do exist.


----------



## Holden McNeil (Jul 26, 2004)

*Re: (Prairie)*


_Quote, originally posted by *Prairie* »_Allow me to add that yes, there are CIS-L Mk II's out there. I own an original '86 Golf with CIS-L and my best friend has an '85 Mexican made Jetta with original CIS-L as well.
I also have an '85 Jetta with CIS-E minus any knock sensor......so, yes, ALL these variants do exist.

CIS-L MKII = http://****************.com/smile/emlove.gif


----------



## taimaishu (Mar 2, 2009)

*Re: (Holden McNeil)*

Here look it up. http://www.a2resource.com/eandt/engines.html


----------



## BSD (Jul 8, 2008)

My car is CIS-L


----------



## Holden McNeil (Jul 26, 2004)

*Re: (BSD)*


_Quote, originally posted by *taimaishu* »_Here look it up. http://www.a2resource.com/eandt/engines.html

Thanks for the link and the quick education on MK2 CIS variants!! This should be IM'd to Longitundal for the CIS FAQ! 

_Quote, originally posted by *BSD* »_My car is CIS-L
















I should have been more clear that I was directing that mess of a post on what-is-what towards you

















_Modified by Holden McNeil at 3:13 PM 3-11-2009_


----------



## bubba_vw (Dec 3, 2008)

nobody answer my main question. will having the GX head on the HT bottom end hurt the motor any??


----------



## WaterWheels (Aug 14, 2005)

*Re: (bubba_vw)*


_Quote, originally posted by *bubba_vw* »_nobody answer my main question. will having the GX head on the HT bottom end hurt the motor any??

No. It will cause no damage other then being a "lesser performance" head if that matters. If you are having troubles with pinging and are using 92 octane gasoline, it is not because of the cylinder head.


----------



## BSD (Jul 8, 2008)

the only potential "damage" would be doing the mk2 head swap onto a mk3 block, which raises compression quite a bit.. But thats if you don't run atleast 93 octane imo.


----------

