Do you strongly dislike Z32 Coils and PTU as much as I do?

[300NSO]

First, new to the forum and not exactly sure where to post this.

I did this on my 1991 N/A

I have never liked the way the coils look on these cars and PTU's are outdated. So I decided to do something about it. First of all part of why I did this is because I am going to weld a custom intake and I need more room so the coils had to go. I went with VW/Audi coils, partly because they are cheap, more reliable then our stock coils, and I had some laying around. Oh and it gets rid of the PTU. I am not positive on this because I haven't looked up specs yet but I think the newer VW coils have a stronger spark as well. In the process I re-routed the injector and coil wiring to go under the intake plenum to make pulls easier.

If people are interested I will do a full write-up of the swap with wiring details, and pictures. As a warning you do have to grind some off of the intake and each coil, or make a 10mm plenum spacer like I did (yes it still clears the hood just fine).

Anyways let me know if its worth doing a write-up?

Thanks.

-Josh

[300ZXttZMAN]

UM YEA!!! This info is def worth making a write-up! If it works i'll make this into an article on the home page so make it good take some good pics and do some good explaining...

Welcome to Nico!!!

[DanDrath]

i am very interested in seeing this

[300NSO]

Ok, awesome. I will do the write up this weekend and take some more pictures.

[300ZXttZMAN]

i am very interested in seeing this

Exactly its not that I am going to do it but its going to be very interesting and I wouldn't be surprised if others did it also.

[es.biggs]

I'm interested too but I kinda wonder how is a VW coil more reliable than ours? All six of mine are over 20 years old and 110,000 miles on them lol

[whiteknight52]

I too am VERY VERY interested in this!!!!

[300NSO]

First of all you don't need a plenum spacer actually, I found a better way and they fit fine.

I haven't had good luck with the coils on my car and the PTU's are not the best. Plus stronger spark is always better.

Here is the write up:

Disclaimer: This procedure does require a plenum pull, soldering, wiring, time, and patience. If you are not good at or do not have those please do not attempt. Also I performed this on my 1991 N/A so wiring colors may differ in later years. I am happy to help if you can not figure it out but if you break something I take no responsibility. Please read the whole post before attempting.

A warning: With this swap if you need to change the plugs or a coil it does require the plenum to be pulled, although with this swap it makes pulling it a lot easier.

Stuff you will need:
Six VW/Audi Ignition coils part number: 06B 905 115L (make sure it has "L" or "R" at the end as they are the updated parts). These are supposed make 30kv.

Edit: I just replaced all of mine because I put in used coils for the initial install. The latest part number from VW is: 06A 905 115D

I recommend buying new coils. They are pretty cheap.

Side not: All I have found so far says that our stock coils make 21kv.(please correct me if I am wrong)

Six electrical plugs to fit the coils. I got mine from a new VR6 engine at a partsyard. The part number for one plug is: 4B0 973 724
I highly recommend getting the plugs from an existing wiring harness or else you have to buy the wiring and sealing grommets. The 1.8T Plugs will work too you will just have to find two harnesses to cut from.

Solder, soldering iron, flux, heat shrink, heat gun, and electrical tape.

The how to:

First: Pull the upper intake plenum. This has been covered many times so I will not go into it.

Second: Plan ahead and figure out how much of the harness you want to open up. You can simply cut the plug for each coil off. I chose to re-route the injector wiring to run under the plenum so I opened up the harness almost all the way to the main harness near the brake booster.

Injector and fuel temp. sensor wiring:


Third: Now that you have your plan of attack its time to wire the coils. On our coils the middle wire is B+, the small black wire is ground, and the red/color wire is the signal(except number one which is black). On the VW coils they are numbered 1-4.
#1 is B+ so it connects to the middle wire from stock plug.
#2 is ECU ground circuit so it connects to the small black wire from stock plug.
#3 is signal from ECU so it connects to our signal wire. Cyl. 1 black. Cyl 2 Red/White. Cyl. 3 Red. Cyl. 4 Red/Green. Cyl. 5 Red/Yellow. Cyl. 6 Red/Blue.
#4 is ground, our coils do not have four wires so you will need to either ground each coil or connect the three on each side of the engine and run one wire to ground.
Plug wires.


I found a good ground on the right side off of the cam timing adjuster, I also grounded the fuel rail ground there.


For the left side i used the stock ground location on the upper plenum near the idle air control valve.


Step Four: You should now have the six plugs wired up. You can now install the coils, it should look something like this.
Right side.


Left Side.


Step Five: You can now install the upper plenum. Make sure the coils clear, they should all be straight except the number two coil should turn slightly forward. Make sure if you opened up the harness that nothing is getting pinched or pulled on.


Step Six: The PTU bypass wiring. Its pretty straight forward. Just connect the wires straight across. The ground is not used.
I had relocated my PTU previously so it made the wiring pretty easy. If you have an S2 PTU then you can remove the little harness that came with it and splice it out of the car.
Orange-Pink
Blue-Brown
Green-Purple
Red-Light Blue
Yellow-Grey
White-Turqoise


The end result is a clean upper plenum. You could take it a step further and grind off the tabs that the old coils bolted onto.





It now takes less then 10 minutes to pull my upper plenum.

This is my first write up so if I left anything out or you have any questions please let me know.

[DanDrath]

wow man very well done! looks awesome

[300ZXttZMAN]

Hmm. Interesting good job.

[xclusivez32]

specs on the 2 coil outputs?

[300NSO]

Updated the write up. In searching for coil output voltages I found a better Hitachi made VW coil to use, added the part number.

All I have found so far is our stock coils are supposed to make 21kv.

The stock VW coils 06B 905 115L or "R" are supposed to make 30kv.

[Gino]

have you been driving the car with the VW coils and PTU bypass? How does it perform? Same as stock? I'm very interested in doing this with my set up but am slightly weary of deleting the PTU...

[300ZXttZMAN]

have you been driving the car with the VW coils and PTU bypass? How does it perform? Same as stock? I'm very interested in doing this with my set up but am slightly weary of deleting the PTU...

I wouldn't do it. I don't think any TT's should do it because it could simply make problems.

NA's I say go for it maybe there will be a performance gain.

TT's I say stay the hell away.. I know yall are going to ask why I say stay away... Here is the answer: There is no sense in changing something if its not broke.

[300NSO]

I do not expect anyone to do this. I just wanted to share what I did. So far it has been working good. It's a mostly stock N/A though so I didn't expect to see any gains. This is for my future plans. You have to remove the PTU because on the stock coils the PTU uses the signal from the ECU to ground the primary coil inducing a spark whereas the VW coils have the PTU inside them so they just need the signal from the ECU.

As far as TT's I expect with more coil voltage to work with you could run a slightly bigger spark plug gap and get slightly better combustion.

[300ZXttZMAN]

^

I am glad you shared the info with us. I am going to start putting it into an article as soon as we figure out if its dependable.

[raremotive]

have you been driving the car with the VW coils and PTU bypass? How does it perform? Same as stock? I'm very interested in doing this with my set up but am slightly weary of deleting the PTU...

my-ls2-ls7-coil-swap-t353832.html

You could also go with lsx individual coils.

[Gino]

after doing a little more research, this is actually a pretty good idea...as you said, the VW coils are higher output than the stock Z coils, which will actually benefit a car like mine...a hotter spark, ability to run a wider gap, more reliable spark, and should relate to overall better performance. With a higher output there shouldn't be any issues with blowing spark out at higher boost (30+ lbs). I think once my car is tuned and I won't need to keep pulling and cleaning plugs I will be doing this

[300NSO]

I also found some coils that are from a newer VR6 and they look like they would just clip on to the spark plugs and would come on and off without having to pull the plenum. I will get a picture and post the part number. The wiring numbers on the coils are a little different but if I get time I will add it to the write up.

[HowlerMonkey]

300NSO might have just clinched the "highest value per post" award at nicoclub with this thread.

[mrmoose]

im not expert with the electronics, but wont removing the ptu fry the ecu? at least thats what i heard. anyways i thinks its a great idea, i always have had ptu problems. make some vids!

[HowlerMonkey]

Each VR6 coil has it's own power transistor.

If the original poster's car is running and not throwing a check engine light, then I see no harm.

[johnathanbarnes]

Is there any update on this?

[Oh Em Zee]

This is bad a**.
Also; Welcome to Nico, JB!

[RubyRed300ZX]

Best thread in a long time.

[t.mcginley.jr]

Wow that's a pretty unique mod, especially if it's still working.

The OP hasn't posted since Feb when he first posted this, so I don't think he's checked this thread (or site) for a while now.

[swimshark]

Have you has any issues with the coil packs yet? If you search the part number 06B 905 115L, is shows that there is a recall and they are putting in the 06B 905 115"D" at the dealership which are supposed newer and better coil packs. Just wondering cause planning on doing this while car is still down. Been over a year now.

[HowlerMonkey]

If you have a way to tune that will allow you to change how the ecu outputs to the coils such as dwell, "offset", and other settings, you should be able to use any coil.

I have been seeing a lot of Volvo coils in the junkyards that look pretty sweet but not a lot on specs.