GM Ignition swap write-up - Prelude

[50-50]

What does this do?

1. Eliminate need for COP and nissan ignitor2. Convert ignition to GM waste spark DIS3. Coils last longer from cooler operation and are cheaper, easier to get4. Ignitor is readily available new and used5. Hot ignition spark (modified dwell map)6. Easier to check your timing with timing light/gun (no special tools or rigging required)7. Cleaner possible emission from waste spark8. Easier to maintain9. Improved aethetics, no need to run without the coil cover

Important Requirements

- Soldering knowledge or basic wiring skills- Socketed ECU- eeprom optional but recommended- NGK spark plugs gapped 0.7mm (0.028")

Terms used:- PnP (Plug and Play)- COP (Coil on plug)- OEM (Original Equipment Manufacturer)- DIS (Digital Ignition System)- GM (General Motors)

Tools Needed: (Including a phillips head screw driver)



Hardware and GM Ignition Parts used:

- GM Harness pigtails- GM Coils- GM Ignitor- Mounting hardware



Building the PnP Harness:

I raided the local junk yard to find a nissan or infinti with the 2 Male plug ends needed to make this harness.

Parts List:

- 2 x 6 pin male connectors

- 4 x 1N914 high speed switching diodes

- radio shack pre-drilled board (optional)- High temperature electrical tape- 1 x GM ignitor power pigtail- 1 x GM ignitor trigger pigtail- crimp on round connector with 6mm (0.25") hole

PnP harness wires



Step 1:

Start by soldering the (4) 24" wires, diodes and (2) 8" wires together. I used a pre-drilled board from radio shack to complete this part:

Step 2:

Connect the 4 free ends on the 24" wire to the male oem connector as in the diagram (right plug). Matchup the ignition 1 - 4 wires as labelled in the diode pic above with the appropriate signal connection on the male plug. The red power wire can also be connected with the other male plug (left plug). This is the only wire used from this plug to provide the switched 12V for the GM ignitor. The other end of the 12V wire goes to the matching pinout on the GM ignitor power pigtail. Crimp the circle "eye" connecter onto the ground wire and the other end to the matching ground on the GM ignitor pigtail:



** Completed Plug and Play Harness **



Pre-Install Requirements:- Remove the Coil plug cover- Remove OEM COP setup including the coils and harness- Install the spark plug wires. I used wires for a 94 Cavalier. Although the 7mm wires work, try to upgrade to a 8mm wire.- Label the spark plug wires 1,2,3,4- Replace the coil plug cover



Mounting and Installing the GM Ignition

Try to locate the Coils and ignitor somewhere in the engine bay that would allow convection cooling of the coils. I chose either of two methods using custom aluminum mounts:

Mounting brackets

1. - Mount the GM coils and ignitor in a front mount configuration

The following are required:

- Front aluminum plate/ heat sink, grounded- Electric fans- Modify the coil cover by removing 3/8" from the front of the coil cover



PROS:Cooler operationEasier accessLots of spaceCooler than oem coil operation

CONS:Longer spark plug wires required compared to top mount setup

2. - Mount the GM Coils and Ignitor in a top mount configuration

The following is required

- top mount aluminum plate/ heat sink, grounded



PROS:Shorter spark plug wires compared to front mountCooler than oem coil operation

CONS:Coil runs a bit hotter compared to the front mount configuration

Plug in the custom PnP Harness

- Plug in the GM end of the harness to the Ignitor- Plugin the shorter 6 pin male PnP plug for the 12V switched power to the ca18det EFI harness female connector where the OEM COP harness originally connected. Connect the ground wire of the PnP harness with the crimped on connector to the EFI harness ground on the side of the intake manifold.



- Disconnect the bigger 6 pin female connector from the oem ignitor. The other plug can be removed as well since the oem ignitor is no longer needed in the engine bay. Basically up to you.- Plugin the other longer 6 pin male plug on the PnP harness to the 6 pin female connector on the oem efi harness. For euro models S13, this connector is part of the main harness but essentially the same plug.



Check all your connectionsStart the car - The engine should idle and rev normally under no load

Dwell Map modification

In order for the coils to function properly the following changes MUST be made to the dwell map on the eprom. You can use ECUEdit to make this change or if you're using romedit, you can setup one of the additional maps with the hex location for the dwell map. These settings provide a nice hot spark while still maintaining cool coil operation. I've tested the spark to 15psi with no breaking up with my GT3071R turbo. 20psi should be more than capable for this setup without blowing out the spark.

the ca18det dwell map is located at H3890 and is 32bits long

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Modified by 50-50 at 8:00 PM 5/3/2007

[float_6969]

AFAIK, there's nothing on NICO about it. Do a well written, documented writeup with pictures and diagrams, and if the article guys like it, they'll make it an article in the write up page and you'll get a custom title under your screen name.

[50-50]

AFAIK, there's nothing on NICO about it. Do a well written, documented writeup with pictures and diagrams, and if the article guys like it, they'll make it an article in the write up page and you'll get a custom title under your screen name.

Thanks. I edited my first post with the writeup. Can an article guy look at it and make any recommendations. There are lots of pics but I tried to edit them down to as small a size as possible for 56k people. I'll be reading over to check for errors.

Thanks

[davidricardo86]

Thanks. I edited my first post with the writeup. Can an article guy look at it and make any recommendations. There are lots of pics but I tried to edit them down to as small a size as possible for 56k people. I'll be reading over to check for errors.

Thanks

Great write-up 50-50! This needs to be stickied and made into an "article" ASAP!

Again great job on the awesome DIY coil near plug setup. First time i see something like this for the CA.

[driftin8ez]

OMG dude that is a sick *** write up. Are you selling those coil pack mounts? They look awesome. What about the chips can you make me one with some other custom values for injectors/maf?

[50-50]

Great write-up 50-50! This needs to be stickied and made into an "article" ASAP!

Again great job on the awesome DIY coil near plug setup. First time i see something like this for the CA.

Thanks. Hopefully this would help make the swap easier for those interested.

[50-50]

OMG dude that is a sick *** write up. Are you selling those coil pack mounts? They look awesome. What about the chips can you make me one with some other custom values for injectors/maf?

Thanks. I can make the mounts with a custom logo like a did for another forum member. I'll leave it up to him to post pics. I travel by plane almost every week for my work, so if I do make them they would be in very limited numbers.

I cant really mess around with the tuning to much aside from what I did with my 1.8 If anybody wants the file they can have it. You can see a dyno chart of my setup in the dyno thread and the modifications.

http://www.fileden.com/files/2...S.bin
Modified by 50-50 at 8:57 PM 5/3/2007

[float_6969]

The article guy is gone for a few days, but I'll turn him onto this when he gets back.

I'll also try and get it stickied in the next couple of days.

[ragenasian]

As soon as I get it in the mail I will post pics of the setup. I will still need to send 50-50 my ECU for the tuning though. I will keep everybody updated. Hey you all can thank me for asking him to do a write up too Just kidding

Thanks 50-50 for doing the write-up I hope it will benefit a lot of these guys on here. Can't wait to get rid of those damn coil packs

[mikesim]

that is so sweet! i was considering the option of replacing the ignitor and COP setup for an ignitor and DIS setup like MSD or the HKS Twin Power Ignition Amplifier, but the idea fell apart.

I'm glad someone posted their setup and how to. that's awesome!

[Nunook]

Nice write up.

at radioshack they also have little black plastic boxes that can hold that little circuit board with the 4 diodes.

How much power can these coil handle and how much can the stock coil handle?

[Bwana]

The article guy is gone for a few days, but I'll turn him onto this when he gets back.

I'll also try and get it stickied in the next couple of days.

I am in Paris, but they have internet here too (suprisingly... )! I am on my mac though, which isn't as handy for doing articles, and I don't have the articles iServe info on it. I'll note this thread though, and get on it when I get home. Good job man!

[r34 gtr]

hotness. quite the badass article is i do say so myself.

[boost_boy]

I am in Paris, but they have internet here too (suprisingly... )! I am on my mac though, which isn't as handy for doing articles, and I don't have the articles iServe info on it. I'll note this thread though, and get on it when I get home. Good job man!

In Paris? . Life must be grand . Anyway, enjoy yourself "B" and definitely give this thing some consideration. Great job 50-50 .

Dee

[dvd]

any in on which GM coils? or any should be fine that looks like that.

[50-50]

I am in Paris, but they have internet here too (suprisingly... )! I am on my mac though, which isn't as handy for doing articles, and I don't have the articles iServe info on it. I'll note this thread though, and get on it when I get home. Good job man!

Thank you. I'm happy to contribute and I appreciate all the compliments and comments.

I will try to ans some of the questions:

The stock coils are great units if you can keep them cool and would handle quite a bit of horsepower. In fact, nissan ignitions in my view are quite robust. The problem is keeping the oem coils cool. When you change the spark plug type or heat range from the oem specs, the oem coils run alot hotter in an already hot environment created by the coil cover, so removing the coil cover helps to remedy this but not completely, plus these oem coils cost $$$$$$$ to replace. The GM coils also handle way more power than I think any street driven CA would generate. I would guess in the 1000hp range. The GM setup is famous in many standalone systems and an aftermarket 60kV coil is easy to get.

If the coil looks EXACTLY like the one in the pics above, then it's probably GM OEM since there is a patent on the design (2000 S10 2.2L, 94 Cavalier, Grand Am etc). MSD has a 40kV coil and there are aftermarket 60kV coils available to suit your hp needs. Nissan OEM COP coils run in the 15kV to 25kV range. If anyone knows the exact info please correct me on any of the above.

Thanks
Modified by 50-50 at 6:56 PM 5/4/2007

[johngriff]

Awesome setup. Did you get a chance to measure exhaust temp before and after? I am personally not a fan of waste spark.

I like the LS1 coils better, for their built in ignitors, and single output use. The install would be close to identical, minus the diodes, and the map would need to be different for dwell.

How did you map the coils against the values?

Do you have the factory values?

This is awesome.

[1SlowCA18DET]

50 50 quick what size injectors are you running and what maf?

[ca18detgabby]

by far one of the easiest write ups to follow I have ever read. Def will have to work on doing that in the future.

[AWDB12wagon]

I saw someone selling these brackets and setups on ebay, was that you??? Also, do you have any of the brackets? I want one!!!

[srt4monster]

can some one please re host the pictures?

[float_6969]

Email the guy directly. They were being hosted by him.

[sjbsuperman1425]

i've noticed alot of the photos on the tech pages are missing as well.

[l0nestar]

i've noticed alot of the photos on the tech pages are missing as well.

I saw this article a while back and I created a PDF of it with pictures embedded. PM me your email address and I can send it to you. 50-50 hasn't signed in since October 2010.

[float_6969]

send it to ME, and I'll get it stuck up in the tech articles so we won't ever have to worry about loosing pics again.