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99RS Coupe
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116 Posts
Discussion Starter · #1 ·
I'm partway through my turbo engine build and ran into a bunch of parts from an 06 sti for very cheap. I have a set of coil on plug (COP) and am wondering if it is possible to convert from my old dying stock coilpack to the new updated coil on plug style. Might be nice for lots of RS-T guys out there to have a stronger spark and better engine accesibility.

Can I connect the coil firing wires to the ignitor firing pins on the COPs and power them up and have it run? Is it more complicated than that?

Refrence thread detailing wiring scheme of the coil on plug system:
http://forums.nasioc.com/forums/showthread.php?t=1192028
 

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Wiring Guru
01 RS, 97 Ducati
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357 Posts
I'm not sure how you would send the signal to each coil pack. It seems like a good idea however you are going to have to overcome that issue.
 

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Premium Member
98 OBS, Black/Grey
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2,724 Posts
how do you plan to bolt them to the valve cover?
 

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Premium Member
95 L, 96 OUTBACK
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2,916 Posts
You can make it work but why? If you really want to do this just pair them up like the stock setup and run them in a wasted spark. No point to do this only to save the cost of changing wires every so often. Though have fun finding a place to mount the coils.
 

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99RS Coupe
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116 Posts
Discussion Starter · #8 ·
You can make it work but why? If you really want to do this just pair them up like the stock setup and run them in a wasted spark. No point to do this only to save the cost of changing wires every so often. Though have fun finding a place to mount the coils.

Wow everyones raining on the parade. As stated I already have them for free and I need a new coilpack and wires so if I can do this with minimal effort why not... it cleans up the engine bay and provides some, if minimal benefit.

I also didn't realize that the coils didn't fit into the standard valve covers but I also have a set of sti covers laying around. The only question now is if the sti covers will fit onto stock rs heads? I doubt it :(

I was planning on running them wasted spark but just want to know if the trigger signal from the ecu for the coilpack will work, voltage level and timing wise for the COP's?
 

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02 F-150 Extended Cab
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2,610 Posts
waste of time man..plug wires ftw!!

my ej18-t is 100% easier to work on them my wrx..coil on plugs is teh gay.
 

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needs more cowbell
95L, 07 2.5i, R6
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9,316 Posts
You won't be able to use the rex covers on your rs engine. Unless you find an easy way to mount them, you might want to save them for the turbo engine you'll probably end up swapping in. Or just put them up for sale here. :)
 

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Premium Member
95 L, 96 OUTBACK
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2,916 Posts
I was planning on running them wasted spark but just want to know if the trigger signal from the ecu for the coilpack will work, voltage level and timing wise for the COP's?
Yes you are correct. Both use a logic level voltage. However dwell might be different between the coils and cause problems if it is too different. I wouldnt think it would be a problem on this install.
 

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Black 1998 2.5RS-T
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1,842 Posts
COP is much better for tuning. With my standalone I will eventually try it with some USDM ej205 cop's and see if they make a difference
 

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Premium Member
95 L, 96 OUTBACK
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2,916 Posts
COP is much better for tuning. With my standalone I will eventually try it with some USDM ej205 cop's and see if they make a difference
Your reasoning behind this is?


On a 4 cylinder with two coils you have more than enough time for dwell so why would you need COP if your current coils are saturating properly?
 

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99RS Coupe
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116 Posts
Discussion Starter · #14 ·
You won't be able to use the rex covers on your rs engine. Unless you find an easy way to mount them, you might want to save them for the turbo engine you'll probably end up swapping in. Or just put them up for sale here. :)
How much different are the Sti/wrx valve covers? Is there basically no hope of making them work or can I do a little light machinign and make it work?

And btw I wouldn't waste my time building an engine to keep it na :blol: I have sti pistons and rods in my block along with all the associated hardware and EM to keep my td06 18g quite boost happy :D

IBsamecostasaswapbutfastaaaar
 

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Black 1998 2.5RS-T
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1,842 Posts
Your reasoning behind this is?


On a 4 cylinder with two coils you have more than enough time for dwell so why would you need COP if your current coils are saturating properly?
I have been told by a couple tuners, if I can run COP it will be a lot better.

What do you mean by two coils? I guess you are right if your dwell is correct. I dont know much about this so if what I heard was wrong correct me :)

EDIT: nevermind about the two coils...
 

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Premium Member
95 L, 96 OUTBACK
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2,916 Posts
I have been told by a couple tuners, if I can run COP it will be a lot better.
What tuner told you that? Did they give a reason? Like I said if you have enough time to saturate the coil you will have full spark energy.


The reason you might need COP is if where reving to 15k+ on a 4 cylinder. There are very very few piston engines that spin that fast. At 8k you would have more than enough time on the stock wasted spark setup to get full spark through induction.
 

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97, Legacy 2.5GT, silver
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937 Posts
I am going to be running into a similar situation. I am swapping an ej20 from a jdm 90-94 liberty rs into my 96 brighton. the ej20 has cop. I will be swapping out all of my wiring to an 01 rs wiring(I also swapped the full interior adding power windows, ect.) and then I am merging a usdm 90-94 legacy turbo harness with the rs harness. both vehicles the wiring is from use coil pack and wires. from what I've researched so far I should be able to take the wires that go to the coilpack and connect them to the cop's.
 

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General pain in the ass
98 Superu Impreza 2.5 rs...
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3,978 Posts
just for kicks and giggles I'll tell you guys a little secret.

All valve covers 98+ have threading for COP.
 
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