COP conversion harness vs full conversion

Wiseguy302

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Hey All,
I'm dead set on converting from packs to COP's. I know the conversion harness has mixed success on supercharged applications, but I'm willing to try it out (and buy a BAS if it'll fix it), but has anyone tried swapping in a 99+ module and doing it the correct way? In the past this might have been difficult, but now we can go to just about any junkyard and facebook marketplace to get the proper pcm and harnesses. My big question is would the entire car harness need to be re-wired or just the engine? If it's just the engine harness great! But I'm thinking if it requires all new dash wiring, the conversion harness would be a better route.

Thanks all! Just hoping someone has come across and done this before!
 

SVT GI

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Like he said you’ll need everything or your dash and cluster won’t work. I put mine on the firewall. Then cut the firewall sides of the plastic wire covers to feed the wires in from the back. With black factory coil packs and some nice black wires they hide pretty well.

Or when MS3 releases their Plug-n-Play 96-98 ECU, you can run 4 additional wires from the ECU to a COP harness and run COPs the correct way. Their ECU can run wasted spark or COP style setup with a software tweak. Their ECU just swaps out with the stock one and you’ll retain all dash and cluster functions. It’s a stand alone platform. I’ve pretty much maxed out the factory ECU with my setup and will be switching to MS3 as soon as it’s out.
 

Wiseguy302

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SVT GI, you have any pictures of how the look on the firewall? I've searched and found one or two, but doesn't seem to be a ton of people moving them around.

I thought about a megasquirt, it just seemed like a big step to just get rid of some spark plugs wires.
 

SVT GI

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Here’s mine. Yes it’s a pricey step if just going for aesthetics. I do my own tuning and although the factory ECU has done well so far, there’s a lot left on the table power wise and I’m ready to step it up but have way too much money in the motor to take those chances. I don’t want to completely strip everything out to use a Holley stand alone, so the Mega Squirt is a good cost effective compromise.
 

Wiseguy302

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Safe to say you have the nicest looking engine bay I've ever seen. That all black is just sexy, kudos to you for the hard work put into that. Have you tried converting to cop's before, or just always kept the wires? I'm also assuming you used the regular plug wires meant for our cars, it doesn't look like they need to be extended or anything. Did you cut and re-weld the EGR stem off the intake? Last question.. how large are your fuel lines? When I ran mine I used a y-block to split the 10-an feed line to dual -8 for the fuel rails. I've always hated the look of it, and would much rather feed one side and crossover into the other, but wasn't sure how much power it could handle. I don't have twin turbos, so clearly if it works for yours, it'll work for anyone else.

I have considered going with a megasquirt anyways. I mean if you think about it, you wouldn't use a 20 year old computer at home, so how much better/nicer would the car run on an updated, faster ecu?
 

mysteed

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Or when MS3 releases their Plug-n-Play 96-98 ECU, you can run 4 additional wires from the ECU to a COP harness and run COPs the correct way. Their ECU can run wasted spark or COP style setup with a software tweak. Their ECU just swaps out with the stock one and you’ll retain all dash and cluster functions. It’s a stand alone platform. I’ve pretty much maxed out the factory ECU with my setup and will be switching to MS3 as soon as it’s out.

Does anyone have a timeline of when this will happen?
 

SVT GI

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Safe to say you have the nicest looking engine bay I've ever seen. That all black is just sexy, kudos to you for the hard work put into that. Have you tried converting to cop's before, or just always kept the wires? I'm also assuming you used the regular plug wires meant for our cars, it doesn't look like they need to be extended or anything. Did you cut and re-weld the EGR stem off the intake? Last question.. how large are your fuel lines? When I ran mine I used a y-block to split the 10-an feed line to dual -8 for the fuel rails. I've always hated the look of it, and would much rather feed one side and crossover into the other, but wasn't sure how much power it could handle. I don't have twin turbos, so clearly if it works for yours, it'll work for anyone else.

I have considered going with a megasquirt anyways. I mean if you think about it, you wouldn't use a 20 year old computer at home, so how much better/nicer would the car run on an updated, faster ecu?

Thank you, I have a build thread in here somewhere you can check out for more details. I thought about converting to COPs but after some researching decided against it since I was able to relocate the coils and wires. Yes I used standard plug wires for these cars. You have to be mindful where you mount the coils, if too far apart you’ll end up having a couple wires that will be stretching and will be tough to “tuck” for a clean install.

For the intake lid, yeah I just cut off the EGR, welded and smoothed it out. I also plugged the vacuum hole on that side. I only have 2 vacuum ports on the passenger side that feed my vacuum distribution block for all the turbo stuff.

I’m running a dead head return setup. Fed by -10 to a Y block and two -8 feed the back of both rails. The cross over in front acts as a balance tube now to keep both rails equal. I’ve built return fuel systems on cars where the regulator was post rails, whether in series or parallel. All work and support the power, the dead head return keeps the fuel cooler because it returns the unneeded fuel back to the tank before it circulates through the rails. I was skeptical of this setup initially, but it works.

As for the 96-98 ECUs, they are actually better than the 99-04 except 03/04 Cobras. I cut my tuning teeth on 03/04 Cobras way back when. Standard 99-04 ECUs have stricter hard limits and have a tough time keeping things running over 7K RPMs. I’ve had no issues with 03/04 and 96-98 Cobra ECUs at 8-8500 RPM. I have inputs I want to integrate, boost controller, wideband tuning, like the Coyote’s, 2 or 3 step feature, fail safes, flex fuel sensor, etc that can’t be done with factory ECU. Like I said, I want to keep all the factory dash stuff. My car still has A/C, etc.

Does anyone have a timeline of when this will happen?

Ive been emailing one of the engineers at MS just this past week trying to ensure this was going to meet my needs. He said they are very close to releasing. I just asked him the expected release date question, I’ll update if he answers.
 

SVT GI

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Update back from them...”We are probably easily 6 weeks out from a general release of the ECU. Our first round of customer testing went well, and we're close to doing a 2nd round.”
 

98 Cobra Vert

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I did the COP conversion on my 98 Cobra, but it's NA. I just picked up a wiring harness from The Red Monster, changed out the Valve Covers, and everything works great! I get a slightly better throttle response and a little smoother running engine. I like the less cluttered look now. Not sure I'd do it again, all said and done it's a little North of $500 to do the conversion.

Sent from my SM-T580 using the svtperformance.com mobile app
 

Wiseguy302

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Thanks all. I'm thinking I may just try the cop harness and see how it goes. I already have the ford COPs, I picked them up off a wrecked car with super low miles at a salvage yard like 10 years ago. Figure I can just try out the harness, if it works great, if not just switch back to the coil packs. My local pull-a-part yards have a few aviators, I was just gonna go grab the valve covers off one of those (they're only like $10 a piece), so I'm not going to have too much invested in giving it a shot. We'll see how it works with a procharger.

I'm assuming you can still use plug wires with the cop valve covers if I decide to switch back? Likely just have to notch out the coil cover a tad?
 

ViciousBlack97

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Thanks all. I'm thinking I may just try the cop harness and see how it goes. I already have the ford COPs, I picked them up off a wrecked car with super low miles at a salvage yard like 10 years ago. Figure I can just try out the harness, if it works great, if not just switch back to the coil packs. My local pull-a-part yards have a few aviators, I was just gonna go grab the valve covers off one of those (they're only like $10 a piece), so I'm not going to have too much invested in giving it a shot. We'll see how it works with a procharger.

I'm assuming you can still use plug wires with the cop valve covers if I decide to switch back? Likely just have to notch out the coil cover a tad?
You can use the COP covers with spark plug wires, but they don't positively snap into the VC and seal the spark plug tube anymore. That's what I had to do for a short time after I became so fed up with the COP swap harness' issues and switched back to the factory ignition.
 

Wiseguy302

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You can use the COP covers with spark plug wires, but they don't positively snap into the VC and seal the spark plug tube anymore. That's what I had to do for a short time after I became so fed up with the COP swap harness' issues and switched back to the factory ignition.

ViciousBlack, you still have the harness you want to get rid of?
 

Wiseguy302

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Yep, the harness I have is the replacement he sent me after the first one wouldn't work. I gave up after this one didn't work as well.
Hmm, sorry to hear that it didn't work. Feel free to shoot me a PM if you want to unload the harness. I was going to just buy a new one, but I'd have no problem taking a chance on a used one if the price is right.
 

mgt351

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If anyone else is looking for a cop conversion harness I have one that didn’t work out with my boosted setup
This one is from the red monster as well.
Ran less than 100 miles
 

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