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Optispark Problem Solve And Fix - F$%)#&% Opti!The Dirty Bird’s Optispark strikes again, and this time we strike back From the September, 2011 issue of GM High-Tech Performance By Justin Cesler Photography by Justin Cesler
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This would be a great place to make an Optispark joke and then tiptoe around GM's failure to build a solid ignition system in the '90s, but at this point we don't even care to make the effort. I mean, sure, we could probably go on to say that it "works every time, 60-percent of the time" or that it operates flawlessly except for when it doesn't, but really, we're friends, let's not mince words here. The Optispark sucks and if it hasn't left your LT1-powered ride on the side of the road or racetrack yet...it will. Like some sort of cruel villain, the Opti waits in the shadows until you really need it to work and then strikes, either with terrible misfires or no spark at all. Sure, it has one good quality in the high-resolution optical pickup, but seriously, for anyone rodding on a budget or trying to get by with a simple bolt-on LT1 for fun, the Opti can be one of the worst and most frustrating part of the experience. What really makes the Opti issue worse, if you can believe that is possible, is that it is stuck underneath the factory water pump and behind the crank pulley, which makes swapping it for a new unit even more frustrating and time consuming than usual. Add to that the cost of a new unit (about $400 on the cheap) and you have a recipe that could keep any project car stuck in the yard for any number of months while you wait to save up the cash and motivation to get out and fix the thing. As you can probably tell by now, this is an article about fixing the Opti in our 1995 Firebird project which we call the Dirty Bird and, as you have probably also gathered, we're a little aggravated to be dealing with this issue again, as it seems like we have to do this to every LT1 project we take on. 1 Last time we had the Dirty... 1 Last time we had the Dirty Bird out on track it exhibited a nasty misfire and managed to just barely stumble its way to a 12.70 run at 107 mph. We had hoped the misfire would just “fix itself,” but as you can see by the dyno graph that wasn’t in the cards. Luckily, for all of the Opti's faults, in this day and age, there are certainly solutions. Racecars can use a crank trigger, streetcars can use an aftermarket billet Opti or some sort of LSx coil conversion, and those without an overhanging cowl can even use a distributor with a carb-style intake manifold (yikes!). For our budget Dirty Bird project, it made the most sense to pick up a used Bailey Engineering LTCC conversion system, which made fixing the Opti issue as simple as laying a new ignition harness in place, hooking up a couple of wires, mounting some used coils and turning the key. Yep, you don't even have to touch the stupid thing (except to pull the stock plug wires off) and you can move on with your build plan knowing it won't ever give you issues again. The LTCC conversion uses a slick module to convert the Opti's high and low resolution signals into commands for a set of LS-style coils, which still utilizes the factory PCM to decrease cost and increase simplicity. Best of all it cost us less then a new Optispark, and installed in just a couple of hours. So, follow along with us as Greg Lovell of AntiVenom EFI takes to fixing the Dirty Bird's Opti problems for good and make sure you check out the results. We picked up 20-plus horsepower, an equal helping of torque and four-tenths of a second with our new LTCC coil conversion system and the Dirty Bird is running better than ever!  2 As usual, the factory Optispark...  2 As usual, the factory Optispark was to blame for the terrible misfire and it was the reason the Dirty Bird ran so poorly on the track as well as on the dyno. We could have ordered a new unit for around 400 bucks but we didn’t want to shell out the cash for something that would eventually fail us again…  3 So, we did what any hot...  3 So, we did what any hot rodder on a budget would do—we turned to rummaging through our friend’s garages, attics and shops to find a better solution. Editor Parker may have forgotten about his old Bailey Engineering LTCC conversion module when he switched over to an LSx PCM...but we didn’t!  4 Here you can see the harness...  4 Here you can see the harness and LTCC box laid out on the floor of AntiVenom in Seffner, Florida. If you order a new unit from Bailey Engineering, it will look much nicer than this but since ours was stolen—err, borrowed—from Editor Parker, it looks a little rough.  5 Of course, the magic of...  5 Of course, the magic of the LTCC conversion is in the coils, which we also stole/borrowed from Scott’s Greenie. You see, with the LTCC, we will still use the Optispark’s optical trigger module, but instead of relying on the unit to pass voltage to the plugs, the LTCC will trigger the LS1 coils, giving us reliable spark whenever we need it.  6 Installing the LTCC conversion...  6 Installing the LTCC conversion box is pretty simple, especially when compared to installing a new Optispark and it took Greg Lovell of AntiVenom EFI just a short couple of hours. He began by removing the old plug wires…  7 …and then laying the LTCC...  7 …and then laying the LTCC conversion harness over the LT1 engine bay. It is important to find a safe spot to mount the LTCC module away from heat and vibration, both of which can damage the unit. The instructions said “forward of the engine is best,” but we found a great spot next to the brake booster, which worked well for us.  8 Next, Greg pulled a portion...  8 Next, Greg pulled a portion of the Optispark harness from the main engine harness, which is located on the passenger side of the engine, next to the fuel rail. The LTCC harness intercepts the Optispark data path here, and two quick plug connections are all it takes.  9 Since the LTCC system converts...  9 Since the LTCC system converts the traditional Optispark system to one that uses individual LS1 coils, there is no need to keep the factory LT1 coil in place. No doubt this would have needed to be replaced by a higher output piece later anyways. Here, Greg pulled the stock unit out and made sure to note the placement of the harnesses.  10 Besides the plug-and-play...  10 Besides the plug-and-play harness we connected earlier, the LTCC module requires two additional hookups to function. The white wire from the LTCC module hooks to the stock “spark signal” EST wire, which can be found in the factory four-prong plug that ran to the stock coil. The LTCC’s red wires (2) hook to the coil’s stock 12v power wire, which is pink.  14 Choosing a proper spark...  14 Choosing a proper spark plug wire is key to success when using the LTCC system. According to Bob Bailey, the engineer behind the LTCC system, “Low resistance plug wires, such as the MSD Superconductor, as well as similar products by other manufacturers, have been known to cause problems on LTCC equipped vehicles.” Bob recommends using Taylor Spiro Pro wires, but they weren’t in our budget…  15 A quick trip to the local...  15 A quick trip to the local auto parts store netted us a sweet set of ’96 Tahoe 5.7-liter Vortec plug wires made by Duralast. Being OEM quality and not especially “low resistance” they worked great with the LTCC and saved us time and money compared to the other options. They’re not the perfect length, but they work just fine for our application.  16 With the wires in place,...  16 With the wires in place, Greg booted up his laptop and checked the Dirty Bird’s tune using the TunerCat LT1 software. After bringing the drivetrain back up to temperature, Greg made some part-throttle pulls to verify that the LTCC coil conversion module was working correctly and that our misfire problem was finally solved. Everything sounded great, so there was only one thing left to do.  17 Success! Not only did...  17 Success! Not only did the LTCC conversion get rid of our horrible misfire and let us spin the motor all the way to 6600 rpm, it even picked up 22-rwhp and 19 lb-ft of torque. Having a proper ignition also allowed the LT1 to pick up 20-25 lb-ft of torque down low, which will help us get down track much faster.  18 With nice results on the...  18 With nice results on the dyno, we loaded Dirty up on the trailer and rode down to Bradenton Motorsports Park to see what it would do given the extra horsepower and RPM. Additionally, we hooked up the LTCC 2-step rev-limiter, which allowed for easy and consistent launches.  19 Last time out, with our...  19 Last time out, with our broken Optispark, the Dirty Bird ran 12.701 at 107 mph. With the LTCC conversion, we ran 12.300 at 109.44 on a much better 1.684-second 60-foot. That’s a gain of .401-seconds and 2.43 mph, which is excellent considering the amount of time and money we have into this project so far.  11 With the module wired...  11 With the module wired up and ready to go, the final step is to mount the LS1 coils. A stock Bailey Engineering system doesn’t come with coils, pigtail harnesses or mounting provisions, so it is up to the end use to secure these parts. Since we stole the system from Parker in its complete form, we just had to plug everything in.  12 You can mount the coils...  12 You can mount the coils however you prefer, but we used a set of SunSpec Billet Factory coil brackets on the Dirty Bird, which were a breeze to install. Each bracket holds two coils and they bolt directly to the factory LT1 valve covers using a set of extended length bolts.  13 Greg mounted four coils...  13 Greg mounted four coils to each valve cover, using the two rearmost valve cover bolts. Besides plugging the coils into the LTCC harness, you also need to ground each coil, which Greg did by securing the grounds under the brackets using the valve cover bolt as a mounting point.
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