MSD coils installed
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Race Director
Joined: Jan 2006
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MSD coils installed
Thanks Ground Zero. All I had to do to make these coils fit was to fabricate some nylon spacers. Finished this morning. First thing I've noticed is that the engine idles 100 rpm higher than before. I'll drive the car later today.
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Drove the car this afternoon. It was not a great day for a comparison. It was cool here (60 degrees), and the car always runs good when its cool. It did actually seem to have better throtle response, and run smoother (?). Didn't have the opportunity to really push the car hard up through the gears. Should have more time tomorrow. 
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Had a chance to push the car at WOT today, and got severe backfiring thru the exhaust! Only tried it once, then drove the car home and parked it. Think I'll chat with someone at MSD tomorrow. The car runs fine at part throtle, but as soon as I went to WOT it started misfiring. Wierd! 
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Burning Brakes
Joined: Nov 2007
Posts: 1,083
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From: Buena Park CA
I plan on getting these very soon. This might sound like a "duh" comment, but double-check all the electrical connections again to make sure everything is tight and snapped into place, nothing loose, including the plug wires. Then, you might attach a timing light to each cylinder while your buddy raps it up to see if you can detect any mis-fires. It's very possible you have a bad coil, there are some neat electronics in each one.
Team Owner
Joined: Feb 2001
Posts: 27,254
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From: Short Hills, NJ
Is there any way to use those relocation brackets while still retaining the OEM/stock coils?
Hence why I am quite partial to OEM/stock coils packs. 
I've heard of nothing but problems from aftermarket ones for the LSx motors.
Had a chance to push the car at WOT today, and got severe backfiring thru the exhaust! Only tried it once, then drove the car home and parked it. Think I'll chat with someone at MSD tomorrow. The car runs fine at part throtle, but as soon as I went to WOT it started misfiring. Wierd!
I've heard of nothing but problems from aftermarket ones for the LSx motors.
Racer
Joined: Feb 2008
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From: Kalamazoo, MI Michigan
Thread Starter
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Joined: Jan 2006
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I, too, suspect a defective coil. Purchased these from a forum vendor. I'll call MSD later today and see what they have to say. The coil relocation brackets do fit the stock coils and come from Nasty Performance. They require longer plug wires, avilable from Taylor Made Wires.
Safety Car
Joined: Dec 2004
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From: stafford country, va. Avatar: Me on turn 3 @ Bristol (The World's Fastest Half-Mile)
Had a chance to push the car at WOT today, and got severe backfiring thru the exhaust! Only tried it once, then drove the car home and parked it. Think I'll chat with someone at MSD tomorrow. The car runs fine at part throtle, but as soon as I went to WOT it started misfiring. Wierd!
you may need to adjust the air/fuel ratio at wot, you might need a slight retune to compensate for the 'hotter/longer/multiple' spark and the supercharger combo.
are you sure it's not the 'rev-limiter'?
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Talked with MSD. They said that the coils share power with the injectors thru a common wire, and this wire is very small and the new coils are probably pulling amps either away from the coils, or visa versa (Gee, thanks MSD for not telling this in any of your literature or website). They gave me some troubleshooting tips, which I'll try later today. Solution may be to replace the wiring to the coils from a relayed, independant battery source. This is bulls**t, and I'll just put the stock coils back in.
Le Mans Master
Joined: Jan 2003
Posts: 8,596
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From: Portland Oregon
Talked with MSD. They said that the coils share power with the injectors thru a common wire, and this wire is very small and the new coils are probably pulling amps either away from the coils, or visa versa (Gee, thanks MSD for not telling this in any of your literature or website). They gave me some troubleshooting tips, which I'll try later today. Solution may be to replace the wiring to the coils from a relayed, independant battery source. This is bulls**t, and I'll just put the stock coils back in.
Your stock coils are more than adequate for running the engine with or without the blower. IMHO other than the cool look, aftermarket coils are a waste of $$$
I would be looking for a plug wire that has been fried or a cracked spark plug. Does your tuner have a TECH2 scan tool or a good scan tool? If so he can scan it during a WOT run on a dyno to simulate the problem then using the scan tool he can check for engine misfires to locate the problem cylinder. If it was a injector not firing you WON'T get backfiring in the exhaust but you will get a misfire, if its a plug wire you can often get backfriring in the exhaust because of the unburnt fuel igniting in the hot hot exhaust. If its not an ignition issue you could be seriously lean at WOT.
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Update. MSD suggested that I replace 1 coil on each bank with a stock coil. This would reduce the amperage drawn by a small amount, perhaps just enough to power the remaining coils. I did this, and now the car runs fine at WOT. An MSD engineer is working on the problem, and is suspose to get back with me. The engine does seem to run chrisper, even with only 6 coils firing multi-sparks. I just hope I do not have to operate on the wiring bundles to provide a dedicated power source to the coils. I'll be back...........................
