Good info for those running a Jacobs Rotary Propak
11-10-2002, 08:25 AM
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Join Date: Oct 2002
Location: Morristown NJ
Posts: 252
I've been told numerous times that the Jacobs would fry my stock leading coil. My stock leading coil is fairly new, so I decided to leave it in there and see what would happen. I installed the Jacobs maybe 3 months ago.
Recently the 7 has been getting worse gas mileage (around 12 instead of 15) and hard starting when hot. Also, throttle response seemed sluggish, with boost slow to come on. Top end the car didn't seem to pull as hard.
Friday night before going to the strip, I pulled off my intake manifold in the fading daylight. Busted out the multimeter, and tested the resistance specs on all my coils. All 3 checked out. Matt Schroeder was nice enough to give me a used FC coil (or "race coil"), and it didn't spec out---resistance across the secondary winding coil was 16.7 kilo-ohms when it should be between 9.6 and 16. Quickly called Chris at RP and Kan. Was told that resistance isn't the only way to determine if the coil is bad, and that the FC coils are indestructible.....their voltage output does not degrade from using the Jacobs, unlike the stock FD coil.
Running the race coil involves some cutting of wires---two wires insert into a plug, which goes to the stock leading coil. The FC coil has dual posts with 6mm nuts. I cut and spliced the two wires---their polarity is irrelevant, so you don't have to worry about mixing them up. I mounted the coil in the corner of the engine bay, a bit further towards the driver's side and rear of the car from the spark plugs. I firmly ziptied the coil to one of the thick lines by the master cylinder.
I also threw in a set of freshly cleaned NGK 11 race plugs.
End result----the 7 runs much, much better. All those problems listed above are *gone.* She pulls harder, better throttle response, and (best of all) hard starting is gone. This all from a used FC coil that has lots of miles on it and is out of spec. Of course, my gas mileage seems bad, but I've been driving the hell out of the car, so what do you expect
?
Recently the 7 has been getting worse gas mileage (around 12 instead of 15) and hard starting when hot. Also, throttle response seemed sluggish, with boost slow to come on. Top end the car didn't seem to pull as hard.
Friday night before going to the strip, I pulled off my intake manifold in the fading daylight. Busted out the multimeter, and tested the resistance specs on all my coils. All 3 checked out. Matt Schroeder was nice enough to give me a used FC coil (or "race coil"), and it didn't spec out---resistance across the secondary winding coil was 16.7 kilo-ohms when it should be between 9.6 and 16. Quickly called Chris at RP and Kan. Was told that resistance isn't the only way to determine if the coil is bad, and that the FC coils are indestructible.....their voltage output does not degrade from using the Jacobs, unlike the stock FD coil.
Running the race coil involves some cutting of wires---two wires insert into a plug, which goes to the stock leading coil. The FC coil has dual posts with 6mm nuts. I cut and spliced the two wires---their polarity is irrelevant, so you don't have to worry about mixing them up. I mounted the coil in the corner of the engine bay, a bit further towards the driver's side and rear of the car from the spark plugs. I firmly ziptied the coil to one of the thick lines by the master cylinder.
I also threw in a set of freshly cleaned NGK 11 race plugs.
End result----the 7 runs much, much better. All those problems listed above are *gone.* She pulls harder, better throttle response, and (best of all) hard starting is gone. This all from a used FC coil that has lots of miles on it and is out of spec. Of course, my gas mileage seems bad, but I've been driving the hell out of the car, so what do you expect
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