Some good info for those running a Jacobs Rotary Propack ign. amp/Race Coil Install
11-10-02, 08:13 AM
#1
Original Gangster/Rotary!
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Some good info for those running a Jacobs Rotary Propack ign. amp/Race Coil Install
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
?
03-11-04, 08:45 PM
#3
fart on a friends head!!!
this makes me happy. . . i just happen to have one laying around and have wanted to change out my coils for a while. . . hmmmmmmmmmmmmmmm. . . .
paul
haha, oops. . . forgot i searched for this superduper old thread. . . teehee
paul
haha, oops. . . forgot i searched for this superduper old thread. . . teehee
03-12-04, 12:46 AM
#7
Yellow Dragon is no more
Here is an old thread where I showed what happens to a leading coil run by a Jacob's box.
Old thread
Old thread
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03-12-04, 08:33 PM
#8
Racing Rotary Since 1983
iTrader: (6)
this Jacobs burning up coils is really old news. Jacobs came out with a new model approx a year ago that solved the problem. it is correct that the earlier Jacobs unit burned up coils due to a double (pos & neg) discharge for each spark event. that has been re-engineered according to the guy at Jacobs tech. the new unit was designed specifically for the rotary and is called the Jacobs Rotary Pro Pak. it was redesigned in conjunction w Ari Yellen at RX7.com. i have put limited miles on mine so i am not in the position to vouch for it but i do believe Ari when he says that it is as competitive as any unit on the market, and i believe the tech guy at Jacobs. i do think it is true that the older units burned up coils as per the tech guy.
howard coleman
howard coleman
03-15-04, 11:42 PM
#10
03-16-04, 09:41 AM
#13
Original Gangster/Rotary!
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Originally posted by spyfish007
I rated this thread a 1 ... because it sucks ... kind of like you Rich ...
I rated this thread a 1 ... because it sucks ... kind of like you Rich ...
07-20-04, 01:16 AM
#14
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I have the Jacobs setup! I just had my engine rebuilt and am now just beginning to boost. But my boost pattern is 11-10-14, with no pull on the primary turbo. It shows on the gauge that i have that i have the 11lbs. of boost but it doesnt pull. By the way, the turbos are brand new 99 efini's that were put on the car about 100 miles before the old motor popped. So I know it is not the turbo's, do you think the Jacob's pak could have fouled one of my coils? Someone please help....
07-20-04, 07:25 AM
#15
Racing Rotary Since 1983
iTrader: (6)
Jacobs Rotary Pro Pak Update:
i posted earlier in this thread while in process of putting my motor together... (just a general why i went w the unit.)
i now have 1400 miles on it and has performed as expected to date. i run the 87 T2 coil on the leading plugs along w the Pro Pak. last weekend i drove my car up to my lakehome in northern wisconsin (245 miles each way) and it behaved. 21.5 mpg to boot. that's w a Judge Ito Raceported motor and 73 lbs/minute of turbos running a cruise AFR of 13.5.
as to DVSseven's problems...
your boost pattern looks fine. it could be your leading coil, however generally when a coil goes bad you hear misfires, almost like a rev limiter at a certain rpm... where the coil can't cut it.
if you run an ignition amp you should junk the stock leading coil and go to 2nd gen classifieds and buy a 'good working order" T2 87-88 leading coil. stipulate you want the aluminum base that goes with it. take the base apart, remove the electonics in it, cut it so that you just have the base footprint of the coil. mount it so the plug wires face down on the side of the engine compartment halfway between the 2 rotors. you may use your stock lengthed plug wires after checking them.
howard coleman
i posted earlier in this thread while in process of putting my motor together... (just a general why i went w the unit.)
i now have 1400 miles on it and has performed as expected to date. i run the 87 T2 coil on the leading plugs along w the Pro Pak. last weekend i drove my car up to my lakehome in northern wisconsin (245 miles each way) and it behaved. 21.5 mpg to boot. that's w a Judge Ito Raceported motor and 73 lbs/minute of turbos running a cruise AFR of 13.5.
as to DVSseven's problems...
your boost pattern looks fine. it could be your leading coil, however generally when a coil goes bad you hear misfires, almost like a rev limiter at a certain rpm... where the coil can't cut it.
if you run an ignition amp you should junk the stock leading coil and go to 2nd gen classifieds and buy a 'good working order" T2 87-88 leading coil. stipulate you want the aluminum base that goes with it. take the base apart, remove the electonics in it, cut it so that you just have the base footprint of the coil. mount it so the plug wires face down on the side of the engine compartment halfway between the 2 rotors. you may use your stock lengthed plug wires after checking them.
howard coleman
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