Oh.... Well that makes sense especially considering the GM con mod is cheaper that a stock ignitor lol. I would eventually like to go with a setup similar to the one in this thread https://www.rx7club.com/1st-generation-specific-1979-1985-18/tfidfis-894669/

 

I did this mod a little bit ago.. runs alot smoother but what can I do about the tach ? I switched back to stock so I could at least see my rpms till i figure out a solution. lol

 

Figured I would try this out today. While I don't know how much if any of a power upgrade this gave, I did notice a significant difference in starting. I don't need anywhere near as much choke to keep it running when cool and the car seems to feel better on deceleration from low rpm to idle. Plain idle sounds much smoother as well.

I made a bracket to try to achieve a streamlined install. Ballast resistor is also mounted to bracket to allow any necessary heat dissipation.

 

So what's the consensus on this? Is it worth doing? I have 2 spare FC coils but I don't want to waste time on this if people aren't happy with the reliability.

 

Works pretty good for me. Same results as everyone .
Smooth start. Idle. Torque down low feels good

 

still not a patch on a true DLIDFIS ,, with two leading igniters and two individual leading coils

to go one better then get another j109 and both the trailing FC coils

or go the full hog and go for 2 x bosch igniter and 2 x bosch HEC coils
-as this is easily the best spark
( i have tried all of the SLI and DFI methods with LPG under boost )
and this can be simpler than fussing with trying to mount the extra J109 somewhere and also dealing with dodgy old parts

the DFI is worth it,, the SLI method above is the least gain for the least effort ,, but add big carbs and ports,, or LPG and boost,, and you will soon see where the extra effort shines

 

You'll notice a difference but you should check out the ford TFI coil and GM con mod upgrade first. It's supposedly way better.

 

stock < 2G coil < DLIFIS (using a coil per leading spark)

Also using the j109s is a limiter. Going with either HEIs or an MSD box will allow more power
to the coils. The j109s only pass about 4 amps, the HEIs are rated 6 and up and the MSD ($$)
has even better power.

The stock GM HEIs will probably not work at sustained RPMs over 8K but for a street car they
work great.

See the link in my sig for a possible DFIS setup.

 

i just went through about all of the setups with the exception of the GM HEI since it was a high revving bridged engine.

stock<2GCDFIS<DLIDFIS w/stock coils<2GCDFIS w/TT<MSD w/blaster coils

i'm sure there is coils with better output than the blaster units, i just opted to keep everything in the same boat since MSD is the manufacturer of the CDI.

most people won't need more power than the 2GCDFIS will provide, for more modified setups the TT trick will do better and maintain better high RPM ignition performance, for highly modified setups you need to drop about $500 for a real ignition system and stop screwing around.

problem with the 2G setup is it puts a bit of strain on the already worked J109's, keep spares handy.

 

Anyone have the original diagrams saved by chance? they are no longer on the front page posts.

 

Rotary evolution has it right on the money. I blew one J109 with 5 minutes of spirited driving (using a 2G coil with stock ignitor. I have only one spare.

I have my transistor mod sitting on my table next to me. Waiting to install since I don't have a timing gun.

 

okay the diagram from
https://www.rx7club.com/1st-gen-arch...8/#post5217565
seems pretty good, I just sat down and read through the entire thing (intermittently during work :P)

but there is so much variances and confusion that now I'm just as confused.



where are those black and green wires going to?

ignition power source?

 

Those wires are from your old coils.

 

be sure you're not using too small of a gauge wiring for the upgrades either, i recommend 12 gauge at least even between the ignitor and coils. the 2G coil will be pulling more amperage than the J109 will like to be pushing. i was running rather slim wiring for the TT box when i tried that ignition and it was getting cooked and would overheat after about 10 minutes, would work fine for a bit after letting it cool down, rinse and repeat. we got fed up with it even though it worked much better than the other ignitions but he didn't want to risk reliability with the ignition system so he tossed $400 into my hand and told me to go shopping.

the MSD ignition worked better than anything else we tried including the 2GCDFIS although it was a very slim change. the differences were easy to note because the ignition was breaking up from the large bridged early 13B block with 650 double pumper on it. the MSD cleared up the ignition break up completely where the 2GCDFIS w/TT was barely noticable beyond the transition point of the J109 after 4500RPMs.

 

Larger wire noted *

 

Yeah I have some old wiring that I would mind cleaning up and I figured it went to the original location but just trying to clarify. I wanted just to solve the problem by buying some rx8 hot plugs but even at my racerdiscount its about 100 or 120 dollars for 4!

 

use the ballast resister built into the underneath of the twin leading coil if you are using a single j109 or single bosch BIM024 to drive it.. common sense,, get out the multi and check the primary resistance to see why

 

So the stock igniter will hold up using the 2nd gen ballast resistor? I'm building a track car so reliability is key.

 

yes

 

Great. Thanks for letting me beat a dead horse.

 

im always open to new ideas so how about sharing the part #s to the above items. thanks

 

Hmm, for the last couple of years I've been running the 2nd gen coil with no resistor. Haven't lost an ignitor yet. No upgraded wiring or anything either.

Performance isn't great, but definitely better than stock.

I really should improve the system, but time is always a problem for me.



.

 

Maybe I did something wrong. I have swapped this back and forth for 6 months and see no difference in:
1) Starting.
2) Idle.
3) Gas mileage.
4) 0 to 60 times.

I really want it to show me some improvement but it has not. What could be my mistake? Car is otherwise running fine.

 

Did you adjust your timing after installation?

 

What timing adjustment is supposed to be made afterward? I don't remember seeing anything about timing adjustment in the previous pages....and my 2g coil should be arriving in a day or two....