Transistor trick for 2GCDFIS.
11-14-05, 03:16 AM
#601
I dont remeber the exact price that the yard was charging but they are going to have a sale comming up so maybe I will buy a couple extra and just wait to see how many people need help finding a coil and I would have no problem finding more coils for those who need them.
So yes if you have any people that need one you can send them my way.
So yes if you have any people that need one you can send them my way.
11-14-05, 06:03 AM
#602
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I've been thinking about the mounting issues for those who have AC still installed. Do you think it would be possible to mount the coils directly to the engine? You could locate then close enough to the spark plug that you would only need plug wires about 6" long. Just a thought....
11-14-05, 09:41 AM
#603
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Originally Posted by Kentetsu
I've been thinking about the mounting issues for those who have AC still installed. Do you think it would be possible to mount the coils directly to the engine? You could locate then close enough to the spark plug that you would only need plug wires about 6" long. Just a thought....
Hmmm, intersting idea. If you get rid of your rats nest it shouldn't be that bad to mount there. Use the old rats nest mounting screws.
Do you still need to run Vac to the distributer, or is there a way to disable the vac advance? That would make it easier to mount as well.
11-14-05, 11:01 AM
#604
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You'll want to keep the vacuum advance. My only concern with mounting on the engine would be heat. Not sure how much these units can take, but I'm sure there would be a lot more heat if mounted in this manner. Hmmm, heatshielding? PC cooling fan? Heat not even an issue? I wonder....
11-14-05, 11:19 AM
#605
Heat would be the only real issue. Many new cars mount coil packs on the engine, though. Maybe some spacers to lift the coil from having direct contact with the engine. The other option is a bracket that could come off of the A/C mount or somewhere else on the engine.
11-14-05, 12:01 PM
#606
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Have you seen how far away the coils are mounted away from the plugs on 2nd gens? I was even thinking about mounting the coil near the left headlight area, but I really didn't want to use plug wires 3 or 4 foot long. Kinda defeats the purpose of DF. I can probably gain another 3/8-1/2" by grinding down the coil post (where the 4-screws attach the coil) to get rid of the gap between the actual coil part and the aluminum housing. Then I think it may clear the a/c compressor.
11-14-05, 12:57 PM
#607
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I'll post this in the forsale section too, but for those of you already into this thread that are looking for a TT unit, I have one of the original (non-switching) units that I have decided to let go. I was going to keep it for sentimental reasons (it was one of the 1st ever installed/tested) but my wife says I can't buy any new parts until I shed some clutter. 
PM me if interested.
PM me if interested.
11-14-05, 08:27 PM
#608
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I'm still willing to do assembly and stuff. And I'll also mention that it wasn't directly Radioshack that I ordered from--they have a site called radioshack.partsearch.com. They suck. We knew Radioshack didn't have squat, but even this specialty site could't cut the mustard. If we can get parts, and the boards made, the rest would be cake.
Side note: I would have said maybe not to this, but today I started work at a dentist's office that pays less than what I get for unemployment. So, I'm back on the market and have free time again.
Side note: I would have said maybe not to this, but today I started work at a dentist's office that pays less than what I get for unemployment. So, I'm back on the market and have free time again.
11-15-05, 02:31 AM
#609
Sounds good, devitek. If you do get a position and don't have time to do this, we could then pass it off to someone else for awhile. As you said, once the boards and parts are in hand, the rest should be easy.
Maybe we should stick with kits and assembled units (no blank board only orders). This way we will know in advance the amount of components we need. I'll clean up the board design a bit and double check eveything, and it will then be ready to go. Once I send the file to them, it only takes about 3 days to make them all. I guess we will go for 50 units. 50 units doesn't cost that much more than 30. I just hope there is enough demand for that many.
I need to look into mounting boxes futher to see if I can find one that is a bit smaller. The other issue is the ignitor connectors for the assembled units/kits. I was able to get connectors at the wreckers for the last batch. I bought new terminals and a special crimper to put on the connectors. We may need to either have a couple people get connectors or let everyone do their own thing (use female spade connectos, splice an old ignitor connector, etc.).
I will discuss with devitek pricing and how we want to do this. We may need to do a deposit and wait to get a fixed number of people before ordering.
I sent a pm to Ryan about doing a group buy. Just waiting to hear back about it. I will post in the GB section once the details are finalized.
teejs is coming along on the pics for the simplified circuit write-up. We should have that posted this week sometime.
Kent
Maybe we should stick with kits and assembled units (no blank board only orders). This way we will know in advance the amount of components we need. I'll clean up the board design a bit and double check eveything, and it will then be ready to go. Once I send the file to them, it only takes about 3 days to make them all. I guess we will go for 50 units. 50 units doesn't cost that much more than 30. I just hope there is enough demand for that many.
I need to look into mounting boxes futher to see if I can find one that is a bit smaller. The other issue is the ignitor connectors for the assembled units/kits. I was able to get connectors at the wreckers for the last batch. I bought new terminals and a special crimper to put on the connectors. We may need to either have a couple people get connectors or let everyone do their own thing (use female spade connectos, splice an old ignitor connector, etc.).
I will discuss with devitek pricing and how we want to do this. We may need to do a deposit and wait to get a fixed number of people before ordering.
I sent a pm to Ryan about doing a group buy. Just waiting to hear back about it. I will post in the GB section once the details are finalized.
teejs is coming along on the pics for the simplified circuit write-up. We should have that posted this week sometime.
Kent
11-15-05, 06:06 AM
#610
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Originally Posted by gsl-se addict
Heat would be the only real issue. Many new cars mount coil packs on the engine, though. Maybe some spacers to lift the coil from having direct contact with the engine. The other option is a bracket that could come off of the A/C mount or somewhere else on the engine.
11-15-05, 12:09 PM
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Hey fellow 7 heads. Interesting thread, I have been following it since page 1, which leads me to the next point. I have a "very rare" distributor in excellent condition from a 1980 sitting in my garage, This is the distributor Mazda recommended for any one going racing as it does not carry the ignitors on the distributor body.
I will not have any use for it as the TII project is in the forefront of any other project now. I am offering it for sale to anyone who is interested in doing the current ignition mod who needs a distributor. I paid $230.00 for it a while back so make me a reasonable offer.
I will not have any use for it as the TII project is in the forefront of any other project now. I am offering it for sale to anyone who is interested in doing the current ignition mod who needs a distributor. I paid $230.00 for it a while back so make me a reasonable offer.
Last edited by 13B_boost; 11-15-05 at 12:11 PM.
11-18-05, 02:13 PM
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Originally Posted by teejs
Next to the drivers strut tower there are a pair (twin) of brass cans...relays? I fabricated a small bracket and moved them closer to the firewall...Then I took the bracket off of a 2nd gen Secondary coil pack and (after re-drilling 2 holes in the bracket) slapped it on the primary 2nd gen pack....it has a nice right angle bracket welded to it and I was able to use a pre-threaded hole on the strut tower. I placed a piece of bakelight (you can use plexi, rubber...anything ) to space it and it fits great.
The Coil Bracket Mounting bolt is visible (dull light brass color) just left of the coil pack assembly
Last edited by teejs; 11-18-05 at 02:15 PM.
11-18-05, 02:30 PM
#614
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Thanks for the pictures. I was thinking about mounting it further back on the fender there after you mentioned that. I think you have the best method though. I will see if I can replicate it this weekend.
11-29-05, 11:10 AM
#615
Okay, guys. I just got report of another possible coil failure. jayroc, one of the first people that tested the setup, let me know that his 2nd gen ignitor died the other day. He said that he noticed it when starting up and not during a hard run. This has me a bit worried. One failure may be coincidence, but having two failures suggests we may be driving the ignitor too hard. He was running the variable pulsewidth mode only where the pulsewidth is determined by the J-109.
On the other hand, there have been many users that have put quite a few miles on this system without problem. I think we need to figure this out before doing a group buy. I want to make sure you guys have something reliable.
I think the issue is with heat. I believe that either there is a problem with the coil not being grounded well enough or the dwell that we are giving the ignitor is too high. I can't quite figure it out. When I noticed the coil pack getting hot when first testing, I thought about these possibilities. I tried measuring the voltage drop between the coil pack base and the battery - terminal. I found a very small drop (like 0.02v), so this suggests the grounding was probably fine. I then looked into the dwell being too high. This is when I came up with the fixed pulsewidth version. In this way, the pulsewidth is limited to a predetermined amount. I chose a value of 2.2ms because that is what others have found to be a good value during testing (value just before going into current limiting mode). When I bench tested this setup, the coil stayed cool and I thought the problem was solved. When I put it on the car, the coil still got warm. It may be that my power supply just couldn't provide the current needed to cause the heating found in the car.
Anyway, any input would be greatly appreciated. I can modify the circuit as needed. I just need to figure out the cause of the problem.
Kent
On the other hand, there have been many users that have put quite a few miles on this system without problem. I think we need to figure this out before doing a group buy. I want to make sure you guys have something reliable.
I think the issue is with heat. I believe that either there is a problem with the coil not being grounded well enough or the dwell that we are giving the ignitor is too high. I can't quite figure it out. When I noticed the coil pack getting hot when first testing, I thought about these possibilities. I tried measuring the voltage drop between the coil pack base and the battery - terminal. I found a very small drop (like 0.02v), so this suggests the grounding was probably fine. I then looked into the dwell being too high. This is when I came up with the fixed pulsewidth version. In this way, the pulsewidth is limited to a predetermined amount. I chose a value of 2.2ms because that is what others have found to be a good value during testing (value just before going into current limiting mode). When I bench tested this setup, the coil stayed cool and I thought the problem was solved. When I put it on the car, the coil still got warm. It may be that my power supply just couldn't provide the current needed to cause the heating found in the car.
Anyway, any input would be greatly appreciated. I can modify the circuit as needed. I just need to figure out the cause of the problem.
Kent
11-29-05, 01:52 PM
#618
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Ok, I read the first two pages, but stopped there. I read the directions and whatnot, but I could not find out what products I need to purchase exactly.
I have an 84 12 basemodel all stock. I want to mod it to have the DLIDFIS
I have an 84 12 basemodel all stock. I want to mod it to have the DLIDFIS
11-29-05, 02:05 PM
#619
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skizzle84 Look in the 1st gen archive for full instructions
https://www.rx7club.com/1st-gen-archive-71/ignition-2gcdfis-w-tt-transistor-trick-write-up-simplified-design-484176/
https://www.rx7club.com/1st-gen-archive-71/ignition-2gcdfis-w-tt-transistor-trick-write-up-simplified-design-484176/
11-29-05, 02:48 PM
#620
There are a few different options.
1. regular 2GCDFIS. This uses a 2nd gen coil and triggers it using the 1st gen igntior. It is better than stock, but could use improvement.
2. 2GCDFIS w/ TT. This is what this thread is about. What it is is a circuit that allows the 1st gen igntion to work with the 2nd gen coil and ignitor. This way, the more powerful 2nd gen igntior fires the 2nd gen coil. It works much better than the regular 2GCDFIS. There are a couple variations on this design:
a. regular or "variable pulsewidth" mode: This is the original design. This is the circuit show in the write-up linked above.
b. "fixed pulsewidth mode": This was a modification to the original design. It works better in the high end, but is a little weaker than the "variable pulsewidth" mode down low.
c. auto-switching: This is the latest design. This incorporates the advantages of both of the above modes. You can build this yourself, but can get a little complicated. I will be offering professionally made circuit boards with this design soon. I will have a kit that you can just solder up and install or there will be a pre-built unit offered as well.
If you have any questions, let me know.
Kent
1. regular 2GCDFIS. This uses a 2nd gen coil and triggers it using the 1st gen igntior. It is better than stock, but could use improvement.
2. 2GCDFIS w/ TT. This is what this thread is about. What it is is a circuit that allows the 1st gen igntion to work with the 2nd gen coil and ignitor. This way, the more powerful 2nd gen igntior fires the 2nd gen coil. It works much better than the regular 2GCDFIS. There are a couple variations on this design:
a. regular or "variable pulsewidth" mode: This is the original design. This is the circuit show in the write-up linked above.
b. "fixed pulsewidth mode": This was a modification to the original design. It works better in the high end, but is a little weaker than the "variable pulsewidth" mode down low.
c. auto-switching: This is the latest design. This incorporates the advantages of both of the above modes. You can build this yourself, but can get a little complicated. I will be offering professionally made circuit boards with this design soon. I will have a kit that you can just solder up and install or there will be a pre-built unit offered as well.
If you have any questions, let me know.
Kent
11-29-05, 04:10 PM
#621
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Kent i still want one.. either assembled or not no matter to me.
about the 2nd coils... were they used coils or new coils... just wonder how much they were abused before the TT was installed on them... life expentcy could be an issue... new coil 2 to 3 years... old coil depending on abuse 1 to 6 months. that was an example... not a stone fact.
of all the variables and such just from the TT circut... it could possibly be something else that is not the TT unless those that have not fail are not everyday drivers... driving habbits... maybe a limit to it...
at any rate just some ideas... but i still want one and would still like to assembl them if you need me to.
Thanks again Kent
Pip
about the 2nd coils... were they used coils or new coils... just wonder how much they were abused before the TT was installed on them... life expentcy could be an issue... new coil 2 to 3 years... old coil depending on abuse 1 to 6 months. that was an example... not a stone fact.
of all the variables and such just from the TT circut... it could possibly be something else that is not the TT unless those that have not fail are not everyday drivers... driving habbits... maybe a limit to it...
at any rate just some ideas... but i still want one and would still like to assembl them if you need me to.
Thanks again Kent
Pip
11-30-05, 02:38 AM
#622
Okay. What does "iggy my pm" mean, then? 
Well, both failures were with used coils and both cars see track time. Maybe normal driving there is no problem. I do know the base of the coil gets rather hot even at idle. Maybe just trying to keep the coil cooler would help (add heat sink, fan, or put in a good air flow area). If I could figure out the cause, then maybe we could find a way to deal with the problem. The good thing is this mod can be installed with the stock parts still in place. This way you can switch back to stock in just a couple minutes and you don't have to worry about getting stuck somewhere due to a coil failure.
I will let you know on the assembly. I am trying to have one person handle it so it makes easier to track things. If devitek doesn't want to do it or doesn't have time, you are more than welcome to take over.
Well, both failures were with used coils and both cars see track time. Maybe normal driving there is no problem. I do know the base of the coil gets rather hot even at idle. Maybe just trying to keep the coil cooler would help (add heat sink, fan, or put in a good air flow area). If I could figure out the cause, then maybe we could find a way to deal with the problem. The good thing is this mod can be installed with the stock parts still in place. This way you can switch back to stock in just a couple minutes and you don't have to worry about getting stuck somewhere due to a coil failure.I will let you know on the assembly. I am trying to have one person handle it so it makes easier to track things. If devitek doesn't want to do it or doesn't have time, you are more than welcome to take over.