Teach me about ignition

[vex]

So I'm looking at different ignition setups for my car. I was originally leaning towards an LSx style ignightor that I would mount inside the cabin, then pass through a bulkhead connection to the spark plugs. I was going to do this as I thought it would provide for a cleaner install, but would make it a little difficult to work on/replace the coils themselves.

My other option would be a coil on plug setup. Has anyone ever done this before? If so, what issues have you found with it? Do you find installing them on the plugs to be an issue since we have the frame rail so close? What voltage should be used for our cars? 34,000~ V or 42,000~ V? Does it matter?

What should I look for specifically in chosing ignition systems (These are for a Haltech PS1k)

[t_g_farrell]

On the evil forum I have a write up for an ignition using HEIs and Ford TFI coils.
Makes a really strong spark.

http://www.rx7club.com/showthread.php?t=894669

[TitaniumTT]

Loosen your panties and give me a few weeks there T, Pick which ever unit gives the best torque from my test. Remember I'm testing

Stock FC
Stock FC with MSD Box (waiting on a loan)
Stock FD
Stock RX8 (waiting on Bill ;) )
LS1
LS2 (If someone can donate)
Merc Marine inductive
Merc Marine CDI with an M&W box
Bosch COP converted to a standard unit.

My guess is the Bosch or the Merc Coils will come out on top.

For the type of power that you're looking for, I think inductive is going to be the way to go but the dyno will tell all, well, almost all.

[project86]

i believe MoTeC has coil on plug set up that really has me interested. I know youre running haltech. but as far as clean goes that routes seems like it would be. plus MoTeC claims they have superb spark.

[TitaniumTT]

Last time I spoke with MoTeC they were going to grab a few of the coils that I did and run a few tests. I don't know if they have or not yet. I'm planning on calling them and sharing my results.

If you're referring to MoTeC's Denso COP, it's the LS1 and I gotta tell ya, I woldn't use it on the rotary after what I went though. I don't think they're all that special especially after wet-fouling them while the car was idling :icon_tdown:

[vex]

Loosen your panties and give me a few weeks there T,I can't tell if you're telling me to drop my panties for your benefit or for me to take a dump... Or maybe both? ;) Pick which ever unit gives the best torque from my test. Remember I'm testing

Stock FC
Stock FC with MSD Box (waiting on a loan)
Stock FD
Stock RX8 (waiting on Bill ;) )
LS1
LS2 (If someone can donate)
Merc Marine inductive
Merc Marine CDI with an M&W box
Bosch COP converted to a standard unit.

My guess is the Bosch or the Merc Coils will come out on top.

For the type of power that you're looking for, I think inductive is going to be the way to go but the dyno will tell all, well, almost all.
Sounds like a plan. But everything you listed looks to me like they're regular ignightors. No COP or anything like that. Do you suspect any losses by going that route?

[project86]

Last time I spoke with MoTeC they were going to grab a few of the coils that I did and run a few tests. I don't know if they have or not yet. I'm planning on calling them and sharing my results.

If you're referring to MoTeC's Denso COP, it's the LS1 and I gotta tell ya, I woldn't use it on the rotary after what I went though. I don't think they're all that special especially after wet-fouling them while the car was idling :icon_tdown:


Part number M DEN-580 to be exact

[TitaniumTT]

I can't tell if you're telling me to drop my panties for your benefit or for me to take a dump... Or maybe both? ;)

Both :rofl:

Sounds like a plan. But everything you listed looks to me like they're regular ignightors. No COP or anything like that. Do you suspect any losses by going that route?

The Bosch was designed as a COP but modified to be mounted away from the plug and wires to be easily made.

Aside from building wires and the loss of a few tempers, I don't really see any losses if they're kept close enough. I would suspect that running them inside would lead to more losses than anything just because of the length of the wires.

The thing with the COP's is the mounting. Sure it can be done, but why? I think it would be easier to mount them on the frame rail or where the factory did and make some plug wires than try to mount COP's on to the rotary. Just my $.02

Part number M DEN-580 to be exact

Yeah, D-580 LS1 coils, fuck those coils. Especially for you. You're going to be going for higher revs and those won't be able to handle duty cylce required. The LS2's might work, D585, but even those I'm not too sure about. I'm really hoping to get a set loaned to me, I should PM BHR about it, see if they'll help me out. I think the Bosch's that I'm using would be the best bet for you. Can be dwelled fully to 10k rpm with an acceptable duty cylce. You definaly don't want or need a CDI box though.

[classicauto]

For the type of power that you're looking for, I think inductive is going to be the way to go but the dyno will tell all, well, almost all.

I would tend to agree here. I haven't done a back to back on a dyno comparing the various systems I've ran over the years, but so far, going through many variations of stock coils, stock coils & MSD's, Jacobs coils, jacobs coils + amps........I've found the best balance of a simple ingition system and joules of mad water firing powah in the the inductive coils I have with the TECgt at the moment.

I think an inductive system certianly has its limits, and it may be outperformed at lower power levels by adding a huge array of boxes.........but simplicity/cleanliness/power I believe are quite balanced with inductive.

I'm as anxious as everyone to see the B2B results though.

[Phoenix7]

subscribed! Good thread...

[vex]

Okay, then I think I shall do the bulk head setup--in the mean time I'm waiting on TTT's results so I know where to put the money down on the coils.

[TitaniumTT]

I think an inductive system certianly has its limits, and it may be outperformed at lower power levels by adding a huge array of boxes.........but simplicity/cleanliness/power I believe are quite balanced with inductive.

I'm as anxious as everyone to see the B2B results though.

Really? I would think that at the lower power levels the inductive would be the better way to go. To me the slow rotor speed is in need of a long slow burn - Inductive. It's when you start dousing the flame with water :rofl: that you need the higher capacity/higher energy of the CDI.

water of course just meaning incredibly high combustion pressures and dense dense mixtures that require that type of energy to still jump the gap. Think of wet fouling the plugs.

Okay, then I think I shall do the bulk head setup--in the mean time I'm waiting on TTT's results so I know where to put the money down on the coils.

I would definately skip the bulkhead idea. I don't like long leads or leads that pass through go near so much metal. I would seriously think about mounting them where the stock trailing's went, or on the block, or on the shock tower. That's just me though.

[Whizbang]

im running LS1 type coils from Summit. Summit brand in fact (who knows who they contracted to) They appear to work fine, but honestly, with all the little problems i have with the car, i can't be sure. I have considered just going back to a hotter version of the stock coil.

[jtbshaw]

On the evil forum I have a write up for an ignition using HEIs and Ford TFI coils.
Makes a really strong spark.

http://www.rx7club.com/showthread.php?t=894669

Is there any benefit to running this system over Jeff's DLIDFIS? The only thing that I see is that it eliminates the purchasing of expensive aftermarket coils. Not trying to crack on your setup, just trying to understand it better.

I've often wondered why not run a CAS and do a direct fire setup on both leading and trailing, for boosted applications. Otherwise, the trailing is really not even necessary.

Another option that used to be available is the Crane HI6/LX92 coils setup. I used this before with incredible success. This combo held up very well to boost with N2O. I had to actually change out the plugs every 3-4 weeks becuase the spark was so hot (mixed with burning the N2O and a 10k rpm redline) that the plug electrodes would almost be burnt completely off. I was running BR8EQ14 plugs in the last setup. All 4 electordes would be burned down to barely a nub. The porcelain/ceramic (or whatever that material is) would crack or break off if I didn't change the plugs soon enough.

Of course, Tyler, the last option you (using a general term here) would also have to take a freaking loan out for. I think I had a little over a grand in that setup....then 4 new plugs every month. That's what I get for driving something like that everday.

Todd B.

[t_g_farrell]

Is there any benefit to running this system over Jeff's DLIDFIS? The only thing that I see is that it eliminates the purchasing of expensive aftermarket coils. Not trying to crack on your setup, just trying to understand it better.

No problem. The main benefits over Jeffs setup is the use of readily available,
comon off the shelf parts that any parts store would have. Also most of it can
come from the junkyard at a substantial savings :D No more worries about J109
or J105 igniters being found and the TFI coils really pack a good punch.

I would like to say that it is all inspired by Jeffs previous work and I just
took that another step further. Except in rev limited applications (read boost)
the trailing is really not needed if you have a strong wasted spark ingnition
setup. So I agree with that sentiment for sure.

[jtbshaw]

In this current build that I am doing for my son's TII, I am bypassing the J109s and getting the signal direct from the wiring. This signal will be then fed into the DR100 ignitors (2 leading and 1 trailing) then dispersed accordingly. Direct fire on the leading and back to the distributor for the trailing. It has been an odd experience to be working on a distributor based igntion in an FC.