Teach me Coil on plug

  Ford uses a coil with a twin lead in their V6. 
    Will it provide enough spark  for turbo boost firing off alcohol?  Is there a better alternative? 
   How does it compare to Chevy's LS style coil on plug which I've been told is OK up to 20 PSI in E85?  

It depends a lot on the exact coil. To be honest I have had better luck with v6 mustang coils than some versions of the ls ones. The waste spark coilpacks off the mustangs are good for about 125whp/cyl before you can't be rid of misfires. 

In reply to Paul_VR6 (Forum Supporter) :

Which v6 Mustang? 

01-04 we use them to replace the coil on the 94-01 vw coils and have done near 800whp on them

that being said we have done well past 1k on the vw cops 

In reply to Paul_VR6 (Forum Supporter) :

Good to know. I need to text you actually 

You can hmu at kandpperformance at gmail dot com and my phone is at kptuned.com

Paul_VR6 (Forum Supporter) said:

It depends a lot on the exact coil. To be honest I have had better luck with v6 mustang coils than some versions of the ls ones. The waste spark coilpacks off the mustangs are good for about 125whp/cyl before you can't be rid of misfires. 

That's spectacular. I had no idea they were so good. 
     You are right, the LS numbers I'm seeing are way short of that.   Plus the LS coil on plug forces me to drill and tap into the head to hold them on.  
      Is it just Ford parts or does that include aftermarket coils?    Thank you for that insight 
    

In reply to frenchyd :

You can relocate the LS coils to other places. I've seen the firewall as common.

Not sure on aftermarket we only used junkyard oem. 

Is this for the twin turbo Jaguar V12 that you post regular threads about?  I no longer visit here often, but your question threads seem to pop up when I am here. 

Far be it from me to rain on anyone's parade, but allow me to offer some unsolicited advice: If you have to ask fairly basic questions on a topic, the likelihood of your success is slim.  Time and time again do we see people on the internet with these ambitious build plans that either never get realized or end up in someone wasting a lot of time and/or money.

With that being said, I will attempt to answer what I think your question is.  LS coils are not coil on plug, but coil near plug.  With enough wire, you can effectively mount them anywhere.  This is much easier to adapt to your application.  A quick look at any coil on plug engine will tell you why.  If you want to simplify things further and run wasted spark, a Caravan V6 coil could be made to work as well.  The Vipers used a combination of this and a Neon coil to fire its V10.

May be useful to point out that a coil with a "twin lead" is a wasted spark coil, and it fires both leads at the same time. 

The idea is you fire 2 cylinders that are 360 crank degrees apart with one spark timing signal, and it can be a crank signal because you don't need to know which of the two cylinders is on the compression stroke.

You're effectively firing at TDC every crank rotation, both on the power stroke when you need it, and the exhaust/intake stroke, when it is "wasted". Hence wasted spark.

To run a V12, you (perhaps obviously) probably need two V6 wasted spark coil packs. 

In reply to Robbie (Forum Supporter) :

Thank you Robbie.  Yes I'm aware of all that.   I'm wondering what the sound will be.    I'll be putting a lot of ethanol in to cover the boost and cool the charge. Any overlap in the camshaft should allow a bit of additional fuel in.  So maybe it won't be quite so dry fire? 
  The stock timing  on an HE  is something like 8  degrees before top Dead center. And the vacuum retards the timing under acceleration. 
   I'll start out using timing from earlier engines which I believe is 17 degrees before TDC and the timing will advance under acceleration.    With 104 octane ethanol and the cooling of the charge  the factories numbers won't be valid.   So 
  Then once on the chassis Dyno I'll tune for best power.    

Stampie said:

In reply to frenchyd :

You can relocate the LS coils to other places. I've seen the firewall as common.

I watched Calvin run into misfiring  on his engines under boost and using E85 at around 6500 rpm, using LS coils.    That forced him to go to aftermarket coils.  
  Paul VR6  has said the Ford V6  is adequate at higher boost and  RPM  then I'm planning on using.  

I doubt the "all in" timing on your v12 is 8deg, that's likely an idle timing value. It's probably something more like 25-35deg at 3k and 100kpa.

There may be a curve out there for the distributor, but usually vacuum is advancing the timing not retarding it (there are some old distributors that could advance or retard like the early watercooled 8v vw's oddly enough). 

I'm reasonably sure that is correct.  I know it's way off but the heads used on the HE provide 11.5-1 compression ratio. And the British engines are 12.5-1 compression ( actually pistons& heads).     That  was an attempt to keep the V12  in production with California's proposed smog laws 

     In 1927 Buick came out with the fireball heads that were later acquired by GM and used  in the Chevy 6 cylinder engines into the 1960's.   The idea was to swirl the intake charge over the hot exhaust valve to provide a solid combustion without the traditional  misfire associated with a lean burning engine.  
  Jaguar paid Roger? May something like £250,000 for that  fireball head design.  That combustion chamber design was used from 1981-1997. 
Racers always use the earlier head design. Huron?  head.  Completely flat with the combustion chamber in the piston.   The pre HE head flows  massively better  but suffers from low (  7.8-1 ) compression.    ( The British  had 9.0-1 compression with their lack of smog laws. 
         

Because I was curious and live timing advance... from jagweb

All are with no vacuum applied. Static figure is target for initial setting up. Timing should then be set to higher speed figure approximating to the peak torque regime.

V12 E type (CD carbs) 9:1 compression.750 r.p.m. (static)12 degrees BTDC3500 r.p.m.31 degrees BTDC

Bosch Lucas EFI, 9:1 compression, 1975-80.750 r.p.m. (static)10 degrees BTDC3000 r.p.m.29 degrees BTDC

Lucas 6CU EFI, pre-HE 10:1 compression, 1980-81.750 r.p.m. (static)5 degrees BTDC3000 r.p.m.24 degrees BTDC

The slightly more advance applied to the V12 E type reflects the fuel rating of 98 RON (rather than 97 RON quoted for later 9:1 engines) and also the breathing limitations of the CD carburettor arrangement.

***

With no vacuum applied. Static figure is target for initial setting up. Timing should then be set to higher speed figure approximating to the peak torque regime.

HE V12 XJ-S 1981-88 & HE Saloon 1981-91.750 r.p.m. (static)0 degrees BTDC3000 r.p.m.18 degrees BTDC

Likely the HE is knock limited being 12.5:1 ... and it's weird to see people saying a Huron head flows well 

   I think those are British numbers rather than American numbers. American compression was 7.8-1 not 9.0-1. Then in 1980 for 1/2 year British compression went up to 10.0-1  while American stayed at 7.8-1

  I really shouldn't quote numbers without checking.  I'll check  them when I get home  and report.  

 Regarding the Huron head ; 
Any time air must change direction it costs flow*  In the Huron head when a valve opens the air can head straight out.  Well it's aimed to hit that wall at a tangent. It doesn't have to dodge the combustion chamber walls  ( which is at least 2 direction changes. )   The design has built in swirl based on the way the ports are aimed. 
     As the piston moves up a natural hemispherical combustion chamber  is formed in the bowl shaped pistons. Concentrating a richer fuel mixture in the center by the spark plug.  
    The HE head heats the fuel charge up reducing hydrocarbon emissions .  
     If you look the 1975-1980 horsepower with 7.8-1 compression   is the same @ 260hp as the HE is with 11.5-1. compression   Don't mix up British rating which is 299 hp. 
   * I doubt you would actually see that because most bench flow is done head only.  Not head on block .  

I knew it was 8 degrees advance.  but that's for the UK version  North American version is18 retard with a rising vacuum from 7-10"