How good are LS coils?

[260DET]

Seems to be a lot of conflicting comment around about LS coils, mine are the LS5/7 type and are breaking down ~6000rpm/15psi boost, VG30DET motor.

 

It may be the dwell time which is the issue. I've been told they will run to 8ms no problem, presently they are set for less than 5. MoTec are going to test a coil to see what they will take without overheating.

 

Any experiences?

[ktm]

z-ya did some testing in the Megasquirt forum on the LS1 coils. He found that they'll take up to 7 - 8 ms before saturation. I am running mine at 6 ms to combat high boost miss issues (in conjunction with gapping plugs, etc.).

 

I am running up to 18 psi right now with 20 to 23 psi in my near future.

 

I am using Wolf to drive them. What are your AFRs at 15 psi and 6000 rpm? What do you mean, breaking down? Are you missing at that point?

[260DET]

Breaking down = engine missfire cured by reducing the stock spark plug gap, leads are new high performance type. Car was having its initial dyno tune, got no reason to doubt that the AFR was good, the tuner does all sorts of mainly Euro high performance stuff but has no previous experience with these coils.

[ktm]

Ok. Set the dwell on the coils to around 6 ms. Plugs need to be gapped closer anyway at 15 psi. The stock gap for NGK BPRES6-11 is 0.044", far too much for 15 psi.

 

I found that I had to gap, up the dwell slightly, and lean out to keep from misfiring. I am running an L28ET, but my AFRs are 12 at 15+ psi. Not a misfire to date since the changes.

[260DET]

Thanks ktm, a couple of tuners have suggested ~6ms. Be interesting to see what MoTec recommend, will post that up in due course.

[260DET]

My coils have been identified as LS2/7 coils and MoTec say they are already running at maximum capacity, what a bastard.

 

Any recommendations for better, much better, coils with built in ignitors?

[cribbj]

PMFJI, but 260DET have you checked out the Mototron (IGN-1A) smart coils?

 

Specs & prices here here: http://www.bmepfuelandtuning.com/html/bmep_ignition.html

 

No relation to me - just one of the places to find them on the web. Pantera EFI is another.

 

HTH,

 

John

[260DET]

Thanks for that John, problem is I don't know how to evaluate the potential performance of a coil.

 

Anyone used the coils John has mentioned?

[cribbj]

I don't know how to evaluate the potential performance of a coil.

 

Richard, that seems to be the problem with most ignition coils. There's no way to evaluate them objectively.

 

You won't find these coils in a Summit or Jegs catalog; nor are they encased in racy looking red or yellow plastic cases, but they get the job done. Have a search on http://www.efi101.com/forum/ using Mototron or IGN1-A and see what comes up.

 

Alternately, contact your MoTeC rep, I'm sure he knows these coils as they're often the solution of last resort.

 

BTW, these are not small coils; they measure around 115 x 90 x 50 mm roughly, and weigh around 450 grams, so packaging can be an issue.

 

Javad Shadzi over at 034Motorsports has developed a unique way to mount these on the DOHC Audi motors:

 

Best,

 

John

[260DET]

Having received more feedback on the LS2/7 coils it seems that they are very good and unlikely to be the direct cause of the missfire. So the tuner will do more work with them, in particular a table of some sort, if all else fails then I'll give those BMEP coils a go, thanks again John.