The V8 Owners Forum -

Reading up on Ignition, there seesm to be two ways to go...coil on plug or EDIS module...has anyone done a definative guide to the pros and cons of one vs the other? Reliability, performance, easy of install, cost?

Is one favoured over the other depending on the on the ECU, if so, why?

Thanks and sorry if this has been asked before, but so much choice out there....

virgil wrote:Reading up on Ignition, there seesm to be two ways to go...coil on plug or EDIS module...has anyone done a definative guide to the pros and cons of one vs the other? Reliability, performance, easy of install, cost?

Is one favoured over the other depending on the on the ECU, if so, why?

Thanks and sorry if this has been asked before, but so much choice out there....

EDIS is cheap secondhand, effective and extremely reliable. It's also self contained needed only data communication between its ECU and the main one to control the advance etc.

COP could be just coils or ones with built in drivers, so will require a more specific ECU to drive them. It's probably the very best option since most new cars use it, but will cost very much more in practice to implement. If I were opting for COP, I'd go for ones with built in drivers (ignitors).

If it's an RV8, all the bits for an EDIS installation are readily available. And it interfaces with MS easily.

What ECU are you using?
If megasquirt it can control the coil packs directly so you can do-away with the edis modules. The 1 advantage I know of this is that you can then use spark cut as a rev limiter which you can't when using the edis module. Also looks neater, less boxes!

So I think you're comparing wasted spark/coil packs with COP. I think it depends on how far your going with your engine, wasted spark is already much better than a single coil. There is a lot more time for the coils to charge at high rpm. COP has even more time available to charge the coils but do you really need it? If you're building a high rpm/high cr/high boost engine may be an advantage, if not wasted spark will be more than fine.

Tom.

What ECU are you using?
If megasquirt it can control the coil packs directly so you can do-away with the edis modules. The 1 advantage I know of this is that you can then use spark cut as a rev limiter which you can't when using the edis module. Also looks neater, less boxes!

So I think you're comparing wasted spark/coil packs with COP. I think it depends on how far your going with your engine, wasted spark is already much better than a single coil. There is a lot more time for the coils to charge at high rpm. COP has even more time available to charge the coils but do you really need it? If you're building a high rpm/high cr/high boost engine may be an advantage, if not wasted spark will be more than fine.

Tom.

Thanks.

Want to use it on RV8 (TVR Griff 500)

I *had* intended to use megasquirt, but two things are putting me off:

1. there seem to be lots of versions, options, bolt-ins (solder-ins?) MS version X with daughter board...version Y without, with one reseller offering X and another offering Y but there doesn't seem to be a 'standard' MS box to use. I could be very wrong here and just missunderstood. Would be pleased to be corrected...

2. A Rolling Road tuner I spoke with advised against MS as *he* had had issues getting MS to work well with ITBs. Not sure why, it was an e-mail conversation and he had not gotten round to reccomending anything instead (don't think he retails any, just tunes), but still worrying...

Think I have read (have I read rightly?) there is an argument NOT to drive the coil packs (with wasted spark) directly from the MS ECU, but to use EDIS or is this only scaremongery?

Also, why are 'choices' never simple?

The reason there are so many choices with MS is that it is basically a DIY system. So you are expected to do the research and specify what you want - rather like assembling your own PC rather than just accepting what PC World has on sale.

Ideally, if you have the skills, you'd build it yourself. That helps greatly with understanding how it works and what the options are. And means you could repair it if a disaster happens. But that's not likely.

However, our very own ExtraEFI will be happy to help you with a ready made one which will do what you want, I'm sure.

I can understand some tuning pros not liking them. Lots and lots to learn on programming them. Can't see any reason why MS wouldn't like ITBs.

My own research took me to a MS2 V3. I imported a kit from the US and built it - but I like doing this sort of thing. The MS3 is similar, but smaller since it uses surface mount components - easier for automated assembly, but not for DIY build, fixing or modding.

Other really great thing with MS is their forums - where you'll get help from the horses mouth, if needed. I can't see this happening with a purely commercial product.

Think I have read (have I read rightly?) there is an argument NOT to drive the coil packs (with wasted spark) directly from the MS ECU, but to use EDIS or is this only scaremongery? QUOTE// Think you will find that the earlier glitches with driving the coil packs direct from the MS ECU have all gone,I used EDIS 8 but I possibly would have gone direct fired if I was certain that the glitches had been ironed out at the time of install,think this was more to do with interference/noise but don't quote me on that

DaveEFI wrote:
Other really great thing with MS is their forums - where you'll get help from the horses mouth, if needed. I can't see this happening with a purely commercial product.

MSD have a forum which helped me when setting up their ignition system. Blokes who work at MSD answer the posts.

My posts must have been slightly 'odd' to them because I wanted to use an MSD dizzy pickup inside a Lucas dizzy with the Lucas reluctance wheel.

SimpleSimon wrote:Think I have read (have I read rightly?) there is an argument NOT to drive the coil packs (with wasted spark) directly from the MS ECU, but to use EDIS or is this only scaremongery? QUOTE// Think you will find that the earlier glitches with driving the coil packs direct from the MS ECU have all gone,I used EDIS 8 but I possibly would have gone direct fired if I was certain that the glitches had been ironed out at the time of install,think this was more to do with interference/noise but don't quote me on that

Personally, I don't much like the principle of having high current ignition drivers as part of the ECU. I'd prefer COP with built in ignitors so they only require a switching signal. But that's just me.

However, with a (relatively) low revving unit like the RV8, EDIS is just fine.
Tried, tested and cheap.

I had MS running happily with a Lucas DLM minus the amp, using the Lucas VR sensor. And with the same dizzy but with a home built hall effect. Before going to EDIS.

The biggest benefit on your application of not using 4 tower coil packs. IS opting for COP or Coil near plug will do away with long HT leads everywhere. Which IMO is just messy.

Opting for COP or CNP is just far tidier. It will not offer you any performance advantage though.

DaveEFI wrote:

SimpleSimon wrote:Think I have read (have I read rightly?) there is an argument NOT to drive the coil packs (with wasted spark) directly from the MS ECU, but to use EDIS or is this only scaremongery? QUOTE// Think you will find that the earlier glitches with driving the coil packs direct from the MS ECU have all gone,I used EDIS 8 but I possibly would have gone direct fired if I was certain that the glitches had been ironed out at the time of install,think this was more to do with interference/noise but don't quote me on that

Personally, I don't much like the principle of having high current ignition drivers as part of the ECU. I'd prefer COP with built in ignitors so they only require a switching signal. But that's just me.

However, with a (relatively) low revving unit like the RV8, EDIS is just fine.
Tried, tested and cheap.

Totally agree Dave,that's why I went EDIS too

There are active coil packs that quite a few of us use... ie VW/Audi/Skoda style I think Phil Ringwood has come round to supporting them with his MS's & they have always been standard on KMS ECU's (if you have heard of them).

I just built my Megasquirt a few weeks ago and installed it running EDIS8 in my Landrover 90. Has been flawless so far.

I built an MS1 on a V3 board running MSExtra code, and plan to get it running fuel later this summer. The build manuals can be confusing as the docs don't seem to be totally up to date and you can get conflicting/different info, but I just asked a lot of questions on various forums and got there fine.

I had been running Megajolt previously and that ran for around 2 years (I think) with no problems with the EDIS module itself or the Megajolt. The only failures I had were of coilpacks, both secondhand off ebay so I have no idea how far they went before they both did around 30-35,000miles with me! Strangely both failed in the last couple of months. Simple solution to this is to carry a spare. Both times I managed to limp somewhere safe on four pots and swap in a replacement in a few mins

Ah well, another tenner on ebay and I had two more to put on!

spend wrote:There are active coil packs that quite a few of us use... ie VW/Audi/Skoda style I think Phil Ringwood has come round to supporting them with his MS's & they have always been standard on KMS ECU's (if you have heard of them).

How are they mounted on an RV8? Other thing is how does the heat from the exhaust manifolds effect life?