The V8 Owners Forum -

DaveEFI wrote:I'm intrigued by the claims for this sort of ignition system. Has anyone ever done a comparison on a rolling road? I'm talking about the type of spark, rather than timing, of course.

I have certainly not carried out a before and after rolling road test with my MSD but I have fitted four systems now, each time there has been a very noticable change to the engine. They start quicker, have a more stable idle and the power at high RPM seems to be much better. I spent a long time setting up my Lucas dizzy with the timing figures that I wanted, the engine ran OK but when I fitted my MSD with the same timing figures the power above 5k RPM was much greater. I guess the Lucas system was starting to stuggle at this high RPM and for a standard road car they could get away with a system that was marginal at high RPM.

The downside of an MSD system is that they are not cheap and you need decent HT leads otherwise they will burn away internally.

I have been using MSD stuff for years and like sidecar I am sold on it.

I run the following set up on two car.

Trigger wheel driving an EDIS8 box, with Megajolt box into an MSD DIS-4 box into twin ford coilpacks.

The Megajolt gives me full programmable control over the timing for all situations for idle, Boost, Cruise, WOT, etc.

The MSD give multi sparks at low revs and a single whopping spark above that. Never had a problem with the big sparks as there is no dizzy cap or rotor arm to cause problems.

My fuel system is Holley TBI injection also programmable.

DaveEFI wrote:I'm intrigued by the claims for this sort of ignition system. Has anyone ever done a comparison on a rolling road? I'm talking about the type of spark, rather than timing, of course.

A lot depends how bad the system was that it was replacing.

And dont forget multispark systems usually only multispark below around 3000rpm....after that there simply isnt sufficient time to re-charge the coil for multiple sparks.

stevieturbo wrote:
A lot depends how bad the system was that it was replacing.

And dont forget multispark systems usually only multispark below around 3000rpm....after that there simply isnt sufficient time to re-charge the coil for multiple sparks.

That is very true!

In all the cases that I've fitted an MSD it has been replacing a Lucas system, sometimes a modified Lucas system (as in the advance curve etc.) sometimes not.

On my car I replaced the system because I was fitting NOS, I needed a strong spark and the ability to retard the ignition when the NOS is running.

stevieturbo wrote:

DaveEFI wrote:I'm intrigued by the claims for this sort of ignition system. Has anyone ever done a comparison on a rolling road? I'm talking about the type of spark, rather than timing, of course.

A lot depends how bad the system was that it was replacing.

And dont forget multispark systems usually only multispark below around 3000rpm....after that there simply isnt sufficient time to re-charge the coil for multiple sparks.

It's often someone replaces worn out whatever with new and compares the two. Most often with tyres and shocks.

I was surprised to read MSD improved EDIS, though.

I'd love to see proper tests done on ignition systems and different coils, there really are so many claims, yet so little evidence.

There's no doubt a good spark could help some highly strung engines, but for more sedate stuff, I just find it hard to believe anything half modern doesnt already cover all the needs of the engine.

That said...I've just ordered some new coils for mine LOL....there's no reasoning with myself !

EDIS 8 does multiple spark discharge at low RPM natively providing the SAW signal is altered, although not as comprehensive as MSD no doubt which is renowned for its benefits on yank iron

The MSD DIS-4 that I run has a bypass socket and I can run straight on the EDIS8 box. (Intended as a get you home device if the MSD fails).

Running on just the EDIS8, the engine feels less smooth but this may be due to the cold plugs I use, which may be sooting up a little on the lower HT voltage.

As Simplesimon says - EDIS does have multispark, although I think that different versions of the module may have varying capabilities.

There is a setting to turn it on in Megasquirt - I have never tried it...