Ignore this statement, i messed this up a bit by not comparing the air temperature of the different rolling road sessions. The last one measuring the Hyfire performance was done in 46° C compared to 31° C for the default setup, so we do see at least a small performance improvement here due to using a capacitive multispark system in a small engine.alhbln wrote:...
We also installed a Hyfire 6AL in a race bred 2.4 litres high reving engine and did some rolling road tests and there was no improvement in torque and horsepower (got an additional 5 NM at 3000 rpm, well ok)
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Ignition system with repetitive sparks
Moderators: JeffC, rdoherty, stieg, brentp
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Edwardatherton
- Posts: 30
- Joined: Sun Jul 01, 2007 9:50 am
- Location: Manchester, England
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I would also be very interested in this - my Land Rover runs at about 3500rpm at top speed, and a lot of the time would be less than 2000rpm. It also runs on LPG, so if it helps with that, it would be great.
Having just passed my bike test and got a new Kawasaki ER6F, I still find it hard to get used to seeing a rev counter above 3500 - which it is nearly all the time!
Having just passed my bike test and got a new Kawasaki ER6F, I still find it hard to get used to seeing a rev counter above 3500 - which it is nearly all the time!
Land Rover 1957 S1 88" 2.5 petrol/LPG
Hi Brent,brentp wrote:Hi All,
looking over the firmware code it seems that it would be pretty easy to accommodate the pulse lengthening required to activate multiple spark discharge as outlined in the EDIS specification.
What it will look from the user's point of view is that you would have an additional option in the ignition configuration which would enable/disable multiple spark discharge under 2000 RPM (or so).
I'll put this on the list of things to do- I should be able to test this soon after the V4 release. All MJLJ hardware revisions (V2,3,4) will be able to receive this enhancement.
Did you ever get chance to look at this multi spark/SAW lengthening?
I have 2 classic cars with V3 hardware that I hope would improve when slow moving in trafic with this change.
Cheers
Dave
Hi Brent, I would like to light up this thread again. The multispark feature would be much appreciated by many of the users of the Megajolt that use it in our daily drivers, and in my case a 4x4 SUV. The sub 2000RPM range is where much of 4 wheeling is done, so a little more torque and fuel economy is more than welcome.
I decided to post this reply because reading through your blog, I've noticed that the new Megajolt C is soon to be released and didn't want that this feature got buried under all the frenzy of the new version. I assume that you must be quite loaded with work, but if you could find a moment to get this feature running many of us would be VERY grateful.
Regards
Jacob from Venezuela
I decided to post this reply because reading through your blog, I've noticed that the new Megajolt C is soon to be released and didn't want that this feature got buried under all the frenzy of the new version. I assume that you must be quite loaded with work, but if you could find a moment to get this feature running many of us would be VERY grateful.
Regards
Jacob from Venezuela
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Spockie-Tech
- Posts: 152
- Joined: Wed Jan 02, 2008 12:52 pm
- Location: Melbourne, Australia
I'd be interested if anyone knows of any actual test results that show *any* significant improvements resulting from multi-spark ignitions - when compared against *equivalent* non-ms ignitions. Tests where you replace an old points system with a Hi Energy CDI system mean nothing, since you're not comparing a good non-msd against msd.
MSD and all the other aftermarket ignition marketing teams trumpet their multi-spark systems advantages, but I'm betting 90% of their customers know next to nothing about the combustion processes.
I saw some spark time/combustion chamber pressure graphs a long time ago, and it was very interesting to note that something like about 80% of the pressure-build curve delay was the time taken for the "fireball" to go from 0% (spark time) to 10% of the eventual peak pressure. It was an exponential curve something like this one
It makes sense when you think about it. To grow a tiny little ignition point up to a fireball with significant surface area so the growth can begin to accelerate takes time. a bit like rolling a tiny snowball down a hill.. once (if) it gets some diameter to it, *then* the surface area is big enough to pick up growth rate. The "tipping point" of the curve was about 0.1" IIRC.
*So*. If for some reason, your first spark doesnt get things happening, by the time you have extinguished it, and re-sparked, you have a whole nother 0" to 0.1" delay to go through, I'm guessing, its going to be *way* too late for the second spark to really make much difference.. Especially at any significant rpm. Which is probably why the EDIS doesnt bother to do it past about 1800rpm.
Even then, I would guess that subsequent sparks would help only in the slight reduction of idle hydrocarbon (unburned fuel) emissions (important to the factory with emissions standards to meet), since the piston will likely be too far down the power stroke for any late combustion to add significantly to the pressure/force.
I am very sceptical that *any* noticeable power/smoothness improvements would be made over a non-ms good quality ignition by using Multiple Sparks. Try taking even 10 degrees of timing out of your idle advance and see how well things run, so a 10 degree late spark isnt going to help much.
But, I might be wrong, which is why I would be interested to see if anyone knows of any credible research/dyno tests that suggest otherwise.
MSD and all the other aftermarket ignition marketing teams trumpet their multi-spark systems advantages, but I'm betting 90% of their customers know next to nothing about the combustion processes.
I saw some spark time/combustion chamber pressure graphs a long time ago, and it was very interesting to note that something like about 80% of the pressure-build curve delay was the time taken for the "fireball" to go from 0% (spark time) to 10% of the eventual peak pressure. It was an exponential curve something like this one
It makes sense when you think about it. To grow a tiny little ignition point up to a fireball with significant surface area so the growth can begin to accelerate takes time. a bit like rolling a tiny snowball down a hill.. once (if) it gets some diameter to it, *then* the surface area is big enough to pick up growth rate. The "tipping point" of the curve was about 0.1" IIRC.
*So*. If for some reason, your first spark doesnt get things happening, by the time you have extinguished it, and re-sparked, you have a whole nother 0" to 0.1" delay to go through, I'm guessing, its going to be *way* too late for the second spark to really make much difference.. Especially at any significant rpm. Which is probably why the EDIS doesnt bother to do it past about 1800rpm.
Even then, I would guess that subsequent sparks would help only in the slight reduction of idle hydrocarbon (unburned fuel) emissions (important to the factory with emissions standards to meet), since the piston will likely be too far down the power stroke for any late combustion to add significantly to the pressure/force.
I am very sceptical that *any* noticeable power/smoothness improvements would be made over a non-ms good quality ignition by using Multiple Sparks. Try taking even 10 degrees of timing out of your idle advance and see how well things run, so a 10 degree late spark isnt going to help much.
But, I might be wrong, which is why I would be interested to see if anyone knows of any credible research/dyno tests that suggest otherwise.
Its clear after all the info I'read over the web, that multi spark have a small benefit and its application is only feasible in the low rev range. Manufactures have used it to improve emissions and support smoth idle. Both good for a daily driven vehicle that spends most of the time between 1K and 3K RPM. If the implementation is relatively easy, as it seems, it would be nice as a last upgrade to the Megajolt Jr.
[url=http://www.dtec.net.au/Multi Spark Ignition.htm]
[url=http://www.dtec.net.au/Multi Spark Ignition.htm]
I see what you are saying - and no, I don't think it does help with peak power. I think the advantage is on a "lean burn" engine, where is deliberately setup slightly weak mixture to aid fuel economy. A lean mixture is harder to ignite, so perhaps the second spark is of use if the first doesn't fully ignite the mixture?
My thought is this: It must be of some use or Ford wouldn't have gone to the trouble of using it. Companies like MSD etc have a reason to use it - it is a selling feature for their ignition systems (whether it is actually of use ot not is another matter), but Ford don't use it as a selling feature for their 1300 Fiesta's, so it must be there for another reason!
I must say for an old design pushrod engine, in terrible condition and rattled like hell, my old Fiesta used to idle smooth as silk, even as low as 4-500rpm! My Mini even with MegaJolt hunts at idle below 800.
My thought is this: It must be of some use or Ford wouldn't have gone to the trouble of using it. Companies like MSD etc have a reason to use it - it is a selling feature for their ignition systems (whether it is actually of use ot not is another matter), but Ford don't use it as a selling feature for their 1300 Fiesta's, so it must be there for another reason!
I must say for an old design pushrod engine, in terrible condition and rattled like hell, my old Fiesta used to idle smooth as silk, even as low as 4-500rpm! My Mini even with MegaJolt hunts at idle below 800.
Ian, probably more a factor of carb/cam than spark for a hunting idle. Mine is rock steady down to 600 on my VW flat four. BTW, high-lift cam, 1.5:1 ratio rockers and 1 throat per cylinder Webers.
Previously had a distributor with Mallory Hyfire 6 CD unit. Idle is a lot smoother now with no other changes.
V3 Jolt unit with aftermarket Ford-style coilpack.
Previously had a distributor with Mallory Hyfire 6 CD unit. Idle is a lot smoother now with no other changes.
V3 Jolt unit with aftermarket Ford-style coilpack.