MJLJ LACK OF TOP END REVS

General Topics for configuring, operating and tuning the Megajolt. Also see the <a href="http://www.autosportlabs.net/MJLJ_V4_Operation_Guide">Operation Guide</a>

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raceace
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Joined: Mon Jul 13, 2009 9:46 pm
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MJLJ LACK OF TOP END REVS

Post by raceace »

Advise desperatly needed. I have a MJLJ kit fitted to a kawasaki zzr 1100 on carbs ,which is in a single seat race car. Everey thing works fine upto 9300 rpm at this point the EDIS UNIT retards the ignition timming , preventing the engine reaching full revs Is there any way I can overcome this,with the kit I have fitted. If not what ,stand alone, options are available..
Hope you can help,. Regards JAYPAUL
knock knock

brentp
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Post by brentp »

In the MJLJ, what have you set the rev limit to? Be sure the rev limit is set to the max possible.

The MJLJ has a 'soft rev limiter' which activates 100 RPMs before the configured hard limiter. This soft limiter retards ignition timing to zero degrees to provide a cushion when the optional hard rev limiter module is engaged.
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cng1
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Post by cng1 »

EDIS-4 tops out at 9300rpm so isn't suitable for a high revving engine like that (unless you want to artificially limit the revs). You're not actually seeing a retard at 9300, the ignition is dropping out altogether until the revs drop slightly and then it kicks back in again, giving the illusion of a rev limiter.

The current Megajolt isn't really suitable for your application, so unfortunately until Megajolt2 comes out your choices are to live with the 9300rpm limit or to change to a different ECU.

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Post by brentp »

Thanks Chris.

Is the MAX RPM fairly consistent across the EDIS modules you've tested? I have seen reports of some EDIS modules having a higher RPM limit than others. I have my doubts on this as it would've likely been a significant re-design inside the EDIS module to change the upper RPM limit.
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cng1
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Post by cng1 »

EDIS-8 modules vary from 6600rpm to 7100rpm, EDIS-4 modules from 8400rpm to 9300rpm. EDIS-6 are somewhere between the two but I don't have my notes for that to hand.

The "rev limit" really is no such thing, it's just the point at which the module runs out of puff and either can't distinguish the signal or can't keep up with firing the coils. My hunch is that Ford know what the max rev limit is for a particular installation so made sure that the parts specified for that range were good enough for that with a little headroom - no point speccing the best grade and tolerances if you're never going to need them. Ford are very good at cost reduction measures so would only have specced the best parts for the models that were going to rev high enough to need it.

brentp
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Post by brentp »

I suspect the primary limitation is the EDIS CPU's capacity to accurately process the timing pulses from the crank and maintain stable operation. Going beyond the limit would likely require spec'ing a different processor with an updated clock, and updated code to account for all of these changes, and of course deal with all of the other rippling effects throughout. It wouldn't be a low-cost effort for Ford.
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raceace
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Joined: Mon Jul 13, 2009 9:46 pm
Location: north wales

THANKS

Post by raceace »

My thanks to all for the info posted..all in less than 8 hours fantastic!!!!

MEGA JOLT 2
When is this unit expected to be on sale
What revs will this unit allow
What is approx cost of Maga jolt 2 + any other parts required to run my engine.(I only have 1 arm and 1 leg left,but could consider using 1 gear if required)

Best regards Jaypaul









0
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brentp
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Post by brentp »

You're welcome.

Here is our Megajolt2 Roadmap:
http://www.autosportlabs.org/viewtopic.php?t=2294
Brent Picasso
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