Hard rev limit

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>

Moderators: JeffC, rdoherty, stieg, brentp

MartinM
Posts: 433
Joined: Sat Aug 27, 2005 12:08 pm

Tried it with the relays and

Post by MartinM »

Tried it with the relays and it works just fine on the test bench - can't get much simpler that 2 relays attached directly to the REV LIMIT output and 2 10R 10W resistors.

I'll draw some qualitative pics of what I saw with my 'scope on the coil -ve terminal later, with and without the resistors in place and link to them here - they're quite interesting...

I'm liking this a lot so far!

Just need a car to try it on (don't have a MJLJ'ed car since I sold it 3 weeks ago - but I extracted the MJLJ before it went) to ensure that there's no unexpected side effects

I'm confident that the solution kills any coil charging in progress without causing a spark, so maybe our originally perceived problem of premature sparks has been solved...?

4600cc
Posts: 0
Joined: Sun Jul 11, 2004 1:48 am

I'll stick with David's

Post by 4600cc »

I'll stick with David's original thyristor rev limiter circuit. Why? Well, because you (only you) had a problem with it. AND, because you just let me know today you don't know how to open a file.

I don't find your argument, that David's circuit does not work, credible. As a matter of fact this raises the question, why would David post a non-functional circuit of a hard-cut rev limiter? It is more likely that the circuit is a little complex and hard to trouble shoot, and lacks sufficient documentation.

DannyP
Posts: 417
Joined: Sun Apr 09, 2006 3:48 pm

nevermind

Post by DannyP »

I had a very wrong idea and deleted it.
Vintage 550 Spyder replica VW type1 2165cc 9.8:1 Dual Weber 44 IDF RABY motor MJLJ V3/TPS

4600cc
Posts: 0
Joined: Sun Jul 11, 2004 1:48 am

Motor all right?

Post by 4600cc »

Motor all right?

dr.occa
Posts: 243
Joined: Fri Feb 23, 2007 10:52 pm
Location: TX

Post by dr.occa »

has anyone already suggested retarding ignition to let's say 10 at desired rpm? e.g 36>0 degrees throughout load range at 8000 for a "soft rev limiter". good/bad idea?

brentp
Site Admin
Posts: 6282
Joined: Wed Jan 24, 2007 6:36 am

Post by brentp »

Old thread alert!

The MJLJ has a soft rev limiter built in. 100 RPM before the hard limit the advance goes to zero. Once the hard limit is reached, the REV_LIMIT output is activated.
Brent Picasso
CEO and Founder, Autosport Labs
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