sequential firing with COPs possible in MJLJ v3 and/or 4?

dr.occa · Post by **dr.occa** » Thu Mar 05, 2009 4:32 pm

i've been prepping another project for MS and have been reading up on the sequential ignition setup. in the megatune software there are settings for the wheel decoder where the base tooth, start and return trig positions for each cylinder can be user defined. is there a chance of that being possible in either of the existing MJ versions or should i have asked this in the "New Project Suggestions" or "Update" forum?

regards,
the "O"

Post by **brentp** » Thu Mar 05, 2009 4:49 pm

Hi Jonas,

Sequential requires knowing which part of the cycle the cylinder is in, so it requires something like a cam angle sensor.

However, the extra coil charging time offered by this this is only beneficial at really high RPMS, like over 8-10K.

So, yep- "new project suggestions".

dr.occa · Post by **dr.occa** » Thu Mar 05, 2009 4:58 pm

brentp wrote:Hi Jonas,

Sequential requires knowing which part of the cycle the cylinder is in, so it requires something like a cam angle sensor.

However, the extra coil charging time offered by this this is only beneficial at really high RPMS, like over 8-10K.

So, yep- "new project suggestions".

ahhh, i see. then essentially what could be done is re-install my 4AG distributor (one of them has a CAS in it can't remember which) and use it just for the second (cam angle) signal.

here's the article i've been reading: Missing Toothed Crank Signal for Sequential COP.

Post by **brentp** » Thu Mar 05, 2009 5:25 pm

*edited!*

Right- that would give you the extra signal. A much more custom option would be to sense right off the camshaft, or off the end of one of the timing gears.

dr.occa · Post by **dr.occa** » Thu Mar 05, 2009 6:39 pm

brentp wrote:Right- that would give you the extra signal. A much more custom option would be to sense right off the crankshaft, or off the end of one of the timing gears.

what could work then would be to affix another trigger wheel w/ a single tooth atop the existing 36-1 trigger wheel but align the tooth 4 or 5 teeth before the missing tooth like in the image attached. one could always just bolt in a single tooth using 2 bolts to place a stationary longer tooth in the proper location.

Post by **brentp** » Thu Mar 05, 2009 7:04 pm

Sorry, I mis-spoke- I meant camshaft. Since you're trying to determine if the cylinder is in the compression stroke or exhaust stroke, you have to sense from the camshaft, which runs at 1/2 crankshaft speed.

dr.occa · Post by **dr.occa** » Thu Mar 05, 2009 8:27 pm

brentp wrote:Sorry, I mis-spoke- I meant camshaft. Since you're trying to determine if the cylinder is in the compression stroke or exhaust stroke, you have to sense from the camshaft, which runs at 1/2 crankshaft speed.

doh!