MS-II Maximum Engine Speed

whizzo944 · Post by **whizzo944** » Sat Apr 01, 2006 12:46 am

Dear All,
Anyone tested the maximum speed that MS-II will control spark
timing. My original plan was to use a MS-I on my bike to control fuel only
and leave the existing ignition system. The engine revs to 15,000 rpm.
Anyone know or think if MS-II will handle ignition timing at this speed?

Thanks,

Dave.

Mike_Robert · Post by **Mike_Robert** » Sat Apr 01, 2006 5:51 am

See http://msefi.com/viewtopic.php?p=109569 ... 000#109569 - This should answer your question.

-Mike

Post by **grippo** » Sun Apr 02, 2006 7:37 am

I would also like to add that what a processor can handle is not just a function of rpm, but of the number of cylinders. The example Mike alluded to was really worst case, since it was run for an 8 cylinder engine. For 4 cylinders you could in theory get double this rpm since it provides a tach interrupt only twice per crank rev instead of 4 with a V8.

Bernard Fife · Post by **Bernard Fife** » Sun Apr 02, 2006 8:54 am

And I will add that the theoretical maximum rpm is 32750 for all engine configurations, because of the way the code handles the calculations internally.

I have tested this to 32750 on the bench (with a '1 signal per ignition event' tach input, not a missing tooth wheel). With a 36-1 missing toth wheel, I have tested up to 25000 rpm with an 8 cylinder configuration and talking to MegaTune at the same time at 115200 baud. In both cases the ignition output signal (to the VB921) was clean and stable (I did not check EDIS).

Lance.

whizzo944 · Post by **whizzo944** » Tue Apr 04, 2006 9:56 am

Thanks for the help guys. Just out of interest, the engine is a 90 Degree V4,
400cc and it fires 0 Deg, 90Deg, 360 Deg and 450 Deg. and it uses wasted
spark system for the front 2 cylinders and back 2 cylinders. Yes, both rear
and both front pistons are up together. I assume that I would need to use a
V8 engine setup and just ignore the non-existant 4 cylinders.
Dave.

keithmac · Post by **keithmac** » Tue Apr 04, 2006 12:07 pm

Honda VFR400 NC30 by any chance?

whizzo944 · Post by **whizzo944** » Wed Apr 05, 2006 9:14 am

Yes, but it couldn't really be anything else could it? Maybe an NC35.

keithmac · Post by **keithmac** » Wed Apr 05, 2006 3:25 pm

They did the 21`s and 24`s?

Will be interesing to see what gains you get on MS!

Got a bit of a soft spot for the NC30`s, we used to import Grey`s from Japan a few years back, must of prepped 50 or more for sale..