Confirm:Tacho pulse/rev 4 Cylinder Lyco with Mags?

[RudiGreyling]

Hi Guys,

Can someone confirm for me that the Pulse/Revolution setting on the EMS is 1 for an XP 360 a 4 cylinder Lycoming clone with 2xstandard Slick Mags on them?

My enginering head tells me it should be 2, but 2 on the ems gives the way wrong values, and 1 looks better, but I am still not convinced. It is a new engine and new EMS setup installation, so I am not sure if the engine develops full RPM OR/AND the instrument RPM pickup is wrong. By starting with at least the correct EMS setup confirmed I have eliminated 1 possibility already...

Thanks
Rudi

 

[dynonsupport]

Re: Confirm:Tacho pulse/rev 4 Cylinder Lyco with M

Rudi,
Lots of customers end up using "1." Technically, the mag does put out two pulses per revolution, but one is positive and one is negative. The EMS only picks up positive pulses, so we only see 1 of the 2.

I'll also note that the difference here is huge. If you set it to "1" and it was supposed to be "2", you'll see 1500 RPM at idle, and you'll be able to generate over 5000 RPM at full power. It's not like the difference is 2700 vs 2900 RPM. If "1" feels right, it's right. The difference can be fuzzier for someone trying to figure out if it's 4 or 4.5.

 

[RudiGreyling]

Re: Confirm:Tacho pulse/rev 4 Cylinder Lyco with M

Hi Mr Dynon Support.

Thank you and yes I can confirm it is "1" for standard slick mags, and it works perfectly! Everything is sorted 100% now.

Regards
Rudi

 

[brothwood]

Re: Confirm:Tacho pulse/rev 4 Cylinder Lyco with M

Hi.
Installed 4 x CHT and 4 x CHT sensors for my D180 - can I shorten the leads from these sensors or is the length critical?
Regards, George

 

[dynonsupport]

Re: Confirm:Tacho pulse/rev 4 Cylinder Lyco with M

You can shorten them. Just follow the manual guidelines - you don't want temperature changes across any junctions you create (ie - junction at firewall is bad), and any wire additions need to be the right type of thermocouple wire.