[Toobuilder]

You better be really careful with the advanced timing of most EI's with 10-1.

Yep. Thinking the same thing. Big compression, big cam and retarded cam timing all point to high RPM operation. In this case, the move away from EFI and its multitudes of tuning options is a step in the wrong direction, IMHO.

 

[ltampico]

I've had dual Lightspeed on my RV8 for over 11 years, not a single hiccup! Works great

 

[Walt]

Thanks for your heads-up Walt, but could you please eloborate ?

10-1 with advanced timing = detonation, bad juju
I run 9.7 cr fixed timing with good old reliable Bendix mags.
Be cautious on the prop as well, many are not approved for hot rod engines with EI.

 

[Floog]

(2) DC Mini-sensors. 'Bendix' style fuel injection.

 

[Toobuilder]

10-1 with advanced timing = detonation, bad juju

Agree. And in the context of this thread, the Pmag will most certainly be advanced beyond the data plate value at high power settings. So that leaves the Lightspeed as the only reasonable option - assuming that the timing control module is used to retard the timing at high power. This is especially true if the “hot rod” engine discussed is an angle valve head.

 

[Carl Froehlich]

Agree. And in the context of this thread, the Pmag will most certainly be advanced beyond the data plate value at high power settings.

This is reversed. At high power settings the pMag fires close to base timing (assuming that is what you set it up to do). Timing advance comes in as manifold pressure drops. This is the advantage for timing advance - increased engine efficiency at typical cruise conditions.

For the pMag the maximum timing advance is 9 degrees (four cylinder engine, jumper in). In practical application timing never goes that far advanced. My reading on this is 9 degrees is the maximum you ever want to have.

For the six cylunder pMags, you can tailor the timing advance during install. You also have a switch to revert to base timing at any point.

But - for the OPs engine I’d start with base timing around 20 degrees. Collect data and then decide if you want to move it up.

Side note - if memory serves the Lightspeed II+ had a more aggressive timing advance.

Carl

 

[Toobuilder]

At high power settings the pMag fires close to base timing

There are many threads on this site that show the Pmag MP curve comes in early and aggressive. And in this context (High compression, hot rod engine), that’s something to be wary of. It’s my experience that you want an ignition that can “retard” as well as advance for a hot rod (or angle valve) engine. P mag does not have that capability. I “think” the Lightspeed can do that, with the appropriate timing control box.

 

[vlittle]

A bit of history... here are some musings from my extinct 2005 RV-9A website:

Spoiler alert: 20 years after I wrote this *opinion*, I have chosen EMags for my new build. I have no in-flight experience.

" When I heard about EMagair,the maker of P-MAG and E-MAGs, I thought 'what a great idea!'. I designed out my conventional mags and designed in the EMagair products with their assistance.

I placed my order and waited, but the products were delayed several times and I finally had to get my engine built so I cancelled my E/P-Mag order and switched backed to conventional mags. I'll leave all of the wiring in place for a future upgrade, so if EMagair can ever deliver and proved their reliability, I can upgrade. It will cost me more money, but it's a safe way to go.

I have been involved in dozens of new product introductions in my career, and many of them had technical problems and delays at the beginning. The company I have worked for the last 17 years (PMC-Sierra) was very proud of it's record on getting new products out on time with minimal technical problems, but sometimes we had some problem cases.

My opinion is that EMagair is having technical problems, and they want to take the time to get their products right. That's what they should do. In my discussions with them, however, I became concerned about how they are going about things. It's entirely possible that they will have a great product, but a broken business plan. I hope they are getting good business advice.

My background is engineering, marketing and business analysis (mergers and acquisitions). I have seen a lot of companies fail, even though on paper they have a killer product. It's all about the right plan, the right people, execution and documentation.

Documentation?? Yup, 90% of the businesses I analyzed failed because of poor documentation.When you have 50 people designing a 20 million gate integrated circuit, you better get the engineering documents, manufacturing and customer documents right or you will never, ever find all of the bugs, never ship the product for revenue and never have a successful business.

EMagair is a different animal, I agree... but being successful with a product like this (eventually to be certified) will swamp them in paperwork. For example, what is their qualification test plan?

Are they going to let their customers debug their products for them? I hope not. If I were them, I'd get 3 or 4 aircraft test beds in the air as soon as possible with backup magnetos, and run them through a battery of tests, collect data and analyze it before I shipped any products to customers.

Things to think about...

- will they work at temperature extremes?
- will they work with a lot of temperature cycling?
- what about high altitudes?
- what about vibration (normal and abnormal)?
- what about contamination from engine fluids or dirt?
- what about reliability in corrosive atmospheres?
- what about susceptibility to electrical interference (comm radios, transponders, etc.)?
- what happens when the internal micro goes insane?
.... and so on.

There are many questions.They have been good at answering some, but not others. Food for thought. Good luck to them. If they are successful I will upgrade."

I think they passed the corporate longevity test! In my Harmon Rocket, I used one impulse mag and an Electroair. The Electroair had problems due to the timing ring installation (caused by the engine builder). First engine run in my new build with EMags is coming up soon...