MolsonB

I'm going to design an ECU more specific to my mission. Is there anything in particular that could hurt the engine during tuning? Spark timing fire into apex seals?

Just wondering if I should buy an engine from the wreckers and play with building my own ECU first, before touching my good engine.

Loki

iTrader: (1)

Detonation is your main enemy. One knock event at high load could take out a seal. Probably best to have an engine to practice on.

Are we talking Megasquirt or something else? That sounds like a serious project

What's missing from the Mazda ECU for you? Altitude compensation?

MolsonB

The engine will just be on a test bench for the next 8-10 months, (6500rpm max).
Very similar to mega-squirt's hardware setup, but I'll write my own programming code for the chip I'll be using. Android software via bluetooth to do the actual live tuning. It's a big task, but I have the next 6 months to work on it daily.

My project involves very high altitude. Aviation. No emissions, Throttle body or oil metering pump to deal with. Basically I'll be adding dual sensors (And ecu) for failsafe operations. MAF, MAP, IAT, Coolant, WideBand 02, E-shaft sensor (looking to add a dual E-shaft sensor somehow.)

We aren't trying to squeeze HP out of the engines, but lean them out for cruise millage is our primary design. Our load is more constant, which makes tuning a bit easier. If I fail miserable, I'll end up using 2 MS.

TeamRX8

iTrader: (25)

You'll want to stick to the early 4-port engine

MolsonB

I need to update my 'engine' post, but the RX8 is p-ported and the side's intakes are closed off with devcon.

Over the next few months, as I build the engine and start testing out the sensors and programming code. I'll keep an eye out if any used engines pop up. In Ontario, Canada. $1500 cnd is the going rate for a complete engine. I'd only need the longblock though.

Rub20b

Should work just fine. as long as the engine is NA you have to do serious thign wrong to make it knock. I ahve been runnign 6 port rx8 for some years in a miata with MS2, aux ports etc all working and it work just fine. I would install thermocouple per exh port and mkae sure EGT doesnt go high as it will kill the side seal soon.

But if you only run 6500 rpm I also forsee no problems with EGT as long as you dont spark anywhere too far of optimum.

I would just try to find best spark timing and run lambda 1, if you dont have excessive EGT you can stay around lambda 1, if not you slightly richen it up.

logalinipoo

Since it's an airplane, I would imagine he'll have 2 egt sensors and a meathod to lean/richen it on demand.

MolsonB

Yes will have EGT and CHT to monitor heat levels, along with wideband O2 for the fine tuning. For now, my thought is I don't want to go into a full FADEC system yet and stick with a manual lever (that the computer will read as an input) to go into lean/rich.

My concerns is first getting the system up and running, if I can fire the sparkplugs at a bad time to hurt the engine. Other then right ontop of the apex seals. Once I know the system can run, then I'll get into the fine tuning with leaning and spark advance.