New member, & 1 hp per cc prototype

This is my first post at HPA. I just finished EFI tuning fundamentals - it's all very new to me, but the courses are excellent & make complex concepts much easier to understand. Hopefully most of it sticks the first time through, and then repeat as needed.

The reason I'm here is a prototype top end I've been developing over the last year or so, using engmod2T software. It's a single cylinder externally-scavenged valveless 2-stroke:

1) 120cc, 120hp / 48 ft/lbs @ 10K rpm (simulation)

2) GDI, dual piezo injectors, 1.6ms max pulse width at 10K

3) crank-driven supercharger or e-Turbo, 3 bar peak / 1 bar trapped boost

4) dry sump, 4T lubrication

Once I started on the fuel injection and began talking to tuners a few months back, I realized I was in way over my head and needed to do my homework to understand what was involved. The GDI timing and fuel-delivery requirements for this engine would be similar to those of a 20K 120cc GDI 4T cylinder, if such a thing existed.

The prototype vehicle is a '24 Yamaha WR450F supermoto, which I got last week. Space is pretty tight, but hopefully everything will eventually fit.

At any rate... I'm very happy to have found HPA, and any comments and input appreciated.

Ray

Why is the term 4T used in place of 4-stroke? Is your engine a 2-stroke or 4-stroke? I thought that 4T oils were designed for motorcycles where the engine oil also lubricates the transmission gears.

How will you deal with heat on a motorcycle?

How are you going to reduce the displacement of a 450cc motorcycle to 120cc?

What does 1 bar trapped boost mean?

What sort of GDI fuel pressure will you need to spray the necessary amount of fuel for 120hp in 1.6ms?

What sort of compression ratio do you expect to use?

Why is the term 4T used in place of 4-stroke? Is your engine a 2-stroke or 4-stroke? I thought that 4T oils were designed for motorcycles where the engine oil also lubricates the transmission gears.

My top end ONLY (it's not a complete engine) is a 2-stroke externally-scavenged design, which will use the WR450F four-stroke bottom end, gearbox, and rolling chassis. If you're not already familiar with this type of 2-stroke engine you might want to look it up online, it's quite different from the usual 2-stroke. Previous web sites I've posted at used 4T for 4-stroke and 2T for 2-stroke, but I'll spell them out completely from now on. Yamaha uses the same oil in both engine and gearbox for their 4-stroke MX and enduro motorcycles, but I believe similar Honda dirt bikes use separate gear oil in the gearbox and 4-stroke type engine oil in the engine.

How will you deal with heat on a motorcycle?

The same as Yamaha did - liquid cooling with radiators. I'll also be using an air-to-air intercooler to reduce boost temperature.

How are you going to reduce the displacement of a 450cc motorcycle to 120cc?

By replacing the entire top end (cylinder, cylinder head, piston, rings, piston pin, etc.). Bore/stroke is 50 x 60.8mm.

What does 1 bar trapped boost mean?

'Trapped' is a 2-stroke term referring to what remains in the cylinder when the exhaust port closes. In my design that would be 1 bar or so.

What sort of GDI fuel pressure will you need to spray the necessary amount of fuel for 120hp in 1.6ms?

I don't know yet - my injectors are out being flow-tested. It will surely be more than 100 bar, and hopefully less than 300 bar.

What sort of compression ratio do you expect to use?

@ 9.5:1