ESE's works engine tuner

[TZ350]

.
Well after a bit of traveling away for work, a grand tour of New Zealand's South Island and helping out on the sidecar CVT project last week I have finally been able to get back to my fuel injection project.

I had the pseudo MAP co processor working and responding as hoped. But I was puzzled for a bit about why, when the throttle was completely closed the crankcase pressure went up. On reflection I figured that when there was no suction from the pipe atmospheric air and exhaust fumes flooded back up the exhaust pipe and through all the gaping holes in the cylinder.

Filling the crankcase to near atmospheric pressure with dirty exhaust gave the underside of the piston something to compress resulting in a misleading high pseudo MAP value. The crankcase pseudo pressure quickly dropped, actually the difference between max - min crankcase pressure dropped as soon as the pipe started sucking again and the piston was left chasing air that was rapidly disappearing up the transfer ports.

Some tweaks to the co processors software soon sorted that and now my two strokes pseudo MAP value looks much like you would expect from a four strokes MAP sensor and hopefully will be a good indication of changes in mass air flow for the EFI's CPU to work with.

I expect, with a bit more software tweaking and some time tuning the fueling map with Tuning Studio I might soon have a fuel injected two stroke bike I can race.


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[wobbly]

Just in case anyone is interested , the question I asked about the position of an oil feed hole in a big end pin.
The answer is its of no importance as long as its away from the highest load positions at TDC and BDC.
The side position ensures the squeezed oil film in the high load area does not all but block off oil flow.

And back to 2T reality - TeeZee , your fight with the injection system using good tech and electronic nouse is a real inspiration.
Hope you find the keys buddy.
And then we can all sit back and know it was on here first.

[cotswold]

Attachment 341456

We are looking at resurrecting this old four stroke two stroke hybrid project.

The sidecar with a 28hp two stroke motor and CVT could be real exciting.

I think I could be persuaded to throw a leg over that

[TZ350]

And back to 2T reality - TeeZee , your fight with the injection system using good tech and electronic nouse is a real inspiration.
Hope you find the keys buddy. And then we can all sit back and know it was on here first.

Thank you for the encouragement.

The 2S pesudo Map (Yellow line) is starting to behave like a good MAP should but is cutting out at about 6,000 rpm (White line). Also interesting is that on overrun when the throttle (Green line) is opened a crack and the motor fires the MAP line shows a peak indicating increased air flow through the motor.



The pseudo map co processor code works well with the simulator and checks out Ok on the scope. The simulator simulates rpm and high and low crankcase pressure up to 14,000 rpm. So I think that the map sensor itself may not be able to keep up with the changing crankcase pressure. Or the peak pressure moves away from the sampling point. The processor is not fast enough to sample continuously so for high pressure I read three points around 135 deg atdc and keep the highest. I will have to try different crank angles and maybe some different map sensors.



The yellow dots are pressure samplings and the purple line is simulated crankcase pressure, RPM is a bit over 12,000 in this picture. The Volt meter is reading the pseudo MAP value.

[TZ350]

Just in case anyone is interested , the question I asked about the position of an oil feed hole in a big end pin.
The answer is its of no importance as long as its away from the highest load positions at TDC and BDC.

Its interesting about crankshaft B/Ends. The most wear is on the underside of the B/E pin and greatest on the side closest to a main bearing. Makes sense when you think about it. Because the underside takes all the loading at TDC and BDC and the side nearest a main is unable to flex away from the load.

[lodgernz]

What is the general opinion on the amount of gap either side of the small end bearing to the inner faces of the gudgeon pin bosses?
I want to use a piston that has a space of 18.7mm between the bosses, but the widest bearing I can find is only 17mm wide. Does this sound like a disaster waiting to happen if I use it?
A second possible issue is that the conrod small-end eye is only 13.5mm wide.
I'd appreciate any advice on this. The rod is located by the side plates on the crankpin.

[wobbly]

The only issue to consider is that disaster is likely if the caged needle ends can slide sideways sufficiently to overhang
the rod small end bore.

[lodgernz]

The only issue to consider is that disaster is likely if the caged needle ends can slide sideways sufficiently to overhang
the rod small end bore.

Thanks Wobbly, of course the needle is the issue, not the cage as I was thinking.
The needles in this bearing are 13.0mm long, so worst case scenario, if the bearing moves hard up against one of the pin bosses, which I imagine it will, the needles will overhang the eye by 0.4mm.
That's assuming the rod stays central. Although 0.4mm doesn't sound like much, I guess it could cause the ends of each needle to become less worn compared with the central part. I've no idea how significant that is.

Would it be safe to add a thin alloy shim either side of the bearing? Or some other material? Obviously they only need to be 0.5mm thick to prevent the above situation.

[wobbly]

I have seen hard anodised alloy spacers used for exactly what you are trying to prevent, needle overhang.

[lodgernz]

I have seen hard anodised alloy spacers used for exactly what you are trying to prevent, needle overhang.

Thanks again Wobbly. So that's my solution.

[TZ350]

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In one of the Team ESE GP's we used anodized alloy spacers like Wob described (common in KT100's). We used them for years, probably still going. And the Suzuki RGV250 uses steel spacers at the little end.

[F5 Dave]

Needle overhang will cause the needles to dig in to the sharp edges of the rod, securely clamping onto the gungeon pin and thrusting it sideways overwhelming the circlip and into the bore.
Don't ask how I know

[TZ350]

In my Suzuki GP-NSR110 engine I use a pair of RGV250 little end thrust washers to centralize the little end bearing because it is several mm shorter than the gap between the piston pin bosses.

In the picture there is also the Kawasaki KE175 rotary valve cover, over-sized be spoke RV blade, RD400 con rod, RGV250 big end bearing and extra long big end pin for the widened crankcase, de stroked crank and not seen is the NSR250 cylinder.

[TZ350]

A bit of progress on the 30rwhp Suzuki GP-NSR110 F4 CVT project. Used the drop saw to hack the CVT gearbox out of the old scooter power plant.



I am planning on joining the CVT gearbox to the Suzuki crankcase by mounting the gearbox on a 12 mm alloy plate and inserting the plate between the crankcase halves like I did with the first GP-NSR110.

[peewee]

got alittle more done. ill try to get the side caps welded on this weekend