ESE's works engine tuner

[RomeuPT]

Did a couple more test's, dont really think there is more power, but let the pipe get some carbon on it and maybe do some jetting to see if feels an improvment.

[peewee]

Should work just fine, but be sure to have the hose perfectly sealed before starting.. but you knew that of course.

yes its perfectly sealed with a rubber plug on the ID and a rubber cap on the OD. while it wasn't cold yesterday (fuel temp of 60F/15.5C) I did squirt some petrol in the primer tube to see if it would work and it does. within three kicks it started so I think it will work fine when colder also. some more good news from yesterday is, the third jet is barley one turn open with the 5% nitro. since it has a max of six turns, I think ive got enough fuel enrichment for up to 20% nitro or maybe even higher. unless that article was correct in saying that up to 33% will use the same AFR as straight methanol. in which case I wont need to add anymore fuel

my plan next time is to try 10% and work up to atleast 20%, provided theres no mechanical or fuel delivery problems. yesterday I tested full throttle operation to 650' and it did fine. the bad news is, I richened the current needle as much as it can go and its just barely rich enough. after two consecutive 650' runs, closing the throttle causes the idle to runaway just alittle. so as the nitro pecent and oxygen content is increases, I think for sure ill need the next size richer needle. so this week ill try to get another needle

heres a question for anyone. ive been reading with nitro you can advance the spark lead even further than with straight methanol but I also read just the opposite. anybody know the truth to this ? right now ive got only 3* static advance and the reason is because im afraid of it back firing and trying to start the engine backwards which often time can break the kcick start gears in the crankcase. yesterday it back fired and tried to push the kick lever in reverse. so im thinking I should leave it alone or be very cautious if I advance it any further as I don't want broken crankcase or gear cogs

[TZ350]

I was just about to recommend using the map switch I tried it out this weekend, its not dialled yet, but it's the best so far, I can roll along at 8500rpm and open and close the throttle as fast or slow as I like and it always responds. I will tune the main map by lambda feedback (it's pretty much done using values from before), and the misfire map by holding the engine at a load point, then holding the kill switch for a second or two, then release and judge the response when it comes back on as rich or lean, it should be instant and clean like a carb.
The map switches when the peak pressure between 85 crank degrees and 125 crank degrees, measured at the PV vent (with an adjustable bleed to atmosphere) reaches 102kpa, atmosphere is 101kpa here.
Means I'm confined to riding at sea level until I sort out a better implementation. Hoping the piezo pulse sensor will be the ticket, since it doesn't care about absolute values, If it works I'll make a bunch of them.

Just realised/remembered that the ecotrons EFI system does have a switch for switching between two maps. I had been using it for so long as an input for the wide band O2 sensor that I had forgotten about it.

But after I have got the on the pipe map sorted it looks like I may be able to use one of your switches to then develop an off pipe or miss fire map.

The performance switch just switches in another table of values that are used to divide the values in the main map. Ie if you have a load value of 120 in the Alpha-N map and switch in the performance map that has a Lambda value of 0.85 then the Alpha-N map gets divided by 0.85, 120/0.85 = 142 ie the result is a richer mixture for exceleration.

I guess there is no reason why the performance switch can't be used to lean the Alpha-N map off when the engine has misfired or is off the pipe.

[husaberg]

Not sure where I was the other day but I was told never jump into heavily bubbling water, you will drown. After a few thoughts I realized it was true. The float will sink lower.

which makes it the opposite?
I think what happens in the bowl rather than a river or waterfall where you have undertow is the bubbles raises the effective level. Much like a boiling pot overflowing.
I was confused i couldn't recall the post, but i see it was ten months ago lol

[Flettner]

Pipe pressure varies not only with throttle and rpm, it can also vary locally because of wave superposition.
It might be instructive to experiment with several pressure take-off points along the pipe.
Attachment 332834

Is there any data from this test we might be able to read about?

[Frits Overmars]

I was told never jump into heavily bubbling water, you will drown. After a few thoughts I realized it was true. The float will sink lower.

I think what happens in the bowl rather than a river or waterfall where you have undertow is the bubbles raises the effective level. Much like a boiling pot overflowing.

When I see heavily bubbling water, it's usually time to put the eggs in. And no, I would not advise jumping into it. Maybe you won't drown, but you won't like it either.

Now let's take a closer look at bubbling fluid. It has a lower density, hence less buoyancy, and you'll go in deeper. But then you'll drown or suffocate in the froth,
not in the fluid.

Will a float sink lower because of the bubbles? No. The level of the froth will be higher than the level of non-frothing liquid would have been. But the float will keep its original height with regard to the top and bottom of the float chamber. If the float sinks, more fuel will enter the float chamber, increasing the float's buoyancy until it is sufficient to carry the float to its original height and close the float valve. And the main jet entrance is usually situated low enough to always be immersed in liquid,
so it won't be bothered by the froth either.

So how come a vibrating carburetter can be drowning the engine?
The froth is not the culprit. It may rise so high that it exits the float chamber air vents (indeed, just like a boiling pot overflowing). But the fuel pressure at the main jet entrance depends not only on the head of fuel above it, but also on the density of that fuel. The bubbles themselves and their level would not effect this pressure.

There's a cause for the bubbles: vibration. Frothing is just a side effect; the real problem is the float valve bouncing on its seat: it just doesn't close the way it should any more. And this raises not only the froth level but also the level of the non-frothing part of the fuel, hence the fuel pressure at the main jet entrance.

[Frits Overmars]

Is there any data from this test we might be able to read about?

Queens University of Belfast holds those data, but approaching Gordon Blair has become rather difficult lately...
I'm sure there is a paper containing this test but I don't know the relevant SAE number, Neil.

[Vannik]

queens university of belfast holds those data, but approaching gordon blair has become rather difficult lately...
I'm sure there is a paper containing this test but i don't know the relevant sae number, neil.

sae 2004-01-3561

[Frits Overmars]

You're priceless Neels .

[WilDun]

Good one Frits, I'll file that away!

BTW, I originlly lived 56 miles from Belfast, but seldom went there even before all the strife (I don't really like cities even though I live in a suburb of Auckland now).
Queens University was always right up there and Gordon Blair was right there for motorcycles and engines in general, helping them into the computer age.

You probably know, but others may not know that he died around 2010. (this may be the reason why approaching him has become rather difficult!).

[Flettner]

sae 2004-01-3561

Thank you, I'd like to think i had my own data soon but it would be good to read what I might find beforehand.

[Nath88]

I guess there is no reason why the performance switch can't be used to lean the Alpha-N map off when the engine has misfired or is off the pipe.

If it's another TPSxRPM table with multipliers it should work great. I'm doing the same thing right now but in a spreadsheet, then dropping the numbers into the tuning software. The multiplier is the pipe effect on airflow so it's a more sensible value to use anyway. You'll need to extrapolate the tuned 'firing' map you have into the skip-fire/misfire regions as best you can. Making the switched input to feed into the ECU will be the hard part, but I want to do that for my setup as well to free up the MAP input, and make the sensor unit a plug and play product for any ECU.

Had a play with the piezo disc for the exhaust pulse sensor, looks promising, very sensitive, minimal noise, nice.

[TZ350]

If it's another TPSxRPM table with multipliers it should work great. I'm doing the same thing right now but in a spreadsheet, then dropping the numbers into the tuning software. The multiplier is the pipe effect on airflow so it's a more sensible value to use anyway.

Had a play with the piezo disc for the exhaust pulse sensor, looks promising, very sensitive, minimal noise, nice.

Yes that piezo looks promising as the basis for a switch. I will definitely be a customer for one.



This is the Ecotrons EFI softwares Basic 16x12 Alpha-N map.



When the "Performance" switch is activated the corresponding cells in this 16x12 map are used to divide their related values in the original Alpha-N map to give an alternative fueling value.

This seriously looks like it could be used in the way you have described previously of leaning the fuel off when there is less air flow when there is no pipe action drawing air through the motor.

[husaberg]

When I see heavily bubbling water, it's usually time to put the eggs in. And no, I would not advise jumping into it. Maybe you won't drown, but you won't like it either.

Now let's take a closer look at bubbling fluid. It has a lower density, hence less buoyancy, and you'll go in deeper. But then you'll drown or suffocate in the foam,
not in the fluid.

Will a float sink lower because of the bubbles? No. The level of the foam will be higher than the level of non-foaming liquid would have been. But the float will keep its original height with regard to the top and bottom of the float chamber. If the float sinks, more fuel will enter the float chamber, increasing the float's buoyancy until it is sufficient to carry the float to its original height and close the float valve. And the main jet entrance is usually situated low enough to always be immersed in liquid,
so it won't be bothered by the foam either.

So how come a vibrating carburetter can be drowning the engine?
The foam is not the culprit. It may rise so high that it exits the float chamber air vents (indeed, just like a boiling pot overflowing). But the fuel pressure at the main jet entrance depends not only on the head of fuel above it, but also on the density of that fuel. The bubbles themselves and their level would not effect this pressure.

There's a cause for the bubbles: vibration. Foaming is just a side effect; the real problem is the float valve bouncing on its seat: it just doesn't close the way it should any more. And this raises not only the foam level but also the level of the non-foaming part of the fuel, hence the fuel pressure at the main jet entrance.

Right you are Frits
This was my complete original post (complete with pics)
https://www.kiwibiker.co.nz/forums/s...post1131021127
It came about as we were talking about adding weight to dampen the resonate frequancy of the carb (something i had read Jennings had done) or changing the rubber stiffness to achieve a similar affect.

Cameron also mentioned that the first KR3 was near impossible to carburate on account of it severe vibration.

The fuel frothing (i think) does two things first it gives an inconsistant mixture that can be actually be alternating between rich and lean depending on the RPM.
It can also i believe shuts off the fuel supply, as the frothy mixture raises the float level.
The liquid fuel can also be diverted directed away from the mainjet. being replaced by a bubbly air/fuel mix
Some mikunis and Keihins have jet sheilds that might help. Aftermarket FCR bowls have deeper wells and different designs to overcome frothing on whoops and similar conditions.
These below are stock CRF230.
Attachment 327510Attachment 327511Attachment 327513

This is the mikuni part
Attachment 327514Attachment 327515Attachment 327516

[SwePatrick]

heres a question for anyone. ive been reading with nitro you can advance the spark lead even further than with straight methanol but I also read just the opposite. anybody know the truth to this ? right now ive got only 3* static advance and the reason is because im afraid of it back firing and trying to start the engine backwards which often time can break the kcick start gears in the crankcase. yesterday it back fired and tried to push the kick lever in reverse. so im thinking I should leave it alone or be very cautious if I advance it any further as I don't want broken crankcase or gear cogs

No, don´t advance spark from optimal degree of 100% methanol use.
You are adding more air with nitro, this speeds up the burnprocess, it´s like turbocharging, decrease ignition.
What you should look into is piston to cylinder clearance, you also need to increase the ring gap from methanol setup, also due to increased heat, you don´t want to warp the ring.
Nitro engines need more clearance to be sure the piston does not smear on cylinderwalls, if so happens the piston is toast really quickly, also the nicasil will often be scraped off the cylinder.
This is because if piston smears you will get insane blowby because of the really high cylinderpressure.
This heats up the piston insanely fast.

I run with 18.5-1 in compression on 100% methanol, and my ignition is set to around 14-15 degree at ~3000rpm and peaks at ~5500 with 27-28degree, then almost linear retard to 12 degree at 11000rpm
This gives me ~460-480 celsius exhaust temp in header where it is around 580 degree on petrol.
One need to recalculate the pipe if running this low temps.
But nitro raises the temp again.

Be careful!

Rgds

Edit:
A methanol engine produces max power around 85-90 degree engine heat.
A 20% nitro engine produces max power around 110-120degree celsius.

Keep this in mind, do not be afraid to run the engine hot, but do not overheat it!
Like balancing on a thin line. but it awards you =)