ESE's works engine tuner

[peewee]

Haven't had much time lately.
I have replaced the intake valve and will be back with further experimentation on methanol/nitro soon. As of now I've gone from 15.3 to 17whp, nothing changed except carb settings. The no intake valve thing is put on hold for a while, want to establish a baseline on this fuel and start modifying the cylinder and pipe.

did you try straight methanol previously ? there was a article where the author claimed that straight methanol required nearly the same afr as a 0-33% load of nitro. im thinking that might be rubbish, atleast to some extent. i say that because my low throttle position went very lean immediatly when i introduced nitro to the methanol. wasnt sure if you had the same experience

[adegnes]

did you try straight methanol previously ? there was a article where the author claimed that straight methanol required nearly the same afr as a 0-33% load of nitro. im thinking that might be rubbish, atleast to some extent. i say that because my low throttle position went very lean immediatly when i introduced nitro to the methanol. wasnt sure if you had the same experience

Haven't tried straight methanol but I share your skepticism about that article. I had read it before my first attempt with 20% nitro, and jet sizes were calculated with the specific gravity of each fuel component taken into account. I richened it some on top of that too. First pull melted the plug in seconds...

[SwePatrick]

Weekend in success and nosedive *lol*

Started her up this saturday with working lubrication for turbo.
First dynopulls showed 0.5-0.55bar of boost with a lot of leak from between cylinder and pipe, and between stinger and pipe.
Had some fueling issues, sorted that out with hanging a fueljug to the ceiling to get more fall for the fuel.
Then needed to richen it up a whole lot on the powerjet, from 1/4 turn to about 3 full turns.
It showed promising results, never recorded anything due to i wasn´t aiming for a powerpull, just to make it rev free throughout whole register.
Even though i had small issues it spinned the tire on dynoroller, which it never has done before.

Then yesterday (sunday) i fixed the exhaustleaks and turned out the powerjet one more full turn.
This time i was curious about what has happened as it was feeling quite nasty/angry
She actually ran so nice i was suprised how easy it was to get it working.

This time i had 0.75bar of boost and this was around the level i am aiming for to get 100rwhp.
I also before the coming pull retarded the igntion about 10degrees.(whole curve)

It was a bit less revhappy due to that, but it builded boost really easy, i could run it at 8000rpm and hit the throttle and boost was almost instant up to 0.5bar, then at ~9000rpm it hit 0.75bar

Now i was ready for a powerpull as it sounded really nice.

So i started at ~6500rpm, it hesitated a bit when running into boost when having full throttle all the time, but i let it pull through.
And then all hell broke loose, totally insane *lol*
I revved it to about 12000rpm
It sounded like perfection, no misfire no nothing.

Hit the brake on roller to make a verifying pull.
Coolant temp was only 53degrees.

On it again,,
The same procedure, but now at roughly 11000rpm it was like a handgrenade through the carb.
I saw the rocketflame, it was about 50cm long *lol*

I instantly hit the brake on dyno, having a thought that it was a lean situation.
After about an hour, (had to do some garden work )
I pulled the sparkplug, and the sight was the nosedive earlier mentioned, aluminiumsand all over the isolator.
F*ck!!
What happened?



The only thing i can think of what heppened after thoughts were running around in my head is that on the compressorhousing there is an recirculating bypassvalve, and i didn´t have it attached to any boost.
So it could creep open and regulate boost pressure without notice.
If doing that the backpressure in turbo skyrockets, and twostrokes DO NOT like those pressurelevels, i promise

Heat builds and melting pistons comes as a letter on the mail.
I came to this conclusion as i never heard any ping or something alarming at all in first pull.

To end story happy anyway, the result was almost fulfulling my goal in first powerpull.

98.56hp at 11600rpm at the wheel =)

So, i need a new piston and a hone of cylinder(i hope it stays there as i haven´t taken engine apart yet.



But, it will take some time before i can follow up on this, my dog needs an operation in right rear knee and,, well budget has gone to zero.
Need to take a break from this for a while.

Regards
Patrick.

[TZ350]

Weekend in success and nosedive *lol*

Now i was ready for a powerpull as it sounded really nice.
The same procedure, but now at roughly 11000rpm it was like a handgrenade through the carb.
I saw the rocketflame, it was about 50cm long *lol*

Nearly a 100hp, great result Patrick.......

We too have found it sometimes costs a piston or two to find the right formula.

[TZ350]

Below is an extract from DirtBike that talks about the EFI KTM250. Interesting it mentions exactly the same problems with throttle response that I am having and that it mentions a crankcase pressure sensor.

https://dirtbiketest.com/fresh-dirt/two-stroke-fuel-injection-ktms-path-to-tpi/#ote9PlJBGtOBGJI6.97

Now using accepted and understood parts it all came down to processing the information and getting the mixtures right. Quickly. The window of time for the injector to be open and getting the large amount of fuel a two-stroke needs is the challenge, especially in even smaller displacements we are told. Plus when a two-stroke has a “flame-out” inside the combustion chamber, it can take up to 50 strokes for the engine to recover. This was a big issue in high RPM, low throttle times. For instance when you are going down a hill with the engine revving and then you give it a little gas. Making the throttle response as good as that antiquated carburetor was very difficult. There is not a lot of time for the computer to decide how much fuel and when to shoot it from one stroke to the next since the conditions inside the two-stroke engine can change drastically and very suddenly. Even small things like having the engine’s crankcase pressure sensor and fuel injectors mounted so that vibration was not affecting them were lessons learned in testing. Luckily the new 2017 engine was designed from the beginning to eventually have a non-carbureted fuel system so it would vibrate less and also be able to produce as much electrical power as would be needed.
Read more at https://dirtbiketest.com/fresh-dirt/...1B4YRrV2OU2.99



The crankcase pressure sensor seems to be taken off the back of the cylinder and go up to a sensor in a plenum behind the motor.

Very interesting .....

[peewee]

Below is an extract from DirtBike that talks about the EFI KTM250. Interesting it mentions exactly the same problems with throttle response that I am having and that it mentions a crankcase pressure sensor.

https://dirtbiketest.com/fresh-dirt/two-stroke-fuel-injection-ktms-path-to-tpi/#ote9PlJBGtOBGJI6.97

Now using accepted and understood parts it all came down to processing the information and getting the mixtures right. Quickly. The window of time for the injector to be open and getting the large amount of fuel a two-stroke needs is the challenge, especially in even smaller displacements we are told. Plus when a two-stroke has a “flame-out” inside the combustion chamber, it can take up to 50 strokes for the engine to recover. This was a big issue in high RPM, low throttle times. For instance when you are going down a hill with the engine revving and then you give it a little gas. Making the throttle response as good as that antiquated carburetor was very difficult. There is not a lot of time for the computer to decide how much fuel and when to shoot it from one stroke to the next since the conditions inside the two-stroke engine can change drastically and very suddenly. Even small things like having the engine’s crankcase pressure sensor and fuel injectors mounted so that vibration was not affecting them were lessons learned in testing. Luckily the new 2017 engine was designed from the beginning to eventually have a non-carbureted fuel system so it would vibrate less and also be able to produce as much electrical power as would be needed.
Read more at https://dirtbiketest.com/fresh-dirt/...1B4YRrV2OU2.99



The crankcase pressure sensor seems to be taken off the back of the cylinder and go up to a sensor in a plenum behind the motor.

Very interesting .....

about a year ago I snatched up a '17 carbed model and kind of glad I did , since electrical stuff is something I really know nothing about. how is the oil managed and is there a way to customize the fueling ?

its no surprise they been working in this for a while. seems like there was a article saying they had been working on a counterbalancer since the 90's I think, but never could get it sorted out at the time

[F5 Dave]

They could have copied my 1979 Honda MB50 and no doubt Moses had a counterbalanced 2 stroke when he popped over to the other side of the lake or ocean or puddle.

[ken seeber]

OK you forensics out there, looking for opinions on the rod in the pic. This shows very slight discolourations, almost blueing, at two very small spots on either side at the very bottom of the rod. Why ? is the question. It has tons of side clearance which can be seen between the thrust washer and the crank wheel side. This particular brand of engine is a 54*54 with an 18 mm crankpin, vertical crank reed induction and revs to 15.5/16k. Interestingly this particular brand of engine also has problems with crankpin failures, possibly as a result of crank twisting, thereby causing cyclic loadings on the pin and then fatigue failure. Whether the two are related is unknown.
Anyone else seen rod temp effects like this?



As a total aside, apparently the bucket class in Queensland now allow air cooled engines to go to 125 cc.

[Grumph]

Is there a chain pull on the crank ? Possibly in line with but opposite to the cylinder ?
I'm wondering if it's causing a pinching at TDC due to crank flex.

I'd heard that it was Pauline Hanson holding up changes to the Qld bucket rules....

[Lightbulb]

OK you forensics out there, looking for opinions on the rod in the pic. This shows very slight discolourations, almost blueing, at two very small spots on either side at the very bottom of the rod. Why ? is the question. It has tons of side clearance which can be seen between the thrust washer and the crank wheel side. This particular brand of engine is a 54*54 with an 18 mm crankpin, vertical crank reed induction and revs to 15.5/16k. Interestingly this particular brand of engine also has problems with crankpin failures, possibly as a result of crank twisting, thereby causing cyclic loadings on the pin and then fatigue failure. Whether the two are related is unknown.
Anyone else seen rod temp effects like this?



As a total aside, apparently the bucket class in Queensland now allow air cooled engines to go to 125 cc.

Hey Ken, how sturdy is the crank case. That looks to me like it is flexing to the point where the clearance you do have is still not enough.
I may be wrong as well.
Neil

[wobbly]

The discoloration is localized overheating of the lube film.
So if the pins are failing then you would have to make the guess that they are bending, due to the inertial loads at 15+K rpm.
When they bend the clearance will drop to zero ( or less ) inside the rod at the highest rotational load point,thus trying to crush the needles.
Keep doing this and the cyclic load will eventually break the pin, or lock up the bearing.
Either way 18mm isnt big enough,and or the pin material and its associated heat treatment are suspect.

[Nath88]

The same procedure, but now at roughly 11000rpm it was like a handgrenade through the carb.
I saw the rocketflame, it was about 50cm long *lol*

So the flame was from the carb? Timing too retarded or running too lean?

The only thing i can think of what heppened after thoughts were running around in my head is that on the compressorhousing there is an recirculating bypassvalve, and i didn´t have it attached to any boost.
So it could creep open and regulate boost pressure without notice.
If doing that the backpressure in turbo skyrockets, and twostrokes DO NOT like those pressurelevels, i promise

Do you mean the internal wastegate on the turbine/exhaust side? Without boost pressure hose attached it should stay closed until the exhaust backpressure overpowers the spring. Then the exhaust pressure will drop and the turbo will slow down, and the intake pressure will drop. As you said it should creep open rather than suddenly open, I'm not sure it would cause your backfire problem.

98.56hp at 11600rpm at the wheel =)

An awesome effort, hopefully you'll be able to sort it out soon.

[2T Institute]

OK you forensics out there, looking for opinions on the rod in the pic. This shows very slight discolourations, almost blueing, at two very small spots on either side at the very bottom of the rod. Why ? is the question. It has tons of side clearance which can be seen between the thrust washer and the crank wheel side. This particular brand of engine is a 54*54 with an 18 mm crankpin, vertical crank reed induction and revs to 15.5/16k. Interestingly this particular brand of engine also has problems with crankpin failures, possibly as a result of crank twisting, thereby causing cyclic loadings on the pin and then fatigue failure. Whether the two are related is unknown.
Anyone else seen rod temp effects like this?



As a total aside, apparently the bucket class in Queensland now allow air cooled engines to go to 125 cc.

just keep it under 15,499 rpm , fixed FOC for you Ken

[SwePatrick]

So the flame was from the carb? Timing too retarded or running too lean?



Do you mean the internal wastegate on the turbine/exhaust side? Without boost pressure hose attached it should stay closed until the exhaust backpressure overpowers the spring. Then the exhaust pressure will drop and the turbo will slow down, and the intake pressure will drop. As you said it should creep open rather than suddenly open, I'm not sure it would cause your backfire problem.



An awesome effort, hopefully you'll be able to sort it out soon.

1, i think it selfignited in crankcase due to overheating of piston.
2, i have chopped away the internal wastegate, so i´m talking about the BOV, blow off valve that is integrated in compressorhousing.
(where arrow points)

This is a recirculating blowoff valve that helps overcome some turbolag between shifts in a car.
With no referenceboost on the outer side of diagraphm it can creep open from boost in turbo.
And as it is recirculating i can´t see if it does this.
I will some day this week pressuretest it to see if it creeps, if it does i have the answer.

And, when this valve is open the turbo spins freely with no resistance.
This creates backpressure in exhaust turbine.
And to much backpressure is deadly, and it kills fast.
Just as in my case, it left me questioning why it happened, i heard nothing bad from engine at all except that blam through the carb.

Maybe the reedpetals will tell me also.
But engine ran nice on idle before i shut it off after the pull.
So i figure the petals are ok, but i haven´t taken it apart yet.
I´m in middle of porting a couple of foulstrokeheads to ensure the operation of my dog.

And thank´s, it was actually quite easy.
I also had some support from a snowsledguy who has turboed his snowsled.
Also i have a lot of turbo experiance of foulstrokes(Have been designed and built heads for 2 litre engines that has dynoed above 1150hp)

But methanol isn´t the first choice to take when boosting with draw through carb setups.
They are really HARD to get running nice out of boost.
I actually had frost on the compressorhousing after the first pull.

My bad on forgetting connect the bostreference to the BOV.

Rgds.

[SwePatrick]

Nearly a 100hp, great result Patrick.......

We too have found it sometimes costs a piston or two to find the right formula.

Thanks.. yes,, one has to put some sheep for offering to the gods of speed =)

But i feel that the smart choice is to revert back to NA engine on methanol and try to get max out of that.
I still have some tricks up my sleeve regarding that =)

I want to race it next summer, not change pistons all the time.
It´s like i took a giant leap before beeing done with the last one.

Turbosystem is built, i can whenever i want try it again =)
I want more control so maybe i need to go EFI, or some way of controlling the ignition better (3d map)