ESE's works engine tuner

[TZ350]

if BDK were able to get almost 20hp out of a 93cc aircooled at only 10,000rpm ... and they are running a 26mm oko.

OK lets have a look at something Bucket and Thomas put together.

Data goes into the yellow squares, answers appear in the green ones.

Enter 20hp (this number should be crank hp), 0.093L for 93cc and 10,000 rpm in the 2-Stroke BMEP calculator.

BMEP.xls

I make it 140 psi BMEP or 9.6 bar, pretty good numbers for an air cooled, but certainly possible.

[RomeuPT]

Attachment 281862

Got me a nice new 10mm ball end milling cutter today.

Attachment 281863

Its great for digging holes and leaves a nice radius on the back of the newly excavated transfer ducts.

Attachment 281868

Hopefully I will have better directional control of the flow streams this time.

Following Wobblys mantra of "Low and Wide".

The plan is to make the transfers as wide as possible and open the main port at 116 and the secondary's and boost at 117.5 ATDC.

With 1ex, 73% wide, that opens 80 deg ATDC. STA's and EngMod2T simulation at 83% combustion efficiency. Transfer Port Details.

Will you point the rear angle of the secondary's transfers really towards the exhaust?

Once I had a little experience, a cylinder I was working had that angle, almost towards the center of the exhaust, then I opened the secondarys to give more area, just a bit, without knowing I changed that angle and now was directed more to the main transfers, as result I felt I had loss a bit of peak power, but the engine was broader and botton end seemed a bit better to. This was way before Frits exposed the pizza tower concept on pit-lane. My thoughts were that short circuiting to the exhaust at some point would compliment the power when the exhaust is working on his ideal resonance rpm.

Filling the transfers with epoxy to make the final internal angles might even help keep the gases a little cooler before entering the cylinder than if they are exposed to the aluminium. Right?

Regards

[FastFred]

Fuel injected two stroke second in national MX series.

There should be a brass band playing and ticker tape parade up main street for Flettner.

A fuel injected racing air cooled 2-Stroke. Proving itself over a whole race series, now that's a very good effort, a world first maybe.

[Flettner]

It's just that there is a lot of negitive press about EFIing Twostrokes. I've been told it can't be done, even by those that have had a go. This result must at least show that those that say "can't" are uniformed or doing it wrong. I'm sure what I've cobbled up could be much better with some serious development.

[F5 Dave]

OK lets have a look at something Bucket and Thomas put together.

Data goes into the yellow squares, answers appear in the green ones.

Enter 20hp (this number should be crank hp), 0.093L for 93cc and 10,000 rpm in the 2-Stroke BMEP calculator.

BMEP.xls

I make it 140 psi BMEP or 9.6 bar, pretty good numbers for an air cooled, but certainly possible.

Actually I did re-read one of the latest issues & realise its not a 83cc kit the mag is using its a 93cc like the BDK example. 10cc will make quite a difference.

Still think 10,000 & a 26mm carb will be a step too far, but I don't want to sound like a knocker & I'm seemingly unintentionally taking that role.

[F5 Dave]

No it doesn't and neither does Robs?

. . .. they weren't building a stream liner, just a std bike.

how much clearer do you want?

[wax]

It's just that there is a lot of negitive press about EFIing Twostrokes. I've been told it can't be done, even by those that have had a go. This result must at least show that those that say "can't" are uniformed or doing it wrong. I'm sure what I've cobbled up could be much better with some serious development.

I think alot of the negative press is by some clown called hgt causing all that. He was the most arrogant prick out there and so everyone just enjoyed watching him fail. Which he did on numerous occasions quite badly.
With the collective mind of a few smart people I think you could get it to work as to how well Im not sure. The issue I see so far so is no one is measuring airflow.

[FastFred]

With the collective mind of a few smart people I think you could get it to work as to how well Im not sure.

Flettners one already works and has completed the National VMX series finishing second overall, so the setup must be fairly stable.

TeeZee's one is in the early stages so not to sure about that but as you say, a few collective minds and with Flettners experienced input it should be a runner too, then there is Burts 2-Stroke EFI project.

[TZ350]

Posted as someone wanted to see what they looked like.



25 and 45 L/hr Fuel Pumps and 3K Ohm TPS.



128g - 248g - 490cc - 650cc injectors



The smaller injectors have a securing screw hole the bigger ones need to be clamped down by the fuel rail.

These are some of the optional parts that can be purchased with the EFI Kits from Ecotrons.

http://www.ecotrons.com/2_Stroke_Sma...e_EFI_kit.html

[husaberg]

There should be a brass band playing and ticker tape parade up main street for Flettner.

A fuel injected racing air cooled 2-Stroke. Proving itself over a whole race series, now that's a very good effort, a world first maybe.

http://www.motorcycle.com/manufactur...xp2-15170.html

In fairness to Neil their R&D team and budget was a little larger...........like a million times.

It's just that there is a lot of negitive press about EFIing Twostrokes. I've been told it can't be done, even by those that have had a go. This result must at least show that those that say "can't" are uniformed or doing it wrong. I'm sure what I've cobbled up could be much better with some serious development.

I must admit i was one of the nay thinkers ,so virtual hat has now been virtually eaten.

how much clearer do you want?

err...I wasn't replying to that quote though anyway thanks for clearing it up.
I wonder why they went for such a small carb. The local Kawa ar80 "ish" seems to go pretty well.
Judging by Vid. At Ruapuna it seemed able to chew quite a few FXR150's

[F5 Dave]

Ahh that blue RS framed 80, yes it went ok, but my MB could chew it up & spit it out. Also that is a late watercooled model.

[husaberg]

Ahh that blue RS framed 80, yes it went ok, but my MB could chew it up & spit it out. Also that is a late watercooled model.

You might have a point re the motor, to tell you the truth i have never looked at it (Greymouth is a big city don't ya know.)
Not sure exactly what the motor is I think it might be Philippino or something ? His father called in to work one day, but unfortunately it was one of those rare days when i was a bit distracted with work, Rather than visa versa


The Video bike is the Dutch Stig. Ruapuna. Everytime i watch most the North Isand video's i can't help but think how lucky us South islanders are what with all that space for straights and larger tracks.
This is the Kawa Dave and i were talking about.(It appears around 3.40 on the timer) Maybe someone will chip in with some info?

The Rider on 981 hasn't ridden in the last 3 years.He is filling in for Justin ,whilst Justin is out of action with his shoulder injury.All in all Liam rode the ar80 ,like he hasnt been out of racing for 3 years .Well done YOW you showed them their is life in the old dog still.

The other Video of the Dutch stig out by himself is also worth a look (if not a listen.)


I hope Mike doesn't mind me posting them

[Yow Ling]

. The issue I see so far so is no one is measuring airflow.

You could make a pretty reasonable approximation from throttle position and rpm. this would be similar to the alpha N stuff tz was describing. one of the problems with measuring airflow is the sensor, it big, has restrictions, even the hot wire and ultrasonic ones with low restriction are usualls sized for car sized engines

[TZ350]

Friday night, a few beers and chewing the fat looking at what can be done with the CVT idea.



Interestingly the straight cut primary/starter gears from a 4-Stroke mini/pit bike have the same primary gear shaft centers as the GP. Expect to see straight cut primary gears from a pit bike in my next GP engine.



The CVT has pretty much the same gear ratio range as the GP gear box.

So one possibility is to run the variator of a modified gear box input shaft and run the rear pulley on a shaft through the engine mounting plates with the front chain sprocket behind it. Effectivly replacing the GP's gearbox with the CVT.

That would have the benefit of reduced rotational speeds on the variator and clutch and friction from pulling the belt out from between the sheaves, which I like, but the disadvantage of increased torque having to be transmitted by the belt and clutch shoes.



Another possibility is to cut the rear reduction box off and weld the whole thing onto the back of a GP engine that has had its own gear box cut away.

[richban]

Everytime i watch most the North Isand video's i can't help but think how lucky us South islanders are what with all that space for straights and larger tracks.

Not going to let you get away with that one. We have plenty of big tracks mate. We are just lucky we have some great short ones as well. For hard, mental, crazy racing you just can't go past a Kart track.