ESE's works engine tuner

[andrew a]

Attachment 324544

I have pulled 28hp on the dyno with this Tillotson HL360A carb (24mm venture) hard mounted to the engine. The bike was vibrating so bad fuel was spewing out of the fuel tank. Getting drenched in fuel on the dyno provided its own interesting moments.

That how to make a bucket go WOOF in flames. A mouth ago I was working on a VW powered off roader It didn't have exhaust on it and backfired. Up it went in flames. Very exciting for a while. Got it out Ok but could have been so much worse!

[SwePatrick]

Attachment 324571

Got the EFI Suzuki GP/NSR110 on the dyno tonight.

Not great, only 26hp, was hoping for 30. But still its promising, even showing some promising driveability .

Attachment 324572

Nowhere right yet but improved the midrange with a bit of fiddling with the PV, I expect there is plenty more yet. I need three computers at once, one each for ignition/PV - EFI and dyno.

Dunno if it´s been tested, but is the injector placed so it injects 'upstream' against airflow in secondary transfers?
What i refer to is that air is so light, and fuel is so heavy.
The injectorflow will reduce speed in airflow.
Or is fuel injected when transfers is closed?(then no problem with airspeed)

If injectorbeam is flowing WITH airflow, you can actually get a small increase of airflow(ejector effect).

Rgds
Patrick

[Flettner]

A stock F9 is 28HP, and that's a 350.

[TZ350]

... is the injector placed so it injects 'upstream' against airflow in secondary transfers?

Yes secondary injectors are against the airflow in the B transfers. I read somewhere that against the airflow aided mixing. I hope they were right.



Second dyno session. Red is where we were last night, Blue 27.5hp is where we got to tonight. 28 looks very possible 30 maybe with a bit of work on the cylinder.

Also because the head insert is 2mm deeper than normal the combustion chamber is a crazy shape, looks very much like the old Kawasaki top hat design. To get it any better requires a total re design of the head cover and insert. It needs an insert that I can sink the plug down into.

And the inlet timing is, opens 135 BTDC and closes 90 ATDC. With the big disk I really don't need that much duration so I will try closing it earlier.

[Frits Overmars]

Yes secondary injectors are against the airflow in the B transfers. I read somewhere that against the airflow aided mixing. I hope they were right.
And the inlet timing is, opens 135 BTDC and closes 90 ATDC. With the big disk I really don't need that much duration so I will try closing it earlier.

Injecting against the airflow does help mixing. Each fuel droplet encounters more air. And hopefully the air stream will consume or at least slow down those droplets before they hit a wall and form large drops again.
Can you rotate the inlet disc? 145°/80° should function OK and you would not have to make a new disc.

[dark art]

Also because the head insert is 2mm deeper

I wonder if that sharp corner all round may be a good place to promote detonation.

[jonny quest]

That's a flat torque curve for a 2 stroke TZ!

[SwePatrick]

Yes secondary injectors are against the airflow in the B transfers. I read somewhere that against the airflow aided mixing. I hope they were right.

Yes. they´re correct.
But also am i.
I have seen losses in power on foulstrokes when people getting creative with injectors
Same story with shooting a lot of nitrous into an inlet manifold, suddenly the carburetor can stop doing it´s job, due to high loss of airspeed.
Therefor there is an market with special built holley carbs to people who want´s to shoot huge amounts of nitrous.

Rgds.

[jamathi]

Yes. they´re correct.
But also am i.
I have seen losses in power on foulstrokes when people getting creative with injectors
Same story with shooting a lot of nitrous into an inlet manifold, suddenly the carburetor can stop doing it´s job, due to high loss of airspeed.
Therefor there is an market with special built holley carbs to people who want´s to shoot huge amounts of nitrous.

Rgds.

Would it not be better to inject the nitrous directly into the crankcase?
Has anyone tried this?

[jamathi]

[QUOTE=wobbly;

Wobbly, did you ever think or try to turn the exhaust duct 'upside down'?
Now I think it could be better for flow, especially blow-down.
We once did a small and inconclusive test at Aprilia.
But not really well done....
Not nearly enough I think now.
I mean with a 'hollow' underside, like an original ROTAX has.
And the same restricted duct size as we use now, filling in the top side.
So keeping the same volume and port size.
And Frits, what do you think?

[ief]

Something like this Jan?

[Muciek]

Tz , what kind of radiator are You using and did You measured the water temp?

[wobbly]

But Jan has also stated that the optimum down angle of the roof he tested was 25*.
Maybe increasing this,along with lowering the floor at the port exit could be "better ".
Maybe I can get to try this idea with Franco at TM - the roof change would be easily done by scraping the core,but a hollow floor
would need a CAD change, not as easy.
Fear not, I want to do it.

[Frits Overmars]

Wobbly, did you ever think or try to turn the exhaust duct 'upside down'? Now I think it could be better for flow, especially blow-down. I mean with a 'hollow' underside, like an original ROTAX has. And the same restricted duct size as we use now, filling in the top side. So keeping the same volume and port size.
And Frits, what do you think?

What do I think? I built it; behold my hollow underside . And at last there is progression, as Harm van Gaalen is now preparing an engine with a 50 cc FOS cylinder.

[SwePatrick]

Would it not be better to inject the nitrous directly into the crankcase?
Has anyone tried this?

On a twostroke i would say yes!
Once you trapped the air engine draws in and start building pressure, you add pressure with nitrous injection.
And get very very good mixture as nitrousbeam will blend it all up.
And a huge tempdecrease as nitrous shots get very cold.
This will also increase 'VE' on the twostroke, works a bit like an intercooler.

On foulstroke it would be a disaster