ESE's works engine tuner

[husaberg]

Have a think about how long a 300cc pipe would be , off the back of a reverse cylinder parallel twin engine.
Not going to happen.

So if its an LSR bike (my guess) if this is the case what is the advantage of the 90 deg crank?

[Frits Overmars]

Have a think about how long a 300cc pipe would be , off the back of a reverse cylinder parallel twin engine.
Not going to happen.

Unless your name is Robin Tuluie. This is his 800cc Tularis vibrator two-stroke twin. The pipes seem to fit; the silencers may be less convincing.

[Storbeck]

So if its an LSR bike (guess my guess)what is the advantage of the 90 deg crank?

I'm guessing it has to do with the pistons coming to a stop and changing direction at top and bottom of their stroke. 180 degree firing they are both doing it at the same time, 90 Deg firing one is mid stroke when the other is at top or bottom.

Possibly to reduce fluctuations in rpm or maybe it's a vibration thing. (Or both).

[Frits Overmars]

I'm guessing it has to do with the pistons coming to a stop and changing direction at top and bottom of their stroke. 180 degree firing they are both doing it at the same time, 90 Deg firing one is mid stroke when the other is at top or bottom.
Possibly to reduce fluctuations in rpm or maybe it's a vibration thing. (Or both).

You are on the right track Storbeck.
In a 90°-firing twin, the fluctuations in the torque curve per revolution are much more gentle than in a 180°-firing twin.

[Flettner]

360cc reverse cylinder

[Grumph]

I wouldn't want to try and outbrake that into a tight corner.

Anything been said at scrutineering about pointy bits ?

[wobbly]

No its not a LSR engine , its a track day roadracer.
The Tularis pipes were past a vertical line up from the rear tire , thus illegal before even fitting mufflers.
Sure Niels thing fits with swoopy bends , but getting two in would be akin to self flagellation - and having mid section bleed tubes takes more room and is
a packaging nightmare.
The 90* firing is proven " Big bang " theory , plenty of reasons to do this , even though it requires two discs to accomplish with odd fire.
I got close to 100Hp from a 400cc Banshee with the worst transfer ducts on the planet , and in a RS250 Cup Chassis it weighed just over 100Kg.
With an easy 120Hp on tap and Niels Gibbs providing torque like a tractor, in this case smaller is going to be better.

[Grumph]

No its not a LSR engine , its a track day roadracer.
The Tularis pipes were past a vertical line up from the rear tire , thus illegal before even fitting mufflers.
Sure Niels thing fits with swoopy bends , but getting two in would be akin to self flagellation - and having mid section bleed tubes takes more room and is
a packaging nightmare.

I agree with the point on packaging two long pipes.

But the vertical line up from the rear tyre is I think an FIM reg.
Some years back while scrutineering I had an annoying pest hanging around who tried to quote the FIM rulebook at me.
It took some very direct and not polite conversation to convince him that locally at least we worked to the MNZ rulebook
and until we ran a meeting under an FIM permit he could keep his FIM rulebook in a safe "personal space."

So before abandoning a layout, check your local rules.

[wobbly]

Good point Grumph , but the Dr will race it in the USA where the same rule about " pointy bits " past the rear tire applies.
But truth be told I wouldn't be comfortable having those things out the back - legal or not.

[Flettner]

Here is a more modern picture, a little more sensible pipe outlet.

[Flettner]

Speaking of pointy pipes, this was my Uniflow 440 engine in a jet boat for load test. This run involved these four pipes, mid section bleeds. I drove to the Hamilton boat ramp in the middle of town just down at the river from the police station, where we usually did test runs.

Well it appeared we arrived right in the middle of some police practice exercises at the boat ramp. I had not even got out of the car when there appeared two officers at my car door. They were very concerned about the four 'missiles' sticking out of the back of the boat.
It took quite some time to quell their fears, even having to show where the pipes were attached to the engine. They never the less kept their eye on me.
Had I known the police were there, Id have painted some red and yellow tips on the sharp end of the chambers for effect and made them really look like missiles 😁.
Probably would have been locked up for that.

[Frits Overmars]

Here is a more modern picture, a little more sensible pipe outlet.

Any difference in behaviour compared to the side bleed pipe?

[Rudex]

Swap the TM A port front/rear wall crossing points - the front wall pointed back the most.

Yes, You are right!.

I find it curious that the port A front wall is further back than the rear wall. Why not every wall in 75%?.

For global view, what are the ports A&B radial position (angle or %) and axial angles?.

Best Regards.

[beta]

Yes, You are right!.

I find it curious that the port A front wall is further back than the rear wall. Why not every wall in 75%?.

For global view, what are the ports A&B radial position (angle or %) and axial angles?.

Best Regards.

TM has nothing to do with that picture

[Flettner]

Any difference in behaviour compared to the side bleed pipe?

Too hard to tell, there were so many problems with the tuning at the start that I changed it back to what I was comfortable with. Tuning the EFI on this project has turned out to be somewhat of a problem. Even switched back to normal TPI.
Turned out it was a combination of aulternator not keeping up, and a few other issues, where have I seen that before. ��

Pissing around with this twin port AG100 has taken my attention (and resources) for the time being.