ESE's works engine tuner

[Muhr]

I agree with you! at 239 * it looks like this when I tried.

[porttiming124]

With a VeeForce your idea looks perfect , if you wanted to try biasing the flow you could make the top hollowed out area deeper and or even higher.
Unless you can get varying petal thickness for this model its a bit harder to change the flow regime thru the tips.
We use different thickness petals and much different petal backups top and bottom.
After literally hundreds of dyno runs this was worth average 1.5 Hp in 50 over stock which was a pretty trick setup to start with.

ok thank you

[TZ350]

I agree with you! at 239 * it looks like this when I tried.

Yep, that is the RV blade shape I would expect to see at 239 deg inlet port duration.



Our Suzuki ones were about 210 deg duration.

[TZ350]

Easy for you TeeZee , put in 140/90 into EngMod and work back till you loose power.

140/85 turns out to be the best. I tried all sorts of combinations from 155 to 130 combined with 65 to 95. 140/85 is it.

[wobbly]

Im glad you came up with what I would have thought was perfectly reasonable.
Does that give you a Inlet STA that matches the Blowdown and Transfers.

[TZ350]

Im glad you came up with what I would have thought was perfectly reasonable.
Does that give you a Inlet STA that matches the Blowdown and Transfers.

Yes .........

[Muhr]

It happens that if you make the disc straight on the opening side (if it is meant to be turned that way) it will be exactly 239 °. but as said, it may well be my mistake

[husaberg]

The black and white one might be an early Debri prototype?


No where as cool as the RSW shapes
but i guess the RSA was ofsett.

[Frits Overmars]

The black and white one might be an early Debri prototype?

Nothing to do with Derbi or Aprilia. It is the BBFT engine by Alfio Tosi.

[husaberg]

Nothing to do with Derbi or Aprilia. It is the BBFT engine by Alfio Tosi.

Cheers ....
it was saved under RSA with "moteur" in some froggy looking dialect.
Any idea what language this is
moteur%20rsa

Google is a baren wasteland under Alfio Tosi?
care to fill in the gaps

Anyway here are some other pics of the more intersting discs

[andreas]

What is the black magic involved in shaping the disc's edges. When it would be more precise and area-efficient to have them rounded as in the drawing?

[Condyn]

What is the black magic involved in shaping the disc's edges. When it would be more precise and area-efficient to have them rounded as in the drawing?

I have been advised that the rounded corners will “ flutter “ and dig into the rotary housing on the case. Not sure if that was good advice or not.

[Peter1962]

Nothing to do with Derbi or Aprilia. It is the BBFT engine by Alfio Tosi.

In what year was that, Frits ?

[wobbly]

I spent months at ZipKart testing the new Rotax 256 for Hines 250 Superkart World Champ winning engine. With every disc shape known to man. Convex and concave radi on the closing edges , angled back , angled forward timing edges , everything.
At the same timings of 140/88 nothing made any more power anywhere.
The forward angle on the closing side was adopted as the outer leading edge gave support to the disc and reduced the bad wear occurring on the case face , due to the inlet column inertia pushing hard
on the disc as it closed. Even with trick coatings applied this problem never really went away.

[andreas]

No free lunch again