ESE's works engine tuner

[richban]

Anyone know anything about the 2 stroke engine in these. They must have plenty of power.

http://www.jet-surf.com/en/machines.php

[bjorn.clauw.1]

Anyone know anything about the 2 stroke engine in these. They must have plenty of power.

http://www.jet-surf.com/en/machines.php

http://ing.jetsurfmexico.com/docs/manuals.pdf
~17hp 100cc, interesting location for the intake (overall size vs hp compromise I believe)

http://www.msrengines.eu/vyvoj.htm

[Brett S]

The official CIK list is out, Ryger is on it.
All we need now is the homologation papers...

[Makr]

Didn't you say you had to use the original cases? Is there some percetage rule?

I thought a lot about that when I did it.

This only became an issue when someone complained that an S&S powered Harley with no actual Harley parts in the engine really wasn't the rule. There are many records on the books with that combination.

Mine is still 75% Yamaha!

Small repairs are allowed

Right! :thumbsup

[richban]

http://ing.jetsurfmexico.com/docs/manuals.pdf
~17hp 100cc, interesting location for the intake (overall size vs hp compromise I believe)

http://www.msrengines.eu/vyvoj.htm

Cheers thanks for that. I would have guessed it had more power to push the thing through water with someone standing on it. An interesting toy.

[wobbly]

Here is the sim power graph and the Mach numbers for a race RZ400, to show how to interpret the traces.
The approach with this engine was to maximize power spread, rather than outright max power.
This makes a racebike with good suspension and sticky slicks faster, with plenty of off corner power,plus the RZ has very
compromised transfer ducts due to the bore centers,thus high peak power is hard to generate without badly narrowing the powerband.
Add to this the fact that the gear ratios available are not particularly close, and a good spread of power is essential.

If you look at the Mach numbers for both the stinger and the duct nozzle, they are both a little under Mach 0.8.
Having a slightly bigger nozzle and stinger restrictor favors mid power, over outright peak production, so the Mach numbers tell me, as did the power
output that I was choosing the right approach.For peak power the stinger would have gone sonic then been close to/above Mach 0.8
and the duct exit would be on 0.8 for much longer.
It made 96Hp on a load controlled Dynojet with no power fade at all, and has tons of mid torque - job done.
The other thing of note is how accurate the sim represents the power.
Take off around 12% from the crank power and you get real close to the Dynojet rear wheel power output.
And the real engine has a 2 stage PV blade that works way better than that simulated, so the mid power is even better than expected in reality.

[MotleyCrue]

Were there specifics given out already about the port timing and exhaust dimensions for this RZ400 engine or is that guarded info?

[AndreasL]

Thanks wobbly.

This is great info and very helpful.

[wobbly]

The RZ400 cost the customer plenty, but the real issue is that this is very much a 1 off special synergy of parts.
It has a CPI Cheetah cylinder on a long rod 58 crank, and the cylinder was a special with large Ex spigot diameter to enable the duct to be CNC machined
to make a nozzle.
It also had a curved 2 stage PV blade driven with the Ignitech and a servo, not the complete shit Rotax style pneumatic bellows type.
The cylinder was dropped to enable reverse stagger transfers to be ground, and the Aux were welded to make them triangular right at bore center.
The Ex port floor was lifted 4mm, and the corner rads filled.
It also has 60mm CR125 VF3 reeds in there on bore center with side stuffer plates.
As it was found that the big 68mm CR250 reeds, positioned off center, gave asymmetric inlet flow and lost 5 Hp, despite the better flow characteristics.
I am happy to give out the port and pipe specs, but they are useless information unless the whole engine is recreated in every detail.
Where else do you find a race 2T with peak torque and Hp near 3000 rpm apart.
To get this sort of project right,you gotta pay to get it done completely, even if only in sim form.

[jfn2]

wobbly:
What did you use for piston pin plugs?

[wobbly]

Torlon plugs

[bjorn.clauw.1]

Is it possible to elaborate a bit more on the last graph. (Mach numbers) I never thought 2 stroke software was this close to real world results.
Is this software available/affordable for the enthusiastic amateur?

I noticed the A-transfer inlet is lower than the B-transfer inlet. Also no boyesen ports in the inlet duct. Both a result of space limitations or is there a design philosophy behind it?

[FastFred]

I never thought 2 stroke software was this close to real world results. Is this software available/affordable for the enthusiastic amateur?

The last time I looked, Engmod2T was $400 USD ...

To put it in prospective, Engmod2T is cheaper than a good set of porting tools:- http://www.ccspecialtytoolstore.com/

[FastFred]

Were there specifics given out already about the port timing and exhaust dimensions for this RZ400 engine or is that guarded info?

This whole thread is like a University course where you learn the principles so you can successfully apply them yourself.

[jfn2]

Thank you wobbly.
Is it the #4203 or the #4301?
Did you machine as per Fritz's drawings? Can/will you sell them or does someone sell them?