ESE's works engine tuner

[wobbly]

The Banshee castings are identical to the RZ, its just they are available still - as a new part, so there is no issue with getting that portion of
the argument past MNZ.
I spoke to everyone involved over a year ago when starting to get near finishing another customer bike.
An RGV chassis with Honda 400 tripple.
At that time all of the MNZ people stated that building hybrids was the whole point of the new class rules,mainly so that old race chassis lying around could be used again - but
with road based cases, thus getting more participants on track,without letting in million dollar GP bikes.
I am sitting here ( I do that most of the time - bugger ) fingers etc crossed that by inadvertently doing a good job, I have shown the way forward to having 2Ts at the pointy end.
Some may find this will stick in the 4T craw,I just hope it doesnt derail the whole intent of the Superlite regs, that with luck, will be ratified officially on Sunday - as is required by the MNZ constitution.

[wax]

I hope you havent done to good a job wobbly. They will outlaw you if your to good. Its what they do when they cant do it themselves

[bucketracer]

They will outlaw you if your to good. Its what they do when they cant do it themselves

So true .......... and all you can say is ...

[husaberg]

Not picking on Air cooling

OK there is Nothing mind blowing in here. It is also tempting to be lured to the Air cooling side what with that 25cc advantage and all too.
Each indeed has its own pros and cons.

Interesting thing is how much sense the bit from Peter Inchley makes... with regards to what Frits also has said.

The second two are just some japanese designer interperated....Back when it was becoming fashionable again (long hair was also in i guess and smoking pot too)
The last two are the SPX engine for giggles.

PS i see Jan Thiel also popped in for a look last night. It would be lovely so hear some gospel from him too
Not to say that Frits and Wob are not doing an excellent job of educating us

[Brian d marge]

The Banshee castings are identical to the RZ, its just they are available still - as a new part, so there is no issue with getting that portion of
the argument past MNZ.
I spoke to everyone involved over a year ago when starting to get near finishing another customer bike.
An RGV chassis with Honda 400 tripple.
At that time all of the MNZ people stated that building hybrids was the whole point of the new class rules,mainly so that old race chassis lying around could be used again - but
with road based cases, thus getting more participants on track,without letting in million dollar GP bikes.
I am sitting here ( I do that most of the time - bugger ) fingers etc crossed that by inadvertently doing a good job, I have shown the way forward to having 2Ts at the pointy end.
Some may find this will stick in the 4T craw,I just hope it doesnt derail the whole intent of the Superlite regs, that with luck, will be ratified officially on Sunday - as is required by the MNZ constitution.

Probably the one thing that would get me back ,,to watching road racing in NZ ...loads of home built strokers fanging around Paroa ...how awesome would that be

Stephen

[Frits Overmars]

Frits alluded to issues with the Aprilia GP engines - they would deto badly on part throttle when doing smokies for the crowd, so the riders were banned from doing it.

Yes I read that & was surprised that they couldn't adjust them for more retard when part throttle vs lower revs. Surely it wouldn't have affected higher rev settings & might have saved some damage. or am I missing something?

Part-throttle deto at high revs (that is what you use in a burn-out) has nothing to do with ignition timing. At high revs the blowdown time area is still sufficient to let the cylinder pressure drop below the crankcase pressure by the time the transfers open, at full throttle.
But at part throttle, the crankcase pressure is a lot lower, lower even than the cylinder pressure, so exhaust gas will enter the transfer ducts, polluting and heating up the fresh mixture. This mixture will then show its displeasure by detonating.
One last word about ignition timing: part throttle, or reduced cylinder filling in general, allows for more ignition advance.

[dinamik2t]

One last word about ignition timing: part throttle, or reduced cylinder filling in general, allows for more ignition advance.

That I noticed too in EngMod2t parameter "combustion efficiency". The lower the value, the higher you could go in ignition timings. So the number reflects the cylinder filling I guess - among other things.

[Haufen]

Not picking on Air cooling

OK there is Nothing mind blowing in here. It is also tempting to be lured to the Air cooling side what with that 25cc advantage and all too.
Each indeed has its own pros and cons.

Interesting thing is how much sense the bit from Peter Inchley makes... with regards to what Frits also has said.

The second two are just some japanese designer interperated....Back when it was becoming fashionable again (long hair was also in i guess and smoking pot too)
The last two are the SPX engine for giggles.

PS i see Jan Thiel also popped in for a look last night. It would be lovely so hear some gospel from him too
Not to say that Frits and Wob are not doing an excellent job of educating us

When I read the words getting hot and losing power at the beginning of the article you posted, an old article by Dale Alexander came to my mind. I have not read it for a long time, but I remember it being useful when racing aircooled two-stroke engines. Basically, the things mentioned in the article have already been discussed here in one way or another, but it's a good read anyway. In case you don't already know it, enjoy!

http://justyamahard350.com/articles/dale_1.htm

[wobbly]

Heres hoping that MNZ allows us to do what we Kiwis are good at, making shit that works.

The SPX read brought home one thing AGAIN, I have been thru this so many times its boring.
Peak power at 6000, means the pipes are about 2 metres long - and you are going to fit these WHERE???
I got involved with a project where an idiot wanted a 1200 triple 2T to go into a ZX10, he just couldn't accept that with and engine that big I
simply couldn't fit pipes in.
Same with a 1000 twin proposal.
Go down to say a slightly oversquare 900 triple and it may be possible - and could easily make over 200 Hp, but no,it had to be BIG.
ie inversely proportional to his dick size.

[kel]

Part-throttle deto at high revs (that is what you use in a burn-out) has nothing to do with ignition timing. At high revs the blowdown time area is still sufficient to let the cylinder pressure drop below the crankcase pressure by the time the transfers open, at full throttle.
But at part throttle, the crankcase pressure is a lot lower, lower even than the cylinder pressure, so exhaust gas will enter the transfer ducts, polluting and heating up the fresh mixture. This mixture will then show its displeasure by detonating.
One last word about ignition timing: part throttle, or reduced cylinder filling in general, allows for more ignition advance.

Excellent explanation Frits, it explains what we see in the RS/RGV250 igniton curve posted by TZ and also explains why I kill TZ's motors as I like to carry part throttle to stay in the power band. Looks like I need to swtich back to my crazy days of youth approach of full brakes or full throttle and nothing in between.

[wobbly]

Re coating pistons with ceramic - the cool boundary layer in the squish helps suppress deto of the trapped end gases.
The ceramic surface is HOT, the alloy underneath is COOL.
Coating the piston or head in the squish CAUSES deto.
HPC have done dozens of pistons and heads for me with a spray mask, to keep the coating in the middle only.
Even doing a clear ceramic for classes where coatings are illegal - woops didnt say that.

And I got the Britten Ex ports coated to help stop the thing boiling on the grid - worked a treat and made more power as well.
Except the first time it was done the valve seats all fell out from the baking process.

[2T Institute]

Previous owner of a mates 256 engined GP bike found that back in late 80s. think he got bumped up to thier equiv of F1 when it became apparent his battles with the top 600(?) ducati was he was foxing & managed a last min pass to win. But if he made a mistake or got baulked he was able to catch up the distance in less than a lap.

Yes I urge a owner/rider of a extremely quick Armstrong 256 here to enter a BEARS meeting to see if this will happen.

[jasonu]

Some of these old posts are worth a re visit. High 30's hp with a 24 mm carb so long as it has a diffuser shape tapering out from the slide.



TeeZee spent hours on the Dyno re discovering or at least understanding what Sonic_V meant by a diffuser carb and the angles involved.

The trick with the diffuser angles is to not make them to steep and have the expanding mixture becoming turbulent, breaking away from the walls and reducing the effective flow area inside the carb.

125 reed induction Kart engines making 38+hp with a 24mm carb and TeeZee has wrung 34 crank hp out of his engine.

So it makes you wonder, whats the point of continuing the 24mm carb restriction for F4 125 2-stroke Bucket engines....

The other side of your reasoning could say 'Why change the 24mm carb rule as TZ abd co. are makeing good HP with the rule in place.'
If you get rid of the rule TZ makes 40hp, then the 100cc watercooled bikes will want 125cc then the coal burners will want 180cc. The rule works just fine as it is.

[F5 Dave]

Part-throttle deto at high revs (that is what you use in a burn-out) has nothing to do with ignition timing. At high revs the blowdown time area is still sufficient to let the cylinder pressure drop below the crankcase pressure by the time the transfers open, at full throttle.
But at part throttle, the crankcase pressure is a lot lower, lower even than the cylinder pressure, so exhaust gas will enter the transfer ducts, polluting and heating up the fresh mixture. This mixture will then show its displeasure by detonating.
One last word about ignition timing: part throttle, or reduced cylinder filling in general, allows for more ignition advance.

um, thanks i hadn't thought about it like that, my outdated simulation software (my alcohol added brain) tends to think of things at max throttle dyno run performance. If throttle is turned less, less power produced but who cares?, as long as its smooth enough to predictably weight the wheels in the order of rider preference at the time.

so that leads to the point where the unskilled jockey (me) is at max lean or thereabouts & is unweighting the front with some light throttle before the time you can whap it on full. Surely on a small bike that is pretty high revs part throttle position.

Are you saying that with serious RSA style sub ports creating mondo blow down area; its a game changer to when deto sets in?

I can't imagine that a datatrace of even a GP rider is a) on or b) off. On the 500s I think they used to say it was full for like (can't remember) 30% of the time (if you trust journo reporting).

I'm still struggling with this.

[wobbly]

One other point to consider is that the GP bikes have a shift drum sensor, and use different powervalve and ignition maps for each gear.
In this scenario it is acceleration rate/throttle sensor/deto sensor readings that determines how much advance can be used.
In 1,2,3rd gear it can use way more advance as it accelerates way quicker than in say 4,5.6th,when transitioning from part throttle,or simply a full throttle squirt.
The Ignitech can be configured to compute acceleration rate to switch maps, or can use a shift drum sensor.