ESE's works engine tuner

[Yow Ling]

Percentage of time at full throttle rarely exceeds 2 percent.
.

you need to ride a bucket at ruapuna, probably closer to 50% wot, maybe more

[Grumph]

Also races are not indefinite periods of time.
Nor is power output. Percentage of time at full throttle rarely exceeds 2 percent.

There are two rules of thumb here husa.

1/ The smaller the bike, the longer a race seems to take...

2/ The smaller the bike the longer the proportion of a lap it will be on full throttle.

The last is very real and applies regardless of circuit size though obviously bigger circuits show up any shortcomings whether mechanical or cooling, quicker.
Pukekohe in particular was death for small bikes with only two spots each lap where the throttle was closed. Even the aussie V8's were reporting around 60% of each lap on full noise.

[wobbly]

The intake length question depends entirely on the rev range to be used.
What rpm at peak and max will be used in the twin.

And re the question about what engines run under 52*C the answer is all of them should be.
Karts run best at around 42 to 45 and any GP bike over 50* is simply throwing away HP - the difference between
50* and 60* is 2 to 3 Hp when making near to 50.

[FastFred]

2T's dominate at Mt Wellington Sunday.

Mt Wellington, First A grade race, two strokes 1 - 2 - 3 and 4. Second A grade race finishing order, two strokes 1 - 2 and 3 with one of the 4 having crashed out, Dave M sets new lap record 28.9 something riding what I think is a Speedpro tuned MB100 based 2T in an Aprilia 50 chassis.

[Moooools]

but to push it past 52 degrees takes nearly 13 times as much energy.
How many bikes do you know that run under 52 degrees?
Also races are not indefinite periods of time.
Nor is power output. Percentage of time at full throttle rarely exceeds 2 percent.
Also its not only wax though is it if you use a composite.

In this case your understanding is wrong. http://en.wikipedia.org/wiki/Enthalpy_of_fusion
The 210kJ/kg is the enegry taken to push it past 52 degrees.

I accounted for a 10 minute race. That is where 13422kJ came from 22.xxkW x 60 seconds x 10 minutes = 13422kJ.

My assumption was full throttle all the time. This is a common assumption for cooling design. Mainly because if your cooling fails, so does everything else, which is shit.

If you wanted to live on the wild side, you could maybe assume a 50% average throttle (50% of maximum engine power that is) for the entire race. Congrats: 22kg of wax.

[peewee]

The intake length question depends entirely on the rev range to be used.
What rpm at peak and max will be used in the twin..

in engmod ive got it set to 11000 rpm for peak power. if i port it to the time areas eng mod is saying and use an apropriate pipe then i should be good i think.

[TZ350]

2T's dominate at Mt Wellington Sunday.

Mt Wellington, First A grade race, two strokes 1 - 2 - 3 and 4. Second A grade race finishing order, two strokes 1 - 2 and 3 with one of the 4 having crashed out, Dave M sets new lap record 28.9 something riding what I think is a Speedpro tuned MB100 based 2T in an Aprilia 50 chassis.

Getting fast in A grade. Great to see the 2T's leading the pack. http://www.amcc.org.nz/index.php/men...acingnews.html

Hi all,

Yet another great day of racing in the sunshine at Mt Wgtn. Our good fortune with the weather over the past couple of seasons continues and two lap records were set this weekend!

Congratulations to Dave Manuel for his 28.913-second lap record in F4 race 1! And in race 2, Dave put some serious pressure on Nathanael Diprose and came away with the win. It was Nathanael's first loss (in either F4 or F5) and first crash in a points race this season.

Congratulations also to Rick Ford and Henk Zeeven for lowering their own sidecar lap record to 34.522 seconds. They were chased all the way by Dean and Erica which undoubtedly gave them the necessary hurry up. It was great sidecar action for the spectators.

The details are published on Mylaps here: http://www.mylaps.com/en/events/1125894

Current F4 points: http://organisation.mylaps.com/champ...w.jsp?id=38264
Current F5 points: http://organisation.mylaps.com/champ...w.jsp?id=38265
Current B-Grade points: http://organisation.mylaps.com/champ...w.jsp?id=38262
Current C-Grade points: http://organisation.mylaps.com/champ...w.jsp?id=38263
Current Sidecar points: http://organisation.mylaps.com/champ...w.jsp?id=38266

We even have some pitbike points since the guys were using transponders this time: organisation.mylaps.com/championship/view.jsp?id=42900

The AMCC website bucket racing news page is updated here: http://www.amcc.org.nz/index.php/men...acingnews.html. This includes all the current lap records at Mt Wellington.

Happy viewing.

Tim

Holy crap look at the pace of A grade! Congrats Dave, that's a stupid lap time right there.

You're telling me, I ran sub 31s clockwise for the first time ever I think, good enough for fifth and sixth

What an awesome weekend at Mt Wgtn.

F4 A-grade saw 2Ts place 1-4 in race 1 with Dave Manwell 2nd and Gary 3rd. Manwell was on a mission but Nathaniel held him out for the win. Race 2 looked to be shaping for a repeat. Dave put a move on Nathaniel in the sweeper but Nathanial wasn't having any of it and shut the door on Dave good & proper with the result that Dave lost a lot of ground and spent a moment on the grass. I was flagging and saw Nathaniel go past with no Dave in pursuit and thought the worst, but Dave flew on past a moment later. It seemed that Nathaniel could pull a length or 2 on the straight but Dave made it all back in the sweeper by carrying some serious speed all the way. Running clockwise, exiting the infield onto the back straight he had it sliding sideways. Pretty impressive to watch. Nathaniel was caught back up in a couple of laps and the pressure put back on. Possibly he succumbed to that pressure, but whatever, he slid off on the infield a few laps later and his race was over. Gary was having a good tussle of his own but managed to hang on for 2nd. So race 2 has 2Ts in places 1-3. When I heard Dave had set a new lap record I thought it must have been in the 2nd race given how he seemed to be riding to catch Nathaniel but the time was from race 1.

Those Aprilia chassis are pretty good. Anyone who has ridden Dave's one really likes it and of course Tim's 50 goes round corners pretty good as well. Both of them are superb riders of course. Gary had his MB flying but he was definitely pushing the limits of a stock MB chassis even if it now has RS125 running gear. One moment exiting the back straight had him pull over to check the front wheel wasn't loose or jamming on something. The likely problem was that he was slightly off his usual line and ran over ripples which caused a bit of an upset.

Cricket was the only 2T in F4 B-grade riding Gary's MB100. He had a handy power-weight ratio and used it to advantage. Having said that he does seem to like diving up the inside of other riders at the end of the sweeper. He placed a fairly handy 5th in both races.

Gary had the camera on for the points races so hopefully we'll have video to post later.

No changes to either bike since Tokoroa. In fact they were put in the shed after Tok' and pulled out for this weekend. They are now back in the shed and will probably only get looked at when we pull them out for the next meeting, unless the new billet watercooled heads turn up. Really looking forward to getting hold of them as both bikes fade badly after a couple of laps at the moment.

Alright ladies, here's some photos from the weekend. There aren't many because I only stuck around for practice, qualifying
Wish I stayed around longer to see the lap record being beaten and the Dave taking on Nathaniel - finally someone has to do it!
It was fun taking photos again, even if I went there to ride

Anyone got a clutch cover I can buy?

CLICK HERE FOR ALBUM
https://www.flickr.com/photos/sonscc...7652099920135/

[Kickaha]

you need to ride a bucket

Yes he does, I doubt it will happen in my lifetime

[wobbly]

Here is the intake model for a HV Lectron 40 with Honda RS125 manifold on CR125 VF3.
This is 3rd harmonic tuned to 11,000 with end correction and 2/3 reed length.
Going 10mm longer gives +1 Hp at 8000 but looses that above 11,000.
Works perfectly on RZ or TZ400 with CR125 reed box welded on.

[peewee]

for now i think ill stay with the original cylinder inlet and vf4 reed. to give a simple answer, does a short intake manifold usually work better at high rpm than a longer one ?

[wobbly]

There is no short answer, as we are talking about the interaction of the particular intake harmonic tuned
length and the petals natural frequency, so its complicated as hell.
You can tune to have the intake length work at peak power to enhance that area, but its just as possible to go alot longer
and pick up a heap of mid, with no loss up top by using a different harmonic.
How much crank power are you shooting for - as the small Banshee VF3 and 4 very quickly run out of flow - also needing big Boyesens
and piston cutouts to work well.

[seattle smitty]

"KTM’s engineers put lots of thought into their radiator design. Rather than just put old-school plastic guards on the front of their radiators, KTM used wind tunnels to design a new radiator guard shape that flows more air (and is made from a stiffer plastic to help the flow and act as a radiator brace). The radiator shrouds also seal against the outer edge of the radiators to direct airflow into the radiator’s cores. There is a new filler cap and filler neck that seals better than last year’s design. The end result of all of this work is that the exact same capacity and surface area produces 10 percent better cooling efficiency"

But did they only wind-tunnel-test just what shows in your photo, Peewee? Or did they also test the airflow in front of those radiators as disturbed by the tire/rim/brakes/forks/fork-clamps/etc. ??

TeeZee, I like that 3-part bad/okay/good diagram. Notice that in the "good" version, velocity is traded for pressure immediately in front of the radiator core.
Aircooled recip aircraft engines all have "pressure-cowlings." Interestingly, when a cowling was built for the gigantic Pratt & Whitney R4360 28-cylinder radial, with four rows of seven cylinders (two sparkplugs each, 56 per engine), it was found that the aft-most row of cylinders ran cooler than the cylinders in the other three rows!

[peewee]

wobbly im shooting for around 90hp which i dont think is unreasonable if everything is done right. as you know my low temp brazing rod idea failed, atleast for the large amount of welding that needed to be done but im going to have a new tig machine soon, so ill be able to weld all the apropriate areas. inside the trans ducts, water jackets for the aux exh, stud pockets for the boyens, etc.

ill have plenty of case volume, slightly below 1.32. i am a little concearned the 34mm down sloped carbs i just picked up may no be sufficient but i really dont know. maybe they will be fine, one guy claimed he bored some to 36mm but im sure they were extremely thin. vf4 looks good in engmod, far better than the yamaha block. nothing much else i can do besides cut the inlet off and do a cr125 inlet like you mentioned but i dont want to attempt that right now.

i just picked up 2 stock heads. one i plan to use and the other is junk but im going to cut it open and see how thick the combustion chamber is. what i want to do is use the good head with a chamber design like what the rsa had, if theres sufficient material to do so

smitty i have no idea exactly how ktm did the wind tunell test. the only info i have at this time is what i posted, as that was the only info given in the article. could they be stupid enough not to account for all obstructions like you mentioned (tire, forks, fender, etc) ???

[Dutch Fisher]

What kind of coolant is allowed in MotoGP racing? Is it pure water only, or are you allowed to mix with some anti-corrosives, too?

Distilled Water, with Glycerol anti-freeze. The Glycerol has noncorrosive properties and raises the boiling point of water, it also reduces the surface tension of water. To further reduce surface tension Acetone can be added in a ratio of 1 drop to 1 litre of water.

[jasonu]

2T's dominate at Mt Wellington Sunday.

Mt Wellington, Dave M sets new lap record 28.9 something riding what I think is a Speedpro tuned MB100 based 2T in an Aprilia 50 chassis.

What direction around the track was this time set?