Рет қаралды 127,317
This is one of the videos of the high power version of the Minarelli Stage6 Kreidler 70cc with Ftt7014S exhaust, made in 2010.
Several G-measurements with Mr Dyno showed an average power of 22hp at about 14.000rpm
The Minarelli Vertical Stage6 cylinder is tuned max as possible, but still in standard Kreidler cranckcases with narrow (44mm) studs and no welding extra material. If that would be changed there would be more room for transfers and so more power.
The only purpose of this engine was to show a simple and a cheap way to get much power. After the G-force measurments and some movies for exhibition the engine was dismanteled.
It may look some violently, but that was not my intention. That experience is mainly caused by the lacking of a clear view and the 24mm wideangle of the carmera which all seems to go much faster than in reality. This video is only about the acceleration.
If you want the highest attainable power of a 70cc or 90cc or any other twostroke engine. Or much more information about racing - dragracing - ignition and tuning see my facebook and read my notes: / luc.foekema ...
Specification the engine this video made in 2010:
- Kreidler engine Minarelli Vertical 70cc cylinder
- Air cooled (not forced cooling)
- 5 speed standard
- UltraSap Ignition
- Ftt7014 exhaustpipe
- Standard Kreidler crankcases with narrow studs 44 mm wide
- Driving position was fully upright, just behind the camera.
- Carburetor Mikuni TM24
- Reedvalve V-force Minarelli horizontal without the center bridge and 4 big polini petals
- 22 hp at 14.000rpm
- topspeed 145 km/h without fairing (driven on A12 sorry no movie)
- bike is standard Kreidler about 75kg
- driver 70 kg
A part of my history:
I started racing in 1964. Computers were still not there. I did hardly no calculation. With the advent of the computer everything has changed and complicated calculations are no problem any more. All old historical notes were struggling. In the past 15 years I got a number of programs. Beside I did developed many programs myself in Excel. It was my profession to do so for my employer for many years.
In 2003 also start making calculations for on request. The most important details can be calculated very accurately for any twostroke engine. For instance the exhaustpipe can be calculated in almost exactly the correct speed for which the setup and cylinder is optimal.
Most important I found out that most tuned engines are not in full balance, that means one or more details are not tuned for the rpm for which the engine was made or was supose to be made.
All details should be made for the same rpm range to stumulate eachother to the top of there optimal function and so to get the most reachable power for any level. Low level or high level makes no difference.
Even by a large kart engines manufacturer (TM) was found to be not entirely correct. With a new calculated combustion chamber and exhaustpipe it was far better then before. Read the results of a super kart at the European Championship in "the comments of requestors on Ftt calulations".
This is also partly due to the information I got from Jan Thiel and was freely available after retiring from Aprilia racing end 2007.
Also the UltraSap ignition developed by my son Raimond was a very important part. The combustion and power are strongly influenced by the kind of ignition. Read about this subject my note on Facebook.
2t tuning is first of all to have fun !
Sincerely,
Luc
here are some notes
Read here the history about the symmetric twostroke engine:
www.kiwibiker....
Ignition and combution in a twostroke. / 4209180766868
Kreidler eitank met 19pk (model 2009) / 3047300000575
Kreidler 20pk-met-smalle-tap (2010) / 3060051479354
Kreidler rotary-valve-dimensions / 3200107980679
FST-twostroke-design / 4080202582494
My racing profile: / 10203048642856073
Foekema's Interview: www.motorracehi...
First Dutch dragracer-1967 / 3021388752810