SeayHiPerformance
Member
Alot of debate has been raging on many threads about conventional kart race engines vs big displacement , big singles. Years back, many were ready to fold up and say karting would never be the same when the Wankel began its domination. Then the BRC 150ww debuted and soon eyes were opened that not all was lost. As the big singles began to develop and chassis such as the Ultramax Excentric showed its abillity to handle the big horsepower, then the mix has become quite interesting.
NO ONE SINGLE POWER PLANT IS DOMINATING.... and will not.
The small displacement 2-strokes are STILL showing they are and will continue to be a threat. The reason for this is two fold. Jackshafts have the ability to greatly enhance torque with it MECHANICAL LEVERAGE. MECHANICAL LEVERAGE is superior in its ability to take a small amount of input and transfer it into big torque. Another principle of the the small displacement 2-stroke is OVER-REV. OVER-REV is and always has been a priciple of two-strokes that make them superior. Europe has always known this and with alll there GREEN energy and Enviromental controls they still continue to strive towards the small displacement high reving engines.
Now- That being said, how does this translate on the track?
You would think 10-15 more peak horses would blow by the little motors. Doesnt happen. OVER-REV (ability to continue the gain rpm past peak horsepower, vs hitting a brick wall and gaining no rpm) As long as a kart is gaining rpm it is INCREASING IN SPEED. When a motor stops gaining rpm, the kart actually feels as though it puts on the brakes. Another principle seen here is ACCELERATION and MOMENTUM. Current kart drive trains are limited in its ability to translate torque into forward motion. One of the draw backs one must always consider is drivetrain WEIGHT. Currently, jackshafts and dry disc clutches do somethng real well though- Provide and light weight, quick ability to allow the small displacement motor to QUICKLY rev to peak TORQUE and increase in RPM rapidlly. The big torque motors struggle here. WHy?? Weight of the rotating assembly of the motor and the ability of the current drivetrain to transmit the kart into acceleration. That is why the small engines consistently bust off the line with the big motors.
The smalll, high reving motors utilize the current jackshaft and ability to run low gear ratios to not only match the big torque motors but in many times beat them ion acceleration. Then as the kart increase in acceleration a SLING SHOT affect through the peak power band increases the speed of the kart on top end way beyond its peak horsepower band.
So what does this mean???
Until the large displacement motors gain ability to overev allowing them to run lower gear ratios they will still be at a slight disadvantage in my opinion on tracks that are 1/5 mile and smaller. There are exceptions of course, but until someone consistently dominates I will stand on my theory.
So- Continue to builld those BULLER Sudams and 116'S. They will do the job. And of course, the BRC 150WW is still in my opinion the best package available. We have never felt outperformed in the speed department.
In closing- NOBODY FREAK OUT: The 15,000 jawa kart is no more competitive than the 116 reedjet on a 1/5 mile and smaller track. However, when the big displacement engines learn that the SAME principles that allow the small motors to be quick ALSO applies to them, and they tune and setup towards that, then things will change. But until then, we race on.......
NO ONE SINGLE POWER PLANT IS DOMINATING.... and will not.
The small displacement 2-strokes are STILL showing they are and will continue to be a threat. The reason for this is two fold. Jackshafts have the ability to greatly enhance torque with it MECHANICAL LEVERAGE. MECHANICAL LEVERAGE is superior in its ability to take a small amount of input and transfer it into big torque. Another principle of the the small displacement 2-stroke is OVER-REV. OVER-REV is and always has been a priciple of two-strokes that make them superior. Europe has always known this and with alll there GREEN energy and Enviromental controls they still continue to strive towards the small displacement high reving engines.
Now- That being said, how does this translate on the track?
You would think 10-15 more peak horses would blow by the little motors. Doesnt happen. OVER-REV (ability to continue the gain rpm past peak horsepower, vs hitting a brick wall and gaining no rpm) As long as a kart is gaining rpm it is INCREASING IN SPEED. When a motor stops gaining rpm, the kart actually feels as though it puts on the brakes. Another principle seen here is ACCELERATION and MOMENTUM. Current kart drive trains are limited in its ability to translate torque into forward motion. One of the draw backs one must always consider is drivetrain WEIGHT. Currently, jackshafts and dry disc clutches do somethng real well though- Provide and light weight, quick ability to allow the small displacement motor to QUICKLY rev to peak TORQUE and increase in RPM rapidlly. The big torque motors struggle here. WHy?? Weight of the rotating assembly of the motor and the ability of the current drivetrain to transmit the kart into acceleration. That is why the small engines consistently bust off the line with the big motors.
The smalll, high reving motors utilize the current jackshaft and ability to run low gear ratios to not only match the big torque motors but in many times beat them ion acceleration. Then as the kart increase in acceleration a SLING SHOT affect through the peak power band increases the speed of the kart on top end way beyond its peak horsepower band.
So what does this mean???
Until the large displacement motors gain ability to overev allowing them to run lower gear ratios they will still be at a slight disadvantage in my opinion on tracks that are 1/5 mile and smaller. There are exceptions of course, but until someone consistently dominates I will stand on my theory.
So- Continue to builld those BULLER Sudams and 116'S. They will do the job. And of course, the BRC 150WW is still in my opinion the best package available. We have never felt outperformed in the speed department.
In closing- NOBODY FREAK OUT: The 15,000 jawa kart is no more competitive than the 116 reedjet on a 1/5 mile and smaller track. However, when the big displacement engines learn that the SAME principles that allow the small motors to be quick ALSO applies to them, and they tune and setup towards that, then things will change. But until then, we race on.......
