Max stable rpm

[Dude]

So i have been digging around in old posts and dont really see a conformed answer.
What is the max rpm these cranks can turn before going supersonic and destroying themselves? Same with the rod and bearings.

Is there power to be had above 10 thou in a blaster motor? Assuming you can feed it enough air and enough flow out i mean.

Due to the 2 stroke cycle does there become massive turbulence in the cylinder with such high velocity? IE: Can the ports be ported enough to flow that much mixture/exhaust.

 

[sheeblast]

i would be more worried about heat.

 

[Dude]

I am thinking of designing a peltier setup for the head to remove some of that. Using the head gasket would be ideal to achieve this effect.

 

[sheeblast]

and how do you plan on doing that????

 

[brandoz28]

you could just get one of these.......i don't think its cool because its liquid cooled but it has interchangeable domes!
Yamaha Blaster High Performance Liquid Cooling Kit

 

[Dude]

Thermoelectric effect - Wikipedia, the free encyclopedia

I run peltiers and nitrogen setups on some of my pc's at home that are clocked 5ghz. The jist of the effecgt is in that link without going into advanced physics on why it works.

Also looping cooling lines threw the head Fins to remove heat could also be achieved via a electric water pump. Ie: a liang5 used in Water-cooling Pc's. Small pc radiator could also be used as they are cross flow bar and fin.

All it needs to do is remove 20-30 degrees to keep it in check. Obviously prolonged use at such a high rpm would negate this effect thus requiring another solution. But for quick sprints threw the woods or for that extra umph during a climb is my main goal.

 

[Dude]

Interesting anyone here have experience with that? Heat issues aside i would like to know from someone who has built high end drag quads how far they can push it.

Meth/water injection is a idea as well. So is Efi via a megasquirt and a gutted carb and inline injector.

 

[98blaster+4]

if you are jetted correctly you should have no problems with heat, from my own personal findings using a right bend pipe helps to keep some of the heat away from the engine as well as the air scoops. i use an old styl scoops design but there are some real good looking ones out there to be had.

 

[sheeblast]

^^^ even if it is jetted correct, when your engine is firing 167 times a second, it is going to generate a lot of heat.

 

[royalt67]

Flotec builds drag motors....

 

[98blaster+4]

^^^ even if it is jetted correct, when your engine is firing 167 times a second, it is going to generate a lot of heat.

well then you damn well better be hauling ass so there is some wind to keep it under control.

 

[sheeblast]

^^^^ it is sad that people cant get his name right, it is Flotek. not flotech, not flowtech, or some other stupid versions.

 

[phragle]

it should be able to spin 10 grand all day. the ignition and pipe are your primary bottlenecks.

 

[Dude]

Cdi unit governed? I like how no builders chime in This is not a black art.......

 

[sheeblast]

Their isn't a rev limiter that I know of.

 

[98blasterworked]

no rev limiter... just the limit of the engine itself... i.e. better engine revs higher and worn out 1's dont... ect.

 

[phragle]

no rev limiter... just the limit of the engine itself... i.e. better engine revs higher and worn out 1's dont... ect.

Uhmmmm, not what is was getting at. the timing and ignition curve need to support the rpm.

 

[Dude]

can peak trq happen higher up. will the crank fail from sonic resonance?

 

[phragle]

The crank is fine, your limiting factor will be piston speed. its a bunch of math I dont have infront of me right now, but the blaster motor will live at 10,000 rpm if your willing to spend the money to get it spinning that fast. Torque will move up, the power band will move up and possibly narrow. your asking the motor to run more like a 125 than a 250. Other than pure drag racing or possibly flat track, the end result will probably be a bike that performs worse overall because you will loose low end.

 

[Dude]

Please do kick the algorithm over to me.

Here is what this all boils down to.

I have been driving around for 2 days with a epizia microphone/knock sensor from a gti strapped to the inside of the flywheel side. I have been logging resonance from the crank and it starts to get really pitchy at about 6,350 rpms (logging rpm as well) This is what prompted to me to inquire about the strength of these cranks and there torsional rigidity.

Assuming there internal balanced.... i hope. Maybe not with the way they vibrate like a mother. The plan was to build a motor than can turn 10-12 grand on a daily basis. Peak trq on my motor happens right at 6,100 rpms and i am right at 15:4 for afr's which is good on the way to peak trq i am 13:7 which is just perfect.
But after 6,300 i am just making noise which is strange. Granted stock carb and all.

Wanted a motor that made peak power trq around 8 grand and max hp around 10. Maybe i will strap a 12a or a 13b to it lol i have a sachs though here with new apex seals.