Comp ratio for one of these new 150cc oil cooled lifans

[macca97]

Im thinking of getting one of these bikes and put the motor in my go kart, than bolting a little turbo to it, id like to no if anyone roughly what the compression ratio is so if i need to get a decomp plate or brew up some of my own high octane fuel, will most likely have water injection, if i go ahead, it wont happen till next year because ill do it my D&T major work for year 12

Danny

 

[rotn50]

A stock Lifan 150 is 10:1 comp ratio

 

[macca97]

so ill defiantly need to ether put 2 head gaskets, or a decomp plate and 2 head gaskets.

 

[headsmess]

a turbo huh?

this ill have to see!

i cant find the turbo on "monkeyrun" anymore...the site died for a while i recall. it was a work of art!

apparently a fiat 500 carb is a direct bolt on down draught... so he was attempting "blow through" which is pretty hard to get right... it all ended with "sent the turbo back to repair an oil leak,never really worked properly anyway"...

suck through can work. otherwise, go EFI. got money? or, computer skills? can set pic chips up to run EFI...

the turbo is the tricky part. you got money? but i did see a few lil "universal" ones go on fleabay for about 300 a pop... like, lil. small. tiny. ideal

 

[zwebx]

so ill defiantly need to ether put 2 head gaskets, or a decomp plate and 2 head gaskets.

efi : http://www.ecotrons.com/Small_Engine_EFI_PNP_kit.html
turbo: http://www.ecotrons.com/Small_Engine_RHB31_VZ21_turbocharger.html

do your self a favor... run pull through it will be better to tune and also look on youtube for a turbo pitbike "150" only one video though yeah i have already considered it...

you could get a piston and then get it machined down (the dome that is) so it will lower the compression further...

 

[headsmess]

i was bored. nice keyring out of 1inch bar

busted my finishing ballnose. stupid fleabay carbide snaps if you sneeze at it! but the HSS tools for roughing work well



i tried making a kart for my yr 12... cb250 that had been factory blueprinted, never seen a bike. 5 horsie more than stock. twin carb. shame that my D/T teacher had had to pay for it after his son nicked it and sold it to someone a few years earlier. i wasnt allowed to make a kart after all instead i half heartedly tried making an alloy bmx...

if i was in school again, and had options again... for d&t, i would retro fit a cnc mill. make something thats practical and i would still be using it in ten years time...(and getting the folks to fork out is nice!) and id probably have stuck with aeronautical/civil engineering as a career instead of just a factory worker thats underpaid for what i do...

( if you think a mill might be interesting... get something a bit bigger than mine)


anyway...turbo has me thinking again...

an actual exhuast powered supercharger (a turbo) isnt really suited for these little motors. the speed the turbine spins at is proportional to its circumference. a big turbine doesnt have to spin as fast as a small turbine. remember the diameter is a 3rd of the circ... so a little turbine has to go...FAST. bearings, lubrication, balancing... its why trucks have huge turbos and once you get below a litre capacity theyre almost impossible to find.

the exhaust turbine has to be able to spin it up to this speed... at a certain point, sizes are working against you. restriction on the exhaust, etc,etc.


but a belt driven centrifugal supercharger....now that could work..

im gunna try and make one of these impellers 100mm across. belt drive from the crankshaft, in a housing that bolts onto the head. bolt on carb, and hopefully, with some fiddling with pulley sizes, get a working supercharger...


bear in mind that a d&t project has to be achievable to produce marks... KISS!

 

[zwebx]

remember you may need 100,000 rpm for a centrifugal supercharger to produce good boost so it needs to be balanced
get a screw or roots charger from a small subaru and cut it in half it will probably be easier

 

[zwebx]

and people have turbo'd 150cc lifans with about 15 psi with tiny turbos with 25mm impellers

 

[zwebx]

also to lower compression you could install a couple of mm longer bore

 

[macca97]

I had though about make a miniature roots style blower as i've got a big mill and lathe here at home, dads a mechanic and im fairly knowledgeable so we've got enough knowledge. the hardest part would be getting the clearances just right so it would work to its full ability, if i did end up doing it id probs just stick an old holden stromberg on it with a variable main jet as i've got a few.

in my mind a blower is always better than a turbo, they've got alot less lag and usually sounds better which is important. but the cost of making one would be fairly high and id do it right and get the impellers teflon coated, buying one of the little 25/27mm turbos is easy. but if i could i would get a blower

Danny

 

[zwebx]

if you are cutting one down all you are doing is taking the rotor and housing and cutting off the same ammount and then sliding them back together the way they were not to much to worry about clearances as because you are not making the end cap

 

[my67xr]

have you seen this setup?
http://www.youtube.com/watch?v=uX76JacFaAY

 

[macca97]

was talking to my cousin and him being who he is bought one of these bikes, uped the comp ratio to 12.1 put twin 28mm carbs custom manifold ported, polished head, a cam with huge duration (custom grind) and premium with abit of good old methanol added to the mix, so i might buy it off him cause boy it flys. and not worry about doing supercharger/ turbo setup

 

[zwebx]

i dunno about the twin 28's
carbs would never work right because there would be no atomisation of the fuel because of no airflow