Turbos

[dangerous]

if you build a 200hp engine you have to build all the components to handle 200hp
Anything I've missed?

for example: the CX500 engine upgrades from naturaly aspraited to turbo charged (48hp - 82hp cx650 - 102hp) are smaller/stronger valves, very heavy clutch, semi drop forged con rods and toughened pistons, lowered compresion etc all adds to the cost.

Na you covered shit rather well

[dangerous]

And if a certain Mr Cotton stops dicking about we'll see one out on Pre82 racing this season

If hes too chicken shit too.............. then I'll bloody well do it

[Motu]

Yeah,pretty good Death - another thing,turbos convert heat to energy,it's not gas pressure and flow,they don't work until they are given heat....that's why you do silly things like retard timing,lean out open the ex valve like you mention,this gives the heat to make the turbo work faster.

[RiderInBlack]

As pointed out ,a turbo is much more efficient than a charger,80% effiency as compared to about 50%,but the screw compressors blow all this out of the water with about 90% efficency,dunno why these aren't real popular....

Just waving my ignorance around here but, what's a "screw compressor"?

[sAsLEX]

Just waving my ignorance around here but, what's a "screw compressor"?

What is a screw compressor and how does it work?

A screw compressor is a positive displacement machine that uses a pair of intermeshing rotors instead of a piston to produce compression. The rotors comprise of helical lobes affixed to a shaft. One rotor is called the male rotor and it will typically have four bulbous lobes*. The other rotor is the female rotor and this has valleys machined into it that match the curvature of the male lobes. Typically the female rotor will have six valleys*. This means that for one revolution of the male rotor, the female rotor will only turn through 240 deg. For the female rotor to complete one cycle, the male rotor will have to rotate 11/2 times.

from link
http://www.power-technology.com/cont...compressor.jpg

[RiderInBlack]

Cool! So what is their compression ratio? 1: 1 1/2, 1: (1 1/2)squared (1:2.25), or 1: (1 1/2)cubed (1: 3.375) taking that the rotation ratio is 1: 1 1/2?
Do they use up much power driving them?
Are they being used to supercharge combustion engines?

[pete376403]

A supercharger doesn't have any internal compression - it just takes a "packet" of air and pushes it to the other side - ie the air is delivered to a container (eg manifold, plenum, etc) which the engine draws air from. If the other side cannot use the air as fast as it is delivered then the air pressure will rise. The extra air allows extra fuel to be burned and this is where the power increase comes from.
Nitrous oxide is another form of supercharging - in this case, when the nitrous is heated, it releases oxygen, which is then available to burn extra fuel.
Adding oxygen on its own, without any additional fuel, is a recipie for instant super-lean condition, and the piston crowns will be found sprayed all over the crankshaft very soon after.

[Pixie]

Lag ,that is why turbo bikes are not very pleasant to ride.\

But the Peugeot Jet Force scooter is the first production supercharged two wheeler.125cc

[Pixie]

Do away with the piston engine bits and put a combustion chamber between the compressor and the tubine of a turbocharger.

Oh, sorry some guy called Frank Whittle says he's already tried it.

[Pixie]

All these pros and cons go out the window with turbo diesels,they are a natural for turbo boost and it's a win/win situation all round - you don't need lower compression,you don't need more fuel,temps are cooler not higher,no strengthened parts...more power,more torque,less fuel consumption.Nearly every haulage truck,locomotive,ocean going vessel will have a turbo - it's for efficiency not power.2 stroke diesels like the Foden V12 ran twin blowers/twin turbos.

The Napier Deltic was an intriguing design.
See who can figure this out:

18 cylinders
three crankshafts
36 pistons
no heads
two stroke
6 cylinders long

[bugjuice]

Do away with the piston engine bits and put a combustion chamber between the compressor and the tubine of a turbocharger.

Oh, sorry some guy called Frank Whittle says he's already tried it.

when you do away with the piston engine, it only leaves one giant 'turbo' to get you movin..

[Pixie]

when you do away with the piston engine, it only leaves one giant 'turbo' to get you movin..

I saw a test of this.The response is so poor that you have to throttle back three seconds before a corner to get off the power, and open up before you enter the corner inorder to accelerate out of it.
But it does run on diesel.

[TonyB]

That's because they used a fricken great helicopter turbine. I'd love to see a bike with a small purpose built turbine + gearbox.

[Motu]

Just waving my ignorance around here but, what's a "screw compressor"?

I used to work on compressors for a living,back then a mobile compressor like an Atlas-Copco would be a V4 reciprocating job with 2 large low pressure pistons feeding high pressure pistons,powered by a 6cyl Ford turbo engine - they were complicated to set up and we did various things with the 2 taps to load and unload the compressor to test valves etc...with both taps wide open it would be working at max to keep 100psi.I remember the first rotary screw that I worked on,it was powered by a Duetz aircooled diesel - starting with taps closed it would start with a blip and idle - that was it up to pressure...with taps wide open it would sit just above idle maintaining it's 100psi working pressure - fucking amaizing,and with a pump you could fit on the carrier of your bike.I remember some compressors were rotary vane,same as a Shorrocks blower - superchargers are just compressors after all.

[Ixion]

The Napier Deltic was an intriguing design.
See who can figure this out:

18 cylinders
three crankshafts
36 pistons
no heads
two stroke
6 cylinders long

Yeah that was a neat design. Fred Lanchester had something like that in the 1900's. It's always seemed wasteful to me, having cylinder heads. You apply all that force which could be used to make the wheel go round , to the cylinder head, then have to put in lots of strong bolts (and weight) to stop the force breaking things. In effect half the energy in each combustion cycle is completely wasted.