Bro I'm the guy who did D 2nd fiero with the help of that great man.

How is the bike bro.. Can we have some stats??

I have on idea.Instead of conventional turbo or supercharger why dont we use the idea of a electric supercharger or hybrid turbo charger.But on our small capacity bikes electric turbo will be of no use since it requires very high electric output which even after recolling is very difficult to obtain.So why not use hybrid turbo.Now in hybrid turbo setups exhaust gases drive a turbine which is connected to a high voltage alternator.Now the alternator is connected to a compressor which is on the intake.Using this technique we can find the parts, rather than making a small turbo this setup will be easier to make(according to me correct me if i am wrong).According to me it has merits of both turbo and supercharger,since it uses exhaust gases to drive itself its efficient than a turbo and since it is using electricity we can proper circuitry in between alternator and compressor which will reduce turbo lag and give linear power(like supercharger).This setup also can save other hardware and waster gate and BOV.We can use the MAP or MAF sensor inputs and at when the particular pressure is acheived we can limit the extra current produced by alternator.

Now it's in a local workshop here. making it back to somewhat stock(now using 62 mm piston).But alot of parts gone missing during the course f project now figuring it out and collecting.All other components that machined are now safely kept includn SC.No intention to use it atleast for now.

The idea is interesting.Using turbine to drive the alternator.But the speed variation of turbine ,from the meanspeed ,will be higher in single cylinder engines. To my knowledge this high fluctuation is not desirable when it drives an alternator directly.(somebody throw in more light in this)
Another issue will be weight- Turbine + casing,alternator assembly,compressor, necessary shafts. The combined weight seems to exceed the weight of turbo/SC.Even with electronics the BOV/waste gate shouldn't be removed since in the event of elec. failure excessive press. build up can be thus managed.
At the same time the idea is not really bad. A lil bit f refining will make it better,for sure.If this idea came as a part of ur academic project, don't leave the chance. Work on it ,work hard, seek guidance BUT DO IT YOURSELF. Results will be surprising one way or another.And let us know.

Thanks for your response Nitin, I hv just passed my 12th from mumbai and am getting admission for mechanical engineering.So this might be my project but after a couple of years.For now i just have little theoritical knowledge and even lesser practical knowledge but as i learn more i will surely try to do more.As of now i note down all such ideas which come to my mind in a diary/journal.And i even tried something which lavs did(RAM air intake)and it does require some tuning and proper design but will works wonders if did more properly(professionally).

this is such a brilliant thing yeah.. i'm a mech engineer and i own a karizma zmr.. would love to try this out.. if u can shed some more light on this topic.. plz

I very much Agree with Nithin.

Cause i have seen a couple of Mechanical engg, diploma holders Supercharge a 100 cc honda cd100 engine.

Procedure:
1)The said ppl had done the supercharging for their 8th semester project, it wasnt anything fancy, they had salvaged a Turbo from a used Toyota diesel engine. (dunno which)

2)They welded a pulley to the shaft, put a V belt on it, put a pulley on the engine crankshaft, and its a supercharger.

3)They used the stock carb, as they had to show the difference in Power and FE w/ and w/o the supercharger.

4)Now this was just a Engg project hence it was crude, and basically it woudnt have lived for long in real life.

5)It cost them around 7k~8k for all the necessary parts.

6)The supercharger wasn't a high pressure compressor, they weren't that mental.

Result:

For all their effort they managed to get better FE, some marginal power increase. (power was calculated the hard way, with a old school flywheel loading/brake and Tachometer. )

Problems they didn't address: (or chose to conveniently forget)

1) Cooling of the Supercharger (The impeller needs lubrication)
*Note:Turbos float on a thin film of oil, and usually a inter-cooler is used to cool the oil circulating through them.*

2) Charting Performance at higher RPM, preferable where the engine would have made max horsepower.
The system did improve torque, but at higher revs ,
a)The compressor would have cooked.
b)Engine would have run lean, and then the engine would have cooked too.

There was no spectacular Engine blowups, will have to wait till Diwali for the fireworks.

But then again it was a Student project so we are allowed to leave loopholes. And like any good Engineering student.

Conclusion: Hence we have proved that any 4 stroke Petrol Engine can be successfully supercharged to attain better Fuel Economy and more Torque.

So maybe we should try Supercharging our bikes. ^ ^

EDIT: Reformatted the words and checked punctuation.

I am in the final year of my mechanical engineering and I had the exact same thing in mind for the project but was dismissed as a tough one to implement by my damned groupmates

^^ you can always contemplate a electric supercharger ( like the leaf blower that is commercially available, DC based, shifts about 18,000 Cu ft of air per minute ). The idea would be to power it from the alternator thru a battery.

Else i remember long back in a magazine a 2 stroke RX was supercharged by routing the intake from the magneto side, and a normal impeller like rotor was attached for the compression.

Though turbine superchargers are there, i thought the root or vane type would work better ( maybe my terminology is wrong, but the kind which has two petals meshing together to create compression ).

But then again, superchargers good for the lower end of the rpm, for the low end bump in power, at higher rpm they take too much power from the engine to justify the boost provided by them. Turbos work the exact opposite.

Why not mate both of em?? I think someone has tried that as well. But the plumbing is gonna be a PITA.

what you can do is a basic comparo of ram air, vs supercharging vs turbo charging and get what will be ideal for a bike engine.

what you guys are planning to do here is purely suicidal..

supercharging is not just about putting a lot of air into the engine with no means to support it..

if u supercharge a puny little <250cc 4 stroke engine, which is not even injected, u are asking for trouble.
firstly, the carb requires a vaccum to feed fuel into the engine. high pressure (due to supercharging) will close the carb needles and shuts off the fuel supply and hence the engine will never run properly

even if u manage to get the engine running, the engine will instantaneously run lean causing overheating, top speed will reduce like anything.

secondly, the max efficiency of any ic engine is not more than 30% so every bhp that you are producing more means that the twice ammount of heat has to be dissipated by the engine and will also consume 3 times more fuel.
most aircooled engines cant cope up efficiently with higher temperatures and so you will have to tune the carb to rich setting and this again means lesser f.e

the high pressure also closes the carb needles and shuts off the fuel supply

a fuel injected bike with an intelligent o2 sensor will perform better but that too will require higher capacity injectors and a reprogrammed ecu.

all in all, this topic is good on paper but in real life, the problems far outweigh the advantages.

Ram air coupled with a Cold air intake setup would be the most favourable. as it doesn't add much weight and should improve your power output.

Cold air intake: piping to suck in air as away as possible from the engine (so that the air is cooler) and located as low as possible, cool air is denser, and dense air is heavier. (the temperature difference will not be huge or magnificent to look at, but every positive input counts.)

I bet every person who does tinkering and mods of such caliber will know the consequences and dangers associated with the mods.

And if you are supercharging/ yew will have to change the carb, (as your air flow has increased.) or put in a TPI(Tuned Port Intake)

You need a lot more fuel to maintain the correct a/f ratio.
Moreover for supercharged engines the a/f ratio is highly rich 9.8:1 (even for the the multi cylinder, liquid cooled engines)
This is so that 1) the engine doesn't over heat 2) the increased engine head might cause the mixture to pre ignite, hence a richer mixture.

What does closing of carb needle mean?

I am guessing if the supercharger produced too much boost it may cause the air in the carb to stall, because the engine is single cylinder and forced induction will cause the air to build up, Affecting the needles of our carbs, causing a backflow.
But this is solved by having a waste gate/dump gate/ relief valve.
(and maybe a non return fuel line from the carb to the wick,needle. Just a weird solution, i dont know its effectiveness. Might have to be mechanical instead of Spring return.)

Carb requires Vaccum, in other words it needs positive pressure head on one side and negative pressure head (vaccum is because of the pressure difference) on the other side of the venturi.
This pressure difference is still maintained when we use forced induction. The positive pressure head will have a greater value that is all.

That being said stock carbs will not be able to function properly because they are designed to handle naturally aspirated airflow.
Some people use TPI, its basically converting your carb into a FI.


What are your thoughts about this?

PS:Every engineering problem has a solution.

what i mean by the pressure is that in a naturally aspirated engine, the pressure inside teh carb is always less than the atm pressure and that is the reason why the fuel is sucked into the carb. and this is the reason why carbs with throttle body sizes more than 40 mm do not work efficiently.

i agree with your point that the pressure diference because of the venturi causes the fuel to be sucked in but when the engine is being supercharged, the pressure at the venturi throat, increases above the atm pressure, at this point, the fuel stops flowing and the engine stops working or hitches.

so at this point, the carb becomes useless and a fuel injection system is required to provide the fuel supply

Can the problem be solved to some extend by fixing the carb btwn air filter and the supercharger inlet.Here the press. build up won't interfere with venturi like before.Seen that setup working.

This solution is kinda smart

But wont the fuel hit the supercharger's/blower's impellers? and instead of going to the cylinder might accumulate over the impeller's surface?.

Which kind of Supercharger was used in the setup that you witnessed?