Re: Building two turbo Bikes

Finally someone with tech questions

Well. This was totally a last min decision project. Would like to re do the entire thing again more systematically

Well starting off: the turbo chosen was from a mahindra Maximo. Its the smallest garette turbo available. Meant for a twin cyl 600cc diesel 3250 rpm engine, this turbo does the job.

The 180 engine revving up to 10k rpm compensates for the volume mentioned. For single cyl, you have to make sure your piping is at least long enough to hold the capacity of the engine's volume of air. Pulses issue is solved with this. Although you do have some initial issues setting the waste gate absolutely right to avoid return pulses and higher back pressure not allowing the engine to rev or if the waste gate is set too open then you have no boost. Along with this you also need to monitor boost. We pulled a max of 3psi but the engine ran good at 2.7. I figured my carb tunning skills are really not very good yet because of which I took a long time to get it right.

But here's how you get a draw through setup correct.

Take an NA bike. With the stock carb.
Buy a wide band O2 sensor kit (i have one extra )
Set your AFR to 11.8-12.0 on idle by enriching the carb
Then mount the turbo in the draw through layout. Keep the distance between the carb and turbo, turbo and inlet as min as possible. And make sure its down stream at all times.
When stopping the engine, shut fuel supply first. Let all the fuel in the system be used off. Else you will have puddling and flooding of fuel.

Keep the pipe after the turbo (exhaust) as short as possible.

Start the engine and keep an eye on the Afr. The easiest way to destroy your engine is to run it lean and on bad fuel. So make sure AFR does not exceed 13.8

Need a boost gauge. Our boost gauge maxxed out at 3psi but the engine dint revv beyond then. So lowered the boost to 2.7. Correct balance between boost and rpm is the key.

I'll be back (lunch)

Re: Building two turbo Bikes

I guess this is a must read in regards to turbo charged bikes and history for the readers as well :

Turbocharged Motorcycles | Turbo Tactics | Super Streetbike

interesting project [MENTION=13481]hemank[/MENTION]

Cheers,

Re: Building two turbo Bikes

Hemank are you using the stock carb?
coz for the air flow, it will tooo low.
I would prefer, a flat slide since suction will be more uniform compared to, NA 2 strokes.
I would calculate, the fuel requirements first and then have the jetting sorted out accordingly.
The issues we faced on the 800 were due to, the sealing and carb leaking due to pressure.
We were running around 12psi, also was starving coz the stock fuel pump was inadequate.
You have got me thinking a similar setup on a 220, with more cc's.
Also regarding the pressure pulses, wouldnt a expansion chamber like in 2 strokes help for better, flow n pressure on the turbine.
Just my thoughts on it.
Also along with wide band i preffer plug chop test.
Also some porting to decrease the compression.

Re: Building two turbo Bikes

I did think and try similarly. But flat slides work better on blow through turbo. Upsizing stock jets n using the stock carb turns out good.

The 800 I'm sure you used a blow through setup if your carb is under pressure. And well you have to seal off everything. And no wonder the engine died of fuel. You need a pitot tube setup adding pressure to the carb fuel bowl through a fuel regulator that varies fuel pressure based on turbo pressure. The pump may or may not be adequate. But I'm sure you didn't add a pitot tube pressure line. That made it starve.
220cc: let's do it.
Porting is good. But just prefer changing to forged low com pistons. And valve timing needs a lil calibration.

HD

Re: Building two turbo Bikes

Hey hemank, nice to see the bikes.
Just a few heads-up for you on the turbo project.
A CV carb will mess with boost as the slide has the tendency to fool around with engine intake pressure going positive.
A slide carb is better, but carbs always have issues with holding consistent AFRs with boost and under lift-off conditions. Fuel injection is the way to go to get consistent boost load performance, better idle, cold start and avoid constant flooding. Draw through setups affect fuel atomisation to a great extent reducing throttle response and also weakening the power band. Boosting into the carb/TB is always a better bet. You will need a fuel pump (carb specific) for higher boost at higher revs.
A longer header to the turbo increases turbo lag. Shorter length with the right diameter improves boost response greatly. Trouble is figuring out the right diameter. 3psi is fairly low for making any positive bump in power, you need some more boost. You will need to focus on the engine as well to get better efficiency from the package.
Hoping to see an improved turbo motor from you and your stroker EVO getting faster for the next valley run

Re: Building two turbo Bikes

surely. Thanks. Will see you next year.

Hemank