Yz250 2 stroke carbed turbo possible?

[Two2]

Hi everyone finally I decided to try to turbocharge a yz250 carb.
I'm not interested in a bigger displacement I want to make the max power from the small250cc using the carburetors and not efi!
It's a challenge!

Possible do it?

Anyone with some experience in turbocharging o a two stroke single cylinder??

Some useful contacts are goods for me!

All helps are allowed!!

 

[eric82930]

Start here and then learn how to cut and weld

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[Two2]

Ok, a self oiling turbo could be interesting but there are too big to my displacement.
Or not? I'm not too expert on it!
For the carb what's best between a lectron and smartcarb??
And the plenum before the carb what size?

It's an amazing work but too difficult!

 

[kempmechanics]

Don't do it i have had turbocharged bikes and while the power is good the extra weight is its downfall and makes them not playfully. Buy a yeti kit and make it into a 300

 

[Two2]

Don't do it i have had turbocharged bikes and while the power is good the extra weight is its downfall and makes them not playfully. Buy a yeti kit and make it into a 300

Understand what you say but I'm really curious about it! More weight isn't a radical matter for my built. What turbo bike do you had? Are these 2 stroke?

 

[sledneksam]

I think it should work! As long as you can figure something for oiling the turbo. I immagine it would be a"blow thru" setup as in your gonna be pushing the charged air thru the carb?

 

[eric82930]

Downloads | aerocharger

www.aerocharger.com

Harleys don't flow much air. the aerocharger kits are really small and make boost at idle.... The smallest one they show peaks at 100cfm. Quick spool and no oil needed. Only bad thing is the price tag if you don't buy used.

Type of carb won't matter you need to focus on the plumbing of the vent tubes to feed boost pressure into the float bowl. Smarty vent is already in the bell I think but no big deal to do the same with a pwk and some hose to the plenum. Then a fuel pump and a 1:1 low pressure regulator. Basically you need boost pressure in the float bowl so the gas doesn't flow backwards through the main jet and boost pressure +1psi on the fuel inlet so gas can flow into the float bowl. The plenum should be twice as big as the cc of the cylinder. Other than that throw some richer than sea level brass in their and start tuning!

 

[eric82930]

And the turbo needs to be after the expansion chamber on a 2 stroke.

 

[wwillf01]

Don't do it i have had turbocharged bikes and while the power is good the extra weight is its downfall and makes them not playfully. Buy a yeti kit and make it into a 300

Agreed... with the yz you will have to keep that crank bearing well oiled to stay in one piece .. we run our yz250 on a yeti and it is very capable...

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[Two2]

I think it should work! As long as you can figure something for oiling the turbo. I immagine it would be a"blow thru" setup as in your gonna be pushing the charged air thru the carb?

Correct blow trough set up it is what I tought

 

[Two2]

Downloads | aerocharger

www.aerocharger.com

Harleys don't flow much air. the aerocharger kits are really small and make boost at idle.... The smallest one they show peaks at 100cfm. Quick spool and no oil needed. Only bad thing is the price tag if you don't buy used.

Type of carb won't matter you need to focus on the plumbing of the vent tubes to feed boost pressure into the float bowl. Smarty vent is already in the bell I think but no big deal to do the same with a pwk and some hose to the plenum. Then a fuel pump and a 1:1 low pressure regulator. Basically you need boost pressure in the float bowl so the gas doesn't flow backwards through the main jet and boost pressure +1psi on the fuel inlet so gas can flow into the float bowl. The plenum should be twice as big as the cc of the cylinder. Other than that throw some richer than sea level brass in their and start tuning!

Ok an aerocharger could be the best choose, self oiling is awesome! Thanks Eric for your help!!

 

[Two2]

Another question is... A small 250cc could has enough exhaust gas flow to make a bit of boost???

And when boost increase (if it can do boost... Lol) how to compensate the fuel?

I don't want use electronic injectors on the intake. I want to use just the carburetor. How people solve this problem on the old 2 stroke turbo sled without auxiliary injectors?

Sorry for the questions but I'm not an expert...Just a little bit crazy

 

[Two2]

Someone?

 

[eric82930]

You don't need injectors. Just put bigger jets in the carb. Our riding is at 10000 feet we run 5 to 7psi boost to get back to sea level hp and end up running real close to sea level jetting. If you run more boost or go to lower altitude you will need richer than sea level jetting. If you don't yet understand how to jet a carb then a turbo is probably not a good project until you learn more. Don't just search here, Google the web and car forums the original svo mustangs were carb turbos from the factory.

 

[Two2]

Understand what you say but here I've see guys who put jets on the plenum and In the carb throat. What about it?

 

[Two2]

You don't need injectors. Just put bigger jets in the carb. Our riding is at 10000 feet we run 5 to 7psi boost to get back to sea level hp and end up running real close to sea level jetting. If you run more boost or go to lower altitude you will need richer than sea level jetting. If you don't yet understand how to jet a carb then a turbo is probably not a good project until you learn more. Don't just search here, Google the web and car forums the original svo mustangs were carb turbos from the factory.

Trust me I've search and search again on Google but it's all info about 4 stroke turbo. I'm not interested on it. Do you know some text to learn more about 2 stroke turbocharging?

 

[eric82930]

There isn't any real difference between turbos on 2 or 4 just that a 2 will melt the piston much quicker if you go lean. The extra jets were popular on the older sleds that were pipey, with round slide carbs with crappy needles and they ran like poo at quarter throttle even before adding boost..

 

[Two2]

Yes so in my case are these auxiliary jets necessary when boost come up?? Or are not mandatory? I mean a bigger main jet can supply itself?

 

[wwillf01]

Big jet for ses level should be a start... no aux ... lots of good oil.

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[eric82930]

You won't need the extra jets if you can tune your needle to run clean at 1/4 throttle while using a huge main jet. It should be easy with a stock yz with a pwk and less than 10 pounds of boost. The lectrons and smartys don't have as many needle options so it might be tougher to tune.