Turbo on the hawk 250?

[zanoknight]

So before I go too far deep into the rabbit hole I have a few questions.

First: is there any benefit on adding a small turbo on a small engine?
Second: I have the aftermarket oil cooler already installed on my hawk, can I tap into that to cool my turbo?
Lastly: is it more beneficial to make it a blow through or suck carb?

Thanks to everyone who responds. I kind of want to try this over the winter. I am graduating in December and I will have a lot of free time and extra cash from graduation gifts.

[slowroller]

A efi tunable bike would be 100x better to start with if its a have to have thing.

[zanoknight]

I would love to try this but that kinda project is out of my comfort zone. I’d rather do an engine swap then trying to convert this one from carb to EFI.

[Tashka]

yes turbos will definitely increase engine performance on a small engine. You're essentially increasing the displacement of the hawk, which would drastically increase performance, even if you were to do a moderate blow through.

The stock hawk has a pretty low compression ratio already, supposedly 9:1, however I have a large suspect that it is actually even lower. the tt250(which is the same engine) has a compression ratio of 8.7:1, while at the same time having a thinner head gasket. so i think the hawk has an even lower ratio than that.

You would need to buy the world's smallest turbo, the RHB31. this website sells clones of it for not too expensive of a price. http://www.ecotrons.com/products/small_engine_rhb31_vz21_turbocharger/

You can turbo a carburetor, and there are tuning ways to do so, however it's likely you'll run into fuel issues, as it needs different amounts of fuel depending on how fast the turbo is spinning. Id definitely go fuel injection, they have a lot, although it is expensive, it'll probably save ypu from blowing up an engine

But to be fair, one large issue you may run into is cooling. turbos produce alot of heat, and an intercooler of some kind may be necessary to keep combustion temperatures down. Id definitely run as rich as you can, especially at WOT.

I've thought alot about doing a turbo on my hawk. i decided a supercharger would be better for an off-road purpose bike(less intense power bands generally, don't have to get it spooled up), but the biggest thing stopping me is the price.

If you were set on doing carbs and turbo, I say blow through for better throttle response

[Tashka]

a turbo on this air cooled engine would probably put it right on the edge of blowing up the engine, or putting a hole in the piston tbh. it's a price to go fast. EFI will help, by ensuring you never run rich.

But I'd install an electronic fuel shutoff valve, aswell as an oil temperature gauge, both for safety reasons.

[roundhouse]

I always thought it would be cool. I have seen several vids in the past of guys with pit bikes who turbo them.

[zanoknight]

I always thought it would be cool. I have seen several vids in the past of guys with pit bikes who turbo them.

Honestly what made me want to do it was this barbie gokart that had a turbo. It's an awesome video

[pete]

So before I go too far deep into the rabbit hole I have a few questions.

First: is there any benefit on adding a small turbo on a small engine?
Second: I have the aftermarket oil cooler already installed on my hawk, can I tap into that to cool my turbo?
Lastly: is it more beneficial to make it a blow through or suck carb?

Thanks to everyone who responds. I kind of want to try this over the winter. I am graduating in December and I will have a lot of free time and extra cash from graduation gifts.


you can't blow though with the carb...hows the fuel going to come up from the main jet when pressure is
going down into the fuel blow blowing the fuel out the over flow all over the motor.. could also make
a kool bubbly sound in the tank...

can build a presurised box around the carb.... still have the kool bubbly sound... i quess you will need a fuel pump...


you use the oil to lube the turbo bearing not cool it...



...

[bogieboy]

you can't blow though with the carb...hows the fuel going to come up from the main jet when pressure is
going down into the fuel blow blowing the fuel out the over flow all over the motor.. could also make
a kool bubbly sound in the tank...

can build a presurised box around the carb.... still have the kool bubbly sound... i quess you will need a fuel pump...


you use the oil to lube the turbo bearing not cool it...



...

Pete, you can infact do a blowthru carb. Requires careful orifacing of the vent of the carb into the intake tract (so the fuel bowl is also under pressure, slightly higher than the intake charge)

But it can be done....LOL

[JerryHawk250]

As bogieboy stated it can be done with a carb but I wouldn't recommend it. Very tricky tuning. To easy to have it run lean and then Boom! If you are going to do a turbo , EFI is the way to go. You have to be able to control fuel mixture under boost. I've had plenty of experience in tuning with turbos on car engines. The thought has crossed my mind on doing it with the Hawk but the cost killed that idea quick. If i'm going to sink that kind of money on a complete turbo system it won't be on a 250cc engine.

I'll sit back and grab a bag of popcorn and watch this one.

[Tashka]

i encourage you to do this though, I'd really love to see it.

[Weldangrind]

i decided a supercharger would be better for an off-road purpose bike(less intense power bands generally, don't have to get it spooled up), but the biggest thing stopping me is the price.

A smog pump can be used for a small engine blower; check it out on Youtube. The issue on a bike is figuring out how to spin it. You could machine a hole in the left side cover and figure out how to adapt a pulley to the end of the crank, but it would be cumbersome. The good news is that smog pumps are cheap.

Here's a fun vid of a smog pump installed on a scooter:
https://www.youtube.com/watch?v=XuQ3FaAmNro

[roundhouse]

I would like to see if that actually worked. I wonder how many CFM a smog pump can push?

[wheel spinner]

I am in favor of superchargers over turbos.... I have had several cars with superchargers and lowered the pullies to make them faster... my wife has blown several Turbos in the past... but never a supercharger... Now.. Fitting this on a bike... hmmmmm I would need to think hard about this one... but trust me.. it can be done... but you need a shaft to spin the pully... you would need to take the crank to a machinist... a good one... and have him fabricate a shaft on the end of it.. and need to make a hole through the crankcase... and go from there...... a lot of trial and error... :hmm:


I am sure that a motorcycle speed shop will have a good idea if they haven't already done it....

[timcosby]

i have a pic of one on a ktm if i can find it ill post

[Huck369]

I'm in favor of the Smog pump blower ideal, been wanting to try that for years....

[timcosby]

kinda custom but still a ktm engine.

[NzBrakelathes]

I would love to try this but that kinda project is out of my comfort zone. I’d rather do an engine swap then trying to convert this one from carb to EFI.

Here's a cheap deal! I saw this for sale in China via a local clearance guy

[roundhouse]

NO WAY< that is a great deal.

too good to be true?

[NzBrakelathes]

NO WAY< that is a great deal.

too good to be true?

I live in China and YES it is true, If not sold I can have that sitting in my shop for about $500 but I cannot legally ride it in China as not compliant here.

[Tashka]

that's insanely cool. I'd want one for sure...