revtothelimit - motorbike forum

One of the lads on PB forum bought 2... yes 2... Petronas FP1s..... this had 0 miles on the clocks at the start of the session... brand spanking new, his first thought..

"trackday"

weeksy wrote: Thu Jul 08, 2021 6:34 am One of the lads on PB forum bought 2... yes 2... Petronas FP1s..... this had 0 miles on the clocks at the start of the session... brand spanking new, his first thought..

"trackday"

I know a man that has a few more. The vicar that found them all and is now selling them.

Woo, turbo

I'm trying to work out what turbocharging a two stroke would do, pressurise the crankcase is about the best I can come up with.

Le_Fromage_Grande wrote: Wed Jul 14, 2021 4:49 pm I'm trying to work out what turbocharging a two stroke would do, pressurise the crankcase is about the best I can come up with.

And would need a spannie more than normal.

What a pointless waste of £6K's worth of bike.

Le_Fromage_Grande wrote: Wed Jul 14, 2021 4:49 pm I'm trying to work out what turbocharging a two stroke would do, pressurise the crankcase is about the best I can come up with.

Its like running it somewhere with higher atmospheric pressure innit? Think about what would happen if you ran one somewhere there was very low atmospheric pressure (like up a mountain) and what would happen, that might be easier to visualise.

Mr. Dazzle wrote: Wed Jul 14, 2021 6:51 pm

Le_Fromage_Grande wrote: Wed Jul 14, 2021 4:49 pm I'm trying to work out what turbocharging a two stroke would do, pressurise the crankcase is about the best I can come up with.

Its like running it somewhere with higher atmospheric pressure innit? Think about what would happen if you ran one somewhere there was very low atmospheric pressure (like up a mountain) and what would happen, that might be easier to visualise.

That's the case with a 4 stroke or 2 stroke diesel, but with a conventional 2 stroke the fuel, air, oil mixture is sucked into the crankcase by the piston going up, then pushed/sucked into the combustion chamber by the piston coming down, if you pressurise the crankcase it will make it harder for the piston to come down, and it won't increase compression in the combustion chamber.

Le_Fromage_Grande wrote: Wed Jul 14, 2021 7:20 pm if you pressurise the crankcase it will make it harder for the piston to come down, and it won't increase compression in the combustion chamber.

It will, you just have to hope/ensure that the extra bang you get from shoving more fuel outweighs the above. It's not too dissimilar with a 'conventional' 4 stroke turbo, you chuck more air in and hence make the engine work hard pushing it all about and compressing it. You just need to be sure the cons are outweighed by the pros.

Turbocharged 2 strokes have been around forever - most piston engines have haven't they? You can buy a turbo 2 stroke off the shelf and the idea was played around with a lot in aero engines before WW2.

https://powersportsbusiness.com/top-sto ... nowmobile/

https://www.snowmobile.com/trails/polar ... gine-65385

Le_Fromage_Grande wrote: Wed Jul 14, 2021 7:20 pm

Mr. Dazzle wrote: Wed Jul 14, 2021 6:51 pm

Le_Fromage_Grande wrote: Wed Jul 14, 2021 4:49 pm I'm trying to work out what turbocharging a two stroke would do, pressurise the crankcase is about the best I can come up with.

Its like running it somewhere with higher atmospheric pressure innit? Think about what would happen if you ran one somewhere there was very low atmospheric pressure (like up a mountain) and what would happen, that might be easier to visualise.

That's the case with a 4 stroke or 2 stroke diesel, but with a conventional 2 stroke the fuel, air, oil mixture is sucked into the crankcase by the piston going up, then pushed/sucked into the combustion chamber by the piston coming down, if you pressurise the crankcase it will make it harder for the piston to come down, and it won't increase compression in the combustion chamber.

Don't contradict him. He's a self confessed expert in 2 strokes.

Fair few trains are powered by turbocharged 2-stroke diesel engines.....

v8-powered wrote: Wed Jul 14, 2021 8:08 pm Fair few trains are powered by turbocharged 2-stroke diesel engines.....

Indeed - turbo 2 strokes are really really common. But generally they don't have pressurised crankcases, they have 4 stroke-esque cranks and 'open' cases. In that situation you must turbo/supercharge 'cause there's nothing else to 'push' the air in.

I'm guessing cheesy is asking why'd you'd bother turboing a bike style 2 stroke with transfer ports but as above the idea was thought up years and years ago. You can now buy an engine like that off the shelf.

v8-powered wrote: Wed Jul 14, 2021 8:08 pm Fair few trains are powered by turbocharged 2-stroke diesel engines.....

They are nothing like petrol 2 stroke engines.

Mr. Dazzle wrote: Wed Jul 14, 2021 8:11 pm

v8-powered wrote: Wed Jul 14, 2021 8:08 pm Fair few trains are powered by turbocharged 2-stroke diesel engines.....

Indeed - turbo 2 strokes are really really common. But generally they don't have pressurised crankcases, they have 4 stroke-esque cranks and 'open' cases. In that situation you must turbo/supercharge 'cause there's nothing else to 'push' the air in.

I'm guessing cheesy is asking why'd you'd bother turboing a bike style 2 stroke with transfer ports but as above the idea was thought up years and years ago. You can now buy an engine like that off the shelf.

FFS. Thats diesel engines. Nowt like a petrol 2 stroke engine.

But carry on.

Diesel engines are a lot like petrol except for the ignition system and consequent heavier engineering....most diesel engines can be petrolised, doesnt work well the other way round.

David wrote: Wed Jul 14, 2021 8:19 pm Diesel engines are a lot like petrol except for the ignition system and consequent heavier engineering....most diesel engines can be petrolised, doesnt work well the other way round.

Do you know how a 2 stroke petrol engine works?

Yorick wrote: Wed Jul 14, 2021 8:15 pm

Mr. Dazzle wrote: Wed Jul 14, 2021 8:11 pm

v8-powered wrote: Wed Jul 14, 2021 8:08 pm Fair few trains are powered by turbocharged 2-stroke diesel engines.....

Indeed - turbo 2 strokes are really really common. But generally they don't have pressurised crankcases, they have 4 stroke-esque cranks and 'open' cases. In that situation you must turbo/supercharge 'cause there's nothing else to 'push' the air in.

I'm guessing cheesy is asking why'd you'd bother turboing a bike style 2 stroke with transfer ports but as above the idea was thought up years and years ago. You can now buy an engine like that off the shelf.

FFS. Thats diesel engines. Nowt like a petrol 2 stroke engine.

But carry on.

Did you actually read any of the links?

Mr. Dazzle wrote: Wed Jul 14, 2021 8:24 pm

Yorick wrote: Wed Jul 14, 2021 8:15 pm

Mr. Dazzle wrote: Wed Jul 14, 2021 8:11 pm

Indeed - turbo 2 strokes are really really common. But generally they don't have pressurised crankcases, they have 4 stroke-esque cranks and 'open' cases. In that situation you must turbo/supercharge 'cause there's nothing else to 'push' the air in.

I'm guessing cheesy is asking why'd you'd bother turboing a bike style 2 stroke with transfer ports but as above the idea was thought up years and years ago. You can now buy an engine like that off the shelf.

FFS. Thats diesel engines. Nowt like a petrol 2 stroke engine.

But carry on.

Did you actually read any of the links?

Yes. They contradict all you said.

the world’s first factory-built 2-stroke turbo engine. 

Your ignorance and perseverance is staggering.