Turbocharging carbureted petrol 2 stroke engines

  • #51
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Hi, please remain on topic, we speak about turbocharging 2 stroke gas engine carbureted. The primary question is if the picture set up can really do more hp than the naturally aspirated. Gas mileage is not important we speak only about hp gain between the same set up with and without a turbo.
Am6 turbo.jpg
 
  • #52
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Hi, please remain on topic, we speak about turbocharging 2 stroke gas engine carbureted. The primary question is if the picture set up can really do more hp than the naturally aspirated. Gas mileage is not important we speak only about hp gain between the same set up with and without a turbo. View attachment 269436
I'm with you all the way on this one, I was wondering where things were starting to go myself.
 
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  • #53
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Online I have found a research(???) conducted by some Indian students on the 2 stroke turbo but there aren't many details.
In this research carb is blow trough and there is not an expansion chamber.
Is not the set up of the previous image I have attached but can help us to understand something.

Here the link of the research:

https://www.academia.edu/37091140/Turbocharged_2_Stroke_Single_Cylinder_98_2cc_Si_Engine

(but we're is the turbo oiling system in this research? )

IS this research valid?
 
  • #54
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I'm with you all the way on this one, I was wondering where things were starting to go myself.
Yes the question simple

For example:
Turbocharged 2 stroke (reed valve, or piston port) carbureted: 5hp

Turbocharged 2 stroke (reed valve, or piston port) carbureted: hp?? More or not??

Same engine same parts not turbo and with turbo (just carburetion setting properly for each set up)
 
  • #55
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We can understand this, this thread is really costruptive and interesting!!:muscle:


Luth
 
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  • #56
Tom.G
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...costruptive...:DD
And obviously rather creative!
 
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  • #57
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Anyone have seen the Indian research I've posted? What do you think about it?
 
  • #58
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Anyone have seen the Indian research I've posted? What do you think about it?
I read it and it looks like they are blowing through the original carbs. The picture wasn't clear enough to see if they had a way to pressurize the float bowls with boost pressure. If they weren't they would get bad results.
 
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  • #59
Baluncore
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Anyone have seen the Indian research I've posted? What do you think about it?
Couldn't download it without giving access to my address book. So no go.
 
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  • #60
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Couldn't download it without giving access to my address book. So no go.
Don't download it you can just watch it online. Download it is required only if you want do it!
 
  • #61
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I read it and it looks like they are blowing through the original carbs. The picture wasn't clear enough to see if they had a way to pressurize the float bowls with boost pressure. If they weren't they would get bad results.
Yes its not detailed. But seems they have made some conclusions.I don't understand if it is a valid research or not.
 
  • #62
Baluncore
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IS this research valid?
No.
They claim to have designed their own turbo. But the unit pictured on the first page is a commercial unit with a manufacturers tag. There is no mention of balancing a turbo. There is no picture of their turbo installed on a bike.

They claim to have a waste gate on the exhaust manifold to limit the charge.

There is so much that appears to be imagined in this paper.
Maybe the Prof needed to be lead author on another publication, so he got a student to write it.
 
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  • #63
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No.
They claim to have designed their own turbo. But the unit pictured on the first page is a commercial unit with a manufacturers tag. There is no mention of balancing a turbo. There is no picture of their turbo installed on a bike.

They claim to have a waste gate on the exhaust manifold to limit the charge.

There is so much that appears to be imagined in this paper.
Maybe the Prof needed to be lead author on another publication, so he got a student to write it.
Like I suspected! Completely agree with you on this! thanks Baluncore.
So there are no details. I'll try to search again around the web but there is nothing at all. Bluechipx reported his positive experience (thanks again) but to understand we need more detail.
There are some sled guys forum that speaks about it but some say it work and give hp and other not.
Here 2 YouTube interesting video link the first about the impossibility to turbocharge a 2 stroke the second is the Rotax E-tec turbo 2 stroke. One the opposite of the other.

(but it is an EFI not carbureted like I mean)

The video of the impossibility in supercharging two stroke:

The video of a 2 stroke turbocharged available on the market (EFI not carb)

In the second video is possible because the fuel injection is done after the piston cover the exhaust post. But in a carbureted 2 stroke motor how can it work?
 
  • #64
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FWIW, I bought a Haltech electronic fuel injection system for my Mercury outboard. I had the dealer come over and he had me bring it up to various rpm's under full load on my dyno while he monitored his instruments and set up the fuel curve. $1000 system (still have it, anybody interested?) With equal boost as carbs you could give it any fuel mixture you wanted but it never worked as well as Mikuni draw through carbs did for some reason. Go figure. Maybe I just got lucky on my first attempt with the draw through system because nothing I changed afterwards did anything but decrease performance, sometimes by a lot.
 
  • #65
Baluncore
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I took a look at the two stroke engines used in the chainsaw equivalent of a drag race, the (Stihl) Hot-Saws competition. Engines are limited to a single cylinder, of any capacity. They must have a tuned exhaust and a chain guard.
The limit is how much weight and power the operator can control, not the maximum power from a standard capacity engine. That partly explains why hot-saws are not turbocharged, although one competitor is named "Turbo".
Turbo lag may also be a problem. An assistant has one minute to start and warm up the competitor's saw. The three competition cuts can then be completed in less than 6 seconds.

It is easy to lose sight of the bigger picture while focused on the technical challenges of turbocharging a two stroke engine.
 
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  • #66
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I took a look at the two stroke engines used in the chainsaw equivalent of a drag race, the (Stihl) Hot-Saws competition. Engines are limited to a single cylinder, of any capacity. They must have a tuned exhaust and a chain guard.
The limit is how much weight and power the operator can control, not the maximum power from a standard capacity engine. That partly explains why hot-saws are not turbocharged, although one competitor is named "Turbo".
Turbo lag may also be a problem. An assistant has one minute to start and warm up the competitor's saw. The three competition cuts can then be completed in less than 6 seconds.

It is easy to lose sight of the bigger picture while focused on the technical challenges of turbocharging a two stroke engine.
Interesting! Yes, I think turbo lag maybe more evident than a turbo 4 stroke, a correct tuned pipe maybe reduces a bit this problem. Two stroke (50cc 100cc 125cc 250cc) have a different power and torque curve than a 4 stroke and also in n/a the low rpm often have a "naturally lag". The low rpm are not the "strong point" of these engines.

Here another video about a 125cc 2 stroke turbo carbureted tested on the bench.

Maybe real results or fake????
 
  • #67
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Nobody is interested anymore?

What a pity it was an interesting topic.
 
  • #68
Baluncore
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It is certainly an engineering challenge, and an entertaining novelty for the spectators.

It is interesting that when double the power is needed from a two stroke engine, it can be achieved with a turbocharger. But that is really only justified when the rules of a sport specify a maximum engine capacity, and there is a competitor who can benefit from more power than a tuned inlet and exhaust could provide.

Unfortunately fuel costs and emissions rise to the point where it would not now be approved for regular use. If it became common, the rules of the game would be changed to level the playing field.
 
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  • #69
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It is certainly an engineering challenge, and an entertaining novelty for the spectators.

It is interesting that when double the power is needed from a two stroke engine, it can be achieved with a turbocharger. But that is really only justified when the rules of a sport specify a maximum engine capacity, and there is a competitor who can benefit from more power than a tuned inlet and exhaust could provide.

Unfortunately fuel costs and emissions rise to the point where it would not now be approved for regular use. If it became common, the rules of the game would be changed to level the playing field.
Yes, but mine is just a simple test to understand if really a two stroke turbo can produce more power than the same aspirated.
 
  • #70
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50cc 2 stroke do a complete cycle anytime so could be correct match a turbo used in a 100cc 4 stroke?
 
  • #71
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50cc 2 stroke do a complete cycle anytime so could be correct match a turbo used in a 100cc 4 stroke?
Noboby know this? 😭
 
  • #72
jack action
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50cc 2 stroke do a complete cycle anytime so could be correct match a turbo used in a 100cc 4 stroke?
Yes, but "could be" are the appropriate keywords.
 
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  • #73
Baluncore
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50cc 2 stroke do a complete cycle anytime so could be correct match a turbo used in a 100cc 4 stroke?
There are too many words missing. I could not understand the question.
 

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