The $350 reedcase engine.

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Z.hb71 said:
It will need added reed porting I would think, because you only reep the benefits of a reed with special reed porting.
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Not completely true. Intake timing is a bit better on reedcases because its not cutoff by the piston so you can get your maximum case fillrate also there is no air blowback because its cutoff by the reedsystem. It makes more rpm and torque however torque is USUALLY lower on reedcases because the greatest benefit is usually RPM.

This is why I used such a thin copper gasket for a tiny squishband. I know I won't be able to get the RPMs I want without a 5th port so I want to gain torque. More ports = more fuel and air and less piston ring friction.

Funny thing is while developing my 50cc reedcase I learned a quite bit about flowdynamics in the lower case that most people theorize about and most of it isn't true. Once you add a reed system that isn't restricted by let's say "an air leak" you will fill your topend more reliably. This is why most motorcycle and atv engines work this way just slightly different because the power is significant over piston intake which is only a thing because of money saving. The limits of 4 ports haven't been reached and I think my running video will be proof of that. TBH I'd like to loan this motor out to a youtuber if they find it interesting because I don't have a donor car to put it in right now and have decided that I don't want to strip my already built baja.
 
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This thread makes me wish I went reed over that red arrow:cautious:... so how much benefit with the reed case are you losing when you put a piston port top end on it?
 
Rep732 said:
This thread makes me wish I went reed over that red arrow:cautious:... so how much benefit with the reed case are you losing when you put a piston port top end on it?
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You can gain 20 to 40% more power its significant and the reason for it is if you think of it this way. Each port makes it less difficult for the piston to push the air from the case to the top end "there is a bit more to it then that but that's the big one". Windowed pistons that align with the ports essentially do the same thing. Make it less hard for fuel and air to reach the top end while allowing more of it and it does a better job of expelling exhaust. You need to be careful though because this changes the resistance of the engine. Having a higher exhaust port can gain you more rpms but you loose torque which is OK in these cases. Im more of a fan of split exhaust ports for wider and taller exhaust timing however thats very difficult to do.

Now if we were able to make 2 stroke pistons look like this "not the top part" https://cdn.shopify.com/s/files/1/0...s-k628m875-23069770435_2048x.jpg?v=1589387041
We would see way more power like adding an extra 10% ontop of porting which is what I would like to experiment with.
 
I went and did some looking on obr's website and im not sure if their pics are generic but their replacement piston for a full mod g320/g340 looks stock. Anyone with an obr reedcase here know if they did windows on their pistons?
 
Troopermaniac said:
Not completely true. Intake timing is a bit better on reedcases because its not cutoff by the piston so you can get your maximum case fillrate also there is no air blowback because its cutoff by the reedsystem. It makes more rpm and torque however torque is USUALLY lower on reedcases because the greatest benefit is usually RPM.

This is why I used such a thin copper gasket for a tiny squishband. I know I won't be able to get the RPMs I want without a 5th port so I want to gain torque. More ports = more fuel and air and less piston ring friction.

Funny thing is while developing my 50cc reedcase I learned a quite bit about flowdynamics in the lower case that most people theorize about and most of it isn't true. Once you add a reed system that isn't restricted by let's say "an air leak" you will fill your topend more reliably. This is why most motorcycle and atv engines work this way just slightly different because the power is significant over piston intake which is only a thing because of money saving. The limits of 4 ports haven't been reached and I think my running video will be proof of that. TBH I'd like to loan this motor out to a youtuber if they find it interesting because I don't have a donor car to put it in right now and have decided that I don't want to strip my already built baja.
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Send it to me I'll put it on the DYNO ! I got a chassis lol
Rep732 said:
I went and did some looking on obr's website and im not sure if their pics are generic but their replacement piston for a full mod g320/g340 looks stock. Anyone with an obr reedcase here know if they did windows on their pistons?
Click to expand...
I know ESP sells window ported pistons on DDM
 
Rep732 said:
I went and did some looking on obr's website and im not sure if their pics are generic but their replacement piston for a full mod g320/g340 looks stock. Anyone with an obr reedcase here know if they did windows on their pistons?
Click to expand...
OBR does on certain series of engines. Full mod means head, piston, and crankcase is not stock but to what extent do they modify pistons is the question. Just shoot em an email.
dougstar said:
I helped a mate rebuild his 32 obr reed and it was a stock piston??
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Don't tell me that. I got an SS and it better have windowed pistons for what I paid for it. Then again the engine does sound really good.
 
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