Piston Window Porting for 2T Boost Ports

Рет қаралды 2,853

Күн бұрын

I added a window to the piston on my 70cc case inducted kit. Its pretty easy and allows the premix to flow much easier into the combustion chamber.
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Пікірлер: 18

@Avantone 10 ай бұрын

Nice mod, and should also help small end lubrication. You're braver than me; I would have gone for two windows and retained a little more skirt strength. Thanks for the videos 👍

@brandoncox7474 4 ай бұрын

Dude. Awesome. Not many ppl want to share secrets

@Corn-ped 4 ай бұрын

Yeah haha people are stingy

@TumTuhm 10 ай бұрын

I always window just because that’s how the original metrakit design was… I also cut the bridge out of the skirt. Seat dyno’d, no idea on impact. Most of the fresh charge is through the side transfers so 🤷‍♂️ Thanks for the hard work bud, I owe ya a coffee.

@Corn-ped 10 ай бұрын

Thank you! I believe the boost port pushes the mix that is already there from the transfered to the head. I feel like it makes a difference. Thank you for the coffees!

@TumTuhm 10 ай бұрын

@@Corn-ped yeah, and I think it was in Bell that the boost port should open first, pointing directly at the head, so that it will force expended mix out the exhaust port and improve fresh mix retention.

@tyleraugustine2436 10 ай бұрын

Ive seen the argument that by increasing flow through the boost ports while the ex port is open that the only real thing happening there is that you are losing more unburnt fuel through the exhaust at the scavenging stage. Personally I think you want a smaller amount of fuel to do the job without reducing efficiency. I have tried both ways and have had the best performance without a windowed piston but thats just me measuring by the seat of pants dyno. However I am just a common moron, and this is mainly just for the al gore rhythm. ❤ya 💋

@Corn-ped 10 ай бұрын

yeah I can see that. On this cylinder the boost ports are aimed aggressively towards the head so it should help with scavenging and the ex/transfer duration over lap is pretty minimal. Without a dyno and fuel measurement I don't know how you would tell if it worth it? If it feels faster I dont care too much about lower mpg. My black derbi has the window cut and this one didnt, the black derbi feels a lot better, but yeah my butt also is not the best dyno.

@HoarderErik 10 ай бұрын

great tech info!

@Corn-ped 10 ай бұрын

Wooooo

@maxpionier5241 10 ай бұрын

If you ever get access to a dyno, I would love to see you try your piston vs a normal one. I don't think you can see a big difference. Many garage tuners have their tricks, and maybe you are on to something here but I doubt it.

@Corn-ped 10 ай бұрын

I really wish I had a dyno so I could do testing. I m just going for it and testing it out.