Dyno tested....Mastermind's ported 261cm vs Stock 261cm Gotta see this one.

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chadihman

chadihman

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graph_zpse67rd14d.jpg


I'm in awe of how the HP hangs on in the high rpms. Thats 2.362 HP more than the stock 261 at 13k. Has a pretty stable max HP between 10,000-11,500 rpm.
 
Mastermind

Mastermind

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That really is pretty impressive. Not a huge gain at 9000.......but as RPM increases the spread gets insane.

I wish I had the knowledge to explain what we are seeing, but I don't. I made a hairy guess......and it paid off.

The way I stumbled onto what I'm doing to this saw is from studying a lot of different saws, and their factory timing numbers.

Thinking about the fresh air that is brought into the transfer passages, and what happens to that air when the transfers first begin to open, then looking at a 562s timing numbers, made me think..........I wonder what would happen if I raised the ever loving hell out the transfers in this saw?????

That's the best I can do for an explanation.
 
chadihman

chadihman

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That really is pretty impressive. Not a huge gain at 9000.......but as RPM increases the spread gets insane.

I wish I had the knowledge to explain what we are seeing, but I don't. I made a hairy guess......and it paid off.

The way I stumbled onto what I'm doing to this saw is from studying a lot of different saws, and their factory timing numbers.

Thinking about the fresh air that is brought into the transfer passages, and what happens to that air when the transfers first begin to open, then looking at a 562s timing numbers, made me think..........I wonder what would happen if I raised the ever loving hell out the transfers in this saw?????

That's the best I can do for an explanation.
How about I send you a couple 261 cylinders with my 261 for my 8/28 appointment? You do three different port jobs of your choice then I'll test each one.
 
chadihman

chadihman

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I hope a 461 headed ur way Chad has a hang up about it!!!! Lol
Its sitting in a box in my garage right now along side with a special 460 in a box. I've been doing some 660 tests lately. I'll fit the 461 in tonight or tomorrow night and get it shipped out asap. the 460 will hopefully get tested on tuesday.
 
Mastermind

Mastermind

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How about I send you a couple 261 cylinders with my 261 for my 8/28 appointment? You do three different port jobs of your choice then I'll test each one.

I'd do all three exactly the same Chad. I've done over 50 of these 261s......and have tested every combination of numbers you can imagine. This is as good as it gets.
 

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