I've seen several people mention using his break-in methods, and was wondering if anyone had tried the port work he suggests?

If you've never seen it before, here a link to one of his articles:

http://mototuneusa.com/super_sonic_nozzle.htm

Mark

 

It makes sense, but I'd assume that eventually you'd reach a high enough rpm, and be trying to flow too much air for those smaller ports. And I wonder how it holds up in FI emvironments. It sounds like the same old story of top-end/bottom-end trade off. Adjustable port sizing would be the way to go. Maybe some sort of diaphram that drops out of the way at a certain rpm, he he he.

 

Could be that there's a limit somewhere, but the guy was using the technique in engines that turned 15k RPM after having restricted the incoming stream to 65% of the intake valve diameter.

From what I read, once the air hits supersonic velocity, resistance goes way down. I haven't read what the upper limits might be.

Another benefit is an engine which is less 'peaky' -- a broader, flatter torque curve.

All of which is why I was interested to hear if anyone had actually tried this with on of our favorite engines... The technique has been used on motorcycles with displacements not so far from what we're looking at, so it seems likely to produce decent results.

Thx,

Mark

 

heheh. motoman just mind be refering to larry's old 1980 car mag articles. see.

http://theoldone.com/articles/

scroll to bottom look:

February 1986 Hot Rod - Talking Heads part 1 (317 KB)
February 1986 Hot Rod - Talking Heads part 2 (306 KB)
February 1986 Hot Rod - Talking Heads part 3 (316 KB)
February 1986 Hot Rod - Talking Heads part 4 (308 KB)
February 1986 Hot Rod - Talking Heads part 5 (366 KB)
February 1986 Hot Rod - Talking Heads part 6 (342 KB)
February 1986 Hot Rod - Talking Heads part 7 (230 KB)

January 1986 Circle Track - Commentary by Larry Widmer (323 KB)

August 1985 Circle Track - Swirl Power part 1 (287 KB)
August 1985 Circle Track - Swirl Power part 2 (338 KB)
August 1985 Circle Track - Swirl Power part 3 (351 KB)
August 1985 Circle Track - Swirl Power part 4 (342 KB)
August 1985 Circle Track - Swirl Power part 5 (346 KB)

July 1985 Hot Rod - The Soft Head part 1 (310 KB)
July 1985 Hot Rod - The Soft Head part 2 (313 KB)
July 1985 Hot Rod - The Soft Head part 3 (332 KB)