Author Topic: intake/crankcase stuff  (Read 2046 times)

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Offline 1manband

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Re: intake/crankcase stuff
« Reply #40 on: April 09, 2016, 06:36:44 am »
...found a couple of references that mentioned gains.  was going to put this all behind me.

eric gorr writes that..'effect will be unmistakable, engine will pull very strongly when it comes on the (sic. intake) pipe.'

engleman paper......'effect over very broad rpm range'

gorr goes on to write that mcculloch gave him some insight on how they test for this.  they affix a very short exhaust stub, to take the exhaust effects out.  they then cut and try differing lengths of intake pipes, to find which work the best.

this is somewhat contradictory to what nagao & shimamoto write......'finding an intake tuning alone (without considering exhaust) may or may not be optimum when an exhaust is affixed.'

another way to test intake tuning was in the engleman paper.  the lauson company, spun up a motor with a compression gauge attached to it.  the tuned intake gave higher compression numbers accross the board. 

would be just about impossible to spin up a saw motor to its power range?.....to use this method.

the lauson test showed about 10 psi gain minimum depending on length and area of inlet pipe tested.

.........
at this point, i am just going to get the formula more accurate by putting in a temperature and open end correction, and that is it, for less cut and try hopefully.

the motor manufacturer's most likely already incorporate intake runner tuning into their designs these days anyway for the rpms they spec out.
wondered just what would happen when the rpm range was changed with porting, etc.

have never read of a thread where someone tried working numbers out for these small high rev motors, so i thought would give it a go.  is what it is.

hiatus

 

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