kpr

Inlet trumpet dyno testing

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17 hours ago, Roman said:

I've got a new scheme I might print for you to try. 

Basically a runner with a smaller inner entrance but then a chamber area around the perimeter to see if you can amplify a reflected wave back down with minimal energy loss / max doorts


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Sweet  keen to give them  a jam.

I also tried a runner inside a runner the other day,   but my sizes were off. so didn't give the results i hoped.  will get a pic tomorrow  of what i was attempting

 

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So,  black pipe is 37mmm id.      orange 51mm.       below chart  is with the  pipe slid in and out like pic one and pic 2 .   red being out.  blue being in.  the pipe wasn't slid out as much as in pic one.  but it didn't make a lot of difference how far out it was.  What i was trying to do here, is to see if a 2 stage,  small then big diameter variable setup is worth attempting.  Obviously my pipe sizes are off and the outer would need to  be a lot bigger.  Since loosing 15kw over normal setup up to,  and down low is acting like a smaller diameter pipe still.

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green line added is the big 51-62 pipes as per bottom pic

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  getting rid of the  outer 51mm run.   leaving the   37mm in the position of pic 2  vs the big 51-62.     Would likely be very hard to combine the 2 whilst having a working mechanical 2 stage without screwing up the flow on the high rpm side.  but could be worth chasing with some different sized fixed setups to see if its possible.      I would set it up opposite to what i've done here. so the inner smaller runner was fixed. the outer would slide back towards the engine creating a higher flowing shorter path.

 

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Doesn't look much in the above chart,  so some numbers on this one.   pretty decent gain at those low rpm's 534930984_bdogv37mmnumbers.jpg.ee08c0d7d8c93b810d7ca60ded20d709.jpg

 

 

 

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Yup.  basically if i can get a setup that looks the same as that to match the top end of what i have now.    then at low rpm have the outer bellmouth slide up against the bottom of the inner bellmouth. which will only allow flow through the smaller middle runner, increasing  low end power

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black all fixed  ,   red bit slides  up  for low rpm position

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or   maybe like a slide throttle setup that sits at the bottom  and blocks the outside runner at low rpm .   so the runner would be fixed setup  and slidy bits would do the work of selecting high/ low rpm

inside only

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both

 

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Edit:    / TVIS

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just 4.   mounted in the throttles not far back from stock location

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So, does this mean that wave tuning is more important in the low/mid range and up top is all about mass flow? 

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42 minutes ago, Truenotch said:

So, does this mean that wave tuning is more important in the low/mid range and up top is all about mass flow? 

Not really, length works at both ends. so does diameter.   Trying to combine the 2.     on my first lot of tests   best length for bottom end was  205mm.    best for top end was 165mm.  (or dropping way back to 65mm)  but gains not worth the effort of a variable setup
But combine the 205mm runner with with smaller diameter gives even more bottom end.   then if can switch to the 165mm  at top end with big diameter  will have the gains from the airflow and correct length.  Looks more worth chasing..    Would be a 2 stage  variable length and diameter runner

Would need to retest the lengths for the small runner to confirm.     then see if its possible to get the power from the outer runner without the inner screwing the top end.

 

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4 hours ago, kpr said:

 

black all fixed  ,   red bit slides  up  for low rpm position

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Wellll shit thas a friggen cool idea! 

 

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Made even bigger taper runners.   the 2 on the left are new ones,  70mm - 52mm .  then the red tape one is the 62mm-51mm that worked best so far.    then the  51mm straight. 

 

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Will be a little while before can test them.   but the plan is to test them as is.     then  jam the small one down the middle.  see if its possible to make top end power with the 2nd pipe in the middle.

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Those graphs are hard to read on my phone.

Any chance of a spreadsheet showing the result from each tested configuration?

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Looks like there's something good happening here. How many KW difference at this point of the graph? Looks like 5ish kw to me. 

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@RUNAMUCK I posted some of the dyno graphs from the airbox testing a page back.  but can post them all here if you like.     

@Truenotch  Thats same graph as a page back.    Yeah about 5kw there.  but a dip the other way either side of it.  so just trading power from one place to another.  Hard to get a gain in one place without loosing it somewhere else.

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