kpr

Inlet trumpet dyno testing

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Earlier i posted in the 3d printing thread.   Was going a bit off topic  so,   here we are. 

On 04/05/2020 at 15:15, kpr said:

Hey  3d printing GC's,     Would anyone  be interested in designing and printing some itb trumpets?    Heres the catch  I cant really pay for them,  But  In a few weeks time i will be dyno testing a whole bunch of different shapes that i can make myself with ease out of pvc  and the likes.  plus some i have left over from other projects.

So  i will dyno test  your trumpets for free on my 4age,  which is very sensitive to inlet tuning. so will be a good test.  Will put all the results together in a video with dyno graphs.  Plus you get that internet fame if yours wins.

Ol mates  @Roman  @NicT and i talked about it some time ago but never really happened.

 

Will need to fit into the following dimensions.   keeping with the same length to make it a fair test.    they only need to last a few dyno runs, so anything slightly better than cheese will work. long as they don't fall apart and go in my engine.   heat isn't an issue, will be barely over room temp.

inlet - 54mm id
inlet - 60mm od -  can be a little bigger long as i can get a the silicone joiner over them,  maybe 62mm
87.5mm  throttle spacing (centre to centre)
75mm long

Have plenty of space in engine space, so no drama to run massive bellmouths that are cut into each other on the center throttles

 

 

2 hours ago, kpr said:

Been having a sharn  to @Roman    who suggested more room maybe useful.    so...

 

option  A:    75mm same as first one i suggested,  clamps  to my existing pipe with 54 to 52mm taper.

 

75.jpg.f202037c70edd774f1876470354425cc.jpg

 

Option B:   145mm.    52mm id, i will  make the spacer in red145.jpg.9ee865aca2c0335c3699e2beb3fe8ed4.jpg

 

 

Option C    185mm.    52mm id. replace whole trumpet to throttle

185.jpg.e8f0994200bdb31053dd5698c7674e16.jpg

 

 

 

 

@Ned @BobbyBreeze @Roman @NicT

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1 hour ago, Ned said:

tag me when you do plz as i wanna follow it :)
also, whats your preferred mounting method? bare tube, something barbed, dimensions of joinery/clamp/whatever?

silicone hose and hose clamp,   just need about 20mm of straight 60mm od.  nothing fancy.    will be clamping onto the shiny ali pipe bit

19.jpg

 

 

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Also they don't have to be 3d printed  will test anything that fits into the dimensions.  long as it doesn't fall apart! 

Also open to testing other stuff related or not

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Isn't there a formula for working out the curve of a velocity stack bellmouth? similar to that of how they work out sizing of trombones and of the like. 

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Different lengths for different torque curves for each cylinder to even it out over a wider rpm range? 

 

20200506_081346.jpg

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Love this idea! Looking forward to seeing what the dyno results are. Good chance to try some different styles and see what happens.

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10 hours ago, cletus said:

Different lengths for different torque curves for each cylinder to even it out over a wider rpm range? 

 

20200506_081346.jpg

Have avoided  doing this, mostly due to  being a tuning nightmare.   would have to tune individual cylinders. 

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Should get someone to print you some slidey trumpets/trombones so you can adjust the length as the revs go up

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  • Haha 1

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Just now, ajg193 said:

Should get someone to print you some slidey trumpets/trombones so you can adjust the length as the revs go up

There was a uk crowd way back that had some basic cones you twisted to make longer or shorter. Then once you settled on your chosen length for application you would make fixed ones with bellmouths etc.

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Just now, Bearded Baldy said:

There was a uk crowd way back that had some basic cones you twisted to make longer or shorter. Then once you settled on your chosen length for application you would make fixed ones with bellmouths etc.

Nah that's boring. They've gotta be dynamic.

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4 minutes ago, ajg193 said:

Should get someone to print you some slidey trumpets/trombones so you can adjust the length as the revs go up

Chrysler didn’t this for testing for the cross ram engines. My Forman has shown me pics of a mechanically injected 265 with a similar setup that was in a jet boat. Was quite a Rocket aparently. Used centrifugal weight to push them out. 

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13 years ago ^  wow.        problems were; 

4 cylinder vibration - would need some isolation from engine
too much friction -  needed better sliding system
travel-  would need to have a lot of travel to chase the harmonic which takes up a lot of room
actuation system - this was a basic 2 stage which was too slow.  ideally  would need fully variable with  with feedback and ecu control to match rpm.
air filter

so yeh got thrown out the window.   i could probably build something better these days.   but a lot of things to overcome to get it to work nice



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