kpr Posted May 5, 2020 Share Posted May 5, 2020 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. Option B: 145mm. 52mm id, i will make the spacer in red Option C 185mm. 52mm id. replace whole trumpet to throttle @Ned @BobbyBreeze @Roman @NicT 2 Quote Link to comment Share on other sites More sharing options...
kpr Posted May 5, 2020 Author Share Posted May 5, 2020 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 2 Quote Link to comment Share on other sites More sharing options...
kpr Posted May 5, 2020 Author Share Posted May 5, 2020 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 Quote Link to comment Share on other sites More sharing options...
Popular Post Roman Posted May 5, 2020 Popular Post Share Posted May 5, 2020 Gonna go for a hoon on the full 185mm option. Will print these when printers working again. 16 Quote Link to comment Share on other sites More sharing options...
kpr Posted May 5, 2020 Author Share Posted May 5, 2020 now we talkin ! 1 Quote Link to comment Share on other sites More sharing options...
Carsnz123 Posted May 5, 2020 Share Posted May 5, 2020 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. 1 Quote Link to comment Share on other sites More sharing options...
Yowzer Posted May 5, 2020 Share Posted May 5, 2020 There is, but it never fits anywhere. 1 Quote Link to comment Share on other sites More sharing options...
Roman Posted May 5, 2020 Share Posted May 5, 2020 Hence the tipping Quote Link to comment Share on other sites More sharing options...
cletus Posted May 5, 2020 Share Posted May 5, 2020 Different lengths for different torque curves for each cylinder to even it out over a wider rpm range? 7 Quote Link to comment Share on other sites More sharing options...
kws Posted May 6, 2020 Share Posted May 6, 2020 Love this idea! Looking forward to seeing what the dyno results are. Good chance to try some different styles and see what happens. 1 Quote Link to comment Share on other sites More sharing options...
kpr Posted May 6, 2020 Author Share Posted May 6, 2020 10 hours ago, cletus said: Different lengths for different torque curves for each cylinder to even it out over a wider rpm range? Have avoided doing this, mostly due to being a tuning nightmare. would have to tune individual cylinders. 2 Quote Link to comment Share on other sites More sharing options...
ajg193 Posted May 6, 2020 Share Posted May 6, 2020 Should get someone to print you some slidey trumpets/trombones so you can adjust the length as the revs go up 3 1 Quote Link to comment Share on other sites More sharing options...
Bearded Baldy Posted May 6, 2020 Share Posted May 6, 2020 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. 1 Quote Link to comment Share on other sites More sharing options...
Yowzer Posted May 6, 2020 Share Posted May 6, 2020 Fuck yes! Quote Link to comment Share on other sites More sharing options...
Yowzer Posted May 6, 2020 Share Posted May 6, 2020 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. Quote Link to comment Share on other sites More sharing options...
Popular Post Spencer Posted May 6, 2020 Popular Post Share Posted May 6, 2020 Variable intake runners and high pressure outboard injection, the NA nerd dream setup haha. /ling 12 Quote Link to comment Share on other sites More sharing options...
Mark_Fleming Posted May 6, 2020 Share Posted May 6, 2020 https://www.youtube.com/watch?v=ONbxhT54nv4 1 1 Quote Link to comment Share on other sites More sharing options...
Carsnz123 Posted May 6, 2020 Share Posted May 6, 2020 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. 1 Quote Link to comment Share on other sites More sharing options...
Mark_Fleming Posted May 6, 2020 Share Posted May 6, 2020 Yammi V-Max's have the sliding trumpets too.... 1 Quote Link to comment Share on other sites More sharing options...
kpr Posted May 6, 2020 Author Share Posted May 6, 2020 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 5 Quote Link to comment Share on other sites More sharing options...
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