Some interesting trumpet changing results

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Some interesting trumpet changing results

Postby RomanV » Wed Dec 21, 2011 2:49 pm

As per this thread here, some great information posted up by Tim Duncan from http://ghettogarage.org/

This is on a beams motor, so the overall intake runner length is not directly comparable to a blacktop engine.

BUT it is very interesting to see how the change in trumpet length basically shifts the whole curve (especially the dip) up and down the rpm range.

Especially so, since theoretically a longer tube should give a lower rpm at which they are beneficial...

However I guess that's explained by the longest trumpets of the lot are just on the verge of using perhaps the 2nd or 3rd reflection, lower rpm using the 4th or 5th perhaps.

My previous workings showed that 110mm trumpets would be beneficial from 5-8000rpm, and shorter trumpets dont start working until a higher rpm. So it's interesting to see that this somewhat correlates.

Image

Image

I've never seen such a thorough back to back test of different ram tube lengths, for any quad throttle setup. 8)
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Re: Some interesting trumpet changing results

Postby strx7 » Wed Dec 21, 2011 3:26 pm

RomanV wrote:I've never seen such a thorough back to back test of different ram tube lengths, for any quad throttle setup. 8)


there is a good article on a forum somewhere by a guy with a Neon, who spent a few hours on a dyno using PVC pipe for ram tubes, the longer the tubes the fatter the midrange at the expense of a couple of HP up top

found the post
http://forums.neons.org/viewtopic.php?t=294784
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Postby Flannelman » Thu Dec 22, 2011 11:24 pm

By lengthening the intake, the harmonic has more energy to enter the cylinder with a higher pressure than with the small length.

The fact that the longer length works on this set up comes from all other components working together. Cam timing, exhaust components, even ignition timing contribute to the increase.

I would love to hear an audio of the small length and long to see if there is a sound difference between the two
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