Fungus
Part of things
Posts: 960
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Feb 28, 2010 14:31:29 GMT
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Well, after a quick look through Wikipedia I am completely confused by how porting or polishing can effect performance. I know that a completely smooth ports are bad for perfomance, and bigger ports are not always better, but I am still finding it really hard to understand all the technical stuff that comes into the equation ie. turbulance and all that  So can anyone simplify any of this? Also, all the pages that I have found explain what not to do, but none of them actually say how to improve, say, low end torque by modifying the ports and what not  Thanks in advance |
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Last Edit: Feb 28, 2010 14:31:48 GMT by Fungus
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Feb 28, 2010 14:51:03 GMT
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i doubt you will get the info on here unless someone does it for a living.
i used to have a few books on it, its about balance between flow and speed, tumble, swirl etc.
Buy the books, you will learn what you want
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nutter81
Part of things
I joined facebook so i could talk to the missus
Posts: 928
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Feb 28, 2010 16:03:57 GMT
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Fungus
Part of things
Posts: 960
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Feb 28, 2010 16:14:27 GMT
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Thanks, that page is really helpful!
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nutter81
Part of things
I joined facebook so i could talk to the missus
Posts: 928
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Feb 28, 2010 17:43:58 GMT
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glad i can help
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Feb 28, 2010 17:51:57 GMT
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depends on the age of the design of the engine. modern engines will generally be more efficient off the shelf than one designed years ago. David Vizard has written a fair few articles an books of the years which might help www.gofastnews.com/board/technical-articles/1091-porting-school-5-identifying-primary-restrictions.htmlafter reading his work I decided that the inlet ports on my polo engine were too big for the way I drive my car, so I made them smaller. I ended up with an increase in low end torque and top end power. |
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Last Edit: Feb 28, 2010 17:54:34 GMT by optima21
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Fungus
Part of things
Posts: 960
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Feb 28, 2010 19:03:10 GMT
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Really? was there much sacrifice in mid range?
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Feb 28, 2010 19:10:11 GMT
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David Vizard covers the subject in great detail in How to modify your A series engine.
Even if you aren't tuning an A series it has more than enough info to carry over to other cars.
From what I remember, you wan't smooth ports but dull rather than chrome finished. You want them to be smooth enough for the fuel/air to travel unrestricted by rough castings but not so smooth that the fuel condenses into droplets.
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Feb 28, 2010 19:14:24 GMT
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Good link that, cheers! Good to see you're still about too! Nearly got my car running with that engine I had off you. If you do it yourself, be very careful, it's surprisingly easy to make a head completely useless. It's easier to take more away later than, put it all back! |
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Feb 28, 2010 21:04:22 GMT
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Really? was there much sacrifice in mid range? no its so much smoother to drive and pulls better throughout the rev range. people talk about fitting cams which just tends to push the peak torque and power up the rev range at the expense of the the low down driveability. with decent headwork, you should find that you get gains at all speeds |
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