Big port head flow tuning
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04-20-2009, 02:01 AM
Post: #1
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Big port head flow tuning
Hello.
I'm having a '84 JDM Celica AA63 (coupe) with big port MAP-sensored 4AGE. It has miled 160k kms and now it's time to have a good rebuild and free some horses. I want to find some hidden horses in my head, so please, help me Port enlargement is defo not what the big port head needs. Did anybody have ported or flow tuned the big port head? What have you done there, except removing some marks of factory castings and meeting parts to each other? I know that polishing itself doesn't get any result except the fuel flows on the walls and the result is lean mixture and crappy power. |
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04-20-2009, 10:44 PM
Post: #2
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Big port head flow tuning
A few weeks back I did a bit of porting... MILD porting!. Here is the work I just did....
Raw, unworked ports on left........................................................ blended ports on the right Now besides cleaning and blending around the valve seat, the exhaust ports are usually rather rough. Here again, blending is the call. This time finished ports are below raw ones Finally, for a street port, blending and doing mild shaping to the exhaust port as it approaches the manifold. Not BIGGER, but shped to allow the flow out as easy a path as possible The above photos are of one exhaust port, each view focuses on one valve. *IF* you are unsure of what to do... doing nothing is superior to a bad porting job Dan - You can | .... OR you can ask for help!!! OST Porting service - http://hachiroku.net/forums/showthread.php?t=19991 |
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04-21-2009, 02:33 PM
Post: #3
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Big port head flow tuning
OST - I have basically done the same as your self with a spare head, mainly just for the sake of experience more than anything else. Would post some photo's but I am struggling taking them with my Iphone.
I have focused on the bowls and cleaned up / smoothed the various lips etc. I have also run down the ports cleaned up the casting marks and applied the appropriate finish to the ports. Out of interested have you noticed depressed areas in the ports just before the valve (seems to be more prominent on the intake side)? Just wondering if this has an effect or if removing the various sharp edges and excess material and smoothing the bowl out will be suffcient and aid flow? http://www.eight-six.co.uk - read the blog! UK AE86 Forum - http://www.phpbber.com/phpbb/index.php?m...ghtsixcouk |
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04-21-2009, 05:14 PM
Post: #4
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Big port head flow tuning
eight-six Wrote:Out of interested have you noticed depressed areas in the ports just before the valve (seems to be more prominent on the intake side)? Actually what I believe you are talking about is a ridge that is created because the valve seat isn't perfectly centered. The valve seat needs to be ground so the seat and port wall do not have a ridge. When doing streetport work... remember flow direction, some ugly things need more work than others Dan - You can | .... OR you can ask for help!!! OST Porting service - http://hachiroku.net/forums/showthread.php?t=19991 |
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04-21-2009, 08:31 PM
Post: #5
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Big port head flow tuning
Some nice work there OST, could you tell me what tools you used to do the grinding ?
An analogue brain in a digital World |
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04-21-2009, 09:31 PM
Post: #6
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Big port head flow tuning
totta Crolla Wrote:Some nice work there OST, could you tell me what tools you used to do the grinding ?Give away my secrets Dremel, and flex shaft 1) alum oxide grinding stones for removal of material(coarse), 2) Sanding bands for lighter removal, and 1st, and 2nd step smoothing after stone use. Available in coarse, medium, and fine grit(60, 120, 240) I don't use the 240, 3) Abrasive "puffs" no not POOFS, puffs. I prefer medium grit, but medium is only available with a fine. HOURS of knowing what I can do... and what I cant. Knowing that I can seriously screw-up if not done correctly. I'm talking MORE than hitting a cooling jacket... Dan - You can | .... OR you can ask for help!!! OST Porting service - http://hachiroku.net/forums/showthread.php?t=19991 |
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04-21-2009, 09:50 PM
Post: #7
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Big port head flow tuning
These photos are all thanks to our Aussie friends down unda! Dan - You can | .... OR you can ask for help!!! OST Porting service - http://hachiroku.net/forums/showthread.php?t=19991 |
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04-22-2009, 10:01 PM
Post: #8
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Big port head flow tuning
*IF* you are unsure of what to do... doing nothing is superior to a bad porting job
Thanks Dan, duly noted :wink: An analogue brain in a digital World |
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04-23-2009, 08:36 AM
Post: #9
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Big port head flow tuning
Hopefully this explains it all example #1) this is an intake port. As such the red area is the REALLY bad area because it restricts flow into the cylinder. The yellow area isn't as significant, but a proper streetport blends the entire area. example #2) this is now an exhaust port as such the yellow area is the really bad area, because it restricts flow out of the cylinder. the red area isn't as significant, but a proper streetport blends the entire area Dan - You can | .... OR you can ask for help!!! OST Porting service - http://hachiroku.net/forums/showthread.php?t=19991 |
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04-23-2009, 11:59 AM
Post: #10
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Big port head flow tuning
Yeah, man! Thanks for points!
I'm thinking about removing these boundaries also as there are no ones on Formula Atlantic heads... and then slice some mms from the bottom of the head to have 11:1 compression... 1972 Ford Taunus (drift project) 1984 Toyota Celica AA63 (4AGE, 5MT, IRS) |
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