Porting the VW/Audi 8v head with port energy discussion

General engine tech -- Drag Racing to Circle Track

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Carnut1
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Re: Porting the VW/Audi 8v head with port energy discussion

Post by Carnut1 » Sat Dec 02, 2017 1:45 pm

1202171028.jpg[/attachment]Smoke, we are on the same page. I am thinking I can get to all the areas of the runners with one cut and then enlarge the plenum. I will need to do some calculations on plenum size and figure the tapee. Stock runners have a taper and would probably work well if they were straighted and a bit larger. I was also thinking of just building a flange at the cut with 3/8" aluminum plate. Bolt on the plenum for street or bolt on the stacks for racing. Just an idea, customer has the say. Thanks, Charlie
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Carnut1
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Re: Porting the VW/Audi 8v head with port energy discussion

Post by Carnut1 » Mon Dec 04, 2017 6:41 am

1203171110c.jpg
Since the stock intake knocks a full 30 cfm off a modified intake port I wanted to see what could be done without welding and cutting, I was able to slightly enlarge and reduce taper 6.25" into the flange. This was worth 6 cfm. A discussion about anti reversion (a.r.) and subsequent mods lost about 1cfm at high lift and low lift flow took a hit. Now llf will be important on this build due to the engine design restrictions. I will need to consider the advantages of a.r. vs. The llf loss. Thanks, Charlie
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mag2555
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Re: Porting the VW/Audi 8v head with port energy discussion

Post by mag2555 » Mon Dec 04, 2017 6:58 am

Treat it some what like a short turn Charlie!

Widen out and flatten it little by little for a distance of half way thru that 90 degree bend and then switch off to widening the long side of the bend on the other half of the 90 as it approaches the head.

I guess your next issue even if you only pick up 15 cfm per runner is the restriction the throttle body may become now?

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