6/carbs: ? about tall 2ndary venturi's, rich, I miss you. |
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6/carbs: ? about tall 2ndary venturi's, rich, I miss you. |
brant |
Nov 3 2005, 11:50 AM
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#1
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914 Wizard Group: Members Posts: 11,640 Joined: 30-December 02 From: Colorado Member No.: 47 Region Association: Rocky Mountains |
carbs: ? about tall 2ndary venturi's
Hi all... thanks for the help in advance. I want to try a set of the tall 2ndary's on my IDS-3C carbs. I'm running the stock ones and want to try the tall ones, that I've heard called "906-style" its a race car and withoug re-hashing all of my jetting and dyno history, my questions are: 1) pierce manifold says they have 2 different types in stock a 3.5 size and a 4.5 size. I believe this measurement is in reference to bore and not height. Pierce said that both sizes are the "tall" type. Which do I want? Motor is a 1967 2.0/S motor at altitude. (the pierce catalogue references that the IDS carbs came with 4.5 short, but I'd like confirmation before I order) 2) Does anyone know if these tall secondaries interchange on the IDA carb versus the IDS carb. I would assume so, but I once bought some F33 emulsion tubes from Pierce that do fit the IDA, and found that they would not fit the IDS. I didn't know there was that much difference between the two carbs, which surprised me. But again, before I order do people know if the 906-type tall 2ndaries will fit an IDS-3C body? again, thanks in advance everyone! brant |
Phoenix-MN |
Nov 5 2005, 09:24 AM
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#2
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Senior Member Group: Members Posts: 927 Joined: 23-January 04 From: ST. Bonifacius,MN Member No.: 1,590 |
Also found this -
"Other performance-enhancing options for Weber-equipped cars are the tall, auxiliary venturis developed for the 906 engine. These really enhance the metering signal "seen" by the main circuit to sharpen the throttle response when using slightly-too-large main venturis for maximum power. The tall manifolds used on the 906 and 911R were developed to help contain the reversion in the intake tract from using camshafts with lots of valve overlap. Reversion causes a ‘fuel cloud’ to form over the individual intake trumpets that plays havoc with fuel mixture at higher RPM’s. Spacing the carburetor farther away from the intake valve with taller intake manifolds, increases torque and throttle response, especially with racing-sized venturis." Dug up the invoice from AJR for the sec. vent. part # 109.100.985.01 Paul |
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