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carrerarsr65
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smybody running 36mm chokes with 40 webers??
i.m running this set up my 3.0sc build twin plugged 10to 1 je pistons 964rs cams I have a big flat spot at 3=4k any suggestions
 
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03-28-2015, 09:36 PM
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Registered
Join Date: Jul 2001
Location: Portland Oregon
Posts: 7,007
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Flat spot at part throttle, WOT, or just when you squeeze it?
Timing maps? Plug heat range? Exhaust & muffler system? With detailed information, one may be able to help. 
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Steve Weiner Rennsport Systems Portland Oregon (503) 244-0990 porsche@rennsportsystems.com www.rennsportsystems.com |
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03-28-2015, 10:15 PM
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Join Date: Mar 2001
Location: Marysville Wa.
Posts: 22,453
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List your jetting too. What emulsion tube?
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https://www.instagram.com/johnwalker8704 8009 103rd pl ne Marysville Wa 98270 206 637 4071 |
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03-29-2015, 06:19 AM
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carrerarsr65
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more info
timing hpv-1 twin plug dials set at 10,14,+2 soft redline for break in at 5500,carb info,is f26 e tubes,155 mains,55 idle,180 air corrector jets,exhaust is 1 5/8 headers in a 2/1 oem style exhaust, the engine rebuild consisted of je 10.5to1 slugs ,964rs style cams from elgins I hope this helps guys any info would be great the flat spot comes on at 2800rpm,only while driving tho in the driveway revs up sweet
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03-29-2015, 08:25 AM
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Join Date: Mar 2001
Location: Marysville Wa.
Posts: 22,453
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F-3 tubes might help. 0.55 idle jets are kind of small for that setup. 0.60 would help at low end. A somewhat smaller air corrector will richen things up at higher rpm. kind of trial and error until you like it.
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https://www.instagram.com/johnwalker8704 8009 103rd pl ne Marysville Wa 98270 206 637 4071 Last edited by john walker's workshop; 03-29-2015 at 09:53 AM.. |
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03-29-2015, 09:48 AM
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Join Date: Feb 2008
Posts: 1,438
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F3's and 60 idles like John said. 1 5/8" headers might be a tad big. Otherwise it sounds about right.
If you have IDTP Webers then they have a natural lean transition when using large venturis but that can be helped by adjusting idle air bleed size smaller.
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Paul Abbott Weber service specialist www.PerformanceOriented.com |
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03-29-2015, 10:31 AM
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Registered
Join Date: Jul 2001
Location: Portland Oregon
Posts: 7,007
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Quote:
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Steve Weiner Rennsport Systems Portland Oregon (503) 244-0990 porsche@rennsportsystems.com www.rennsportsystems.com |
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03-29-2015, 11:21 AM
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carrerarsr65
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36
sso I shouldn't go and out and get 34 chokes ,the jet are way cheaper!!,40idas by the way
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03-29-2015, 11:21 AM
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Join Date: Feb 2008
Posts: 1,438
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No, 36s good for you and your cams. Check out the venturi selection chart on my web page, for a 500cc cylinder and 36mm venturis you should develop peak HP at 6000RPM or near that. Larger venturis in 40mm throttle bores not so good, you will be limited by the bore size as to how much air you can flow. Smaller venturis will restrict HP quite a bit. You should have enough air flow to make your transition work just fine with 36mm venturis, I have 35mm venturis on my 2.3 liter "S" engine. If you still have an issue with transition then taller auxiliary venturis can help but these are $65 each.
Be absolutely sure your float levels are correct, set with engine running (turn off engine to read the level) and fuel pressure is 3.5 psi. See my tech info for these procedures. Performance Oriented Venturi sizing chart: Performance Oriented
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Paul Abbott Weber service specialist www.PerformanceOriented.com |
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03-29-2015, 01:41 PM
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