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Join Date: Mar 2011
Posts: 271
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PMO jetting on 3.0 S cams
Hi guys,
does anybody of you have any advices what jets I might use for this setup? 3.0 engine with 10.3 cr, S cams, twin plug, headers I know thatīs not the perfect choice but the carbs are 40 PMO. I donīt have 46 for now so I need to make the 40 work. The venturis are 36mm, I have F11 emulsion tubes. It would be great if I can keep those. The jets currently are 55 idle, 155 mains and 190 airs and itīs running way to lean. Can someone give me a direction? Many thanks Malte |
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04-29-2017, 04:49 AM
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Carburetor Jets
Quote:
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Don "Gordo" Gordon '83 911SC Targa |
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04-29-2017, 06:43 PM
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I would disagree. 40mm PMOs are ideal for that setup.
Velocity is where you'll make the power. 46mm are best suited to 3.2 and up Are you sure it's lean? You'd have plenty of fuel with that combination. If even step down to 145 main jets. RR Quote:
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1973 Porsche 911 RS 1981 Porsche 931 Euro-Intercooled-GT 1984 Porsche 911 Euro Carrera widebody 1987 Porsche 924s Rallye Spec Instagram: @soyracer |
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04-29-2017, 07:09 PM
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It's a 914 ...
Join Date: Jan 2008
Location: Ossining, NY
Posts: 4,744
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What's the symptom that makes you believe it's too lean? And under what conditions (RPM, load, etc.)?
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04-30-2017, 04:42 AM
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Join Date: Jul 2001
Location: Portland Oregon
Posts: 7,007
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You need to do some dyno runs at PT & WOT to see where its lean and precisely by how much.
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Steve Weiner Rennsport Systems Portland Oregon (503) 244-0990 porsche@rennsportsystems.com www.rennsportsystems.com |
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04-30-2017, 07:29 AM
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Posts: 271
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Thank you very much, and I am sorry for the later answer!
I havenīt checked it with my laptop with AFR readings yet because I am working at the suspension and canīt drive the car . With a CO reader I am good at idle (3,4 %), but as soon I raise the rpm it goes down to0,5% CO and partly starts backfiring. But when all of you say it shouldnīt be that bad for starting I will finish the suspension check AFR while driving and if this seem to be good I will go to a dyno shop |
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05-01-2017, 11:44 PM
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Q-P
Flat Out
