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Join Date: Dec 2005
Location: Melb, Aus.
Posts: 407
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CIS to PMO Carburetor upgrade
Hi guys - no luck on the aussie forum --- , anyone had any experience in upgrading a 2.7 CIS to the PMO Carburetor's at www.pmocarb.com, I'd be interested to know any feedback.
cheers
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Shane 1975 911 Coupe 2.7L 4Spd CIS Sporto 9115100500 1977 911 Targa, 3.0L, 5 Spd LSD, Zenith Carbs modified, SSI, Dansk 9117310158 |
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11-16-2008, 02:24 AM
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Location: Rancho Cucamonga Ca
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'75 911S Silver Anniversary #164(Formerly JTO's) Rebuilt 2.7 with full ARP, 9:1 CR. SSI, GHL, ER polybronze bushings, finned oil lines. Lowered and corner balanced. CIS retired, now PMOs! '65 912 slate gray sunroof (driving project) |
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11-16-2008, 05:15 AM
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Join Date: Jul 2001
Location: Portland Oregon
Posts: 7,007
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Been doing these since 1977 with Webers, now PMO's,....
 Aside from the decreased (naturally) fuel economy, its really amazing.
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Steve Weiner Rennsport Systems Portland Oregon (503) 244-0990 porsche@rennsportsystems.com www.rennsportsystems.com |
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11-16-2008, 09:12 AM
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Join Date: Dec 2002
Location: Dahlonega , Georgia
Posts: 14,606
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I have a 83SC that went from CIS to 46mm PMO carbs and I love them. And I can get 17-17.5 mpg on the highway which isn't too bad. But that is a fair trade off for the sound and throttle response and as a added bonus it makes a 911 engine compartment look the way they are supposed to.
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2002 Boxster S . Arctic silver + black top/int. Jake Raby 3.6 SS engine " the beast ". GT3 front bumper, GT3 side skirts and GT3 TEK rear diffuser. 1999 996 C4 coupe black/grey with FSI 3.8 engine . Rear diffuser , front spoiler lip with ducktail spoiler . |
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11-16-2008, 01:04 PM
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Join Date: Dec 2005
Location: Melb, Aus.
Posts: 407
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Thanks guys, sound like I should start saving, Aussie dollar at around 65cents makes this rather expensive at the moment, one day. Interestingly an advanced search on PMO I did before posting this found nothing. Nice photos and thread ael911.
cheers
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Shane 1975 911 Coupe 2.7L 4Spd CIS Sporto 9115100500 1977 911 Targa, 3.0L, 5 Spd LSD, Zenith Carbs modified, SSI, Dansk 9117310158 |
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11-16-2008, 01:16 PM
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Join Date: Jan 2006
Location: Santa Barbara, CA
Posts: 2,307
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Did my 2.7 three years ago, junked the CIS and added PMOs. They are wonderful.
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jhtaylor santa barbara 74 911 coupe. 2.7 motor by Schneider Auto Santa Barbara. Case blueprinted, shuffle-pinned, boat-tailed by Competition Engineering. Elgin mod-S cams. J&E 9.5's. PMO's. 73 Targa (gone but not forgotten) |
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11-16-2008, 02:46 PM
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AutoBahned
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Quote:
- weird - same for me; used PMO in caps - 0 hits |
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11-16-2008, 02:54 PM
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Registered
Join Date: May 2002
Location: Portland, Oregon
Posts: 12,650
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Quote:
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Harry 1970 VW Sunroof Bus - "The Magic Bus" 1971 Jaguar XKE 2+2 V12 Coupe - {insert name here} 1973.5 911T Targa - "Smokey" 2020 MB E350 4Matic |
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11-16-2008, 03:49 PM
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Join Date: Dec 2005
Location: Melb, Aus.
Posts: 407
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Other than the carby upgrade and maybe fuel pump upgrade is there anything else that is required when you do this. Can we just bolt on the PMO's without changes to cams, exhaust etc. Understand these may be worthwhile but I am assuming they are not necessary.
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Shane 1975 911 Coupe 2.7L 4Spd CIS Sporto 9115100500 1977 911 Targa, 3.0L, 5 Spd LSD, Zenith Carbs modified, SSI, Dansk 9117310158 |
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11-16-2008, 04:23 PM
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Join Date: Sep 2008
Location: Rio Rancho, New Mexico
Posts: 200
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Shane,
I did my 2.7 a couple years ago. As I live at 5,500 ft. elevation, I wanted the performance lost to thin air. I added 9.5 JE pistons and Solex cams. This 911 is my race car so I also changed the transaxle to a 7:31. The car came alive on the track running down 3.0's and 3.2's. Just changing the carbs without at least changing out the CIS cams, will not impress. It took me about a year to learn everything I needed to know to really get the best out of the carbs. A person familiar with the Webers or PMO's can bring them into top tune quickly. About the fuel pump; PMO makes a simple reliabe regulator that uses your existing CIS pump. It uses both the supply and fuel return lines. A pressure guage is part of the system so you know you are at 3.5psi. I recommend it. Again the key to success is you or someone close to you that is familiar with carbs.
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Doug Was 2.7racer. '76, 2.7 w/Webers, JE pistons, Solex cams. Elephant bushings front & rear, 23mm & 28mm torsion bars, big brakes front & rear, Pertronix. Track car. '85 3.2 stock, Orient red, comfy street car. |
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11-16-2008, 04:47 PM
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AutoBahned
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Quote:
BUT - the whole character of the engine and its ability to make power is due to the cams. |
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11-16-2008, 10:05 PM
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Registered
Join Date: Dec 2005
Location: Melb, Aus.
Posts: 407
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thanks again guys, heaps of good info.
cheers
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Shane 1975 911 Coupe 2.7L 4Spd CIS Sporto 9115100500 1977 911 Targa, 3.0L, 5 Spd LSD, Zenith Carbs modified, SSI, Dansk 9117310158 |
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11-16-2008, 10:20 PM
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