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Join Date: Apr 2005
Posts: 76
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3.2 carburated or not ?
I am going to buy 3.2 engine to put it into 2.7 body shell. The car is now backdating to 2.7 RS. It will be used for racing and hillclimbing.
Would you rather stay with original Motronic fuel system or should I go for PMO or Weber 46' carbs? What else should I change to make that engine properly running with carbs?
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1976 3.0 Carrera sold ![]() 1975 2.7 backdated to 73' RS 1971 2.2 T Targa |
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Location: Portland Oregon
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Go with 46mm PMO's. They are FAR better than Weber's in every way.
The Motronic system will severely restrict what camshafts you can use.
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Steve Weiner Rennsport Systems Portland Oregon (503) 244-0990 porsche@rennsportsystems.com www.rennsportsystems.com |
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Join Date: Nov 2004
Location: Greater Metropolitan Nimrod, Oregun
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The amt. of changes depend on how "properly" you want it to run...
If you want to license it for street use at all, check your states pollution control regs to see if you can use carbs. Otherwise, the courses involved will determine cam choice for your PMOs.
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"A man with his priorities so far out of whack doesn't deserve such a fine automobile." - Ferris Bueller's Day Off |
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I am not going to use it for the street use. The hp of the European 3.2 seems to be enough but more torque would be nice.
But I'm wondering whether it's worth to spend extra 3K$ on PMOs. How much more of the torque can I get from PMOs, having of course racing headers and muffler (megaphones?) installed? I have not planned to change cams.
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1976 3.0 Carrera sold ![]() 1975 2.7 backdated to 73' RS 1971 2.2 T Targa |
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It's the cam change that you really want. See SW's reply above. And, no, it's not cheap.
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"A man with his priorities so far out of whack doesn't deserve such a fine automobile." - Ferris Bueller's Day Off |
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Quote:
A good set of headers and a proper race muffler will really help a 3.2 in the mid and upper RPM range. Megaphones take away far more low and mid-range torque than they add on top. Use a good muffler that incorporates a crossover for best acceleration. To take full advantage of all this proposed modifications requires a camshaft change that will extend the effective RPM range of the engine. On that subject, you should also budget for some aftermarket components that will extend the durability & reliability of these motors; valve springs, valve spring retainers, and rod bolts.
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Steve Weiner Rennsport Systems Portland Oregon (503) 244-0990 porsche@rennsportsystems.com www.rennsportsystems.com |
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Slippery Slope Victim
Join Date: Oct 2001
Location: Brooklyn, NY USA
Posts: 4,418
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I love my PMO's. The throttle response between my 3.0 SC w/ PMOs and my 3.2 Carrera w/ Motronic is quite impressive.
I was floored the first time out. Cheers
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Mike² 1985 M491 Last edited by NY65912; 12-27-2005 at 03:37 AM.. |
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Steve,
Does the 3.2 distributor need recurving working with PMOs?
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1976 3.0 Carrera sold ![]() 1975 2.7 backdated to 73' RS 1971 2.2 T Targa |
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Ha! Let's repeat: "not cheap."
We haven't gotten to twin-plugging yet either...
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"A man with his priorities so far out of whack doesn't deserve such a fine automobile." - Ferris Bueller's Day Off |
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Pictures are worth a 1000 words
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"YELLORS" 1972 911T with a 3.4l, PMO 46's Vierte Tür Klub Member. PCA National DE Instructor |
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Location: Portland Oregon
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Quote:
Thats an excellent question, Sir. ![]() The first thing you need to know is that a 3.2 Motronic distributor doesn't have any trigger unit inside it; it doesn't perform any ignition function except to distribute sparks. All of the ignition functions (triggering-advance) are done by the Motronic ECU, crank sensor/positioning hardware at the flywheel, and of course the coil. One has two choices here: 1) Retain the Motronic ECU and ignition hardware to control and provide all ignition functions. Steve Wong @ 911chips.com can burn you a custom chip for a carbureted application. 2) Install a '76 930 distributor (thats been recurved for these applications) along with a Bosch or MSD CD box & coil for a stand-alone ignition system.
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Steve Weiner Rennsport Systems Portland Oregon (503) 244-0990 porsche@rennsportsystems.com www.rennsportsystems.com |
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Location: Annapolis, Maryland
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Quote:
Pelican parts sells them.
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1981 Porsche 931 w/S1 engine & g31 transmission. Water-cooled intercooler |
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