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| Registered Join Date: Mar 2010 
					Posts: 799
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				2.5L ST Engine Build Questions
			 
			OK, so this is going to be the first of probably many stupid  questions, but here goes. I'm going to start pulling together parts to build my dream engine and I need some input or references to use. I am planning on a 2.5L S/T, twin plug, high-butterfly setup. I expect it will take me a few years to pull everything together, and would like to start searching for a good case. I don't need a period correct case, I want something that will have a long life and work with the 86.7mm (2.5L) P/Cs Do I go with a 7R, or something else? Would the choice be any different if I decided to go with a 2.3L? Thanks K Last edited by kugelfischer; 05-09-2011 at 03:54 PM.. | ||
|  05-09-2011, 03:48 PM | 
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| Moderator Join Date: Dec 2001 
					Posts: 9,569
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			Yes get a 7R if you want the mag case 86.7x 70.4 gets you 2493cc, sure that's what the factory did to get it under the limit, but why not 90 or even bigger, with a shorter stroke? You have a blank canvas and the time to get it right. 
				__________________ '66 911 #304065 Irischgruen ‘96 993 Carrera 2 Polarsilber '81 R65 Ex-'71 911 PCA C-Stock Club Racer #806 (Sold 5/15/13) Ex-'88 Carrera (Sold 3/29/02) Ex-'91 Carrera 2 Cabriolet (Sold 8/20/04) Ex-'89 944 Turbo S (Sold 8/21/20) | ||
|  05-09-2011, 03:56 PM | 
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| Registered Join Date: Oct 2003 Location: Central Fla 
					Posts: 1,864
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				Case
			 
			Being that you have a choice, I would start with an alum. 2.0 case, they have more strength than you will need, the mag cases are a bit lighter but take so much effort/money to prep. and then they still have issues, after the last few full house 2.5 engines that had case failures I just won't start a small bore project with a mag case. My .02, Mike Bruns JBRacing.com 
				__________________ The two most useless things to a driver are the braking distance behind you and nine-tenths of a second ago. | ||
|  05-09-2011, 05:27 PM | 
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| Registered Join Date: Mar 2010 
					Posts: 799
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			Thanks for the advice.  I'd like to avoid the Mag case issues altogether.. I already have enough of those with other engines. Would there be any reason I couldn't go with a 3.0L Turbo (Al) case, 90mm cylinders and say a crank from a 2.2l for the shorter stroke? | ||
|  05-10-2011, 09:16 AM | 
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| Registered Join Date: Jul 2001 Location: Portland Oregon 
					Posts: 7,007
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 You'll need to spend some money on those heads to make the power you want. 
				__________________ Steve Weiner Rennsport Systems Portland Oregon (503) 244-0990 porsche@rennsportsystems.com www.rennsportsystems.com | ||
|  05-10-2011, 09:37 AM | 
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| Registered User | 
			
Great case, but then you might as well use the larger spigot bore of the 3.0 case and go with a set of 95mm pistons. You will also need the 3.0SC heads. So your in the 2.8SS area now.
		 
				__________________ Mark Jung Bend, OR MFI Werks.com | ||
|  05-10-2011, 11:28 AM | 
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