My engine was originally a 2.2e however I rebuilt it as a 2.7l 9.5:1 compression. My heads are 2.2e heads with 32/32mm intake/exhaust ports and 46/40 valves.
Would there be a benefit/problem with enlarging the intake port to 35mm? Stock 2.7 heads have the same valve size and 35/35 ports. I would have the exhaust ports enlarged also however that appears to be a difficult job and I cannot find anyone to do it.
Also I have two sets of headers- 1 1/2" and 1 5/8"
Thoughts on the port size and header size?
I plan on using 1 5/8" on my 3.2
double post
I was under the impression that the 2.7 motors are parts motors...
So, buy some 2.7 heads...
Yes, port size was enlarged to increase gas flow per their design specs. There are several Porsche machine specialists who can correctly increase the port dimensions. if possible, I would suggest a facility close to home. Where are you? If not a requirement, Rennsport Systems, Competition Engineering, Aase Bros., Supertec Performance, as well as other shops. Perform your due diligence in choosing a shop. There are borderline/unscrupulous/incompetent individuals/business out there.
Another option, depending on the condition of your 2.2 heads - since the shop may want to replace/regrind the valves and seats as part of the operation as well as other needed work (truing cylinder head-to-cylinder surface, replace valve guides, etc.), is to source a set of rebuilt 2.7 heads with the correct port sizes. The shop can perform the same above operations with the correct port size to begin with, and you'll have a set of 2.2 heads to sell to offset the cost of professional porting and flow bench testing, perhaps $1000-$1500. Many shops can perform the basic machine work. However, Porsche-specific machining jigs mark a shop who can perform these operations accurately with repeatability.
Knowledgeable tech people recommend 1 5/8 exh. tubes (1 1/2" ID) for engines around 3.2 and larger.
Large tubes on a smaller engine may sacrifice mid-range torque. Thus, 1 1/2" tubes would be recommended for engines <3 liters.
You could also ask for recommendations at 911-specific tech forums such as PelicanParts.com and/or Early911SRegistry.org.
Welcome to the slippery slope of engine rebuilding.
Sherwood
Thank you for the info.
I should clarify my situation. I was not clear in my original post.
I have a completely rebuilt set of 2.2 heads. I contacted cgarr about increasing the port size. Apparently this is not a unusual modification. He opened up my intake ports to 35mm and cleaned up the exhaust port. I am not sure why but he doesn't do the exhaust port.
Since my heads are already rebuilt and have wider intake ports, I am not really interested in getting 2.7 heads.
I am glad to hear that I should be using the 1 1/2 headers. They are a nice new set of MSDS headers. The 1 5/8 is old and ugly.
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