View single post by subwoofer
 Posted: 05-26-2009 09:06 pm
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subwoofer

 

Joined: 04-01-2008
Location: Sandefjord, Norway
Posts: 583
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Esprit2 wrote:
The 907's combustion chamber is very tolerant of higher compression on pump gas.   11:1 isn't a problem on the pump gas available in the USA.   Of course, a lot will depend upon the gas where you are.

If you're considering 104 cams or hotter,  then raise the compression to at least 10:1.   11:1 would be good if you wish to drive in a spriited manner,  but a waste of high octane fuel if you'll be trundling along in traffic most of the time.   Be sure you know what you want,  because it's not a simple change later.


The cars will not be used for commuting, so that is not much of an issue. From what I can remember from the thermodynamics course I took way back when at university, the thermal efficiency will go up quite a bit with higher compression, so for cruising at highway speed, the upped compression should be good.

Regarding the pistons: to date I have only seen higher than 9.5:1 pistons for the 2.0 from one single source, and I can't help but think there must be a reason why, since 10.9:1 and 11:1 pistons are abundant for the 2.2. According to the source, they are actually lighter than the stock pistons, so weight should not be an issue.

As far as carbs go, I am about to order a set of 45mm Dell'Ortos.

--
Joachim

Last edited on 05-26-2009 09:08 pm by subwoofer