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911st 911st is offline
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Join Date: Jan 2004
Location: Sacramento
Posts: 7,269
Not an expert but here are some thoughts.

7R case starts reaching its limit at about 270hp. At the heat of a turbo with severly increased combustion pressures and you might be taking a risk. Might be better to find an early sand cast aluminum case if durability is important.

Small displacement, short stroke, low compression, cams that will support a usable power band up to 8000rpm -- and I suspect low end power and response is not going to be in the cards.

For example, a K27-7200 turbo supports 320 hp. Boost starts to come on at 2500 with full boost at about 3200rpm on a 3.3. Put in on a 2.2 and boost will start at about 3700 rpm with full boost at 4500rpm.

Further, you will not likely get low overlap cams to work well at the rpm you want to reach. Thus, boost will come on later with the same turbo.

Also, you may need a larger lower restriction hot side for less back pressure so there is less hot gasses being pushed back in through the exhaust valve and past intake valve up into the intake manifold.

Think a step beyond a 911S 2.2 (906?) in terms of power band and throttle response. You will probably want the turbo and cams to come in at about 6k to work right. No reason to go twin turbo that adds complexity and weight and you will be looking for turbos that make about 160hp each.

What would be fun would be to run an MFI set up with your 2.3 turbo set up.

The best.
Old 05-26-2009, 07:44 PM
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