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beepbeep beepbeep is offline
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Join Date: Jun 2001
Location: Sweden
Posts: 5,565
Nope, no knock sensors. Just standard "deaf" MAP-based EFI and heaps and heaps of fuel and boost.

It did have it's share of problems though, until everything was buttoned up:

But amazingly, it never suffered from knock-induced damage. Head split after severe mapping-induced backfire. When you have injectors flowing that much juice, it just take one wrong cell in fueling table to hydro-lock the cylinder and do all sorts of nasty things.

I believe that best way to postpone knock in aircooled 911 engine is twin-plugging, efficient turbochargers and intercoolers, lot's of cooling fuel (=rich) and one thing that is often omitted: cool heads! Fan was severely overdriven on this engine, in order to keep the heads cool. So much that it actually munched trough several failed generators and belts until gen got moved and got it's own belt.

As far as I understand, alloy used in 3.6 heads will only take up to 240 deg. C before it goes soft (like plastic deformation) or ruin the things by pinging. If you push double or tripple HP trough heads while retaining same airflow, they will get hotter and ruin the day. Also 3.6 curved fan is quiet(er) but flows approx 70% of noisy straight-bladed turbo fan.

but yes, this is pretty academic discussion as nobody would run 2-bar on the street.

But I've seen guys turbo-converting othervise stock 10:1 C/R Alfa Romeo V6 and running up to 1 bar of boost using E85 fuel! I also experimented myself with E85 and couldn't get darn corn-juice to ping no matter what I did
Thank you for your time,

Last edited by beepbeep; 03-09-2008 at 01:59 PM..
Old 03-09-2008, 01:55 PM
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