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911st 911st is offline
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Join Date: Jan 2004
Location: Sacramento
Posts: 7,269
I am starting to wonder or be willing to accept that the euro 930's may not have any boost retard. This would put them at -29 on boost compared to our US 930's at about -16 to -18 on boost.

A stock euro motor at .8 bar boost and is 7/1 compression for an equivalent compression ratio of about 10.2.

I guess with really good fuel this might be possible as some single N/A race motors on race fuel can do this and more. I think the euro 3.2 is almost at that compression but it dose not have to deal with an elevated intake temp like a turbo. I think it ran about -23 to -25 at WOT.

For comparison I believe the 91-94 C2 turbos run about 21deg of advance on boost +/- 3 deg for intake temperature variations per info Thierry25 posted on the Ultimate 930 Distributor, advance, retard, timing, Turbo lag, MSD, mod, thread. thread. He also noted that FVD sells an adapter to relocate the crank sensor for 6 deg more advance at all points. That could put one at 29 deg on boost so maybe it is possible to run a much more aggressive on boost timing value than the US 930's have been set up for. I am not saying we can run -29 at 1 bar boost but -25 might be possible.

1 bar boost with 7/1 compression is equal to about a 11/1 CR which is close to what the 993's run at. At WOT they run about -16 but with twin plugs for what it is worth. I think I might pull timing back a bit more than to -26 deg that is running a single pot dist on USA fuel.

Buy the way, the C2 turbo pulls up to -40 deg timing on cruse for better fuel economy.

Thus, maybe the single pot dose not have any on boost retard and runs a lot more timing on boost than the two connection pot that has boost retard.

I guess live and learn.

Last edited by 911st; 03-31-2010 at 09:08 AM..
Old 03-31-2010, 09:06 AM
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