injection timing

[Dave J. Andruczyk]

> 
> I believe they were only required on the early C.I.S. cars, what happened
> usually was after a cold start the engine was shut down prior to warm up, and
> then restarted. This resulted in additional fuel from the cold start injector
> causing an extremly rich mixture which would explode in the air intake
> plenum.

they are required for backfire protection.  The 911 owners tend to have a
heavy right foot, and don't like to wait for a full warmup, and thus a
quick stab at the petal when the engine was cold is just asking for a
backfire, which shatters the intake air box,  about a $300 penalty.  The
pop-off valves save the box,  they can be bought from Tweeks, Performance
Products.  (they are on the web, and easily found ( donno the exact URL)

Dave