[Diy_efi] RE: Timing and dyno pulls

[William Shurvinton]

----- Original Message -----
From: "Adam Wade" <espresso_doppio at yahoo.com>
>
> > Can I also infer that OEM apps ( which run close to
> > detonation) do this because they are running leaner
> > than they should?
>
> Do what?  Retard timing?  In some cases.  That's
> usually how a detonation sensor setup works; after
> detecting knock, it retards the timing.

No: dave's point: Best power is way off detonation in a race engine. My
question, why does a modern road car gain 10HP when run on high octane (real
test, think it was a BMW) when all it has to go on is the knock sensor.
Inference: it must be running close to knock all the time.


> > and race cars (F1 in particular) only ran so hot
> > because the aero package demanded a limited rad area
> > and air flow. Hotter was more efficient.
>
> With the engine components themselves, you are limited
> by how much heat the materials involved can withstand
> before weakening.  With highly-stressed engine parts
> that are built to JUST withstand the stresses of a
> race and be as light as possible, managing temperature
> is CRITICAL.  So there are conflicting needs; the need
> to keep the engine structurally sound, and the
> "desire" to have it as hot as possible in the
> combustion chamber.

 I quoted F1 because it is an extreme case. The engines are run at
riduculous coolant temps and revs and until recently were billet unobtanium.
I like beryllium in space apps, but not sure I want it in my car. However
the coolant temp in this case is due to not being able to get the heat out,
not because the engine liked the heat.


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