10V T pics-detonation

[Jörgen Karlsson]

> Also, with experience from tuning my car, I am finding that detonation is
> really a timing problem, not a fuel problem.  In my car, I can tune it so
> lean that at 18psi it won't even accelerate, but advance the timing 4
degrees
> and rampant detonation.  I think it is a myth that detonation can be
> prevented with extra fuel-granted, you can dump so much raw fuel in the
comb.
> chamber that nothing will burn, and a richer mixture can help cool the
> combustion chamber and EGT, but if that spark is just a few degrees too
soon,
> it can trigger pre-detonation very easily.

Dumping fuel to prevent detonation are very effective on some engines but I
don't think that the 10vt engines are one of them.

While I am guessing:
I don't know the AFR where the 10vt are most likely to detonate, this AFR
are not the same for all engines. But I think that everyone will agree that
all engines detonate easier at 13:1AFR then at 16:1AFR. With my latest plug
cuts in mind I guess that 13:1 to 13.5:1AFR is very dangerous, it is very
easy to end up in that range since the car will feel very strong at these
AFRs.

I also think that this AFR is related to the maximum power AFR of the
engine. This is also changing from engine to engine, modern engines tend to
produce best power at around 13:1 or even leaner while older engines are
more likely to produce best power around 12.5:1.

BTW,  my engines all have close to flat top pistons and I run around 25º
timing at 50kPa, I think that I will have to back of a bit even if the EGT
say that it is close to optimal.

ThinkingalotrightnowJörgen
Jörgen Karlsson
Gothenburg, Sweden.