[Diy_efi] Exhaust gas temp

[Michael Richards]

I've seen many engines run lean (especially those people with the 
RRFPR's) and I don't think I've ever seen a turbine wheel failure from 
the heat. If the motor does not detonate apart it ends up with burned 
valves. 

As a general rule with the probe before the turbo I tell customers to 
let off if it gets above 1450. Some valves will tolerate more than this 
type of heat, in particular, the STi, 323GT-R and VW GTI as they are 
all sodium filled. My figure is also conservative. My personal GT-R has 
run to 1500 without any ill effects. 8,000 km of full boost race type 
driving and it's still 3% or better on a cold leakdown.

-Michael

> I have a colleague that has regular contact with an engineer that
> works for Garrett in their test facility.
> 
> The melt point for Inconel turbine wheels is reported by him to be
> just over 1040?C ~ 1900?F
> 
> I have an EGT probe just after the turbo on my engine, and have
> regularly seen 1000?C for short periods on high boost using Garrett
> turbos.
> 
> My engine has been stripped down a few times over the years and apart
> from some wear on the exhaust valve guides appears not to mind the
> temperature.

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