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Porsche dyno testing

It seems like I have been spending a lot of time testing fuels these days!  I have tested the ETS Extra Max fuel in most of the standard late model Porsches to see what sort of gains can be made just by pouring in the oxygenated race fuel.  The various Bosch ECUs respond well to the fuel and the gains have been at least 30hp at the wheels with no other changes made.  On cars that have the ability to retune and add boost then the gains that can safely be made are significantly more!  It is cheap power and great for track days…

996 Turbo DynoPorsche 996 ETS Graph

Testing on the chassis dynos has been a great way to check the tune and show the relative gains to be made from the fuel but using a ‘rolling road’ can be a bit problematic.  There are drivetrain and associated losses through the tyres, inconsistency with overheating tyre temperatures (particularly with race rubber), wheel spin and the electronic diff controls on some of the Porsche four wheel drive models just don’t get on particularly well with some dynos…

An increase in power is one thing, but what doesn’t don’t show on a dyno graph is the increased throttle response which gives that extra punch out of the corner, and sound of the engine is so much smoother!

I have been using my engine dyno to do a fair bit of comparison testing too.  It is no secret that I have never been a fan of premium 98 fuel, the lack of consistency from the pump has always scared me.  It is Ok on a car with a factory ECUs that have closed loop controls that wind back the timing when detonation is detected, but on highly strung engines that are used in competition – it is a bit like playing Russian Roulette.  Using the repeatability of the my engine dyno, I did some back to back tests comparing P98 fuel to ETS Extra Max.  The engine I used was a relatively standard air cooled 911 turbo engine.  Like most 911 turbos, it doesn’t have enough airflow over the intercooler so has high inlet air temperatures, and it has the same problem with the oil cooling, particularly after a few laps at the track on a hot QLD summer.  It is the sort of engine that is a bit scary on P98 with any reasonable amount of boost.

The graph below shows the runs from the two fuels.  Obviously the line labelled ‘Hp(1)’ is P98 and ‘Hp’ is Extra Max.  It is a pretty huge difference and the only change I made to the tune was trimming the fuel sites on the Motec M800 to make the lambda about the same.  The blue line is MAP pressure so the engine is just running on waste gate pressure for this test.
ETS vs P98 Fuel comparison low boost

The engine with a bit more boost.  Unfortunately it is running out of airflow but it does have very conservative cams and heads…

ETS ExtraMax boost

And this isn’t the worlds most exciting video but here is the engine in action…