[Shop-talk] Premium for Turbos

[Eric Murray]

On Tue, Jun 08, 2010 at 12:30:12PM -0500, Dan Kroninger wrote:
 
> Anyway, my daily driver Honda Civic has just hit 150K.  This is my third civic
> and both previous civics made it to about 150K and then the nickel and diming
> started, so I am starting to look for a new(er) car.  The car that has really
> caught my eye recently is the 07-09 Subaru Legacy Spec B.  Lots of HP, all
> wheel drive, sport suspension, etc etc.  The part that concerns me is the
> turbo.  The brochures state that all cars with turbos must be run on 91 octane
> or higher.

Most turbo cars require premium.
Turbocharging puts a lot of heat and pressure in the engine
and that can cause detonation.  That will blow up a turbocharged
engine real quick.

Modern turbo cars will adjust timing and boost and mixture
when they detect knock.  And most cars will be tunes to accept
regular even if they don't perform as well with it.
But you will be closer to the edge of the tuning enveolpe that
the ECU is set up for.  If you run regular and you hammer on it
there's a greater chance of blowing up the motor.

And it'll be significantly down on peak power.

I've run my turbo Eclipse on regular on long freeeway trips
with no problem.  But the car cost me $2500 and if it blows up so what?
And the Eclipse engine is well known to be bulletproof if left stock.
My new Mazdaspeed3 always gets premium.  It'll cost a lot more
to fix if I blow the engine and they are not as robust as Eclise
motors.  It's cheap insurance.

You will also want to replace the oil frequently and use synthetic
in a turbo car.   Turbos make a lot of heat and the oil that goes
through the turbo gets real hot.  I do mine at 5k miles.

I love turbo cars but they are not cheap to run.  
Besides gas and oil you'll be going through tires because you'll
want the sticky sport rubber to keep the thing on the road.
I'm on my third set of tires on the MS3 and I have 26k miles on it.

If you want cheap look at the non-turbo version of a turbo car (Mazda3
wagon, Subaru Outback) and then buy cheap used sport suspension from
the turbo car guys who have replaced theirs with something even sportier.

Eric