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Re: Loss of Power, Turbo? Posted by Ari [Email]  (#2847) [Profile/Gallery]
(more from Ari) on Thu, 24 Feb 2005 06:49:12
In Reply to: Loss of Power, Turbo?, Max, Wed, 23 Feb 2005 23:15:31 Members do not see ads below this line. - Help Keep This Site Online - Signup |
A gradual loss of power usually isn't the turbo. The turbo is capable of much more boost than the car needs - the control system limits the turbo output. As to spool-up speed, I guess this could degrade over time, but not a lot.
If you're getting full boost (boost to end of yellow/beginning of red), then the turbo is probably just fine. I'd look elsewhere-
How old are the spark plugs? Are they the exact right NGKs, gapped per the manual? How do they look? They should be a nice light tan to light grey. Not bleached white or fluffy black.
How old is the air filter? Fuel filter? Have you tried running a tank or two of higher octane gas? Tried a bottle of Techron to clean the injectors? Any vacuum leaks?
There is so much more to power than turbo boost. The engine control is pretty sophisticated, and controls a lot. At a minimum, try doing an Adaptation run (check the archives). The Trionic system in your car adapts and learns the engine condition. If the conditions change, it may be time to force a new pattern.
There are many things that can cause a slight loss in throttle performance. The good part about modern engine controls is that they can adjust to many changes in the system. The bad part is that they can adjust to many changes in the system, so many problems go unnoticed. Unless the fault causes the car to go out of emissions limits, it won't throw a CEL.
The ECU will adjust spark timing, then fuel, and then, finally, boost, to compensate for engine knock. So if you're running just slightly too low octane for your engine, it may not show up as boost, but in slightly poorer throttle response, as the system dials back ignition timing only. Or it's due to old spark plugs, or a clogged fuel filter, or a minor vacuum leak causing a leaner mixture.
And yes, California is known for lots of gasoline additives to reduce emissions, that also rob some power.
Before chasing the turbo, make sure that all of the breathing, fuel, and spark bits are up to snuff- a tune-up, as they used to say.
posted by 192.249....
, Thu, 24 Feb 2005 06:49:12 <-- Viewing This Message
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