hi can any one help me my scooby sometimes loses power and when running well has a very nasty jerky type jolt to it when changing gear quickly.the car has been serviced up to date and was purchased from a mechanic that fitted a scorpion sports cat and baileys dump valve which im sure doesnt close properly every time.i have since fitted a k+n air filter with mini bonnet scoop.
would my scoob need a refined tweak to the tuning because of these minor upgrades do you think or is the problem a lot more than that and how much do you think it would cost for tuning? my scoob is a uk classic on an x/2000 plate with 125k on the clock.
any ideas please help (derbyshire)i know of the scooby clinic chesterfield but they are really pricey

 

alright mate when you say it jerks on quick gear changes is it when the turbo boosts or instantly as the clutch is released after gear change.

 

The person best placed to help you would be the nearest good Subaru specialist to you. If you don't fancy Scoobyclinic's prices, have a lurk round your regional forum and see who else is recommended.

If you want to try and diagnose this yourself, the obvious first step would be to get rid of the aftermarket dumpvalve and put a standard Subaru one on (and ensure it's connected properly). Cruddy performance during gearchanges or on/off/on throttle driving is one of the most common side effects of running a badly adjusted and/or vent to atmosphere DV.

In addition, you say you have an MY2000 car, and have fitted a K&N "filter" and a mini-scoop on the bonnet. Is this K&N a replacement panel, or a cone/induction kit?

If it's a panel, the mini-scoop is irrelevant and probably costing you more in drag than it gains in engine bay airflow.

If you've fitted a cone/induction kit, and haven't had the car mapped properly for it, the best thing you can do is get rid ASAP and refit the standard parts. MY99-00 airflow meters are prone to vibration damage (which cone filters tend to cause large amounts of), while running a cone alters the way the sensor measures the airflow running into the engine. This needs to be addressed via rescaling (remapping) the ECU, and the consequences of not doing so can be anything from inconsistent performance to very serious engine damage.

Incidentally, if you are running a cone filter, the mini-scoop makes it very easy for rain to get into the induction tract, which isn't a particularly good idea.