It’s good to use synthetic in any engine, but extremely important in a turbo.
I use Castrol synthetic 5w50 in all my cars all year round. Switched to Castrol about 10 years ago after Mobile 1 destroyed an engine.
Warm Idle: 18 inches of mercury vacuum.
Cold Idle: 16 inches of mercury vacuum.
WOT (Wide Open Throttle) 2,000 RPM: ~5 PSI boost.
WOT 3,000 RPM: ~15 PSI boost.
75mph @ 3,000 RPM: ~10 inches of mercury vacuum.
Between Shifts: 0 (atmospheric) due to the bypass valve venting manifold pressure to keep the turbo spooled.
$1,000 for a 240 Turbo sounds good as long as it is in good condition, maybe not perfect but solid, straight, and sound. Volvo did not have a DL Turbo, the car will either be a DL which is their lower level model…
Have your current turbo rebuilt professionally. It shouldn’t cost much more than $300. Shop and Compare…
if you continue to run your engine with higher than designed turbo boost, be prepared to replace either the engine, transmission, other parts of the drive train or all of the above within a couple years…
Everyone seems to agree that a properly maintained turbo should outlast the rest of the car but what do you do about a change in performance?
MVS forum member NateR documents a recent experience he had while commuting. He talks about his 89 Volvo 740 Turbo having issues with sudden drops in rpm. The car never actually stalled but came close. How can we come together to diagnose stalling problems with our Volvos? Chime in to add to this great discussion.