When high rpm and when turbo kicks in the motor sputters only when turbo kicks in

HI Derek.

There are a few possibilities that come to mind.
3K RPM is generally about the break-even point for when Turbo boost would kick in. There is a dump valve on the turbo system that opens up and vents the extra turbo pressure under high-rpm situations where the boost isn't needed - say high but steady speed on a freeway. If the dump valve system is malfunctioning, then that anticipated turbo run-up in power won't happen.

Revving fine when in neutral may not tell you much, other than that the engine can rev. The gating system will (or should) run differently under load - whether climbing a hill or accelerating, this is where you want the turbo boost to give you the extra power. THat's where the exhaust gate should stay shut, or mostly shut, to allow the turbo to force more air into the pistons.

You might want to check whether the APC (Automatic Performance Control) for the turbo has a separate fuse. (The name might be different on your model, I'm remembering from my 80s/90s era Saabs). If the fuse is blown, that could also lead to lame performance, especially as I'd imagine that the system would be built to fail or go to full open if the APC fails or loses power - that'd keep people from having run-away power that they can't manage.

Hoping this helps

D

check to see if there is a vacuum operated actuator between the shells of the turbo . This is connected to a rod that varies the vanes inside the exhaust side (turbine ). These blades can seize up from heat and rust and the vacuum hose can become hard and crack

Sounds like you have problems with the turbo as thee is a bearing there and you said it starts rattling once the turbo kicks in. There is one other thing, you may have internal engine damage as like you said, only 500 miles and some of that was racing. May not have been broken in properly. I know I was told you need to break an engine in for 500 - 1000 miles then change the oil. I hope this is not the case for you though.

You would have to do some research to answer that
You could have an rpm limiter & should
The question is-- why would you bring the rpm up
to more than 3000 in park,no test requires more than that
You will some day ruin a motor doing so,unless it is a race car

Usually about 1800-2200 rpm

the turbo is a variable vane type where the vanes in the exhaust shell around the turbine are moved to give maximum gas flow at low engine rpm
these vanes rust in the housing and do not move easily when the actuator is energized by the vacuum solenoid
the vacuum hose goes hard and cracks , actuators suffer from wiring problems
basically check that the rad that controls the vanes is free moving and that the hoses and wires are in good condition

this case , you have to check turbo charger , when high RPM white smoke means lubricate oil goes to engine so give white smoke . on low rpm trubo close coming black smoke means no enough air gose to engine so this need to replace turbo . some type of turbo can be clean the wase gate ( which open with diafam beside turbo) make sure it's moving when accilerate. check vacum is ok . then clean wase gate > only some type have wings inside )if no replace turbo

Sucking air somewhere.

Could be a vacuum leak as it falls off under acceleration and does not play a part then. Check for broken or cracked hoses.....

Hi,

If you have the turbo charged version, this issue refers to the "turbo dead zone" between 3500-4000 RPM. This refers to the no acceleration between these two RPMs and is caused by the time difference between the time the second turbo kicks in after the first turbo has activated. If you are referring to acceleration loss/delay below 3500 RPM, the issue is "turbo lag" which pertains to the delay in time between the stepping on the gas pedal and the 1st turbo activating.

In some other instances including non-turbo versions, the problem may be due to air leak in the intake manifold and the air cleaner. In the turbo versions, it would include the in/out junction of the blower including the clamps.

Hope this be of initial help/idea. Pls post back how things turned up or should you need additional information.

Good luck and kind regards.

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