It won't do you any good. The ECU will pick up the alteration and adjust performance accordingly. Any initial surge you feel is temporary. Turn it too far, and the ECU will shut your engine off and won't let you restart.

Turbo lag is normal, especially in the high pressure turbo. The HP is a larger bore, thus takes longer to spool and pressurize. But once it's up, wooHOO! The LP turbo will get off the line faster, but it's like the Audi/VW 1.8T - it doesn't add much after a certain point. But the HP will get you to 60 and beyond, way beyond, faster.

If you want off-the-line performance, a different ECU is required, plus a stick shift...and for a real rush, maybe a little NO. Fact is, except in drag racing, off-the-line is a non factor as most races (and highway entrances) have a rolling start. But you're not racing and these aren't race cars. Not to mention that hard starts are the number one engine killer in production cars, so don't look for a company that prides itself on long-lived cars to give you enough power to take it to a premature death! The turbo is for passing power, hill climbing, Rte. 128's notorious 40-ft onramps, etc. Yeah, the automatic feels like a slug when starting out, the fun begins at 15mph.
--
(98 S70 T5SE misc mods, mostly lighting) (92 940GLE)

given the car is fwd and assuming the car is automatic transmission, the sluggish feel right off the line in a turbo engine is exaggerated. also, the volvo 850 transmission, though compact and shifts nicely, has a really low torque converter stall speed...rpm is right around when the turbo is just about to kick in. as for fuel, 91 or 92 should've always been used on the turbo. good thing u only have 39k on it using 89.

those tires don't rub? very interesting.

You could try disconnecting the battery overnight to reset the
ECU to original values. On my car, this does provide more "pep"
for about 20 miles (then the ECU re-tunes to local fuel, etc).
Make sure you have the radio code since you will have to punch it back
in to get the radio back.

Turbos do have lag. Not much you can do about it. A less restrictive
exhaust will reduce it (new downpipe and exhaust) but that is costly.

The low pressure turbo models (GLTs model year 97 and higher, and a couple
other models) use a smaller turbo to reduce turbo lag. This gives better
low speed performance but the trade off is less power once things get
"cooking". Basically, larger turbos meen more air moved but the increased
mass means it takes longer to get them moving (turbos can spin up to 100,000
RPM and that takes a second or two to reach). The R models and 70 series
actually use a larger turbo then the 850 Turbo models and may have more
turbo lag then you have (well, the 70s got a revised downpipe to help
with this).

850RCKT~

Is the heat shield you're taking about the one by the air intake box? Where exactly is this located and how does it help performance? Why is it there? Also what is the waste gate arm, and how can I turn that in? What exactly do these mods do? Would it affect my car negatively in any way if I do this? If I could get better throttle response I'm all for it!

Moregolf~

Yeah my problem may be two things. 1.), the previous owners (my folks) never used premium gas, just 89 octane, so I'm going to start filling it up with 91 or 92 premium and see if it advances the timing any, since apparently if you use less octane fuel the computer retards the timing. and 2.) last time the oil was changed was at Firestone and they used some sh*tty Kendall motor oil. I'm going to get it drained out and have Moble 1 synthetic put in it. My folks usually took it to the dealer for oil changes, but last time they took it to Firestone.

What is this BG 44k? Is it a fuel injection cleaner or what? Where can I buy this stuff at? I want to get some if it has a chance of helping.

Thanks!

I found that removing my heat shield and turning in the waste gate arm gave me a much quicker response from the pedal...If I want to I can smoke em off the line.....I don't because tires are expensive and I have 163K on it already !
Enjoy the car.........
--
Erik Volvo 854T 1994 Daily Driver and Project car

How often do you change oil, and with what kind do you use? I have an 850 with 80k on it. My wife just bought a same year 850 with 44k on it. Mine will leave the other one off the line. But..I flush the oil 3 time a year, then add Mobile 1 5W30... It is quick... The other thing I would suggest is putting a can of BG 44K in the gas. Let that guy clean itself out... Especially after winter additives..

Those changes you list won't help performance becuase you never lost any. Turbos take (relatively speaking) quite a while to provide boost because they are powered by exhaust gasses (far down in the heirarchy of engine events flowchart). And they have (obviously) mass, requiring a certain amount of energy before they start doing their job of compressing air by rotating quickly.

This lag problem has been solved by using 2 turbos (see Volvo S80 T6 and other automobiles), one small that spins up quickly (low mass) but provides little boost, and one large (opposite qualities). Also it's solved with supercharging.

Superchargers are driven right off the engine, usually via a belt, and thus spin up proportionately to the engine speed. But (as in everything in life) they have a tradeoff, and that is a direct sapping of engine power, whether or not you're wanting the boost.