...hello, I am sure that this has been discussed but cannot find it in the archives. I have a 1999 S70 AWD and have decided to adjust my wastegate by shortening the pushrod. I have rotated it four complete turns and the car is boosting harder. Are there any long term effects to this or anything I should be concerned about. Also is four times a good jumping off point? Finally, will the car just retard my timing to the point that this is worthless? Everything else is stock.

thanks,
Stephen

Four turns is probably a bit much - I have mine set to two turns, and I'm seeing 0.5 bar in first and second gears (T5M). Full throttle in third and above gets me anywhere from 0.9 to 1.1 bar, depending on conditions.

The only negative - lower gas mileage.
--
'99 S70 T5M, '83 245 DL

You've just got stock readings (9-11 psi, not 1.1 bar or your pistons would be in the oil pan). I'd tell you to read the technical write up at tme.com, but the site appears to be down. Your ECU figured it out in 10 secs, and the rest is pure fantasy.
--
(98 S70 T5SE misc mods, mostly lighting) (92 940GLE)

No, I do mean 1.1 bar. Actually, just shy of. This was taken after a few hard runs with the wastegate adjusted out three full turns. I turned it back one turn since I hadn't yet installed the exhaust.
--
'99 S70 T5M, '83 245 DL

Your car's ECU will pick up the change and adjust performance accordingly. Some have reported a kind of low-end rush but it's temporary. Turn it too far and the ECU will shut off the engine.
--
(98 S70 T5SE misc mods, mostly lighting) (92 940GLE)

Steph, there's a ton of discussion on this on the 'Net. This site should have stuff plus I know for sure t5uk.com has it in (I think) his FAQs. Also on Volvospeed there's been lots of chat. FWIW I usually see 3 turns as the suggested starting point PLUS mark the stock setting, because if you chip the car, you will (i.e. MUST) set the rod at stock.

In short, the boost is under the control of ECU by sensing the pressure and adjusting the opening of wastegate through an actuator rod moved by a diaphragm inside the actuator subject to the pressure.

Shortening the rod temporarily prevents its opening under the stock setting of 3 psi, so that the exhaust gas can continue to spool up the boost till a higher pressure is reached to further push the diaphragm (and the rod) and open the wastegate to prevent overboost. The result is a shorter spool-up time. The ECU will, however, sense the change and adjust it back accordingly.

Installing a boost gauge is highly recommended before playing around with the boost pressure, even without any power upgrade, to monitor the boost and prevent potential damage to the engine.
--
JJ