Is My Wastegate Actuator On It's Way?

[Grimketil]

Hi guys.

Got a BFII turbo ZF 6spd with 140xxx km, running 60lb dekas and an 11 psi tune. All else it stock. Got a dyno run to see how it is all going, and it came back on the low side. 227 at the rears. The readout showed the boost hitting 11psi and instantly dropping in linear fashion until redline where it reads roughly 7psi or thereabouts.

For further testing a mate and I hooked up a boost gauge, which affirmed what the dyno run told us. 11psi down to 7psi over the rev range. What we found out furthermore, is on gearshift the boost returns to 11psi and drops again at higher rpm. So if you ran through the gears on the dyno the boost graph would look like a mountain range.

I called the dyno operator up, and he seemed to think either the stock dump and cat are too small (tried to sell me his 4 inch dump and high flow cat for a grand), or the stock actuator is worn out and opening under the pressure.

Does this sound about right to you learned scholars? From what I have read thus far from others experiences on here, I am thinking actuator. Lastly- is 11-12 psi too much for the stock flapper to control?

Thanks for your time

[FiftyOne]

Bit high but not unheard of. I'd have a go pumping a bit of wd40 in to the actuator & seeing if the spike isn't as bad to start with

[Ralph Wiggum]

Sounds about right for a stock actuator and cat combo. Boost will spike around peak ve for the motor, around 3500 then die off as the flow restriction ford engineered into the car takes over.

It could be a touch soggy with age (like dags) but I doubt that your problem.