LVSBB6

iTrader: (4)

I`m currently running Cobb Stage 1 with peak boost of 21.8psi tapering to 15psi by 7500rpm, which is lower than the boost target set by Cobb (24psi tapering to 17psi).

Rather than adjusting the stock wastegate actuator to reach the desired boost, I am going to install the Jun uprated actuator to achieve more stable boost output.

Now to ensure I`m not overboosting, how much preload should I set on the Jun unit? Most people here run the Forge unit with red springs (19psi-24psi) with 1/2 turn preload with success.

The operating pressure of the Jun WGA is lower at 14psi to 18psi, same as Forge with blue springs (14psi to 18psi), and stock WGA is 14psi to 16psi.

With this info, can somebody tell me how much preload should I set on the Jun unit to achieve 24psi peak boost without overboosting?

Clipse3GT

iTrader: (10)

Why not just get a boost pill?

Hiboost

iTrader: (9)

1/2 turn of preload worked out to be the best for me with one caveat, once you install the unit things tend to stretch out a bit after seeing extreme heat cycles. After a couple days at Watkins Glen I ended up checking it and it barely had any tension on it at all so I went in another 1/2 turn for a total of 1 turn preload out of the wrapper.

Based on my testing on the Forge unit, likely each 1/2 turn will increase minimum boost by 1.5-2 PSI if I remember right. My minimum boost was 22-23 PSI with the 1 turn in. I would suggest 1.5 or 2 turns as a good starting point, using 4th or 5th gear at 3-4k rpm's to measure the setpoint.

Another way to go is to check how many turns you are in from zero on the stock actuator, then add about 1 full turn for the JUN since that will likely give you around 2 PSI higher than your current setting. When replacing the actuator, I found you could slide the exhaust manifold heatshield to the passenger side and then downwards to get it out of the way. For leverage on moving the wastgate arm it's best to grab the actuator with your right hand near the eyelet, and then grab your right arm with your left hand and force it to the passenger side for better leverage.

Let us know what works for you!

LVSBB6

iTrader: (4)

Thanks for the info!

Papi4baby

iTrader: (1)

Hey LVS also use the AP to look at the boost to make sure you are not overboosting. I think COBB is suppose to release a fix soon to remove the boost limit readings. Best of luck, and post a review on the JUN WGA.

Silvermike

the preload is measured from the point at which the actuator arm just fits ove rthe flapper?

... so 1 turn preload is 1 more turn past the point of 'just' fitting?

SiC

iTrader: (1)

Cars with different parts & tunes will react differently to the preload settings. You'll need to lower the preload at first and work up from there. Also, remember to check/adjust your boost in the higher gears (4th or 5th) from around 2500-4000 RPM. Adjusting boost in the lower gears will give you a good chance of boost creap in the higher gears.