when adjusting preload, say using the red spring on an evo 9 acuator, which is rated 19-24 psi. does the wg hold the set psi across the rpm band.... say 24psi form 3600- redline? or does the preload value just adjust the initial boost spike?

 

Shadow: The proper way is to 1st run a 4mm hose directly from your boost reference source(compressor outlet nipple, aka "J" pipe), to the nipple on your Forge WGA. Or the easier way would be to just turn your Forge UNOS WGA out to full-soft(counterclockwise), which would be the lowest boost setting on your UNOS.

Next, loosen the backup nut behind the turnbuckle on the end of the threaded actuator rod with a suitable open end wrench. Remove the cotter pin that holds the turnbuckle onto the WG's pivot arm. Pry the turnbuckle/actuator rod assembly away from the WG's pivot arm by using a flatblade screwdriver.

Adjust the turnbuckle by rotating it on the threaded actuator rod. To start, adjust it to where the hole in the turnbuckle freely slides on and off of the pin on the pivot arm while you tension the pivot arm back toward the actuator canister with finger pressure.

This starting point, where the turnbuckle will freely slide on and off of the pivot arm is known as base WG pressure. It should be between 10-12 PSI. You can take the car out and boost it in 4th to verify base WG pressure.

Next from this base level, you'll want to increase the preload so that the WG flapper valve is not cracking(starting to lift off its seat) at 10 PSI. How tight you want to set it is up to you. On 94 RON gas and 24 PSI peak, with the Lite or a White, I would say set it at 17-19 PSI on the spring and then your final adjustment above that level you'll do with your MBC.

For competition, or, if you want maximum spoolup you may want to shoot for a spring pressure just 1-2 PSI below your peakboost setting. E.G., for a 24 PSI peak you may wan t to preload the gate to 22 PSI.

So, back to the adjustment. From the base setting of 10-12 PSI, once you'e pryed the turnbuckle away from the pivot arm and the backup nut is loose, you'll want to rotate the turnbuckle in toward the actuator canister which will effectively shorten the overall length of the actuator rod.

You'll want to start by rotating the turnbuckle end in by three full 360* rotations. Hook everything back up and do a test run. Boost should read about 14#. From this point you can give it another complete turn in again. If this gets you to about 16-17#, then you should proceed with caution from this level with only half turn increments(180*) till you preload the WG to a point where spring pressure is two to three PSI below what your peak boost level will be. The final three PSI you'll adjust with your MBC.

EDIT: You want to avoid rotating the actuator rod itself. This is why you first loosen the backup nut while the rod is still mounted onto the WG's pivot arm. You only spin the turnbuckle and NOT the rod(arm) itself!

 

Thank you for taking the time on such an accurate and concise response, Sparky!

It all makes perfect sense now...will be an interesting weekend project.

Cheers.!

 

I bought it from a vendor on this forum. It was shipped without a Forge box. How else can I tell? I bought it last November.

 

Positron there is a pressure pistol (pump) with a gauge that you can use to test the actuator while the turbo is not installed in the car. This way you can see for yourself at exactly how much boost the w/g will crack open. The actual boost that you will get when driving will be slightly different because of the hot exhaust gases pushing the w/g to open, but you will get an idea about the spring that is in there. You can always use the FP wastegate and see which one you like most.

 

Hey Sparky - just wanted to thank you again.

I adjusted my preload to 1.5 bar using your methodology and dialled in the rest using the MBC.

20 clicks on the UNOS gets me to about 1.6 bar perfectly, tapering down to 1.5 at redline, which will be my track setting.

70 clicks on the UNOS gets me up to 1.9 bar, tapering down to 1.7 bar at redline which will be my street setting (which I'm tuned for already by kreionic/chad @CBRD - 0 knocks).

Best part is the improved spoolup and consistency. I'm hitting peak boost before 4k rpms every time now just like a BBK Lite should (used to lag a bit more and taper a bit more with my old WGA/UNOS settings - wastegate pressure at 1.3 bar). Also, no issues with creep, spiking or exceeding my target boost in the higher gears - UNOS BOV is limiting me to 1.9 bar perfectly every time, even in pulls from 5th at highway speeds.

Taper is also not bad at all - I'm holding boost well up to about 6.5k rpms and tapering down 0.2 bar by 7500 which is just fine.

So cheers man, you've made me a very happy puppy. Been trying to resolve my boost issues for months, ever since I got the BBK! Car is the monster it should have been now

 

Sparky, how does this work with ECU controlled boost through a solenoid? Do I still adjust to 3psi below my peak? For example I am installing this myself but I have a stock tune right now. What would I adjust my preload numbers to?