ok so ever since i bought my forge wastegate actuator a funny thing keeps happening, everytime...literally everytime i try and make boost **** shoots to wastegate pressure like a champ so in my case 15 psi, now heres the problem i set my manuel boost controller to 20 and it will hit 15 quick then move very very slowly to the 20psi i set...just about getting there by redline, thats for 1st and 2nd gears 3rd and higher and the car usually gets to 20 in a respectable amount of time...but its wierd, a friend of mine had told me that its possible that the wastegate is bad...has anyone had this happen to them or have herd of this and wanna let me know what i gotta do to fix it

 

What boost controller are you running? Is it the stock turbo with a 10.5 hotside? Did you preload the WG at all when you installed it, or did you install with no tension? What is your target boost level? How much boost were you running with the stock actuator before you did the swap?

 

Hey did you try just dialing in more boost with yor MBC?

 

Did you just slap the new actuator on and you haven't touched the MBC's adjustment knob? What do you mean by "wastegate pressure"? Base WG pressure should be between 10-12 PSI, not the 15# that you are seeing?

 

If he has a WG with an upgraded spring but has slack in the adjustment rod it would get to his Waste gate pressure fairly quick and then be very slow to gain once the little opening in the flapper was moved a little further by the WG starting to open.

Try adjusting the preload on the WG actuator as Sparky said earlier and see if that doesn't help. Is that the only mod you have done since all was normal?

Sparky where in Honduras are you? I spent a year at Soto Cano. I'd love to come back!

Josh

 

How did you know that I reside in Honduras? It's always good to hear from a U.S. serviceman! Thank you for defending our country!

I think that maybe we spoke once over the phone when you were stationed down here. You were gonna come out to Tegucigalpa and get together with a few of the local Evo guys one Sunday. Maybe it was you that I spoke to. Take care!

 

Sometimes the ajustable actuator rod on the Forge VIII WGA needs to be tinkered with. It has to fit the VIII 16G with three different turbine housings(9.0, 9.8, &10.5).

The axial distance between the actuator mounted on the VIII compressor housing and the point where the turnbuckle end mounts onto the pivot peg mounted on the flapper valve differs with each turbine housing due to differences in the external diameters of each respective housing.

So, the length of the actuator rod required to attain base wastegate pressure differs depending on the particular housing used on the VIII 16G. Sometimes the rod is too long and the threaded end needs to be cut shorter, otherwise the flapper valve stays cracked open. This may be the situation in this particular case, but I need more info.

EDIT: At least the particular version of the Forge WGA that I had on my JDM VIII RS turbo w/9.8 housing needed to be trimmed when I switched the 9.8 out for a 10.5. See, I think that Forge Motorsport originally designed the VIII WGA back when there was not yet a 10.5 housing available. As I mentioned, the specific dimensioning/spatial relationship varies according to which housing you mount the actuator on.

 

ok guys, not my first rodeo so no there is absolutly no slack in the adjustment its an 8 with a 10.5 hotside, i literally have had to fight the rod to get it onto the flapper "nub" then put the pin thru it, its sealed very very well, i had only switched to a 10.5 from a 9.8 in addition to this...dont see how it cud cause this, and i am running a MBC its a hallman pro and the boost hit wat is set, the problem comes if you try to adjust for it with the MBC b/c in higher gears it hits the target boost so if i set it to 25psi to get it to spool quicker by top of 3rd into 4th ill over shoot the 20psi i want to run and where my tune is setup for...im going to try running the stock actuator n see what happens ill report back lol

 

Run a short length of vacuum hose directly from the compressor housing discharge nipple to the port on the actuator. Temporarily plug the two open ends of your boost/vacuum hoses which you just disconnected. Remove the cotter pin and adjust the length of the actuator rod so that it just slides on and off the "nub" freely.

Take the car for a spin. Do a WOT run in 4th. Check max boost reading. Should be between 10-12 PSI. Park car. Let engine cool off. Readjust(shorten) the length of the actuator rod by rotating the turnbuckle in two and a half turns(two 360* turns, & one 180* turn). Reinstall the actuator rod onto the nub and take the car for a spin again. After doing another WOT run you may have to adjust preload again by rotating the turnbuckle(eyelet) another one or 1&1/2 turns.

You should shoot for a preload level of somewhere between 17-18 PSI with the Forge actuator. This would be the ideal amount of preload for a stock VIII turbo/10.5 combo on pump gas.

After you've set the preload to 17-18 PSI, reinstall your MBC and adjust boost up to your target boost level with your MBC knob. Always set boost in 4th or 5th gear on a 5-spd car, not in 3rd gear.

 

the forge is out and the stock 8 actuator is back in same exact problem is occuring 15psi then rising as i climb towards redline, does anyone think its possible my hallman is taking a crap? i mean its never given me a problem before but honestly it cant be anything else the turbo is obviously making the boost i think its the MBC im gunna try n mess with it see if i can fix it

 

ok well i found the problem the rubber o-ring that seals the nipple of the boost controller to the actual boost controller housing had a tear in it, i replaced it now it hits like a champ, so i guess i gotta put my forge back in lmao dam!