j.packsb

i have a stock d16y8 with a garret t3 50 trim .42/.48. its tuned and the desired boost level is about 12 lbs. the problem I'm having is that in 2nd gear, it makes about 10 lbs and then falls to 8ish, but as soon as i shift into 3rd, it hits 12 lbs and hold for the most part maybe falling .5lb or 1lb. then in 4th, it hits 13 lbs and holds? I'm using a cast mani with an external wastegate and a old school hallman boost controller. the vacuum source is after the intercooler. any reason why my boost is basically fluctuating from 8lbs to 13lbs depending on what gear I'm in and why it falls to 8lbs in 2nd when i want to be hitting 12lbs in every gear??


EDIT before its asked:
Boost controller is new.its just the old school style. I'm tuned on chrome so no boost by gear. External ebay watergate but I've tried a friends tial and that's not the problem. And no boost leaks...
wastegate source is T'd into the brake booster line. its got a 7lb spring in it. ive tried putting two springs in the wastegate and not use a boost controller but it still falls off in 2nd and doesnt make as much boost. everyone i know using bigger turbos like 57 trims and super 60's dont have this issue. is this a small turbo problem?

Turbo-LS

iTrader: (4)

EXTERNAL EBAY WASTEGATE

there junk and you will never get consistant boost pressures. Been there done that man. you can cheap out on stuff even a ebay turbo but the wastegate is important. Id run a used tial or turbosmart before running a new ebayer or obx junker

Also invest in a good MBC like a turbosmart tee boost

j.packsb

i was otld that already and borrowed a friend's ebay wastegate that works perfect on his car and it didnt change anything. still think it could be the issue though? and whats wrong with just a basic hallman screw-type manual boost controller?

Turbo-LS

iTrader: (4)

what manifold are you running? lower boost in lower gears also isnt nessesarily a bad thing, helps with traction. basically you have a boost by gear right now lol

I run boost by gear with my hondata and its the best thing . low boost for great traction in 1-2 gears and the boost cranks up in 3-5 gears

TheShodan

iTrader: (14)

Could be a failing turbocharger as well. some of the parts could be causing a restriction. Not everything that causes failure is related to just "shaft play". Loss of boost is a symptom as well. How old is the unit and where did it come from?

j.packsb

got it from a saab. no shaft play, side to side or in and out. also no oil in my charge piping, nor in the compressor housing...

j.packsb

also, im using a log manifold...

j.packsb

Edit: I did a little searching after the post about the turbo being bad. One of the blades was chipped a little bad when I put the turbo on and its always sounded like a supercharger. Way too loud but I never thought anything of it and apparently that's a sign of the turbo going bad and being off balanced which could be caused by the messed up blade.so I guesses that my turbo is bad and I have an ebay 57 trim in my near future...

TheShodan

iTrader: (14)

Again, there are other ways a turbo can die than just the failure of the sealing ring and backplate and "shaft play". the internal journal bearing can wear down to where the turbo just isn't sustaining boost pressure.