potatochobit

iTrader: (1)

something seems to be wrong, i think its a solenoid.

after light cruising at highspeeds, sometimes i get no boost at WOT. i might get some boost, but its always low. i had 4.4 in 4th gear, then i switched to 5th, and it dropped to 2.2. sometimes ill get almost no boost. after a few minutes, the problem goes away when i go WOT in say 3rd gear and i get 10lbs again like normal.

any thoughts on what would be causing no boost in 4th gear at WOT?

does it sound like the 2nd turbo is not coming online?

alberto_mg

i had some odd issues like that with my old car. only seemed to happen in certain gears. drove me and my mechanic nuts. check the vac hoses under the crossover pipe, check the rubber hoses for the 2 acv/bov things for cracks. test the two solenoids at the front of the uim - i think they are the prespool and wastegate solenoids.

the final cure all for all my boost issues was the profec b spec 1

quicksilver_rx7

If you running the twins, it could be the simple fact that you run the car up past 4,500 rpm when the second turbo comes online and you don't let it drop below 3k to disengage the second turbo. Therfore, the twins are locked in parallel and it's slower to build boost that way.

potatochobit

iTrader: (1)

yea, im using a profec spec 2.

even if i hold WOT all the way to redline, it still wont build boost past a few pounds, but ill check again.

charlies7

iTrader: (4)

dam your redlining your car in 4th and 5th gear....you must be going really fast )
maybe there is a leak somewhere in the rats nest of vac hoses.

jd to rescue

iTrader: (3)

Your probably not maintaining vacuum pressure. A simple check is to pop off one of the hoses on the front pressure tank immediately after you shut down the engine to see if you get a "psst". If not, then you have a vacuum leak somewhere in the rats nest, i.e., crack in solenoid nipple, hose, etc.

potatochobit

iTrader: (1)

lol.... not redline in 5th....