car won't hold boost
 

like the title says
anyways i had my car on the dyno this sat i can get the car to spike just about what ever i want for boost but no matter where i set target boost it will tapper to 20 to 21 psi

we have boost leak checked it
compression check
leakdown test
tightining the wga

have tried
mbc
ebc
ecu boost
all three do the same thing

my mods are

fp red
cos mx1 cams and spring
perrin front mount
ttr hard pipes
forge bov
forge wga
fuel pump
ur exhaust (with test pipe)
aquamist hfs1
dw 800 cc inj

so no matter what we do the boost will spike hold tell about 4500 to 5000 rpm then drop to 21 psi
so if anyone has any ideas please post them up

my results so far are 430 whp and 377 wtq

thx

i'm assuming the boost leak checked out fine right? anyway, ooohh what i'm thinking is a bad red...hopefully not...

do you guys think if i go to an external 44mm wg this will fix my issue?

just had a similar problem with my car. the actuator on the FP red can only sustain about 22psi running a pretty heavy duty cycle. you'll have to look at upgrading it to a heavier duty one

he had a forge unit on there at one point with the same issue

Try swapping out the BOV to the stock one and see if it holds.

I have seen more than one fp red hold 25 at redline, something is goofy.

I agree, put the stock DV back in, that has been an issue with others. My DV works at 30+ psi, you should be fine.

boost leak test is your friend.

check your BOV, MBC, and WGA.

i boost leak check the system up to 27 psi with no leaks
i have changed the bov to the stock and then back again
i best i can get it to hold is 22 to 23 psi with the avcr duty cycles maxed out and the wastegate preload very tight

i guess im going to order a new down pipe with the 44mm external wg and hope for the best

Old but were u ever able to fix the problem?

Vaccum leak can also the cause of this

Did you really bump a eight year old thread?

btw, the stock turbo cannot sustain more than 20-21 psi out the top. This is normal for it to taper boost.

Yes I did because I'm having boost target issues. I would like to know if anyone can recommend a fix to this? I did all of the same stuff the OP did but I'm not able to see high psi at all. Only seeing 22 psi all the way to redline. This is an old thread so someone should have some helpful tips rite?

what turbo setup and what WGA

I'm running a Arashi 25g turbo and the wg that it came with. The turbo is only 4 months old. Never really got into boost bec I was untuned. It has no shaft play, does not burn oil, no smoke. My buddy is running the same exact turbo with no issues. I'm on e85 w/ all the supporting mods and using a mac ebc. Compression test was good. Boost leak test was bad at the throttle body so I got a brand new fb 70mm tb. Haven't got a chance to do a new boost leak test since the new tb was installed last week. The car feels great but I'm only getting 22 psi. I was aiming for 30 psi and then gonna turn it up to 33 psi.