boosting 14psi then dropping down to about 9 at 7k

[fenderguitarist]

ive been having some problems with my boost i recently turned it up to 14psi with a hallman es mbc it ran awesome spinning 1st, 2nd, and 3rd soon after i got a exhaust leak found out it was the bolts on the exhaust side of the turbo housing i fixed it no more leak took it out has alot better response but still falling from 14 to 9psi basically having no power i have a aem wideband hooked up and at wot i have a reading of 10.0 to 10.1 (lowest aem can read probably richer then that) and idle is 13.1 to 13.6 really rich im gonna change the plugs tomorrow and see if it makes a difference can anyone give me some helpful advise on what i should check next im gonna make a boost leak tester sometime this week whats the diameter of the inlet pipe on the t25?
Modified by fenderguitarist at 6:55 PM 2/1/2009

[fenderguitarist]

changed plugs no difference really. i noticed on the highway if im in 5th and boost it will hold a constant 14psi what can the problem be?any help?
Modified by fenderguitarist at 9:15 AM 2/2/2009

[240_SeX]

14psi is really pushing the t25

whats happening is you are out flowing your turbo, basically your turbo cant flow enough to keep up with your motor.

I would turn the boost down some, 14psi on the t25 will cause premature faliure

[fenderguitarist]

but if its flowing steady at 14 in 5th gear why cant it in 1-4? i hooked it up to the wastegate and it seemed like it was dropping at 7psi too so i got a boost leak tester coming in any one got any other ideas?
Modified by fenderguitarist at 8:50 PM 2/3/2009

[240_SeX]

what RPM are you getting 14psi in 5 th?

a boost leak test is not a bad idea

[Emperor_Tha]

Sorry double post

[Emperor_Tha]

Upgrade to a hks wastegate actuator. Or use a electronic boost controller. Might hold peak boost a little longer.

[Donkey Kong]

i have an electronic boost controller it wont help the only reason your car boosts better in 5th is because the motor has more strain on it if, you have a steep hill around you go up it in 3rd and 4th it it will hold 14 longer my car does the same thing, bigger turbo is the only solution

[fenderguitarist]

what RPM are you getting 14psi in 5 th?

a boost leak test is not a bad idea

roughly 3-4 thousand rpm on the highway seems like its holding well i tried a different manual boost controller and no change although my afr's seem to be clearing up a bit im getting some 16's at idle and around 11.5 wot but still falling boost im waiting for my leak tester and im gonna compression test tomorrow ill let everyone know the results thanks for the help
Modified by fenderguitarist at 8:36 PM 2/5/2009

[Emperor_Tha]

If u can search for FlatBlackIan "she lost her viginity on the dyno" (something along that line) thread. It has a perfect t25 boost vs rpm graph. It went from 14psi at 3.5k then droping to 10psi after 5k.

Sorry I can't copy and paste on the iPhone.

[Madriftshocker]

Before or even after doing a boost leak test. Try applying the brake, (ONLY TO LOAD THE ENGINE; I.E. SLIGHT DRAG), when driving and see if that corrects the issue with your boost dropping off. This will help you to pin point the problem.

[fenderguitarist]

fixed boost leaks had a few, cleaned maf put new plugs in and did a compression test 150psi across the board still running really bad idle is something like 12.8 -13.0 wot is about 10's and still loosing boost idk what else to do already **** is driving me nuts should i get a adjustable fpr??

[RPS13 DRIFTER]

anything above 12 or 13 PSI you will have boost drop off at high RPMs because the T25 is out of breath,from my experiance

[the converted]

+1 At high RPM a t25 just can't move enough air to create 14psi. All your really getting up there is a lot of hot air anyway.

[fenderguitarist]

ill drop it down a bit see what happens any idea on my richness problem???

[fenderguitarist]

dropped boost down to 10psi still losing pressure i did a boost leak with the throttle body closed should i redo it and open the throttle body??? would that be able to check for intake leaks?