Boost leak or new inj

[JDR7919]

Ok guys,
Here is the problem. I get lots of knock in the upper rpm range usually 5000 rpms or more. Im running like 20psi of boost my duty cycle is at 105% so I try to turn down my boost all the way down and Im still hitting almost 20 pounds.
Set the boost back up like stock and Im still hitting 20psi. I tried increasing my fpr to 45psi and the car stutters and blows black smoke like mad.
Turned that back down to 38psi does not stutter as bad but I still have really high duty cycle.
I have done boost test after boost test. I found that one of the bolts on my throttlebody is stripped and is slightly leaking.
When I do a leak test should the boost gauge in the car increase? It does not move, is this normal?
I think I just need some bigger inj but Im not sure way the boost wont turn down. I hooked my brother mbc up and it was the same.

What do you all think? Please give me some input.
Thanks
Jon

 

[JDR7919]

Any thoughts?

 

[Old Mitsu Tech]

Yes, Stock injectors, fuel pump etc can handle only around 16 pounds of boost. Get larger injectors, 190 walbro pump etc. Check in the forums to see how to make sure everything is matching. You have to get a handle on the boost situation. Get it turned down until everything else matches or you can melt a piston, valve, etc. Be careful.

Good Luck

 

[JDR7919]

I already have 550cc inj and a fuel pump. Here is a list of all my mods.
30 over je pistons
Eagle Rods
Balance shafts removed
3" down pipe
3" gm mass air flow sensor
upgraded fuel pump 255 Lph
550 injectors
Ported 16g
Ported O2 housing
2g ported exhaust manifold
act 2600
Fidanza Flywheel
4 bolt
Logger
FMIC
AFPR

Does it sound like I need new injectors? If so what size should I go with? What is the biggest I can tune with Maft vs 2.XX? I will be getting dsmlink in a few months.

 

[92GSXBaltimore]

you need to fix your leaks first!! helicoil the throttle body hole and get a new gasket. Make sure your intake/exhaust valves arent overlapped and letting air out of the cylinder when you are doing a boost leak test. If the in-car boost guage doesnt move when you put pressure in the system, then your leaking alot of air.