Gtx3582 495Rwkw, Can't Hold Higher Than 18Psi

[Jesse Williams_49219]

Recently upgraded from the standard 35/40 to a GTX3582, I've got all supporting mods:

1000hp Plazmaman intercooler

4 inch intake,

3 1/2 dump with separate 1/2 wastegate pipe into gutted 3 1/2 cat and exhaust

Plazmaman hot side piping

Either a 10 or 12 psi actuator (I don't remember which one).

The turbo spools and generates 25psi easy, but drops straight down to 18psi and stays there.

Before gutting the cat it did the same as above but only sustained 17psi and 491kw rather than the 18psi and 495 now.

My tuner believes I may be lifting the head slightly

But others believe the actuator is too weak.

Any info would be appreciated

[Trent0]

factory boost controller?

[ratter]

that will make no difference

[Trent0]

Good input

[barnz]

Seems like pretty good power for a 3 1/2 exhaust and gutted cat? Most people at 500kw are running bigger. Alot for a stock bottom end aswell.

[Jesse Williams_49219]

The motors built, has a big fuel system and plenum etc etc. Everything I listed was all I could think that was relevant.

My tuner believes that 3 1/2 should suffice

[unclewal]

gotta be the waste gate not being able to hold pressure, my gtx was hard to get under 18psi

[Kosij]

To much back pressure.

[Kroozin]

Did you try disconnecting the wastegate hose?

If your game you could probly shine a torch down and look at the act. arm while he's running it up on the dyno to see if the arm moves at all..

Or

Remove O2 sensor and basterdize another o2 sensor to take a hose to run to a gauge to check for high back pressure. If your going to run it to a normal boost gauge I've heard of ppl running the exh. pres. thru a copper tube/pipe 1st to take some of the heat so ya don't f*ck ya gauge... however the bloke with the dyno should have the appropriate sh*t to do it too