Ok, so I had a t28 turbo fitted to my ca18det and it now doesn't want to rev anywhere. It's super laggy, but way worse than I thought it would be with a bigger turbo, and when it hits around 5000RPM it doesn't go anywhere, hesitates like mad and the car gets all jerky and stuff. Fuel pressure should be fine, i have a new fuel pump, and pressure gauge reads ok.
Spark might be blowing out still? plugs are gapped fairly small (i think 0.7mm from memory). Do i HAVE to get a tune to run a t28?

my mates car did/does the same thing. only running 4psi till 5000rpm and seems to go nowhere compared to mine thats pretty much the same specs. then over 5000 the boost goes up again, had it at about 13-14psi at 6500rpm. definately goes once it has the rest of the boost into it

weird thing is it never had that problem with the 2.5 inch exhaust. it was just slugish all over and then didnt really want to go past 5000

anyway, to help you
my 1200 is running a t28 on 7psi, pod filter, front mount and 3 inch exhaust, have a walbro fuel pump running i think 36psi fuel pressure on idle. also has no idle control stuff anymore

ran perfectly fine on the mines tuned ecu i had, and runs fine on the ecu in it now
unsure on how standard the tunes are on them but ive also run a dead stock ecu and all 3 have ran fine

so id say no you dont need to tune it for a t28, it would only be if you upped the boost a lot that you would want to get it tuned for safety

Do you have a boost gauge?, sounds like you have a boost leak somewhere.

I would get it tuned, either piggy back or standalone ecu to get the mixtures right, to run with out your running your motor lean n prob detonate, you stock ecu is programed for the T25 if the T28 is flowing more air than what your ecu is programed/tuned to, you will have more air n not enough fuel.

I'm curious to know if the blacktop sr20det T25g flows as much at the ca18 turbo T25

check the ECU codes (flashing red/green lights on side of ECU). that shiz aint normal.

Hook up wastegate actuator to normal vaccuum, bypassing the other bleed valves and factory boost solenoid.

Sounds a bit like boost cut.

I have a manual boost controller, brand new. also a boost gauge. i tried low boost and high (7-13psi) and it still has the same effect. So the pressure is there. Feels like it wants to get on a little bit but then just lurches. I have around 50 psi fuel pressure at idle, I haven't touched the fuel pressure from when I bought it. Could I be maxing the injectors?
So far I am not super impressed with the ol' CA18

hey element normally ca18 should have 36 psi of fuel pressure at idle with the vacum hose disconnected . maybe try running no boost controller and just running it staright of the wasgate which should be around 7 psi and maybe dropping the fuel pressure a bit, its very strange as i have a t28 on my factory computer and run it on 15 psi with no dramas

Sounds like a boost leak my ca didthe same thing in my old ke70

Ok thanks i'll try running no boost controller, and also run a diagnosis. Is it possible to have a boost leak when the boost gauge is reading fine? It wont be at the turbo, I just got some leaks there fixed.