Turbo Manifold issues

[Gravy]

Ok, first few rounds of questions i'll post this, this is not my car i'm working on, but my DSM knowledge is fairly deep.

1992 AWD GSX with LSD and ABS 6/4 combo with a 5 speed. 2.5 turbo back Custom Exauhst with Boost controler. Other then that, stock.

After the 2.5 TB the car went from 11psi to 15psi, and if you give it too much gas it gives you 20psi of hellishly hot air. So, i know the fix for this is Porting out the O2 pipe, and even the turbo exauhst housing a little. My question, do i have to remove the turbo in order to do this porting? Or can i get by with unscrewing the center section, removing the bolts to the exauhst, and just remove the exauhst housing?

My second question, how much should you port off? I've check on VFAQ and they show pictures, and i've read around on other forms(MachV) and havn't got much to go by other then pictures, and "Your gut feelign". Will porting too much off hurt the turbo much? A 16g is in plans in the future, but i'd hate to mess the car up so i couldn't joy ride in it once in a while.

Thirdly, i know the first gen manifolds are prone to cracking, and with this said, i may be removing the 1g stock manifold and since i lack the funds for a 2g, would porting the 1g out just a hair help performance some? I don't think it will kill me to have a small crack, seeing as i'm missing the top bolt on the passengers side, and already an losing plenty of exauhst.(mind you, i'm still creeping to 20psi) But when the manifold comes off, if it does for the turbo, i'll be extracting that bolt and throwing a new one in there.

Thanks in advance for any answers, and don't be afraid to talk like i know what i'm dealing with. I've read up on DSM's for 4+ years and worked on a 1.8l, so you can use the technical Jargin.

[tim]

As far as too much boost I think your MBC is just set wrong. There is no way the 14b would creep to 20psi with the 2.5" exhaust even though the o2 isnt ported, unless the wastegate isnt opening or something.

[Gravy]

More info after your answer, there is NO MBC and the car knocks like a son of a bitch. I can't even drive it any more in fear something will break.

The 14b is climbing up really fast, the car pulls 2x harder at 3/4 throttle(doesn't creap past 15psi till you hit 6-6.5k rpms) then it did before at full.

The wastegate opens when pulled on, the vacume line's are all intact, and when you gas it nice and hard at idle the arm opens. I'll be removing the cotering pin and removing the wastegate actuator to drive it over to my place to work on it.

[Pimpin Dsmstyle]

Wastegate might not be working properly. You said that your lines were all correct but from past experiences, it seems like the line coming off the actuator isnt on. Possibly something wrong with the boost solenoid. You really shouldn't creep like that on a 14b with 2.5 inch exhaust.

[Gravy]

i'll double check all the lines, but when Febo and I ran through it everyting was hooked up, and when you gunned the gas the actuator arm would pull. And it's hooked up. So unless the flaper welded it's self shut inside, it should be working.

I'll give it another one through on the hoses and try and find out what's up.

Going to try and port out the exauhst this weekend. May have some free time.

[Gravy]

Bumping, next week i may be doing the radiator swap, is it possible to take the exauhst side off the turbo while still leaving the rest of the turbo hooked up? I'd like to make the job as easy as possible, but what must be done will.

Porting will take me a good little while, so anything else anyone would recomend on a $0.00 dollar budget to do while i'm working on the exauhst?

[Jepherz]

You can remove the turbine housing with the turbo still in the car. Of course it will require you to remove the manifold and all of that crap too, but at least you won't have to undue the turbo oil/water lines.

When it comes to porting, you don't wan't to have any steps for sure between any transition. you want to port "match" everthing, because these steps cause eddies of interference in the flow which isn't helping you at all. If you haven't ported out the fire ring step, this is obviously the first thing you can do, both on the manifold side and the turbine housing side.