In the following link they talk about shimming the wastegate with washers, is this safe?

http://supras.com/06/techcenter/display.php?QID=18

He said it was safe and easy and cheap. He also notes that anymore than 10psi and you need an aftermarket exhaust. But would this be safe with a stock setup? 6-10psi is a huge difference, almost 40hp if im correct. Input on this mod would be greatly appreciated.

I shimmed my 89T. The big intercooler had dropped stock boost to 7lbs. And I basically just wanted it just over stock. I got it to 10lbs safely but Im now hitting fuel cut. My turbo is pretty much junk anyways, and I have a stock replacement coming so I wasnt worried about hurting it. So long as the rest of your engine can support the extra boost its fine, and I would say with your list of already done mods it would be fine. Just dont get carried away.

Weezl - I thought your car was n/a? or is this a former car?

I sold my 86.5 NA, and bought a 89T.

Oh, didnt hear about that. congrats on the upgrade. I did the same thing haha. Sold my 86.5, bought my 88ttt.

Well I dont know if it was so much an upgrade...as a sidegrade. My NA was pretty friggin nice. Sure it wasnt a turbo, but it was solid and dependable. and I liked driving it.

The new Turbo has been nothing but problems. Sure it looks nice and goes fast...when I can get it started. I know in the end with time and patience and a bit of money I can make Lucy (thats her name, cause she is a freaky redhead) a nice car.

I still have an 89NA HT as well...which is still actually for sale..hint hint!

more power but safe.
 

increase the boost up to like 10-12 psi. you should not exceed 14 psi its unsafe to go over 14. if you dont have a boost conroller, put holes on the wastegate hose. 1 hole is equal to 1 psi.

at least buy a boost controller

i wouldn't recommend this... that statement is open to interpretation
i.e how big are the holes

and if you do overboost not forgetting toyotas little toy called fuel cut ;)

Yes, Mine is the same way. My n/a ran beautiful, Every time. Go outside in the winter and it starts up just like a brand new car. But my turbo runs like crap and now has a blown head gasket. lol. It wont start for crap. And once it does, It takes like 20 mins to warm up before it stops misfiring, And then when driving it seems to run fine, Like there is nothing wrong. But once it gets below like 1000 or 1100 rpms it runs like crap again and i have to nurse the rpms back up. Luckily its an auto, which makes it way harder.

yeah putting holes in your wastegate actuator line is inexact at best and dangerous at least. Shimming the gate is a proven and reliable way to increase boost. Short of getting a boost controller its the only thing I would even consider.

Isphius, my turbo runs great most of the time. Its just that when it gets hot sometimes it wont restart until she is completely dead cold again (like the next morning). I cant make sense of it, and have changed out nearly every part that could be suspect. She just seems to have a mind of her own. I just dont trust shutting her off somewhere where she might leave me stranded.