I bought a 1987 Toy with a 22RET last summer, the guy I bought it from was very meticulous on taking care of the engine, reg tune ups, lubes and oil changes. The truck has 177,000 miles and runs strong. I did have to replace the exhaust system with a high flow cat as well as muffler and the piping is 2 1/2 inch diameter. The reason it was replaced was because I wanted to open the exhaust as well as multiple exhaust leaks. My question is, will the larger exhaust cause any damage to the turbo? Could have the leaks also caused any damage? The leaks were after the turbo. Also is the turbo oil or water cooled or even air cooled and how is the turbo lubricated, does the lubrication come from the engine or does the turbo have a reservoir somewhere?
Enough of the questions. This is my 1st post on this site and I hope I am in the right spot for this.
You can also check out my web site, if you would like. Michaeljacksonsatoyota.blogspot.com
You will have to read it to figure it out.
Thanks again
JMach1

 

The exhuast leaks should not have caused any problems. The bigger exhaust will help the turbo spool easier without the backpressure so that's a good thing. But keep an eye on the turbo exhaust housing, they are known for cracking on the Toyotas. I had an 87 4Runner turbo that had a cracked housing. The stock turbo is water cooled and it has engine oil running through it for lubrication. The stock oil supply line is real close to the exhaust manifold and it can cause it to clog up the oil supply to the turbo because the heat can slowly cook the oil inside that line. I took the time to port out my exhaust manifold and turbo exhaust housing when I replaced the turbo. I think it helped it pick up some decent horsepower because it ran really strong when I put everything back together.

 

In addition to JL8Jeff's comments, I'd add rmoving and cleaning out the oil feed tube with one of those small wire bottle brush deals which will remove the built up, burnt on oil deposits.
Then before reinstalling it, I'd also wrap some "heat tape" along the full length of it to prevent the very same thing from happening again, as a little preventative maintenance, ya know ?!