an 89 2.5 can take 35 PSI of boost?
Any 89 and newer commen block 2.5 TURBO can handle 35 PSI of boost stock. That question is directed at the engine, the engine can handle it.
You must have the computer, intercooler, head gasket, turbo and so on to use it. Just simply turning up the boost to 35 PSI will run the engine super lean and melt all 4 pistons, which would be dumb of course.
Why can a 2.5 stock handle the boost?
Mahle pistons, with copper added instead of more silica, they can handle heat better. The pistons have a moly ring that can handle more heat and there is a steel strap cast into the piston by the ring lands to make them handle even more shock. A really HD piston for a cast piston. Then the rods are nearly 50% stronger than a V8 Chevy rod. There longer and have larger bolts even, they also are a float pin type. The block is iron not a POS aluminum block with floating cylinders like a Honda. The bores are simeased together and the deck is solid, stock.
35 PSI on a stock engine is around 300 + WHP and torque over 400 ft lbs. With a big valve head, large plenum intake and a header and so on things change pretty fast. Build the top end right and run a huge turbo and the WHP will go past 400 WHP towards 500 WHP these days done right. At these levels the bottom end needs more done to it, but the head and POS 1 piece will restrict power below the limits of the engine.
Clearly simple things apply. Raising the boost to 35 out right, which there is now way a Mitsu turbo can push it isn't going to happen. Then you can just take an engine with 200,000 abusive miles on it with wasted rings and bearings and push it either. A low miler or a corectly rebuilt engine to stock specs will do fine. But you have to restore a van first, there 20 years old. Which takes time and money, then add new mods and take off. A little commen sense goes a long ways.
