I see all this, but there are a few guys on customtacos that are running 15psi boost on their stock long block 2rz's (with metal head gaskets and head studs) and makign 250whp no problem, and they also have a high compression ratio.
Hell, they're turboing completely stock 3.4's and making 350hp.. all of these intercooled of course... and no problems.
Howcome the 22re is so troublesome with boost?

Pretty hard to compare a barely-refined forklift motor like the 22RE/RTE with a DOHC mill like the 2RZ/3RZ.

Of course, people can (and do) turbocharge all sorts of motors, some more successfully than others. The 22RE/RTE has a first generation digital EFI system. It has a very simple closed loop mode, a rudimentary knock detection system, and a very old fashioed flapper-door style AFM. You can stuff a lot more air into it, but the computer doesn't know what to do with that air, and you can open a large can of worms trying to fool the computer into giving the system enough fuel to match the increased air flow. Been there, done that, and it didn't work too well, which is why I ultimately moved to a standalone EFI system. MUCH better, but not financially realistic for most people unless you go the MegaSquirt route, something that wasn't available to me when I was at that point in my project.

As for low boost turbo systems: IF you change to larger injectors you can get away with 3-4 psi on a stock 22RE. If you change to lower compression pistons and larger injectors you can sneak that up to 6 psi or so. It may not be painless, and it may not run smoothly throughout the powerband, but it should tolerate those sorts of numbers, and it will give you an extra 15-20 hp and comparable increases in torque. More than that is definitely pushing it on an otherwise stock 22RE.

Keep in mind, the stock RE makes 116 hp at the flywheel, while the stock RTE only makes 136 hp -- and to make that extra 20 hp, the Toyota engineers gave the 22RTE 50% larger injectors (295cc/min vs. 195 cc/min), a different head, lower compression pistons, and a turbo-specific ECU and AFM. All for a very modest 6 psi of boost.

One point that tends to get overlooked in these discussions is that to be successful and reliable, a turbocharger needs to be integrated as a system, not as a bolt on. This isn't a header or a cat back exhaust -- this is a heat pump, and it will draw more air, use more fuel, generate more heat, and expell more spent gasses as a result of its installation. Do it right and it's your friend, do it wrong and you will get to spend future weekends fixing the stuff that breaks.

Sorry if I sound like I'm beating a dead horse, but I get a lot of email from folks who want 200+ hp for $200 and a weekend's worth of work, and then get unhappy when I tell them that it doesn't work that way. My own experience with this motor tells me that there are definitely better motors out there to turbocharge -- where a modest 6 psi gives you a big seat-of-the-pants thrill, and where the stock fuel system is very tolerant and has all sorts of overhead built into it to accomodate a forced induction system. The 2RZ/3RZ is one of those motors. Unfortunately, the 22RE is NOT. I have spent years and lots of money trying to make a silk purse out of a sow's ear. I now have a very fast sow's ear <img src="/forums/images/graemlins/notooth.gif" alt="" />, and learned a lot about the perils of purse making in the process. I have also have a good sense of when does and doesn't work when you turbocharge this motor. Cutting corners DOES NOT work, at least not long-term. Reliable turbo motors require planning and some sort of budget. They also require reliable fuel injection (which, along with the headgasket, is the biggest Achilles' heel in the 22RTE). The stock RTE EFI setup is perfectly serviceable up to 150-ish hp -- people have taken it a lot higher, but I think it gets flakey above the 150-160 mark. The stock 22RE system -- which looks similar but uses different fuel and spark maps, in addition to different injectors -- can barely handle 140 hp.

Even if you are just playing with the idea in your head, make sure you include a RELIABLE, turbo-friendly EFI system in your plans. In all honesty, the turbo is the easiest part of this system to install, while the tuning is the hardest to get right, while also being the most important.

My .02 cents,

-Jeff

remember, this is all speculation at this point! otherwise i'd be making the guys at LC much richer!

you do raise a lot of good points, mosk. the EFI system as a whole is what kind of throws me off, since i'm mainly a carb guy and i'm still learning the fuely thing.