Miscellanious notes and recollections about turbocharging and forced induction.

As echoed by previous posters, turbo's add what my dad deems unecessary complexity to a car. The main reasons are outlined above, but I feel it necessary to add more.

Notes about turbo'd cars:

note: I consider this last note to be the minimum level of modification you should apply to your turbocharged vehicle. It will cost you aprx. $1000, but the longevity and horsepower gain will more than make up for the initial outlay.

Parable: I own a turbocharged, 1990 Ford Probe GT. This car has been one hell of a learning experience. I comitted the 3 cardinal sins of used car buying, all in the same car! 1) I bought a turbocharged car used. 2) I bought it from a mechanic. 3) It was a salvaged vehice. It should be fairly obvious why these are classified as sins. If not, I have a car I'd like to sell you. :)

Anyhow, the car provided decent performance stock (rated at 145HP @ 4800 RPM, 190Ft/Lbs of Torque @ 3500 RPM, according to my Chilton's manual), and after the addition of the above mentioned components, I felt a marked increase in low end torque and horsepower. (I did not have access to a dyno to confirm this, but going from a 15.5s 1/4mi to a 14.2s 1/4mi, I'd say that's good enough.) Also, I started using synthetic oil. All was indeed fine for about a year after I bought the car in 1997.

Around late 1998, I noticed an increase in problems with blown coolant hoses. I was replacing hoses on a monthly basis, during both summer and winter months. (As anyone who's ever had to shop for parts knows, the odd-ball parts on odd-ball model cars gets harder to find as years go by. When you do find them, they become expensive. Case in point: $17 for a small 3" long coolant bypass hose!) After replacing almost all the hoses, a strage, white, acrid smelling smoke was billowing out of my tailpipe.

An independent mechanic inspected the car, and determined that the bearing seals in the turbo were shot. He readily admitted to avoiding turbos, and suggested I see the dealer. I did, and they replaced it to the tune of $1500 for a used turbo, plus labor.

Not sooner than i drove off the lot, did the engine start smoking again. I took it back that second, and they said I should just let the oil burn out of the catalytic converter. (If you're not shrieking at the horrible mistake of that advice, read on.) So I kept driving it. At the time, I was working out of town, and commuting every day. And no sooner than 2 days after I got back to work, I noticed the smoke again.

I took it back, they had to replace the turbo for the second time. This time, they cleaned out all the oil from the rest of the parts (like the intercooler, intake plenum, etc.), but suspiciously, not the catalytic converter.

After a while, I couldn't figure out why my car kept overheating. I took it to an exhaust shop recommended by a good friend. Upon inspection, the pressure at the top of the cat was 3psi under no load acelleration. This is abnormally high, it should be anywhere from 0-1psi, and no higher. And under load, this kind of back pressure was causing my turbo to glow cherry-red under even moderate to light driving conditions.

I replaced the cat, muffler, and down pipe, and the overheating slowed significantly. But it wasn't gone. As it turns out, the fuel mixture was far too lean, causing abnormally high exhaust gas temperature, and the water pump had started leaking. Combine that with a faulty oil pump, and you can see where this goes.

Moral of the story: Buying a used, salvaged, turbocharged car is a very bad idea. Taking such a beast to a dealership, is an even worse idea. Most of the low-grade tech's that work on cars at dealerships wouldn't know a compressor from an engine block if one fell on their foot.