How reliable are turbo engines?

It would seem that a high RPM, small high-output engine (for ex. Subaru
WRX STI or Mitsubishi Evo) cannot last too long. The stress on its
components is
just too much. Can such an engine last, say, 150,000 miles without
major repairs?
Is there any special, expesnive maintanance that a turbo engine
requires?

223rem wrote:

> It would seem that a high RPM, small high-output engine (for ex. Subaru
> WRX STI or Mitsubishi Evo) cannot last too long. The stress on its
> components is
> just too much. Can such an engine last, say, 150,000 miles without
> major repairs?
> Is there any special, expesnive maintanance that a turbo engine
> requires?

Why do you think they are high rpm ?

The whole point of turbos is to avoid the need for high revs.

Graham

Eeyore wrote:
> 223rem wrote:
>
> > It would seem that a high RPM, small high-output engine (for ex. Subaru
> > WRX STI or Mitsubishi Evo) cannot last too long. The stress on its
> > components is
> > just too much. Can such an engine last, say, 150,000 miles without
> > major repairs?
> > Is there any special, expesnive maintanance that a turbo engine
> > requires?
>
> Why do you think they are high rpm ?
>
> The whole point of turbos is to avoid the need for high revs.
>
> Graham

I see. So, does a small, high output turbo engine require special
regular servicing?

223rem wrote:

> Eeyore wrote:
> > 223rem wrote:
> >
> > > It would seem that a high RPM, small high-output engine (for ex. Subaru
> > > WRX STI or Mitsubishi Evo) cannot last too long. The stress on its
> > > components is
> > > just too much. Can such an engine last, say, 150,000 miles without
> > > major repairs?
> > > Is there any special, expesnive maintanance that a turbo engine
> > > requires?
> >
> > Why do you think they are high rpm ?
> >
> > The whole point of turbos is to avoid the need for high revs.
> >
> > Graham
>
> I see. So, does a small, high output turbo engine require special
> regular servicing?

Small ? Like how small ? My own experience is limited to Saab engines of 2.0 -
2.3 litre displacement. In 'hot' factory tune these can develop up to 300 bhp.
Race tuned ones are good for up to 400 bhp but you have to be careful not to
melt the piston crowns.

The use of synthetic oils is highly advised.

Graham

In article om>, 223rem wrote:


> I see. So, does a small, high output turbo engine require special
> regular servicing?

Use a high quality oil like mobil 1 and change it per the owners manual.
Try to operate the vehicle per the owners manual with regard to the
turbo, letting it cool down etc if so specified.

That's it as far as I know.

Eeyore wrote:
> 223rem wrote:
>
> > It would seem that a high RPM, small high-output engine (for ex. Subaru
> > WRX STI or Mitsubishi Evo) cannot last too long. The stress on its
> > components is
> > just too much. Can such an engine last, say, 150,000 miles without
> > major repairs?
> > Is there any special, expesnive maintanance that a turbo engine
> > requires?
>
> Why do you think they are high rpm ?
>
> The whole point of turbos is to avoid the need for high revs.

Uhh, no. The point of turbos is to recapture lost energy.

The more revs you run, the greater the volume of air you can push, and
the more fuel you can burn. High revs is where the turbo does its best
work.

DAGS on turbocharging to learn something on the subject.

E.P.

223rem wrote:
> It would seem that a high RPM, small high-output engine (for ex. Subaru
> WRX STI or Mitsubishi Evo) cannot last too long. The stress on its
> components is
> just too much. Can such an engine last, say, 150,000 miles without
> major repairs?
> Is there any special, expesnive maintanance that a turbo engine
> requires?

The 2.2L Audi I5 runs a K24 turbo and pushes about 15lbs boost, max, in
stock form. Modifiying the ECU will allow the turbo to push 20-24lbs
boost.

There are I5 Audi turbo engines well over 200k miles on stock
internals, with original turbos. This is not unusual.

The only special maintenance required is regular oil changes with
high-quality oil (synthetic, most likely) and a five-minute cooldown
after a high-boost run. Oh, and try not to push a lot of boost until
the oil is warm.

The run it.

E.P.

Ed Pirrero wrote:

> Eeyore wrote:
> > 223rem wrote:
> >
> > > It would seem that a high RPM, small high-output engine (for ex. Subaru
> > > WRX STI or Mitsubishi Evo) cannot last too long. The stress on its
> > > components is
> > > just too much. Can such an engine last, say, 150,000 miles without
> > > major repairs?
> > > Is there any special, expesnive maintanance that a turbo engine
> > > requires?
> >
> > Why do you think they are high rpm ?
> >
> > The whole point of turbos is to avoid the need for high revs.
>
> Uhh, no. The point of turbos is to recapture lost energy.

No it isn't.

It's to 'push' more fuel-air mixture into the cylinder.


> The more revs you run, the greater the volume of air you can push, and
> the more fuel you can burn. High revs is where the turbo does its best
> work.

The rev limit for a blown and unblown version of the same engine will be the
same though.


> DAGS on turbocharging to learn something on the subject.

DAGS ?

Graham

223rem wrote:

> It would seem that a high RPM, small high-output engine (for ex. Subaru
> WRX STI or Mitsubishi Evo) cannot last too long.

True, but that's more to do with the drivers they attract, not the
engineering. In a UK city, you actively avoid Subarus when driving,
simply because of the mouth-breathing Burberry-clad oiks they attract.

Saabs are quite unrepresentative ot turbos too. Low pressure,
relatively low performance (compared to a Scooby) and mainly not
tending to be driven by hooligans either.

> Small ? Like how small ? My own experience is limited to Saab engines of 2.0 -
> 2.3 litre displacement. In 'hot' factory tune these can develop up to 300 bhp.

2 liters is small. 300 horses on a FWD car? That's a waste of
horsepower.

> Race tuned ones are good for up to 400 bhp but you have to be careful not to
> melt the piston crowns.

AFAIK, nobody races in FWD cars.