Toyota: Supra question

Watch out for the headgasket. They are very prone to failure on these
models. Toyota produced a modified head gasket, but many people prefer to
fit aftermarket metal headgaskets.

Might be worth checking the history to see if this has been done. If it
hasn't then unfortunately you may be looking at this yourself at some point
and it can get pricey to fix.

I'm not saying it WILL go but if you ask on the various supra owners clubs
groups what the most common problem is on the MkIII's then i'm pretty sure
everyone will be shouting about head gaskets.

There is ofcourse the 2.5 twin turbo JZA70 model which I have which doesnt
suffer from the head gasket problems, but these are quite hard to come
across.

Another choice is the 2.0 twin turbo GA70 model which also doesnt suffer
from head gasket problems, but the performance is about the same as the 3
litre single turbo model.

Other things to look for, but not major problems are

Knackered electric aerial.
Water in the boot (leaking in through either spoiler or rear window)

Sometimes the front mudguard/front sill panel seems to be bulging out as if
they are full of rust behind them. It also sounds like rust if you try to
puch them back in. It normally isnt rust, but these panels can work loose
and mud can gather behind them pushing them out. I wouldnt be put of by this
as I think these panels can easily be removed and refitted properly.

Apart from the above, these cars are pretty bulletproof.

HTH

Graham
1992 2.5 TT Aero Supra





"LACropCircles" <net> wrote in message
news:supernews.com... 
prices). 

On Fri, 12 Sep 2003 22:15:25 -0700, "LACropCircles"
<net> wrote:
 

Turbos belong in high altitude aircraft and race cars.

It's silly to put them on street cars.

For one thing they dump most of the pressure through the wastegate
(and for good reason). It would be far more sensible to put in a
normally aspirated engine with 15% greater torque.

For the street a super charger makes more sense if you just must have
forced aspiration.

Turbos are accompanied with heat soak and lubrication problems that
don't justify their use in a road car.

--

FJ40©

"Never again a Ford".....

Beware a govt that fears its populace (gun control)...

"I would bet that most top-posters do indeed not signal their lane-changes." - dizz

"Thank you for contacting the Center for Auto Safety (CAS) about your Ford Aerostar or Windstar.
CAS has received many complaints from consumers concerning peeling paint, ignition switch fires,
stalling and brake, transmission and head gasket failures. Ford should drop "star" from Aerostar
and Windstar because neither is a star when it comes to quality."

On Sat, 13 Sep 2003 16:55:16 GMT, FJ40 ® <invalid>
wrote:
 

In your opinion.
 

But turbos typically increase the torque by much more then that.
 

With all the companies making turbocharged cars, you just might be
wrong.
 

Nonsense. They are used with great success in many "road cars".

"FJ40 ®" <invalid> wrote in message
news:com... 

I haven't seen a more seemingly sincere, yet misinformed statement in a long
time. You *are* joking, right? Or, just talking with minimal knowledege of
the topic?
 

No, not most. Only what is generated above the boost limit. This usually
only occurs when closing the throttle (reducing engine demand for boost)
while keeping a constant supply of boost. An example of this would be
releasing the accelerator pedal to shift while at full boost. The wastegate
opens to vent the overage and closes as soon as the pressure is reduced to
the opening threshold.
The wastegate's function is to keep the boost regulated at the safe maximum
for the engine.
The gains for a turbo can be *far* greater than 15%, and turbocharged
engines are superior in the sense that when you are not on the throttle, the
extra energy (gas) is not wasted by having to reciprocate a larger
displacement engine.
 

Not really. Supercharging is a valid method as well, but consider:

1) A supercharger may take 10-20% of the engine's power to run it (read
20-50HP).
2) It is "on" all the time, whether you want it or not.
3) It may be arguable that pound for pound (of boost) a supercharger is
harder on engine bearings than a turbo.

Whereas,
1) A turbo has essentially "free" HP gains, in that it uses waste energy
that would otherwise go out the tailpipe.
2) When you don't need the turbo (low RPM, small throttle application
driving), the boost and energy consumption is lower.
3) The additional mechanical complexity dosen't need to be substantially
greater than that of a supercharger.

A well designed engine can produce full turbo boost, with minimal "lag" as
low as 2000 RPM (or lower).
 

Well, evidently the engineers at Subaru, Porsche (think 911 Twin Turbo - 400
HP 400 pounds/feet of torque and close to 30 years of making turbocharged
engines for street cars. Not one supercharger), Mercedes, Ferrari, Toyota,
Cummins, etc etc etc. disagree with your assessment as well. Did you
consider all the OTR diesel rigs that you probably see on the road every day
that use them?
A properly cared for (and engineered) turbocharged engine can last about as
long a N/A engine. Synthetic oils are a plus, simply because the "hot" side
of the turbo sits in the exhaust stream, but bearing lubrication and heat
soak are non-issues in properly engineered modern engines.
 

all the major problems with these cars have been identified. just make sure
you toque the head down 68-72lb instead of the toyota spec of 52lb.
change the oil and filters every 5000km's and they are a reliable car!
 
prices). 

"default" <null> wrote in message
news:V_09b.6562$austin.rr.com... 
long 
of 
wastegate 
<snip>

Excellent rebuttal! I think you mean the bypass/blow-off valve opens when
the throttle is closed? I could be wrong...

-Tim

On Sun, 14 Sep 2003 16:49:57 GMT, "default" <null> wrote:
 

Not joking but not an expert either.
 

This boost limit is kept low on street cars for longevity. Turbos on
road cars came as a result of their popularity in racing. When the F1
turbo era was at it's peak so were turbos on road cars. There are now
fewer turbos on race cars and so the popularity for road cars is also
declining. I regard turbos on road cars as nothing more than a fad
inspired by racing.

There is great truth to the dictum, "Race it on Sunday and sell it on
Monday."
 

Again that threshold is kept low on street cars for the sake of
longevity.
 

That safe maximum is arbitrary. On a race car that maximum is set to
last a race distance, sometimes only a few hundred miles. On a road
car it is set to last a lot longer hence the lower advantage in HP and
torque.
 

Of course they can. But *far* greater is at the expense of longevity
for the engine.
 

Hmmm.... I wonder what the displacement difference is between a Supra
with a turbo and one without.... that's what this discussion is about
after all. I wonder what the HP and torque differences are between
these two units..... I believe it's 15%.
 

An admitted disadvantage but turbos aren't "free" either.
 

Not necessarily. Most are operated through an electric clutch similar
to those used for A/C units.
 

I guess that depends on the installation. I wonder what the bearing
service rate was on the supercharged MR2 compared to the non
supercharged models. (Rick?)
 

Back pressure?
 

electric clutch?
 

?????????
 

I still regard turbos on street cars as a fad inspired by their use in
racing.
 

Actually they design and engineer these units for racing. "Race it on
Sunday, sell it on Monday". The marketing boys tack it on the road
cars to satisfy the race inspired fad.
 

Actually Toyota marketed one of the few factory supercharged cars to
be offered to the public. Mercedes and Ferrari are heavily into
racing. Cummins are specialized applications for the most part.
 

This is an example of extremes of weight and engine size that I don't
know enough about to comment on other than it's obviously not fad
driven. I suspect that the arguments for turbo use in this area don't
apply to the lightweight street machines like the Supra which inspired
this discussion.
 

Ahh there's the rub isn't it. "properly cared for" I had a friend with
a turbo Supra (I had a non turbo one at the time). He used to sit and
idle his for five minutes before shutting it down when it was hot. I
believe he was following the manual which called for this cooling off
period to allow the turbo to remain lubricated while it cooled and
spooled down from it's 115,000 RPM (race turbos were double that).
Five minutes is a long time to sit and twiddle ones thumbs. If memory
serves he got a 15% advantage for the trouble.

When turbo Supras first came out this is what my dealer said "Should
be good for the shop. That kind of HP will break parts."

However, in practice my friend didn't break any more parts than I did
which were none for both of us.
 

Does Toyota even offer a turbo today?

Just talked to the local Toyota parts man on the phone.

"Not that I am aware of." was his reply.

The turbo fad over? Looks like it.

So are the "properly engineered modern engines" inspired by use other
than street? I think very likely.

So, in the case of the Supra I'd still go with my past real life
decision to go with a normally aspirated one. Remember I also had the
chance to compare my experience with that of my friend over a period
of ownership on the model (if possibly not the year) in question.

It would be interesting to hear what his decision would be. I know he
traded the Supra for a Previa. I don't know if they offered a turbo
the first year (for Previa) or not but I do know his Previa was not
turbo charged.

Unfortunately he no longer lives here so I can't ask him. I do suspect
that the cooling off shutdown would inspire him to reject the turbo
though. He mentioned it more than once so I know it got to him.

--

FJ40©

"Never again a Ford".....

Beware a govt that fears its populace (gun control)...

"I would bet that most top-posters do indeed not signal their lane-changes." - dizz

"Thank you for contacting the Center for Auto Safety (CAS) about your Ford Aerostar or Windstar.
CAS has received many complaints from consumers concerning peeling paint, ignition switch fires,
stalling and brake, transmission and head gasket failures. Ford should drop "star" from Aerostar
and Windstar because neither is a star when it comes to quality."