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CT12a Substitutes for 1JZGTE   2003-07-14 22:42:00 <adrian@...>
As the topic people...

well story goes that i bought a JZA70 that has developed a bit of smoke at idle.. Im kinda hoping its turbo seals and at the same time i was wondering since these are ceramic turbos what else can be used?

i have priced up a engine and that came to $1250 so this might be the go later on if i can fix the turbos.

Is there any way that the turbo centres (sorry dont know the name) be changed over still using the same compressor and exhaust housings?

anwyas let me know..

thanks

Adrian
Reply

Re: CT12a Substitutes for 1JZGTE   2003-07-14 23:28:00 <Marc Archbold>

Hi Adrian,
I've been through (over & over....) this issue with Cully. My JZ would
smoke if parked on an incline with the nose up.
Turned out that a seal had gone as the front turbo was thrusting against
this seal. Altech reconditioned the front turbo in time for the SupraFest,
and a decent 1/4 time for my stock JZ was a testament to a quality repair.
Ok, so Im the owner of the smokeless tyre's too :)

As far as modification is concerned; apparently the stock turbos could be
modified or so called 'hybrid' and while should be 100% successful, in my
case it would have been experimental. I've also seen an Australian site
that details modifying using CT9's, however according to the experts at
Altech, this is nonsense.

If its reliability rather than performance is your goal then hybrid turbos
may be the option, because IMHO there is nothing to gain from attempting to
more power out of these *very* restrictive units. Take a look at any stock
1JZ dyno, you'll see the HP is strangled at high RPM.

Stay tuned though, Im hoping to go single turbo in the near future...

Over to Cully.....








----- Original Message -----
From: <adrian
To: "Supra Club of NZ Mailing List" <sconz@supras.org.nz>
Sent: Monday, July 14, 2003 10:38 PM
Subject: [sconz] CT12a Substitutes for 1JZGTE


> As the topic people...
>
> well story goes that i bought a JZA70 that has developed a bit of smoke at
idle.. Im kinda hoping its turbo seals and at the same time i was wondering
since these are ceramic turbos what else can be used?
>
> i have priced up a engine and that came to $1250 so this might be the go
later on if i can fix the turbos.
>
> Is there any way that the turbo centres (sorry dont know the name) be
changed over still using the same compressor and exhaust housings?
>
> anwyas let me know..
>
> thanks
>
> Adrian

Reply

Re: CT12a Substitutes for 1JZGTE   2003-07-14 23:51:00 <john shannon>

Hi right now ct12b out of a toyota surf diesel 1kz the shafts will fit in to the ct12a with some mods iv done one and so far iv got 279kw so thay must work becoues befor that i only got 226kw still got to do one more yet.

>From: "Marc Archbold"
>Reply-To: "Supra Club of NZ Mailing List"
>To: "Supra Club of NZ Mailing List"
>Subject: [sconz] Re: CT12a Substitutes for 1JZGTE
>Date: Mon, 14 Jul 2003 23:19:55 +1200
>
>
>Hi Adrian,
>I've been through (over & over....) this issue with Cully. My JZ would
>smoke if parked on an incline with the nose up.
>Turned out that a seal had gone as the front turbo was thrusting against
>this seal. Altech reconditioned the front turbo in time for the SupraFest,
>and a decent 1/4 time for my stock JZ was a testament to a quality repair.
>Ok, so Im the owner of the smokeless tyre's too :)
>
>As far as modification is concerned; apparently the stock turbos could be
>modified or so called 'hybrid' and while should be 100% successful, in my
>case it would have been experimental. I've also seen an Australian site
>that details modifying using CT9's, however according to the experts at
>Altech, this is nonsense.
>
>If its reliability rather than performance is your goal then hybrid turbos
>may be the option, because IMHO there is nothing to gain from attempting to
>more power out of these *very* restrictive units. Take a look at any stock
>1JZ dyno, you'll see the HP is strangled at high RPM.
>
>Stay tuned though, Im hoping to go single turbo in the near future...
>
>Over to Cully.....
>
>
>
>
>
>
>
>
>----- Original Message -----
>From: >To: "Supra Club of NZ Mailing List"
>Sent: Monday, July 14, 2003 10:38 PM
>Subject: [sconz] CT12a Substitutes for 1JZGTE
>
>
> > As the topic people...
> >
> > well story goes that i bought a JZA70 that has developed a bit of smoke at
>idle.. Im kinda hoping its turbo seals and at the same time i was wondering
>since these are ceramic turbos what else can be used?
> >
> > i have priced up a engine and that came to $1250 so this might be the go
>later on if i can fix the turbos.
> >
> > Is there any way that the turbo centres (sorry dont know the name) be
>changed over still using the same compressor and exhaust housings?
> >
> > anwyas let me know..
> >
> > thanks
> >
> > Adrian
>
>
>---
>Supra Club of New Zealand
>http://www.supras.org.nz/


Find your perfect match @ XtraMSN Personals!
Reply

Re: CT12a Substitutes for 1JZGTE   2003-07-14 23:57:00 <adrian@...>
Thanks for that!

I just didnt think the ceramics were rebuid-able thats all. With a risk of shattering.

Well if you dont mind could you give me a price of the rebuild/re-seal even off list.

Just mine is intermittent, only smokes every now and then. but when it smokes it smoookkkeessss

would hate to think its the valves/rings

anwyyas might try and get along to the next meet for SCONZ :)

Adrian



Reply

Re: CT12a Substitutes for 1JZGTE   2003-07-15 00:04:00 <john shannon>

If you can find the ct12b the cost to do the fitting the shafts are $350 each.

>From: adrian@clubaw.co.nz
>Reply-To: "Supra Club of NZ Mailing List"
>To: "Supra Club of NZ Mailing List"
>Subject: [sconz] Re: CT12a Substitutes for 1JZGTE
>Date: Mon, 14 Jul 2003 11:46:07 -0000
>
>Thanks for that!
>
>I just didnt think the ceramics were rebuid-able thats all. With a risk of shattering.
>
>Well if you dont mind could you give me a price of the rebuild/re-seal even off list.
>
>Just mine is intermittent, only smokes every now and then. but when it smokes it smoookkkeessss
>
>would hate to think its the valves/rings
>
>anwyyas might try and get along to the next meet for SCONZ :)
>
>Adrian
>
>
>
>
>---
>Supra Club of New Zealand
>http://www.supras.org.nz/


With Xtra Jetstream - you can surf the net and talk on the phone!
Reply

Re: CT12a Substitutes for 1JZGTE   2003-07-15 09:02:00 <Cully Paterson>
>If you can find the ct12b the cost to do the fitting the shafts are $350
each.

John, I'd be interested to know who did the job for you?


Reply

Re: CT12a Substitutes for 1JZGTE   2003-07-15 09:02:00 <Cully Paterson>

> well story goes that i bought a JZA70 that has developed a bit of smoke at
idle.. Im kinda
>hoping its turbo seals and at the same time i was wondering since these are
ceramic turbos
>what else can be used?

As you've seen already most of this has already been covered, but I'll throw
my oar in on the subject, as I am want to do :)

CT12As are a complete bitch. The exhaust side of them is massively
restrictive, and the compressor side just isn't big enough to flow decent
air without super heating it. Being ceramic they're a total bastard to work
on - there's about a 50% chance that they'll snap in half when you take them
apart, as it requires a bit of hammering to separate the turbine housing and
core. (Marc, you probably didn't know that I took your one apart did you?
hehehe).

Options:
Repair the CT12As. Perfectly doable, but inherent risk involved. They also
have a habit of grenading shortly after going back onto the car for no good
reason.

CT12B shafts. Possible. The 1KZ turbos are very hard to find and usually
expensive. We're still yet to see whether John's conversion is going to be
100% successful. You cannot simply fit CT12B turbos straight on - the
firewall gets in the way of the rear turbo.

Single turbo. That's what I'm working on at the moment. Aiming to produce
a manifold that will take any T2/T3 turbo. Luckily the exhaust side of the
1JZ is quite clean and uncluttered once the turbos are removed, so there's
plenty of hope that this'll work out. Most expensive option though.

Cheers
Cully

Reply

Re: CT12a Substitutes for 1JZGTE   2003-07-15 10:59:00 <Peter O>
Cully,

From my general reading I gather that a single turbo option reduces
the turbo RPM power band & usually increases the perceived lag.
Surely this is a considerable sacrifice to be accepted only as a last
resort?

Pete

-----Original Message-----
From: bounce-sconz-200@supras.org.nz
[mailto:bounce-sconz-200@supras.org.nz]On Behalf Of Cully Paterson
Sent: Tuesday, 15 July 2003 8:56 a.m.
To: Supra Club of NZ Mailing List
Subject: [sconz] Re: CT12a Substitutes for 1JZGTE



> well story goes that i bought a JZA70 that has developed a bit of
smoke at
idle.. Im kinda
>hoping its turbo seals and at the same time i was wondering since
these are
ceramic turbos
>what else can be used?

As you've seen already most of this has already been covered, but I'll
throw
my oar in on the subject, as I am want to do :)

CT12As are a complete bitch. The exhaust side of them is massively
restrictive, and the compressor side just isn't big enough to flow
decent
air without super heating it. Being ceramic they're a total bastard
to work
on - there's about a 50% chance that they'll snap in half when you
take them
apart, as it requires a bit of hammering to separate the turbine
housing and
core. (Marc, you probably didn't know that I took your one apart did
you?
hehehe).

Options:
Repair the CT12As. Perfectly doable, but inherent risk involved.
They also
have a habit of grenading shortly after going back onto the car for no
good
reason.

CT12B shafts. Possible. The 1KZ turbos are very hard to find and
usually
expensive. We're still yet to see whether John's conversion is going
to be
100% successful. You cannot simply fit CT12B turbos straight on - the
firewall gets in the way of the rear turbo.

Single turbo. That's what I'm working on at the moment. Aiming to
produce
a manifold that will take any T2/T3 turbo. Luckily the exhaust side
of the
1JZ is quite clean and uncluttered once the turbos are removed, so
there's
plenty of hope that this'll work out. Most expensive option though.

Cheers
Cully


---
Supra Club of New Zealand
http://www.supras.org.nz/

Reply

Re: CT12a Substitutes for 1JZGTE   2003-07-15 11:12:00 <Cully Paterson>

> From my general reading I gather that a single turbo option reduces
> the turbo RPM power band & usually increases the perceived lag.
> Surely this is a considerable sacrifice to be accepted only as a last
> resort?

That's a rather large generalisation there. If you're starting with restrictive twin turbos (ie CT12As and for that matter CT12s) you're going to end up with a far far bigger top end going to a single. Read: the exhaust side of CT12s is sh´tty and kills the top end. Yes, you'll have to live with a big more lag, but that's as a result of the restrictive stock exhaust manifold producing artificially high gas velocity at low revs and therefore low lag.

Somehow I've managed to delete the scans of the dyno sheets off the website, but I have a couple of comparison ones in front of me. One is from my 7M/T04E, one from Stuart Woolfords stock 1JZ+big bore. On mine the horsepower peaks at 5500 RPM and only just falls off past that by about 5%. On Stu's the power flatlines at 5000 and drops by nearly 25% by redline.

Now if you were running a competant twin turbo setup such as on the GTR Skylines (that have effectively tubular large diameter exhaust manifolds) things would be different and comparisons would change. But that's Nissan...

Cully
Reply

Re: CT12a Substitutes for 1JZGTE   2003-07-17 15:53:00 <Adrian Maka>
Ok this turbo subject is bothering me.

I tried having the car on an angle and see if pointing up or pointing down
was the cuase for the leak. I seen that level and pointing down-hill kinda
smoked more that pointing down hill like i think cully suggested.

I am also considering the quality and grade of oil im using to be the cause
of the leak. Im using 10W40 semi-synthetic at the moment. Would you think
this was sufficent?

also maybe its just the valve seals? :/

Thanks for reading ...
Adrian


At 11:06 AM 7/15/2003 +1200, you wrote:

> > From my general reading I gather that a single turbo option reduces
> > the turbo RPM power band & usually increases the perceived lag.
> > Surely this is a considerable sacrifice to be accepted only as a last
> > resort?
>
>That's a rather large generalisation there. If you're starting with
>restrictive twin turbos (ie CT12As and for that matter CT12s) you're going
>to end up with a far far bigger top end going to a single. Read: the
>exhaust side of CT12s is shïtty and kills the top end. Yes, you'll have
>to live with a big more lag, but that's as a result of the restrictive
>stock exhaust manifold producing artificially high gas velocity at low
>revs and therefore low lag.
>
>Somehow I've managed to delete the scans of the dyno sheets off the
>website, but I have a couple of comparison ones in front of me. One is
>from my 7M/T04E, one from Stuart Woolfords stock 1JZ+big bore. On mine
>the horsepower peaks at 5500 RPM and only just falls off past that by
>about 5%. On Stu's the power flatlines at 5000 and drops by nearly 25% by
>redline.
>
>Now if you were running a competant twin turbo setup such as on the GTR
>Skylines (that have effectively tubular large diameter exhaust manifolds)
>things would be different and comparisons would change. But that's Nissan...
>
>Cully
>
>---
>Supra Club of New Zealand
>http://www.supras.org.nz/


Reply

Re: CT12a Substitutes for 1JZGTE   2003-07-17 16:00:00 <Cully Paterson>


> I am also considering the quality and grade of oil im using
> to be the cause
> of the leak. Im using 10W40 semi-synthetic at the moment.
> Would you think this was sufficent?

Should be fine unless it's cheap nasty crap or hasn't been changed for ever.


> also maybe its just the valve seals? :/

Less likely. Valve stem seals being bad will normally result in a build up of oil film that doesn't show up until you put your foot down on the accelerator. Most noticeable if you under engine braking down a long hill and then put your foot down.

Check that your crankcase ventilation hose isn't stuffed. If it's blocked in some way then the excess pressure forces oil that normally sits on the valve stems through into the combustion chamber (almost as if you have bad seals). The JZ hose has a tendancy to kink over and block.

Most likely answer to it all though is that your turbos are stuffed. If there's CT12As involved then it's almost certainly going to be them.

Cully
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