Eddie,
Those Cossie style wastegates certainly simplify the exhaust side of things.The
303-61-L turbine wheel is larger in both major and exducer dia than the standard
wheel and is of a better design which allows more gases to be passed thru
housing and reduce back pressure when larger compressors are used.These wheels
also have the ability to work over a wider range.There is larger T3 turbine
wheels available and a good turbo tech man should be able to advise of at what
point a larger wheel is needed to match comp size and engine size.Standard
turbine wheels can be back cut to around 7 deg when larger compressors are used
as this also reduces back pressure but this is not considered good practice,
although I've just done it to mine as it's cheap ($150 including balancing
verses $600 for a new -61).I've used this with a T4 -25 (V trim) comp wheel and
housing ($100 used).Should be good for 300-350HP.This is old technology and I've
only done it this way because of budget.If I had the money I'd use a 60-1 comp
wheel with suitable turbine wheel.
Andrew Smith
[EMAIL PROTECTED] wrote:
> Andrew,
> Luckily I found a local turbo specialist that's run by an Aussie! He knows
> FJ's and 1600's (nobody else here has heard of either) and he's built an FJ
> to 500hp+ in a Mazda for drag racing before (in Aus not here...think it was
> a series 2 RX7). I'm going with a modified T3 from an Escort Cosworth with
> an integral wastegate (wastegate is in the housing rather than the dump
> pipe) and a 360 deg bearing. I'll get the exact specs off him and post
> them. I said I wanted a capability for 300-350hp (@ flywheel) although I'm
> not likely to run that much on the street right away, but I want the
> potential there for the future without needing a different turbo and
> therefor possibly a different exhaust.
> The built in wastegate on the Cossie turbo simplifies the exhaust a bit as
> the system will now be fabricated right up to the turbo housing so the idle
> clearance is no longer a problem.
> I'll ask when I go back there about _61 turbine wheels. I'd imagine they use
> them. What's the difference?
>
> Eddie
> England
> 1969 510 4door
> [EMAIL PROTECTED]
> www.ratdat.com
>
> ----- Original Message -----
> From: andrew smith <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Sent: Tuesday, January 30, 2001 2:37 AM
> Subject: Re: FJ20DET ex manifold
>
> > Eddie,
> > What turbo are you using, still the T3? How did you go with that idler
> clearance
> > problem? Hope you had the turbo high flowed.Having another manifold made
> can be
> > quite expensive and making it yourself can be time consuming.A lot would
> depend
> > on what HP you turbo is rated at or if you intend to go bigger later
> although I
> > think the standard manifold is capable of flowing enough for at least
> 400HP.Any
> > more HP than this I would be looking at an external waste gate type set up
> and
> > therefore another manifold.The standard manifold will keep air speed high
> and
> > combine with the high exhaust pulses the FJ20's produce allow for quick
> spool
> > up.A larger dia manifold is usually used when ultimate HP is being chased
> or if
> > the standard one is to small or if you change to different bolt pattern.I
> ran a
> > TB34 400HP unit on an FJ20 with no back pressure problems at all.Theses
> units
> > were designed by Nissan for there domestic racing where no external waste
> gates
> > were allowed and standard manifolds retained. These turbos featured a
> turbine
> > housing with a larger nozzle area and a -61 turbine wheel. These are only
> my
> > experiences anyway maybe some others have had problems with the standard
> > manifold.While you were getting your turbo done did you come across any
> > workshops with any used -61 turbine wheels as I think thats what they used
> in
> > the RS500 Cossies.
> > Andrew Smith
> >
> > [EMAIL PROTECTED] wrote:
> >
> > > I'm wondering what the limitations are in respect to power potential
> using
> > > the stock exhaust manifold on my FJ turbo( It's a Gazelle RS-X
> manifold). Is
> > > it worth me getting an aftermarket one now? The reason I ask is because
> I
> > > get my new turbo this week and them it will be time to get the exhaust
> > > system fabricated. I don't want to have to have it done twice if I find
> I
> > > need a better manifold in the future. I'd rather just spend the money
> now
> > > and do it right. Any idea, anyone?
> > >
> > > Cheers,
> > > Eddie
> > > England
> > > 1969 510 4door
> > > [EMAIL PROTECTED]
> > > www.ratdat.com
> > >
> >
> >
>
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