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 Post subject: Head work
PostPosted: Wed Feb 22, 2006 8:18 pm 
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Group N
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Joined: Sat Nov 12, 2005 9:32 pm
Posts: 238
Location: Under the Bonnet.
Car Model: None
Hi,

does anybody have any suggestions for head porting only light work on this head.

where is reccomended

_________________
1990 JDM ST185 Grey.
ST205 head gasket.
ARP head bolts.
ST205 Koyo Rad. (almost)
Front mount intercooler.
Colder plugs.
3" decat pipe.
4 Branch manifold.
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 Post subject:
PostPosted: Wed Feb 22, 2006 8:25 pm 
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Joined: Wed Jul 13, 2005 5:10 pm
Posts: 1953
Location: Sunny Fareham, UK
Car Model: ST205
I am no expert but I think gains can be found by:

Port match the intake to the manifold
Port match the TVIS - if you keep it!
Knife edge the intake dividers to the intake valves
Seems that there often seems to be some casting defects by the valve seats in the intake runners

What d'ya think?

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Kris
95 ST205 - slept for 10 years, now waking up...
Avensis
http://www.gtfours.co.uk
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Turbocharging - the replacement for displacement


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 Post subject:
PostPosted: Mon Feb 27, 2006 10:09 pm 
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Junior WRC
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Joined: Thu Oct 06, 2005 12:28 pm
Posts: 701
Car Model: None
yes all the above. port matching every thing in and out.

the inlet ports,runners etc can be smoothed out, making for better flow, the gaskets are wayout on some of them, every 1/2 mm matters.

lap the valves, match the ports on the exhaust manifold, and port match the turbo in from manifold, its shocking how far out some of it is..

use soft carboard for templating, plus ink all mating gaskets to check for correct smooth operation, as they are often a little out..

good gains can be achieved ..

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Black UK 96 205 shed with heater full on telemetry.

project six million dollar 185, faster, stronger, lighter than before.


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 Post subject:
PostPosted: Mon Feb 27, 2006 10:16 pm 
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Joined: Wed Jul 13, 2005 5:10 pm
Posts: 1953
Location: Sunny Fareham, UK
Car Model: ST205
I have heard that keeping the exhaust manifold slightly larger than the head can help thwart reversion of gases

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Kris
95 ST205 - slept for 10 years, now waking up...
Avensis
http://www.gtfours.co.uk
_______________________________________
Turbocharging - the replacement for displacement


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 Post subject:
PostPosted: Wed Mar 01, 2006 11:20 am 
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Junior WRC
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Joined: Thu Oct 06, 2005 12:28 pm
Posts: 701
Car Model: None
True to a point.

I have seen, worked on quite a few well-tuned engines, all have flowing exhaust manifolds.

Mis-alignment causes big eddy currents, swirling pockets of gas, thus causing flow restrictions.

Matching the intake diameters is worth all the hassle.

exhaust side, still would benefit from port matching the gasket and manifold, if my memory serves me right, there's quite a variation to port sizes. on the 185, both jap and uk , suprising how poor the finish in soome areas.

I know i made all the ports equal, diameter, smooth and enlarged, as well as cutting back and make all the gaskets fit proper, this is something i have done for years..

Every little bit helps.

_________________
Black UK 96 205 shed with heater full on telemetry.

project six million dollar 185, faster, stronger, lighter than before.


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