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Location:
Brisbane CBD
Registered:
September 2004
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turbo head flowing re:1g
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Tue, 05 October 2004 03:36
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Dudes I'm sorry to say but I'm very confused everyone i seem to talk to about this mod on a turbo engine seems to think its not worth it? why is this so? intake flow is everything for a n/a and turbo car right? or am i missing something? i have read various articles on the web and they say to build a good turbo motor start by building a great n/a motor. is it the fact that u cannot fit much larger valves? because i have been looking and it seems you can fit a good 20% bigger valve there? sorry for so many questions I'm just so confuzzeled  Andrew
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Location:
Brisbane CBD
Registered:
September 2004
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Re: turbo head flowing re:1g
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Tue, 05 October 2004 07:03
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can someone just say if its a silly question because like 16 peepz have viewed it but no one wants to sayanything is there a reason? i was just looking to have some head work done on a 1g and i have conflicting reports ?
maybe i can say what my plans are if porting new valves, stemseals, stiffer valve springs
not sure on cam havce heard its better to have standard ?
ummm flowing obviously maybe revisit the chambers im jsut new to this scene i have resonable knowlage of theroetical engine mechanics just not the know how if u get me thanx anyhow
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Location:
Brisbane
Registered:
May 2002
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Re: turbo head flowing re:1g
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Tue, 05 October 2004 07:33
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OK, I'll have a go. In a nutshell, unless you're chasing sky-high power figures there's little to be gained from head work on a 1G. Yes cylinder head flow is important on a turbo engine, but the 1G cylinder head already flows quite well. DOHC and 24 valves, that's a good start, and in terms of total valve surface area it would have to be better than most (if not all) 2 litre engines out there!
So in short, don't waste your time and money unless you've already reached the limits of the more conventional mods (ie turbo, intercooler, exhaust, cams, engine management).
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Location:
Melbourne
Registered:
October 2003
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Re: turbo head flowing re:1g
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Tue, 05 October 2004 08:49
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If the head is off the engine, it's free power just to give it
a little clean up. There are physical limits to what surface
finish/shaping can be achieved by just casting, so there is often
a few area's that can be improved by hand later on.
But if the engine is assembled i wouldn't bother pulling it off to do it unless you were chasing big power. As for doing the valves, bigger isn't always better, -- concentrate on the smallest area's first, before making the big bigger.
Porting a head with a turbo will yield big gains, if the standard
head isn't up to it, but as norb said it's a pretty good flowing
head anyway.
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Location:
Madrid - Spain
Registered:
August 2002
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Re: turbo head flowing re:1g
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Tue, 05 October 2004 11:04
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I wouldn't bother with the bigger valve springs either. Toyota designed the 1G as a fairly high reving motor and I am sure the springs were sized accordingly. Your better off sizing a turbo to make better power at lower revs than reving the ass out of it anyway.
Cleaning up the exhaust ports and matching them to the manifolds will help with turbo spoolup.
Cleaning up and match porting the inlet side will see a small increase on a turbo engine, but don't expect the same sort of gains you would on a N/A engine.
If your doing the work yourself, go for it.
If your going to pay someone else for the head work, then you would see better gains with ecu/turbo/cam upgrades. (in that order too.)
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Location:
Brisbane CBD
Registered:
September 2004
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Re: turbo head flowing re:1g
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Tue, 05 October 2004 12:53
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ok sweet i might just keep to clean up work then yeh cos i ma planning ecu turbo etc thanx for the imput so for 250Kw no flowing really neccassary? was looking at rasing the redline too by balanceing etc what are the limits that i can be rased before forgied conrods etc are needed ? as for low end torque is it possible to bore the 1g out any? it have been raised to me that i can get forged postions custom for about 1200 . lol sorry guys i do get carried away sometimes with questions jsut tell me if i get annoying 
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Location:
Madrid - Spain
Registered:
August 2002
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Re: turbo head flowing re:1g
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Thu, 07 October 2004 10:10
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1G's are dirt cheep, I think and stronger than you would think.
I would look at doing all the external stuff first and then see how far the internals take you. If it grenades, spend $500 on another long engine and then attend to the weak spot. Unless you intend on using it for track racing, the internals probably won't give you any problems.
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