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Location:
Perth
Registered:
January 2005
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Staggered cam sizes - 4AGZE
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Wed, 07 September 2005 08:04
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Hi,
Plenty of times I've seen people talk about using different intake and exhaust cams. eg 264 inlet with 256 exhaust, or even 256 in, with 264 exhaust.
How can the relative effect on an engines torque curve be guestimated? Has anyone produced some curves on the dyno they can share using a 4A-G(Z,T)E motor or otherwise?
I have an SC14 supercharged, bigport running 18psi, custom plumbing, ic, management, throttle, etc and pretty much I think the only thing left to do is modify the head and let it breath a little easier.
I'm looking for data/advice/recommendations.
Regards, Nick.
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Staggered cam sizes - 4AGZE
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Wed, 07 September 2005 08:20
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a guy called Rob, from sydney, used to have a great 4AGZE page where he tried many different things and had dyno graphs of each.
have a look around for rob 4agze or gze or similar.. he sold the AW11 a while ago, but i think the page is still up...
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Location:
Toronto, Downtown
Registered:
September 2004
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Re: Staggered cam sizes - 4AGZE
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Wed, 07 September 2005 10:39
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unfortunatly robs page isnt up anymore  it was a great page i used his transplant journal to great effect when doing my own gze transplant into an aw11 a great shame was a great page would have loved to have of met the guy
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Staggered cam sizes - 4AGZE
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Wed, 07 September 2005 10:47
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any chance it is cached in those www time machines? (seriously)
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Location:
Sydney
Registered:
August 2004
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Location:
Toronto, Downtown
Registered:
September 2004
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Re: Staggered cam sizes - 4AGZE
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Wed, 07 September 2005 11:52
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woohooo but it used to be like the number 1 aw11 site when you looked it up on google
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Staggered cam sizes - 4AGZE
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Wed, 07 September 2005 12:49
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thats farken GOLD...
must.... save... to HDD........ 
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Location:
Toronto, Downtown
Registered:
September 2004
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Location:
Perth
Registered:
January 2005
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Re: Staggered cam sizes - 4AGZE
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Thu, 08 September 2005 05:39
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Yep,
Like most AW11 nuts, I've seen Robs AW11 page. It would have been interesting to see what happened with the CUSCO and the 272's.
I get the feeling that 272s would be too big for me.
So no-one has any info of experience using staggered cam sizes then? How about just 256s or 264's on a 4AGZE ?
Cheers, Nick
http://www.e-wire.net.au/~nrparker/MR2/NewEngine/n ew_engine.htm
-- some videos of my ZE are at the bottom of the page
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Staggered cam sizes - 4AGZE
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Thu, 08 September 2005 06:03
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well... think about it logically..
by changing cams you change open/close points of valve, and also overlap.
with SC you have higher pressure in intake than exhaust, so you shouldn't need to worry about reverse flow as much as the turbo kiddies.
you do need to worry about overlap more than the turbo kiddies tho as you will blow mixture out when overlap is occurring (compared to having high exhaust manifold pressure keeping the mixture in)
so overlap is bad. but overlap is needed at higher rpm (i think) so that there is enough time for mixture to get into cylinder, and so exhaust scavenging does occur. since 4A flows reasobaly well as it is, maybe you could just get away with high lift cams as opposed to more overlap.
as for duration....
closing of exhaust and opening of intake controls overlap, so we are just thinking about opening of exhaust and closing of intake.
you could open exhaust earlier, since end of power stroke may not add so much anyway, but i'm unsure of how early is too early.
you could leave intake open longer, since you have higher intake pressure than NA, and you will continue to fill cylinder past the point that would happen with NA...
so as long as you set the lobe angles to control overlap, have high lift cams with aggressive ramp rates, then you can probably experiment with duration and not lose out too much, since you can adjust them to affect the exhaust opening and intake closing, and leave the other points alone-ish..
what are stock duration cams??
in 272 NA 4AG, cam comes on at what? 4000rpm?? with these in SC, unless you adjust overlap, then you will still have not so good bottom end as overlap is too big to build pressure???
as for staggered, it depends on the relative ability of the head to flow. ie for K motors, exhaust is worse, so you have a longer exhaust duration.
i think the only way to really tell (unless someone has results they are willing to share) would be to get sayy stock, 256, 264 and maybe 272, IN and EX, and dyno the buggers....
which do you thinki smore restrictive? the intake or exhaust?
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Location:
Toronto, Downtown
Registered:
September 2004
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Location:
u.s.a. south
Registered:
April 2004
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Re: Staggered cam sizes - 4AGZE
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Sat, 10 September 2005 18:28
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How does the sc14 run @18psi ? Should pull strong
http://www.twincam.org/forums/index.php?showtopic= 9681
Here's a super nice 7agze ae86 that runs staggered 264 inlet/ 256 exhaust cams. No performance numbers on it yet, but the owner claims it pulls very hard.
I'm very curious about this cam tuning vs torque relation also.
These days, u often see the vast majority of turbo guys run more duration on the exhaust cam - I wonder if everyone does this while trying to hit max peak hp, instead of shooting for more tq. Since folks seem obsessed with high peak "hp numbers" these days, and nothing else.
I'm thinking, a 1.6 with 300whp and 300 ft-lbs tq, may out accelerate another, say with 320whp and 270 ft-lbs tq for instance.
Surely an experience tuner would know the answers.
On a side note, I specifically remember major u.s. cam grinders featured more duration on the intake lobes than exhuast for boosted applications... although these we're older 2valve motors, they had alot of tq. The norally aspirated profiles had exhaust duration > inlet
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