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Location:
Perth
Registered:
January 2005
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20V vs 4AGE 16V with big valves
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Wed, 07 December 2005 06:37
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Hello,
4AGE 16V head inlet 2 x 29.5mm, 2 x 25.5mm
4AGE 20V head 3 x 26.6mm, 2 x 26.0mm
4AGE 16V (custom) 2 x 32.0mm, 2 x 28.0mm
My application is a SC14'd supercharged 4AGZE running 18+ psi.
I am wondering what would work better, a 16v 4age with big valves or a 20V head. Obviously the 20V head is a lot cheaper and also it gets you slightly bigger exhaust, shim under lifters, and a big intake hole! I am thinking I could run conservative cams with bigger valves for better streetability.
Does anyone have any comparisons between big valve and standard 4AGEs and 20V 4AGE cylinder heads?
Cheers, Nick
[Updated on: Wed, 07 December 2005 07:44]
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Location:
Tasmania
Registered:
May 2002
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Re: 20V vs 4AGE 16V with big valves
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Wed, 07 December 2005 08:16
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With the supercharger bolted on, I doubt its going to make much difference what head you use. Especialy if it never revs above 7500rpm. Just be sensible, match port the manifolds and stuff, it will work. Power will come from different camshafts, and supercharger pulley.
Read the other 20v vrs 16v threads. People say its way easier to just use a whole 4A-GZE.
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Location:
Montrose, VIC
Registered:
May 2002
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Re: 20V vs 4AGE 16V with big valves
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Wed, 07 December 2005 09:35
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I expect the limited airflow of the SC14 will be your biggest restriction.
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Location:
Perth
Registered:
January 2005
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I supported Toymods
Location:
melbourne
Registered:
June 2002
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Location:
Perth
Registered:
January 2005
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Re: 20V vs 4AGE 16V with big valves
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Wed, 07 December 2005 12:18
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Hi,
Perhaps. I haven't had any issues with my SC14 @ 18psi yet.
I know of plenty of people who have though, they were using SC12 and ALL were spinning it faster than I am spinning my SC14. So I guess I'm thinking speed more than boost may be the thing that the SC is most sensitive to, but of course I need more speed for more boost....I have been investigating a new coating, INCASE mine fails, but unfortunately the Toyota coating is about 500 microns (0.5mm!) thick and most places can only apply 30 - 50 microns coatings of suitable material. I know this as I have disassembled my spare SC14...
Anyway I just helped hijack my own thread...big valves experience anyone? 
Cheers, Nick
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I supported Toymods
Location:
melbourne
Registered:
June 2002
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Re: 20V vs 4AGE 16V with big valves
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Wed, 07 December 2005 12:23
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yep, speed is the casue FWIHH, as long as you dont spin it faster than a melted SC12, it should be fine, pretty sure the only real difference between the 12 and 14 is the rotors on the 14 are longer.
if you want more boost, twincharge it, just blow a turbo into the superhcarger, couldnt be easier!
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Location:
Canberra
Registered:
May 2002
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Re: 20V vs 4AGE 16V with big valves
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Wed, 07 December 2005 21:38
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One other advantage of the 20v is the higher inlet ports which makes mounting the supercharger easier.
20v's have been proven to work very nicely in forced induction situations in the past, I'd be thinking that it would be the logical choice.
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Location:
Perth
Registered:
January 2005
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Group A 4AGE cylinder head
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Thu, 08 December 2005 14:41
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Hello,
That is true. I saw on the internet, a twincharged 20V setup, using the standard SC12 bottom mount...grr...all my effort (and friends!) to mount the SC14 on funny angles...oh well....
On another note, what is the spec of a group A 4AGE cylinder head? I found somebody who is selling one. I'm not sure if the bigger valves (I dont know how big) and porting are wasted for me since it is apparently a small port head. Or are the valves the bigger restriction?
Maybe I should look at some bigger exh valves for my bigport head. I heard that 3SGE valves can be used. I have not investigated.
Cheers, Nick
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