16v vs 20v turbo

[Bazda]

But you guys have built them to be handle that much power.. Im just saying if you were gonna keep it fairly standard my opinion sees the GZE to be stronger.

my head is stock, apart from stiffer valve springs cos of my higher boost.

mr revhead is correct.

[dash]

oes the 20V (silver or black) have vvt? Will it require special ecu control for it to function properly ?

Many 4agte guys down your way run 16V cams.
What brand, local grinds or JDM, & cost ?
Springs needed & cost ?
Cams "drop-in" or adjustable gears must be added to the 'cost' ?
Is there 'the expected' pronounced performance difference ?

Bazdas' build certainly made a believer out of me for a boosted 20V.
I'd like an 'all toyota' corolla to replace my ca18/ae86 but the 7agte or 3sg route don't even seem to get near even 3 times the swap price
.... won't loose any sleep over it tho

[soopachargen]

I know some people wont agree with this, but i've been reading stuff from a nascar and cart engine builder and his main theory is it doesnt matter how much air flow you have if you dont have good combustion.
The gze piston and the 20v head dont match up as well and the gze piston and the 16v head so with the 16v head in theory you should get better combustion. If you were to go as far as barry has and have custom pistons made up to match the 20v combustion chamber then that may be solved. Good combustion results in less detonation.

[fivebob]

The gze piston and the 20v head dont match up as well and the gze piston and the 16v head so with the 16v head in theory you should get better combustion.

Care to expand on this theory?

As far as I can see the 5 valve head and a 4 valve piston is no worse than having one more valve pockets in the piston, in fact it might even be better

[Bazda]

oes the 20V (silver or black) have vvt? Will it require special ecu control for it to function properly ?

Many 4agte guys down your way run 16V cams.
What brand, local grinds or JDM, & cost ?
Springs needed & cost ?
Cams "drop-in" or adjustable gears must be added to the 'cost' ?
Is there 'the expected' pronounced performance difference ?

Bazdas' build certainly made a believer out of me for a boosted 20V.
I'd like an 'all toyota' corolla to replace my ca18/ae86 but the 7agte or 3sg route don't even seem to get near even 3 times the swap price
.... won't loose any sleep over it tho

VVT is just a solenoid, you control it by turning a relay on or off via the ecu.
My pistons were not desiged for the 20v head they were for a 16v head. It just so happens combustion in the 20v head was very good hence running 27psi on 98 pump gas.

If you think about most of the fast 4agtes are running 20vs,
the speedtech corolla which runs 10s, tony rigolis 20v fwd seca in aussy which ran 11s, backyarder who has a crusty ae82 which runs low 10s!! with a 20v silvertop.

[soopachargen]

its just stuff from here. http://www.theoldone.com/

[soopachargen]

it just seems from what i have read that the squish areas on the piston not matching up with the squish area in the combustion chamber is not optimum for combustion.

[Mr Revhead]

that could come into play in some setups i think.
like if they were really mismatched they could create wierd flow/masking etc in the chamber.
but as the 4agze pistons are just dished in the 8:1 and with slight cut outs in the 8:9 i dont think itll be a factor in the 4age.

as for changing cams in a 16v head..... as iv said before, the bluetop has one set of cams, and all other 16vs share the same cam.
changing the later cams to the earlier is supposed to give some gains. but iv never seen any dyno proof.

[TRD_ZERO]

The gze piston and the 20v head dont match up as well and the gze piston and the 16v head so with the 16v head in theory you should get better combustion.

If a remember correctly the blacktop pistons doesnt even have the 5 valve cutouts anyway for the head.And isnt Barry using Ross 16v Dished Pistons. So he is still using the 16v pistons and gets great results.

[Crucible]

as for changing cams in a 16v head..... as iv said before, the bluetop has one set of cams, and all other 16vs share the same cam.
changing the later cams to the earlier is supposed to give some gains. but iv never seen any dyno proof.

well if someone wants to pay for dyno time, Ill run my car with stock ze cams on 18psi and that will give you all the proof you need

A guy in aussy is running 4agte with a bigport head making over 280kw atws, hes spent $$$ but still not too shabby figure, last I seen he was pushing for 300kw!

[Calvin]

as for changing cams in a 16v head..... as iv said before, the bluetop has one set of cams, and all other 16vs share the same cam.
changing the later cams to the earlier is supposed to give some gains. but iv never seen any dyno proof.

Can anyone disagree with this? I was thinking about going for blue top cams but someone also told me it wouldnt make a difference.. But it seems that a significant group of people seem to think the bluetop cams are better.. Apparently more lift with the NA cams?

I know barrys setup was a bigport with N/A cams..

So does it or does it not make a difference?

EDIT: Just read above post.. any other opinions?

[bluemaumau]

im thinking about going 16v as itll still make the power but wont cost as much

[Calvin]

im thinking about going 16v as itll still make the power but wont cost as much

Whats wrong with the GZE you got now? or is that the one your gonna rebuild?

[Mr Revhead]

the bluetop ones have slightly more lift, i cant remember the duration off the top of my head.

im not saying the definitly dont give any gains.... but no ones managed to prove they do.
bearong in mind the engines with the later cams make more power. but i cant say how much of that is ECU related.

basicly, if your building from scratch, it maybe worth it.
if you have an engine, and want to change, its not worth the effort imo.

i have had one person say they did dyno runs on a smallport with the bluetop cams and lost power.

[Crucible]

im thinking about going 16v as itll still make the power but wont cost as much

and how much more power are you really going to make? same base, 16v vs 20v, I mean are you really gonna run 20 + psi all day, its not really practical....

I made close to the same power as two S/T 20v 4agtes on this forum and with slightley less boost.

[Mr Revhead]

at the end of the day, theres many many factors that dictate the power you will make.

for a large portion of ppl doing this the type of head they use is the least of their worries.

if your going for max power, as bazda pointed out, the 20v head seems to have it over the 16v. but how many ppl are really after or have the capability to make max power?

ie if your goal is 200whp i dont think it matters what head you pick.

so if you have one head, go with that. if your out to buy a head. go with whatever you find first. bearing in mind manifolds etc.

or, just go with what you feel like


btw 20vs pwn u!

[soopachargen]

this is quite a good read
http://www.theoldone.com/archive/quench-area.htm

[bluemaumau]

i should restate this

im thinking about going 16v as itll still make the power but wont cost as much

im thinking about going 16v as itll still make as much power as i need/want but wont cost as much

[RedMist]

In a compressed situation, where swirl issues would be compensated for by flow, I would think the considerable additional valve area of the 20 valve would be of benefit. I'd personally go blacktop as its got a good 15% more exhaust flow over the silvertop. Or port the silvertop exhaust (which I'm sure I've already done on a flow test on one port before).

In regards to valve cutouts in pistons. I havent seen any stock GZE pistons, but the 101 set flycut and the older GZE not? or the other way around? I would think that they may create a detonation point, but only when you are attempting to get 100% from the engine.
Yes the blacktop only has flycuts for exhaust valves. No intake flycuts.

Club4ag lists all bigport cams as .46mm greater lift than that of the smallport and ZE's

[d1 mule]

bluetop cam duration 240 deg. all other 16v 232 deg not sure on lift.
i cant see how more duration and lift could be a bad thing more air = more bang