Topic: 4A-GE 20 VALVE for Dummies

Knowledge is Power,for any newbie wanting to know about the power lurking under there hoods.Would be kul if this could be sticked ??

4A-GE 20 VALVE
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The 20-Valve 4AGE replaced the 4AGZE Supercharged engines. Just like the early and late 16 Valve 4Ges, they also underwent revisions.  The Silver Top was introduced in the Corolla AE101 (1992), and the Black Top in the Corolla AE111 (1997).  Both engines used Toyota’s version of Variable cam timing- VVT.  Bore and stroke remained as in the original 1st and 2nd Generation 4AGEs (early) big port (TVIS) and (late) small port (non-TVIS).  Similarly compression was upped in the later models.  The blocks are identical to the late model AE92 generation blocks (and naturally the SC blocks too).

The 20-Valve engines never came officially into the US (and many other foreign markets where the old 4AGEs were available- and of course it imparts a very exotic presence.  The individual throttle bodies look like they came off the fabulous 503 race engines.   Think about it, no Toyota factory RACE Engine had 5 valves per cylinder!!  Yamaha- who works with Toyota on cylinder head design (and manufacturing), have been a very avid pioneer and supporter of the 5-valve design.  The short-lived Yamaha Formula 1 engines had 5 valves per cylinder.  In terms of maximum valve to surface area- the 5 valve design cannot be beat- theoretically and geometrically.

Aside from the obvious 5-valve and variable timing cylinder head design- the difference from the 4-valve is the dramatically reduced weight of the internal components.  Pistons, connecting rods, and to a lesser degree, crankshafts have all been updated with lighter weight design.  The good news is that it remained an iron block- the engines were still on solid foundation for heavy and serious modifications.

Between the Silver and Black top- the later Black models came with still lighter rotating components.  Laying out the engine components side by side…there are miniscule differences, Toyota was tuning the engines to a higher degree by rotational mass reduction, a lesson advanced from the earlier lightweight block design (of the pre-multi-valve engines).   The difference in the connecting rods between 16 and 20 valve engines is dramatically surprising.   However for purposes of radical modifications a Silver top will probably be a better engine to work with (slightly stouter rod).

In Japan these engines were used in Formula Toyota, a series much like Formula Atlantic where there is only one SPEC engine available to all competitors.  The magic of 20-valve is apparent on the ability to attain and sustain a high RPM threshold.  The addition of variable cam timing allows the engine to surpass both low-end torque and high RPM horsepower figures of the older 4AGEs.  This is the closest to race spec engine Toyota has ever produced.

In terms of Toyota technology, the twin versions of the 20-valve engine- out specified any previous offering in naturally aspirated form.  This is the last true iron block with the ultimate head design and intake set-up.  The newer 1ZZFE and 2ZZGE come with a more advance VVTi head set-up- but with 1 less valve (per cylinder) and aluminum blocks.  The 4AG 20-Valve wins!!

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  02' RXi 20v
  92' GLi Exec [ex]

Re: 4A-GE 20 VALVE for Dummies

done!

DO WAT U HAVE TO ...TO BE AHEAD OF UR GAME
HEAD OF TOPSECRET DEVELOPMENTS!

inquire on the vtec controllers landing!!

Re: 4A-GE 20 VALVE for Dummies

Shot ../../extensions/custom_smilies_2/img1/wink

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  02' RXi 20v
  92' GLi Exec [ex]

Re: 4A-GE 20 VALVE for Dummies

n.p

DO WAT U HAVE TO ...TO BE AHEAD OF UR GAME
HEAD OF TOPSECRET DEVELOPMENTS!

inquire on the vtec controllers landing!!

Re: 4A-GE 20 VALVE for Dummies

I totaly disagree with what your saying, there's a good reason why yahaha and all others have gone away from a 5v design.. its because its inferior! I can go into more detail if would like

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Re: 4A-GE 20 VALVE for Dummies

Sam_Q wrote:

I totaly disagree with what your saying, there's a good reason why yahaha and all others have gone away from a 5v design.. its because its inferior! I can go into more detail if would like

pls do........

Re: 4A-GE 20 VALVE for Dummies

@ Sam_Q - info came from this website: http://www.toysport.com/technical%20inf … _notes.htm
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20V Corolla ../../extensions/custom_smilies_2/img1/devil

Re: 4A-GE 20 VALVE for Dummies

well ok I can into as much detail as you guys want but basicly theres a good reason why all modern car performance engines, F1 enignes and motorbikes over a certain capacity are 4V.

The single biggest problem is that the combustion chamber shape is far from ideal and with the inclusion of the extra valve the squish areas are reduced to a small size and are faced in a poor place.

The effective combustion chamber (non quenched area) is therefore wider causing a more uneven burn and more prone to preigniton.

The intlet ports have an uneven harmonic wave due to the different length ports which limits cylinder filling and possibly causes air stagnation.

Bucket sizes have to be limited in diameter on the intake side to accomodate three instead of two. This causes large valvetrain stresses with aggressive camshaft profiles and limits the total ramp rate and lift of any cam profile.

The middle intake valve causes heavy shrouding to the two outer valves and this is why the toyotas 20V engines flow very well on a flow bench but the real world output seems to not reflect this.

I challenge anyone to show me a non turbo 20v with more than 220hp, when faced with the option almost all the japanese engine builders in the open 4ag based ae86 classed races would use a bigport head on a later bottom end.


As for the toysport website I have some doubts, for example:

"Aside from the obvious 5-valve and variable timing cylinder head design- the difference from the 4-valve is the dramatically reduced weight of the internal components.  Pistons, connecting rods, and to a lesser degree, crankshafts have all been updated with lighter weight design."

This is what I have picked is wrong, someone tell me if I am mistaken:

crank is almost the same weight, I am pretty sure the silvertop rods are actually heavier than the earlier rods, the pistons are not much lighter either.

"However for purposes of radical modifications a Silver top will probably be a better engine to work with (slightly stouter rod)"

the blacktop rod is a hell of a lot more less solid than a silvertop rod and people have found they dont like long term high revs past 8500 on a racetrack

"Between the Silver and Black top- the later Black models came with still lighter rotating components."

pistons margionally yes, rods by 20g or so, crank no... its actually a fraction heavier, go figure??

if you would like to know more I suggest a book by A.Bell called four stroke performance tuning

otherwise I am open to debate on my comments

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Re: 4A-GE 20 VALVE for Dummies

Nicely sed Sam,ive learnt something new today,thanks ../../extensions/custom_smilies_2/img1/cool

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  02' RXi 20v
  92' GLi Exec [ex]

Re: 4A-GE 20 VALVE for Dummies

no problem.

Just for the record I am doing custom work to my 20v and I like it a lot. I just know that its not ideal but I am ok with that for now

also if you want to hear a load of crap have a look what toysport say about a 7age conversion:

"if you like the torque of a 7a engine then buy a 7afe instead", I think this is stupid considering how many people have these in their cars and race cars and love the conversion

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Re: 4A-GE 20 VALVE for Dummies

Sam_Q wrote:

no problem.

Just for the record I am doing custom work to my 20v and I like it a lot. I just know that its not ideal but I am ok with that for now

also if you want to hear a load of crap have a look what toysport say about a 7age conversion:

"if you like the torque of a 7a engine then buy a 7afe instead", I think this is stupid considering how many people have these in their cars and race cars and love the conversion

I would not go back to 7AFE! The 7AGE-20V conversion rocks??? I love the power and the torque output.

94' Conquest 7AGE-20V  科學怪人 
Built By Salim & Tuffy                                                     
CandyMan Tuned


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Re: 4A-GE 20 VALVE for Dummies

exactly my point, it sure puts some doubt on the credibility of the rest of the information doesnt it?

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Re: 4A-GE 20 VALVE for Dummies

I guess so. Maybe they are looking at it from a reliability perspective, but if you run all the genuine after market parts, reliability would not be an issue?

94' Conquest 7AGE-20V  科學怪人 
Built By Salim & Tuffy                                                     
CandyMan Tuned


"We can’t think like Africans, in Africa, generally. We are in Johannesburg, this is Johannesburg. It’s not some national road in Malawi.” - Jacob Zuma
                                           

Re: 4A-GE 20 VALVE for Dummies

yes the only real weak point is the rods which are available from atleast two different companies now, also converting a 20v to rwd is easy enough and the parts are readily available

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Re: 4A-GE 20 VALVE for Dummies

Sam_Q wrote:

yes the only real weak point is the rods which are available from atleast two different companies now, also converting a 20v to rwd is easy enough and the parts are readily available


very nice comment and info

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Re: 4A-GE 20 VALVE for Dummies

20v cool but VVTLI Rocks!!!

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Re: 4A-GE 20 VALVE for Dummies

@Sam Q,good information there,where did you find this?.I found the article that is posted in the link also before i saw it on here,but there is no mention of anything you said.I heard other people also say they prefer the older generation,but i thought it was in turbo conversions..

But i mean,apart from poor combustion shape,and valve positions,the 20 valve simply still breaths better,without itb's than the 16v?.

If you look at the the 20V,its should be the VVT that set it completely apart,if both are running itb's,and the same cams and compression and so on?.It gives you the torque back,after running high cams and itb's,so this is what you want..

Re: 4A-GE 20 VALVE for Dummies

in turbo conversions it's different again and 20V engines are excellent.

Most of the information comes from the book four stroke performance tuning:

http://www.amazon.com/Four-Stroke-Perfo … amp;sr=8-1

I suggest everyone even a little into engines have a read of this

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Re: 4A-GE 20 VALVE for Dummies

I have to say that you have alot of knowledge on this,and this is really good read.Well done.Almost everyone thinks the 20v is superior,until now.So how much faster will the 16v be, each with the same bottom,each with itb's?.Does this principle apply at 150hp also?.

Re: 4A-GE 20 VALVE for Dummies

I have to say that you have alot of knowledge on this,and this is really good read.Well done.Almost everyone thinks the 20v is superior,until now.So how much faster will the 16v be, each with the same bottom,each with itb's?.Does this principle apply at 150hp also?.