2jzgte VVTI vs conventional 2jzgte

[auch]

hey guyz, as most mkiv enthusiast would agree, 2jzgte engine are the lord or all engines in stock form but lets discuss about the major difference between the 98' onwards VVTI version 2jzgte to the 92'-97' 2jzgte motors aside from the more low end torque due to the variable cam timing.

also, do all 92'-97' 2jzgte of aristo and supras the same? are there any preferred year/models produced on a particular batch/year?

thanks and hoping to see your reviews

[RomanV]

I thought it was only the naturally aspirated 2JZ that came with VVTI?

[RomanV]

Yep, looks like i might be right.

http://www.geocities.com/MotorCity/Pit/ ... #JZ-series

Unless anyone knows any different?

[fivebob]

Yep, looks like i might be right.

http://www.geocities.com/MotorCity/Pit/ ... #JZ-series

Unless anyone knows any different?

Err, according to your source...

2JZ-GTE DOHC 4 97-98 2997* (280)@5600 335@3600 86 86 8.5:1 VVT-i JP Supra, Aristo (voluntary 280hp limit, real hp ~350)

[matt dunn]

hey guyz, as most mkiv enthusiast would agree, 2jzgte engine are the lord or all engines in stock form but lets discuss about the major difference between the 98' onwards VVTI version 2jzgte to the 92'-97' 2jzgte motors aside from the more low end torque due to the variable cam timing.

also, do all 92'-97' 2jzgte of aristo and supras the same? are there any preferred year/models produced on a particular batch/year?

thanks and hoping to see your reviews

Not too sure on that model in particular,

but the XR6T engine that we runs has huge gains or losses to be made by playing with the dual VVTi.

I'd imagine that the 2JZ would be similar.

Matt

[CozmoNz]

2JZ-GTE
Type: 2997 L6 Sequential twin turbo
Bore: 86mm
Stroke: 86mm
Comp: 8.5:1
Power: 206Kw @ 5600rpm
Torque: 430Nm @ 3600
The sequential twin turbos and long stroke of the 2JZ-GTE give it phenomenal torque. The staging of the turbos is easy to feel, with the real fun starting at around 4000rpm.

Like the 1JZ-GTE, the standard internals are amazingly strong. There are cars in America running 9sec passes with a stock botom-end. Even the 1200hp Veilside street-drag Supra uses a standard crank.

Apart from the JZA80 Supra, this engine appeared in the JZS147 Aristo 3.0V, though, only with automatic trans. The Supra was known for its six-speed manual, but we have heard of five-speed versions too.

2JZ-GTE VVT-I
Type: 2997cc L6 sequential twin turbo
Bore: 86mm
Stroke: 86mm
Comp: 8.5:1
Power: 206Kw @ 5600rpm
Torque: 451Nm @ 3600rpm
Unlike most of the VVTi upgrades, the 2JZGTE retained lower 8.5:1 compression,but torque still increased by 21Nm. This engine appeared in the 1996-on Supra and JZS161 Aristo V300.

Like the atmo version, it simply feels a bit smoother than the old model in its power delivery, rather than any dramatic change. It is certainly just as strong and as desirable. But you can expect to pay alot more to have those extra letters on the cam cover.

This is from a magazine, i dont agree with EVERYTHING they say, as most of you wont. But its their point of view either way .

eg. 86mm stroke giving massive torque, if its the stroke (being square) why hasnt the 3sgte got so much torque . Wonder if its the displacement, and not the stroke haha.

ANYWAY, hope it helps, Torque comes on at the same rpm (max), however id imagine youd have more usable low end when off boost (due to cam timing obviously)... going by this list of engines, this is pretty much the only one that kept its low comp, the rest went up by .5 (1jzge, 2jzge, 1jzgte, 1uzfe. No info on the 1gzfe, did it come out in a Non vvt-i model?)

[RomanV]

Yep, looks like i might be right.

http://www.geocities.com/MotorCity/Pit/ ... #JZ-series

Unless anyone knows any different?

Err, according to your source...

2JZ-GTE DOHC 4 97-98 2997* (280)@5600 335@3600 86 86 8.5:1 VVT-i JP Supra, Aristo (voluntary 280hp limit, real hp ~350)

My bad. *Cough*

Only the two 2jz-ge motors say '4-VVTI' in the third row across for some reason.

[matt dunn]

2JZ-GTE
Type: 2997 L6 Sequential twin turbo

Power: 206Kw @ 5600rpm
Torque: 430Nm @ 3600
.

2JZ-GTE VVT-I
Type: 2997cc L6 sequential twin turbo
Power: 206Kw @ 5600rpm
Torque: 451Nm @ 3600rpm
.

If you believe that they are actually both 206kw, then think again.
Look at the 1JZGTE, it not far behind from memory.

they are more than that, (how much more never know) but were both rated at that.
I'd be surprised if the VVTi one did not actually make more KW.
hp = torque x revs etc,
It has more torque at the same revs etc etc etc

[CozmoNz]

Thats why i quoted them .

yeh, an rz supra was dynoed from chch wasnt it? made like 215kw @ the wheels when shes ment to be making 206@ engine X_X.

NAUGHTY toyota.

[Si]

not much point in the 2j vvti IMO,

The 1jz vvti however

[auch]

thanks for the infos guys.

yeah i agree that there would be slightly higher kw rating as well on the 2jzgte vvti version since torque had increased. i beleive that would also mean that the rev range would have increased as well due to variable cam timing.

so has anyone seen souped up 2jzgte with the vvti versions?

does anyone know any particular 2jzgte year/make/batches that are more preferred? eg. vr4 4g63bt are the more preferred 4g63t short blocks due to better metallurgy.

thanks guys keep it coming

[Si]

Engine model 1JZ-GTE vvti (single turbo)
Max.power (Net), kw(PS)/rpm 280 ps (205.94 kw) / 6200 rpm
Max.torque(Net), N*m(kg*m)/rpm 38.5 kg*m (377.56 N*m) / 2400 rpm

Engine model 1JZ-GTE (twin turbo)
Max.power (Net), kw(PS)/rpm 280 ps (205.94 kw) / 6200 rpm
Max.torque(Net), N*m(kg*m)/rpm 37.0 kg*m (362.85 N*m) / 4800 rpm

If toyota got these gains from going single turbo vvti on the 1jz, its a wonder why they didnt do the same for the 2jz

[SIKTOY]

eg. 86mm stroke giving massive torque, if its the stroke (being square) why hasnt the 3sgte got so much torque . Wonder if its the displacement, and not the stroke haha.

the 3s has two less cylinders, and for a 4cyl has pretty decent torque due to square stroke and bore.

[auch]

hi can you explain a bit more about the terminology you used about the stroke being "square". sorry i havent caught up to that level of jargon yet

[trueno]

Bore = diameter of the cylinder
Stroke = distance which the Piston travels through vertically

Square means the Bore diameter = Stroke length, ie 86mmx86mm in the case of the 3S.

Cozmo - They are probably comparing it to the RB26? (86 X 73.7)

[auch]

i see... so it just basically means that the stroke is equally the same as the bore diameter. thanks for that. so does that mean that other engines that dont have identical bore x stroke cant be called square?

thanks

[matt dunn]

Engine model 1JZ-GTE vvti (single turbo)
Max.power (Net), kw(PS)/rpm 280 ps (205.94 kw) / 6200 rpm
Max.torque(Net), N*m(kg*m)/rpm 38.5 kg*m (377.56 N*m) / 2400 rpm

Engine model 1JZ-GTE (twin turbo)
Max.power (Net), kw(PS)/rpm 280 ps (205.94 kw) / 6200 rpm
Max.torque(Net), N*m(kg*m)/rpm 37.0 kg*m (362.85 N*m) / 4800 rpm

If toyota got these gains from going single turbo vvti on the 1jz, its a wonder why they didnt do the same for the 2jz

Where did you get those figures from?
Not saying they are wrong, just interested to know where they came from?

Matt

[Si]

The info came from www.english.auto.vl.ru , and are consistent with figures i have seen elsewhere.


auch
Regarding the bore stroke question his might be usefull reading for you :


Introduction
We've already discussed the engine theory around rod to stroke ratios, and this time we get even more elemental with questions about the ratio between bore and stroke.

An engine with an equal bore and stroke, say 82 mm and 82 mm, is called "square" for some obscure reason. An engine with a stroke larger than the bore is called "under square," and an engine with a bore bigger than the stroke is called "over square." Their relative values have been the subject of many a night's bench racing since the first Otto motor chuffed and puffed its way into existence.

History and Theory
Early motors were most often wildly under square, with long strokes and relatively small bores. As materials improved and the additional power from high rpm became desirable, more engines sported a larger bore.

What does it all mean? Tradition tells us that an over square engine should make more power and rev higher than an under square configuration. But, comparing different engine families is a lot like comparing apples and oranges. Sometimes the results are what you expect, and sometimes they don't come close. Consider the Super Vee engine example: When VW switched from the air-cooled Super Vees to the water cooled Rabbit-based Super Vees, they went from an over square engine to a slightly under square engine, which was capable of higher revs and made more power more dependably. So much for theory.

Comparing similar engines (for example, a big bore versus a long stroke VW) often doesn't yield much in the way of a difference. Why is that? Darrell Vittone, whose history with VW racing engines has given him plenty of insight into the more practical side of engine theory, said, "It all comes down to breathing. The ultimate limiter of engine performance, if the mechanical can take the power, is the breathing and the integrity of the valve train." On our air-cooled Super Vee example, the valve train left a lot to be desired, probably a major reason for the success of the Rabbit motors.

Breathing is the important thing, then. Over square engines have an advantage here, in theory. In a big bore engine, the edges of the valve are less obstructed by the cylinder wall. This is called "unshrouded" and helps breathing. A big bore can fit larger valves and give them more breathing room, too. The 2002 and 911 engines are good examples of over square motors which benefit from big valves.

The downsides of a big bore are flame travel and burn time, a reduction in strength, and some emissions related questions. A bigger bore is harder to ignite evenly. That's why the 911 engine with dual plus make more power than with a single-ignition setup. Physically, the bigger span of the open bore contributes less to the strength of a motor, too. Finally, a longer stroke motor seems to offer more favorable emissions conditions than a big bore motor.

Why are big bores so popular? One good reason is that it's much easier to increase the size of an engine with the bore. A stroke increase of 6.4 mm, from 86.4 to 92.8, gains only 127 cc (7 percent). But, only a 3 mm increase in bore, from 79.5 to 82.5, gives a 141 cc increase and just about the same 7 percent increase in displacement. on replaceable bore motors, like the air-cooled VW or 911, it's certainly cheaper to replace the bore and pistons than it is buy a special crank, so price is important, too.

A Matter of Evolution
Metallurgy and other technologies have improved race engines for higher rpm levels in search of more power. More often than not, that means going to shorter strokes, both to reduce the reciprocating mass (the weight the engine has to spin around) and allow wider bores for better breathing. The result is radically over square engines.

Let's look at a past and present English racing engine to show how engine design trends have changed. The current 3.5 liter Ford Formula 1 V8 has a 4.0 inch bore (about 101 mm) and a short -- ridiculously short stroke of about 2.12 inch (53 mm!!). This gives the engine the maximum allowed 3.5 liter displacement. This is an over square engine. The Ford beauty breathes through four-valve-per-cylinder heads with a pair of 40 mm intake valves for each cylinder, and it spins to incredibly high rpm -- purported to be in the 13,000 rpm range or even higher.

Compare this to the classic Jaguar 3.8 liter twin cam as fitted in the XK series Jaquars. Don't think that this wasn't a racing engine -- it was the real thing in its day, with a long string of victories that included Le Mans. The Jaguar motor has only six cylinders and slightly larger displacement than the modern Ford Formula One V8. The bore is 3.45 inch (87 mm) and the stroke is 4.17 inch (about 106 mm) or just about the opposite of the F1 V8. The Jag has an incredibly torquey stump puller of a motor, but one with a redline in the 5500 rpm range. Because the rpm is limited by the long stroke and heavy pistons adequate breathing is provided by a single inlet valve in each cylinder. Under square? Radically.

Politics, Too
Our English examples are apropos of another sub-chapter in the saga of the under square/over square squabble. Scratch an English engine from the Fifties or Sixties and you'll find a whopping long stroke underneath. Jaguar, Austin-Healy, Triumph and MG all had strokes that a tractor would be proud of. Ferraris, Porsches, Mercedes and even lowly Fiats had far more over square engines back in those days, and they revved more freely as a result. With a desire to compete in the world market, and to compete in international racing, wouldn't you think that the English would bend in the breeze of modern technology? You probably can't begin to guess the reason why they didn't.

It was pure politics. In the beginning of the motor age, the English were taxed by bore size, unlike the French who were taxed by displacement, or a mathematical "fiscal" horsepower. Some government boffin decided that by limiting bores through taxes, engines would be small. The government was playing the "let's make rules about something we don't understand" game, while the manufactures were just playing the old "dodge the taxes" game. The result was extremely torquey low revving engines, and an automotive industry that became increasing less competitive. By the 1950s the silly law was dropped, but the impact was already made.

The over square/under square question is not as simple as it seems at first glance, or as simple as it is often presented. Engine bore/stroke ratios, like most engine design criteria, are a complex issue. What does it mean to the average engine builder? For most stock and class racing, you're limited to strictly controlled modifications, and theory shouldn't affect your choices there. For street modifications, you probably don't have a wide range of choices and can't radically later the basic relationship of the engine's bore and stroke. If you are sitting down and designing an engine for yourself, you have some interesting thinking to do.

[auch]

thanks SI it looks like it might be a good read...

keep em coming... thanks guys

[CozmoNz]

Trueno, they could indeed have been....