Variable Valve Timing Mechanism on Toyota

[bulldozer313]

isn't this like an EGR valve?

[MrGeckolizard]

@bulldozer313 No, it adjusts the duration of the valve openings to create a more efficient combustion.

[BreakFreeze]

VVT-i is adjustable valve timing by adjustable cam pulley at certain degree

[BreakFreeze]

VVT-i is not an exhaust recirculating system..also not the overlapping valve timing..all reciprocating engine model in this world got the valve overlapping system, the main purpose is to remove all exhaust gasses from cylinder, during overlapping, both exh & intake is opened, in this position, especially for turbo engine, intake pressure will blow all remaining exh gasses out from cylinder..for NA engine, light pressure will do the same, to improve combustion efficiency.

[jsaulgodoy]

I HAVE TOYOTAS FIRST VVTI......ITS CALLED T-VIS LOL

[valetdabess]

so on a VVT-i does the valve time change once i go over a certain amout of rpm or does it change depending on how far i depress the throtle?

[atleastitsnotcrack]

I've got my VVT-I pully apart at the moment (Redtop 3s-ge intake cam VVT-I only) and I am telling you now the mechanism within is ABSOLUTELY NOTHING LIKE THAT IN THE ANIMATION!!!!!

It uses a piston with a set of splines inside and out that moves between the belt pulley which is driven by the outter splines and the Camshalft which is driven by the inner splines. The piston has a spring that forces it into the high rev timing position making the assembly explode when you dismantle it so beware!

[fatqwert200]

so basically some of the exaust goes in the intake manifold before the intake cycle. how does that solve any issue. the cold air gets heated before the intake cycle and the oxygen gets heated thus the volume expanse thus there is a loss of oxygen in the chamber. wouldnt this rob emmisions and lose power someone explain

[mistameanor420]

@fatqwert200 its operating as an "Exhaust Gas Recirculation"

In light load, cruising conditions it recirculates exhaust gas into the intake. The exhaust gas is inert and takes up space in the combustion chamber diluting the a/f mix. This slows the flame front in the cylinder, reducing cylinder temperature up to 300F reducing the emission of NOx, which is produced in high heat. Also, fuel is reduced in these situations, improving fuel economy.

[JOEWOLCHAK1]

Can an yone tell me where the VVT SOLENOID is on a 2000-02 Prizm/Corolla,, and how it is changed/replaced???

[deadrabbits19772]

small amounts of hot burnt gas's into the intake stream, wont that over heat it and cause pre detination,, how have they fixed that issue ? great tech seems like more things to go wrong,

[smkatb]

small amount of smoke pre heating the fuel air mixture for more efficient combustion

[noskings]

i dont get the whole sending the exhaust gases out the intake then back in again. all that effort to ensure cold air into the engine only to have that happen. also isnt there a chance of the hot exhaust pre maturely igniting the fuel air mixture?

[gird225]

@ samihasib

its benefit is to "preheat" the air to add more pressure and combust the fuel efficiciently.

[samihasib]

what is the benefit of mixing Exhaust Gas with incoming Fuel-Air mixture ?? ...

[Stahlross]

@samihasib

less smoking and less Co².

[littlefatzrow]

I wish they would talk 1 star

[bestamerica]

V VT is more smoking smoggy

[zcrayfish]

It's like an internal EGR... No more EGR valve!

[snimblop]

its taking exhaust gases back through the inlet then quickly back into the cylinder?

[Whipit8rapture]

not quite, the flowing of the exhaust gasses expelling from the cylinder pulls in fresh air and fuel.

[BlueRice]

yeah, when its being push to the inlet its mixes better with gas and air for better compression.

[solidsnakepsycho]

what i dont get is that if you put in a supercharger (not turbo) it creates and injects at a pressure anyways.... so it does the same thing as the VVT-i but better? then why does the 4A-GZE have a supercharger if the VVT-i does the same thing??? i dont understand it, but i'm considering the 4A-GE vs boring out a bunch of things on my 5S-FE engine.....

[jokeracts]

VTEC or valvetronic lift the valve higher allow more air flow into the combustion chamber, the vacuum pressure in combustiin chamber increase when the valve was lift higher,

over all, all the same function.

VVTL-1 is combined system,

is not very good, it will allow too much flame to flow out of the combustion chamber, may cause pre-ignited, loose of power, that why the BMW E90 320Si had removed the valvetronic (N45engine) and just use double vanos to defeat HONDA latest VTEC.

[jokeracts]

it was similiar to BMW VANOS,

the exhaust valve close early to trap some expanded flame/hot air in combustion chamber, then with intake valve open early allow the flame/hot air (flame/hot air is lower pressure than cooler air when finish burn create vacuum pressure) suck the cold air into the cylinder by the vacuum pressure,

the main objective was to improve the vacuum pressure in the combustion chamber during sucktion cycle. it was same function as the VTEC or valvetronic system.

[alonso9504]

why VVT intake Valve is opened too fast?

[dezhi818]

because when an engine running at high speed it needs longer time to suck more gas and air, so the valve got to open earlier and close later.

[alonso9504]

But U can see at this film that when intake is opened it gets fumes in. I dont understand it

[dezhi818]

engine could get better performance under certain circumstances by allowing the intake valve to open slightly before the exhaust valve closes. This increases the time for the fuel/air mixture to enter the cylinder during the intake stroke. In this condition the exhaust and intake valves are open at the same time; this is called 'valve overlap'.

[danothemano666]

its called "scavenging" The exiting exhaust gases act like a vaccum and help to pull in a larger amount of air and fuel. This is also present in 2 stroke engines.

[ralekriver]

That was a good demonstration of Valve Overlap. But there wasn't a clear demonstration as to how the valves and the cam gears were related.

[blackmarshallxp]

this kinda of engine may be the great engine,but nothing can beat the mazda rotary engine....capable of generating 300hp in 1300cc engine....cooooooooooooool

[djretro92]

rotary shit...so many gaz loose and so many problems too!!!

[NorwegianCrows]

Rotary engines and Wankel engines are great, but have a lack of torque.

[alexisgt90]

@NorwegianCrows ummmm..dude wankel engines and rotary engines are the same thing the rotary engine is called wankel cuz the one who invented the engine was called felix wankel...im saying just in case you dont know..i just want to help :)

[NorwegianCrows]

@alexisgt90 Actually, theres lots of different types of rotary engines: The Liquidpiston engine The Sarich orbital engine The RKM engine (RotationsKolbenMaschine) The Trochilic engine The Engineair engine The Rand cam engine The Ramgen Integrated Supersonic Component Engine The original Atkinson cycle engine The Wave disk engine (From Wikipedia) They still have a lack of torque.

[alexisgt90]

@NorwegianCrows cool thakyou for the information i really needed that..im stuying mechanic class and that helps me :) THX

[showusurbeaver]

all that video shows is that vvt-i uses purging, to increase the gas flow on the intake

[RavenAegis45]

well to answer your questions about Honda and Toyota, i'll explain, Originally VTEC only switched between a Low RPM Cam for Daily driving to a High RPM Cam for increased power. Toyota's VVT-i alters the Cam Profile for better response and Efficiency usually the Intake Cam. this increases flow through the valves. However VVTL-i use this and a version of VTEC. Also on a side note most modern VTEC Systems are a mix between the 2 so there both really good designs Toyota just favors fuel Economy

[WeedWizz]

Yo, Fatoni any exp. with this engine!?

[Rafdaganga]

what's better VVT-I or the honda one

[Dreznin]

They are totally different, so there really isn't any correct answer to that. I really is a matter of personal preference with how you want your car to respond.

[fatoni698]

The toyota one because hondas are pieces of shit.

[YadidaDookie]

actually, you are a piece of shit because your close mindedness cant look past a name (honda) and look at how good their product is, so stfu and stop talking shit, all cars are good cars as long as they are built right

[fatoni698]

Toyotas are much more reliable. And most hondas are fwd ricer pieces of shit

[idontcare80]

You're a moron. Honda and Toyota are constantly trading places in the list of top 10 manufacturers with the least problems per 100 vehicles. Toyota makes great cars but they also have their fair share of problems.

[idontcare80]

VVT-i only varies timing, VTEC varies timing, lift and duration. Toyota's VVTL-i was similar to VTEC but I don't think they even produce it anymore.

[jackmitchell123]

The VVTL-i is still in the Lotus Exige or whatever it is called. Please excuse my spelling.

[LeonidK340]

Are two different thinks...

VVT-i it's for economy (MAYBE) but looking to al VVT-i cars they have high RPM range, I don't know the secret but if u look to Toyota Celica SS-II 1.8L with 190HP redlining on 8k-9k rpms lol

VTEC it's for additional powa =D

Normal City driving the VTEC engine works with only 12Valve, when accelerate to 6k rpm the engine active all 16Valve producing awesome sound and powa =D ...

[authmaax]

greedy crossover (lol) that VVT-i ... is

[NSX00000]

VVT-i is just overlapping valve timing. It has nothing to valve lift like VTEC. The valve-lift stays the same. Dual VVT-i means that both the intake cam pulley and the exhaust pulley have the variable timing controller on them. VVTL-i is the one that is similar to VTEC wich involves valve-timing lift control. i-VTEC is the new breed from Honda which involves both the regular VTEC and the variable valve timing controller on the cam pulley which is similar to Toyota VVT-i.

[2009jimmy2009]

well explained

[SF18BRAV0]

soo which ones better? or I should say, which has the most impact, power wise, and fuel economy wise...?

[NSX00000]

VTEC is good at performance and fuel economy as long as u don't floor it all the time but i-VTEC is even better. VVT-i is just a little improvement on performance not as much as VTEC because it does not change the valves' lift but it's designed mainly for fuel economy. VVTL-i is the one that is similar to i-VTEC (RSX Type S). But, I cannot give a definate answer because there are many types of VTEC and i-VTEC out there that are designed for different goals. You should take a look at wikipedia.

[d0g0k]

vtec all the way

b16a2 :D

[claudiovtec]

NO VTEC NO PARTY!!

[blackops101]

The F20C stock rapes the shit out of the 5.7 Hemi in the new Charger.... what's sad is the Hemi pwns it in size by 3.7L and 2 cylinders lol secondly i saw a stock Si rape a mustang with spray i mean sure the stang would own in a 1/4 mile but in 1000m in final drive VTEC kicks in yo and most american cars have no final drive just close gear ratio and JDM cars have a better power:ratio sad how the new hemi lose to 2.0 riceboys if it were the original hemisphereical engine no rice would exsist

[blackops101]

funny thing is that a japanese guy is who made the mustang DOHC even funnnier is that the US doesnt run the motorsports industries and the VTEC does sumthing different cause the VTEC fails cept for the K20a and F series but all these ppl say omg V8 when the hemi's now arent the same hemi's that were in the superbee and when mopar raped the drag strip in the 70's and 80's but now the JDM makes USDM cars look like shit only american cars i respect is the viper and vette cause its worth the $

[perisrac]

you dont need all these extra parts to get valve overlap. An old pushrod V8 with points ignition and a carburetor can do the same thing. lame if you ask me.

It just does the same thing any ricer worth his salt does with a set of adjustable cam gears. Yes that is part of what those things are really for. create valve overlap without having to buy new cams. bet barely any of you knew that, and I'm an american that loves V8s...

[perisrac]

this is no big deal, americans already know about valve overlap. you notice the intake valve opens just before top dead center. The real reason is thermodynamics. When the combustion gasses exit the combustion chamber they tend to create a vacuum in their wake. If you open the intake valve just the right moment, the escaping gases will suck clean air into the chamber, allowing the exhaust gases to be fully expelled and allowing more clean air and fuel into the cylinder. only good for N/A cars.

[poojuke]

go toyota supra... kills any v-tec.

[jindagreatlee]

tell that to stephanie eggum who ran high 7's on a VTEC motor.. and not a poopra.

1200 whp out of a toyota poopra yet you still barely hit 12's.. LMAO now that's funny but hey it's still 1200 whp.

[dubvipers]

but which one is more easier to drive on the streets daily?

i think a 7 second civic owner would spend more time fixing than driving....

for a 7 sec civic you gotta gut it out and do huge motor work and swaps and stuff. plus it's FWD......

[jindagreatlee]

Now if you are making a 7 sec drag car why would it be street drivin? that makes no sense at all. Shit i can make a civic run 12's all motor with only a motor swap STOCK internals. Don't beleive me look up eg hatch with a k20a or k20a2 swap.

[dubvipers]

anyway, you'll end up replacing driveshafts and trannies and everything you will need to handle you so-called high powered 1.6 to 2.2 liter 4cylinder motors. sure they got lots of VTEC motors that honda makes, i myself enjoy my odyssey's SOHC VTEC V6. but would i ever waste my time to make it run 7's? no way dude, you gota do alotta chassis work, suspension, AND engine/ transmission to get that power down...

btw, some 2JZ's have VVT-i, depending that is. but they got boost for intake =]

[jindagreatlee]

yeah you'll end up replacing stock internals and stock shit if you're building a race car, that would be dumb if you didn't. Try to get a supra to run 7's.. It'll NEVER HAPPEN.

FYI, VVT-I is the same as IVTEC. And what do you mean they got boost for intake?

[dubvipers]

most guys running 2JZ's with VVTI would run standalones to control the VVTi but some would just disable VVTi because the turbo pushes all the air in during the intake phase. Forced induction that is.

i-Vtec and VVT-i, i dont give a fuck they are still great things to play with, lets include Dual VVT-i. I love systems that adjust lift duration and timing, its great technology.

Honda makes great NA motors, Toyota makes motors good for turboing, and Nissan owns with VQ37 w/ VVEL redline 7500

[dubvipers]

most supra's are fatass too hahahahaaha

[bchokola]

so... basically, with VVTI, the valve is blue! It makes sense now

[rawrletsgo]

doesnt vtec do the samne thing..

[carlosthenose]

it does more then that its a free running engine and it also acts as a second way of egr = better fuel efficiency

[infectrus]

looks like VVTI just increases overlap.

[TheBenevolence]

feofle the first car equiped with a b16 was a 1989 honda integra XSI(DA6)

[LTF85199]

looks like you have more (already combusted) smoke in a fresh stoke cycle which seem to be less effiecient.

[Swelltron3030]

Exactly. I don't like the look of it.

Go VTEC or go home.

Or buy a HEMI

[beyondthegrave2005]

Epic fail.... I'll give VTEC props, but it doesn't overlap valves that cleanly, trust me. Rip apart the block and run it like that, you'll see it for yourself. As far as the new Hemis... I'd rather get a new MIVEC. The Hemi isn't worth shit anymore, it's a 5.7L V8, and stock it still gets pwned by an F20C or even a 2JZ-GTE under the same conditions.

[Swelltron3030]

I'm sure it doesn't, but I grew up listening to VTEC over the other stuff, and I just like it more. It may just be brand loyalty, but I prefer it. And as far as Hemis for me, I also like the idea of American muscle. I'd prefer an old Hemi with a six pack, but I also do enjoy clean air and decent efficiency. I will always love the F20C for it's raw power pulled out of only 2.2 (or is it 2.3?) liters to put it on par with Turbo'd or larger displacement roadsters.

I will never ever get MIVEC.

[Swelltron3030]

I don't really like Mitsu or Toyotas or Nissans (although I love Infiniti's)

I think it's funny that on the earlier eclipses, Mitsu had to run 24lb of boost to make the DOHC engine even close to "fast"

[zmadman210]

i take it you're talking about the 4G63DET? they would boost 12-13lbs stock. thats it. i had one with a real boost gauge not just the factory one lol.

my friend has one with a 16G evo turbo and all the supporting mods. he can get 25lbs if the conditions are right. and the 1st and 2nd gen 4G63's came with a 14G. much smaller.

[Swelltron3030]

I don't know. I was helping my friend clean his engine bay, and I asked what it runs, boost wise, and he said 24lb, unbuilt. Now, I trust the kid, because he knows what he's talking about. But, I could have misheard him

[beyondthegrave2005]

My only problem with VTECs is they make better circuit motors than anything else really. Honda tried to hard to make the "perfect" engine. Toyota motors are more varied in tuning options. But as far as Honda's F-series motors the F20 is a 2L, but Honda made the series even better with the 2.2 F22C in the AP2.

[Swelltron3030]

Ah yes ah yes, F22C is 2.2. I'd go F20C for the higher redline though, if I had a choice to put in my Accord

I dunno, I find Hondas rather tunable, I've never dealt with Toyotas, and I don't really want to. As of now, the only car they have that is close to "race-ready" is the Matrix XR, which still only dishes up 158 or so, at the crank. An old supra or a new celica, that's all cool and great, but, Toys just don't don't do it for me. Probably brand loyalty again

[HiProfile67]

I have a 67 Firebird with a worked 455 (and my neighbor with a 68 Firebird with a 500whp 455), and I much prefer a lightweight turbocharged vehicle. I get 3x the gas milage, but get better times in the 1/4 mile.

[jeepluv76]

why are you comparing the Hemi in this video its says nothing about a Hemi and second the Hemi is (OHV) not OHC or DOHC I see nothing about the Hemi in this video tard.

[mathewtsab]

vtec and vvti are different. vvti intake cam lift only. vtec depending on dual or single, it got complete lift. what is simular is

VVTL-i. Both have Dual cam lift. VVT-i is simular to that of a K20a3 from an base model RSX or an 03-05 civic Si, these have intake side lift only.

[chrisss240sx]

wat do u think its better and faster the 2jzgte vvti or non vvti

[mathewtsab]

I'm believing that the vvti should have an edge due to the ability to electronicly change its timing. but i dont know too much details because i dont know anyone who owns a Supra TT. so i cant get no feed back. so sorry on that one.

[azngie1]

OMG! this hmonger knows his hmongdas very good :O lol!

[mathewtsab]

well i happen to own an LS/vtec hatch, and my friend Owns a Celica GT-S. both very amazing cars. both work almost the same. but i did my research wondering why the celica GT had less horse power than the GT-S, and vice versa for the RSX base and the RSX-S. just something i wanted to know.

[hause07]

The first type of VVT was used in 1991 on the 4A-GE 20-Valve engine. Toyota produced VVT before Honda's VTEC.

[feoffle]

no

the first DOHC VTEC motors were introduced in 1990 in the NSX and the Civic/CRX, with the C30A and B16A motors respectively

[A2892Z]

VVT-I has no diffrentce in lift but when engine speed is above 6000rpm it opens the intake valve sooner to give more power quickly. Thats why the cam lobes turn.

[allwaysallin]

its just showing overlap

[davinp]

my 2003 Camry came with the vvt-i engine. Toyota calls it VVT-i and Honda calls it VTEC, but they basically the same

[feoffle]

no

VVT-i has adjustable cam duration, but no difference in lift.

VTEC has both. VVTL-i is Toyota's answer to VTEC.

[chrisss240sx]

wat do u think its betetr and faster 2jzgte vvti or non vvti

[FullKontrolDRIFT]

doesnt the air fuel mix change to when it kicks into lift?

[1995bisquick]

had a neibor who overfilled his 86 mazda rotory with to much oil and he litaraly blew the engine because of a "hyraulic effect".

[ratita25]

I don't understand why this VVT-i technology is better than the standard... can someone explain pls?

[mrgrailbomb]

It allows the engine to run well at both high and low RPMs.

[noekiyu]

VVT-I is just a fancy acronym for valve overlap.

[shirolee]

that doesn't seems right, why would you let exhaust gases flow back into the intake valves

[tadpoliosis]

It would seem like if your unlucky and there was still an explosion in the chamber when intake opened you would ignite all of your fuel in hte intake lines... lol.

[anthonyT01]

and then try explaining that to your friends. lol

[sugar888]

thats what i noticed also. that means this engine would need a very high octane fuel or else..... after a few years with normal wear the intake would also become the exhaust.

[JRYANG9000]

Looks like it's leaking.

[suhaimiu23]

why vvt-i is more powerful that use some exhaust gases than the normal engine that use 100% fuel and oxygen

[rhett99rebel]

well it helps it run like a raped ape!! =P lol it reduces the valve lag just a lil tiny bit so it will acclerate better plus it refreshes the air/fuel mixture faster thus making it rev quicker and run better

[jdmboss1]

vvti copied vtec and vvtli copied i-vtec..... you do da math!

[DennisHorn]

VVTL-i did come in 1999 and I-VTEC in 2002, you do the math.

and you have to do som reding to, since i-VTEC it's more like regular VVT-i that Toyota did relase in 96

[gangstalemur]

Ight im going to college to be a mechanic but im having a little trouble understanding the VVT-i (Variable Valve Timing with intelegence)system It looks like both the intake and exhaust valves are open at the same time at the end of the exhaust stroke and the beginning of the intake stroke so wtf? if it is an enviromental thing than i get it but if its performance than im lost someone please explain!!!

[cvanbrederode]

That's called valve overlap, and it is very common. The simple answer is--it increases scavenging (making sure all the exhaust fumes are replaced by fresh fuel-air from the intake) at higher RPM, but too much will cause the engine to run rough at lower RPM's.

[amdforever20072007]

right and to touch that up a little. As the exhaust gases are pushed out of the cylinder they will start cooling down instantly creating a "vacuum" which will then, by laws of physics, "pull" in more fresh air/fuel mixture for the cylinder. The main thing is making sure neither valve hits each other during the process and neither valve hits the piston as well.

[23607]

Of course u could avoid all this confusion by workin on a superior rotary engine:) But if thats not an option remember that economy and perfomance go hand in hand. The goal being 2 burn the air/fuel as competely as possible.

[billabY]

Hmn I dont geddit how does that really Help...????

[metalicarock]

as i think vvt-i is also more fuel effcient than the v-tec....

[evertp1]

yo 187luciano187, r u drunk? i think toyota's 'VTEC' is called VVT-i

[stonerboi27]

no vtec and vvt-i are quite diffrent in performance. vtec takes a bit of time to kick in whereas vvt-i kicks in almost instantly as you hit the gas.

[HiProfile67]

wow, I can't imagine the performance issues you'd have by adding a turbo to this. Vtec is great for boost, but this? You'd have to run a huge t4 turbine to keep reversion from melting the injector seals. Not bad for NA though.

[beyondthegrave2005]

You honestly have never boosted a Honda.... the B20 only pulls 5psi, the K20 should never touch a turbo, it lags.... and the F20 barely pulls 8psi after some serious motor work... The only motor decent enough to hold serious boost pressure is the B18C.

[HiProfile67]

WTF are you talking about? The EPIC Tuning Civic runs well over 20psi (394hp) - on a bone-stock D16Z6! Then there's the dozens of 500hp STOCK K20's, 500hp STOCK F20's, etc.

Boost pressure isn't the end-all: 20psi on a T25 will barely get you 200hp, while 20psi on GT42 will get you FAR beyond 600hp.

BTW you realize what the Hemi principal is, right? A combustion chaimber with intake valves on one side, exhaust on the other, and the plug in the middle. Sound like...a modern HONDA. You fail.

[187luciano187]

Toyotas vtec;)

[vitriumGTS]

simple method of eliminating need for EGR valve...

[freed0m87]

the intake valve overlap...

to let fuel-air mixture to push the exhaust gas out of the cylinder....

[fookfocketyfookfook]

Compresses the intake charge before it enters the cylinder. Cylinder pressure won't go below ambient until you're past tdc and in this case the ex valve closes before tdc. ie. gas goes out rather than in. In reality the ex valve stays open past tdc though, in which case you're right.

[AlbertoXP35]

ajajajja thats called enginering, and TIMING

[redbox21]

valve overlap!

wen the two valves open the same time!

Never knew tha tho