View Full Version : which variable valve control system is ur favourite?
fpv_gtho
05-14-2003, 03:22 AM
out of Ferrari's system, Porsches VARIOCAM, BMW's VALVETRONIC, subaru's new system, toyota's VVT-I, Honda's VTEC, Mazda's S-VT and Ford Australia's VCT, which variable valve technology is ur favourite. If ur favourite isnt listed, vote for other and list it in the forum
Kudosdude
05-14-2003, 05:07 AM
I haven't looked at them all but in my opinion it has to be the Ferrari system -> it is very simple (and ingenious).
This is how it works. (http://auto.howstuffworks.com/camshaft3.htm)
:D
fpv_gtho
05-15-2003, 02:14 AM
i heard somewhere that BMW's valves are organised as 1 exhaust valve/3 intake valve. can anyone confirm that? which manufacturer do u think will be the first to come up with a 5 valve, direct injection, twin spark engine with each valve individually controlled by computer?
ewingss
05-15-2003, 04:41 PM
all systems have advanteges and disadbantages but the best is the honda.
see all the information in
www.CanadianDriver.com
ewingss
05-15-2003, 04:50 PM
all engineers agree hondas vtec is the best by now.
read the articles of jim kerr . canadiandriver.com
Kudosdude
05-16-2003, 01:20 AM
I don't ;) Ewingss
Anyway you may want to have a look here at wards for the top 10 engines in depth (http://subscribers.wardsauto.com/Microsites/index.asp?srid=10088&pageid=5991&siteid=26&magazineid=1004&srtype=1)
fpv_gtho
06-10-2003, 04:15 AM
if hondas vtec is as good as u all make it out to be then why hasnt anyone woted for it yet then
piledriver
06-10-2003, 07:16 AM
Honda has the best relation power/litre for NA engines in the world with the 2.0 VTEC of the S2000...
henk4
06-11-2003, 01:04 PM
Originally posted by Kudosdude
I don't ;) Ewingss
Anyway you may want to have a look here at wards for the top 10 engines in depth (http://subscribers.wardsauto.com/Microsites/index.asp?srid=10088&pageid=5991&siteid=26&magazineid=1004&srtype=1)
Slightly off topic, but American visitors might check the Ford Diesel mentioned in the top ten. Somebody appears to be waking up over there.
Originally posted by piledriver
Honda has the best relation power/litre for NA engines in the world with the 2.0 VTEC of the S2000...
Too bad it lacks torque.
VVT is nothing new. Some may be different than others, but they're all pretty much the same.
I perfer BMW's.
DSM owner
06-16-2003, 05:29 AM
Originally posted by Nash
Too bad it lacks torque.
What do you mean it lacks torque? It has an incredible amount of torque for a 2 liter engine and hte torque curve is incredibly flat.
Originally posted by DSM owner
What do you mean it lacks torque? It has an incredible amount of torque for a 2 liter engine and hte torque curve is incredibly flat.
I heard you have to drop the clutch at really high RPMs because the S2K lacks low end torque, damn it. I obviously heard wrong.
fpv_gtho
06-16-2003, 11:11 PM
maybe Nash means for the amount of power it produces it produces bugger all torque
jadotch
07-09-2003, 03:55 PM
Well I am adding varible valve timing and lift to my ford 302 as soon as I have the cash. I will tell you if I like it.
fpv_gtho
07-09-2003, 07:41 PM
how the **** r u gunna stick variable valve timing and lift on an ohv, single cam engine?
jadotch
07-10-2003, 09:31 AM
go here
http://www.hotrocker.com/
It has nothing to do with the cam, but instead the rocker-arm ratio which is being changed. Basically a the rocker arm is hollow with an adjustable pedistol in the middle that changes positions during a certian RPM adjusting the the lift of the rocker arm. They make them for Chevy V-6's and 350's as well. I am sure it is not the best VVA, but it is a good simple solution for push-rod engines that can be added to virtually any pushrod. And it does effect lift, which only Ferraris and Honda's do. They actually used a similar VVA in some WWII aircraft engines.
crxman
11-05-2004, 12:32 PM
I was wondering who first came up with the variable valve technology in a production car? I thought in was Honda around 1991 in there NSX, but someone has told me that was wrong, he says it was ford and chevy a long time ago. Note he is a Ford fan so i dont beleive much he does say.....
And what is the best "bonus" achieved from variable valve tech, for example
x Liters = y hp compaired to
x Liter(With Variable Valve Tech) = y hp plus how much?
jcp123
11-05-2004, 08:45 PM
not a fan of vvt, it's too complicated and new-fangled for me, and i regard it with a fair amount of suspicion with regards to relaibility. but i picked the toyota vvti, my mom drives a van with it and after 5k miles the vvti still works.
PerfAdv
11-05-2004, 09:55 PM
Reliability wise, I drove a Integra GS-R for 163+K miles and it still had 220 psi in all 4 cylinders, when I had compression tested. The beauty of VTEC or any other variable valve system is that the lower-profile lobes for low speed operation actually put less strain on the valvetrain. Only when the revs climb do the more radical lobes cause longer duration and higher lift. Economy down low and power up high. Before, normal use cars were always a compromise leaning towards economy and the hot-rodder could be picked out by his lopey idle. Both compromising either for high or low, but no more.
I vote for VTEC
jcp123
11-05-2004, 10:13 PM
Ah, I see, but by the reliability I had meant more like the electronic controls for it. The mechanicals are no sweat to build utterly reliably.
PerfAdv
11-05-2004, 10:25 PM
Ah, I see, but by the reliability I had meant more like the electronic controls for it. The mechanicals are no sweat to build utterly reliably.
In the almost eight years I had the VTEC Integra I never had an issue with the VTEC. I went through 2 clutches, a few brake jobs, several sets of Yokos and Pirellis, and the distributor assembly was the only mechanical failure. The VTEC system was completely invisible, never needing any attention. Only other thing that needs regular attention are valve adjustments. Having solid lifters they require adjustment every 15-20K miles.
jcp123
11-05-2004, 10:30 PM
That's not too bad then...and I hear ya on the solid lifters. They're a PITA, though if set properly I've heard some can go upwards of 50k miles. But we digress.
KnifeEdge_2K1
11-06-2004, 12:59 PM
i heard somewhere that BMW's valves are organised as 1 exhaust valve/3 intake valve. can anyone confirm that? which manufacturer do u think will be the first to come up with a 5 valve, direct injection, twin spark engine with each valve individually controlled by computer?
... the head would weigh more then the block crank and pistons combined ..
gtrjazz
11-06-2004, 05:56 PM
VVT,VCT lets not get mixed up .My preference would be the electrically controlled Hydraulic system by Lotus.
fpv_gtho
11-06-2004, 10:30 PM
... the head would weigh more then the block crank and pistons combined ..
and thats supposed to deter people from doing it?
jcp123
11-07-2004, 12:37 AM
and thats supposed to deter people from doing it?
well sorta, i mean you don't wanna raise the center of gravity in a car. DOHC already does this pretty badly, i think carmakers probably shy away from this because it adds even more to the head. but who knows...
NSXType-R
02-02-2006, 02:07 PM
No VVT system is better than Honda's VTEC system in my opinion.
Guest
02-02-2006, 02:42 PM
whsat is it with you and dead threads?
Subaru's system is AVCS (Active Valve Control System).
KnifeEdge_2K1
02-02-2006, 05:54 PM
Honda's is one of very few cam changing systems that accomplishes both changing the timing and the lift profiles of the cams, toyota's ivvt-l is another
none of the other listed systems can do this, so its a tossup between toyota and honda, id prefer honda just because most of honda's systems make a bit more power per litre then comprable toyota systems
fpv_gtho
02-02-2006, 09:17 PM
whsat is it with you and dead threads?
Exactly. Please consider the last post date before you contribute NSXType-R
85RX7
02-02-2006, 10:20 PM
The Nissan VE engines own all!!!!!
h00t_h00t
02-03-2006, 05:06 PM
I remember reading that when Spoon modify honda engines they remove the VTECH system altogether and just run the engine as a 16V DOHC that revs to 9000rpm.
how the **** r u gunna stick variable valve timing and lift on an ohv, single cam engine?
Rhoades lifters do that, kinda
2ndclasscitizen
02-07-2006, 04:14 AM
I remember reading that when Spoon modify honda engines they remove the VTECH system altogether and just run the engine as a 16V DOHC that revs to 9000rpm.
makes sense, the idea behind most VVC/T systems are too give a mix of economy in easy driving and power in hard driving. If you modify your car, you most likely are gonna spend most of the time driving hard
KnifeEdge_2K1
02-07-2006, 06:01 PM
makes sense, the idea behind most VVC/T systems are too give a mix of economy in easy driving and power in hard driving. If you modify your car, you most likely are gonna spend most of the time driving hard
but vvt can still raise low rpm torque with little effect on high rpm power, so it still has its uses in racing and performance applications
kingofthering
02-07-2006, 07:30 PM
well sorta, i mean you don't wanna raise the center of gravity in a car. DOHC already does this pretty badly, i think carmakers probably shy away from this because it adds even more to the head. but who knows...
then why don't you see integras roll over as much as suv's? they have Dohc and Vvt.
jcp123
02-07-2006, 07:40 PM
then why don't you see integras roll over as much as suv's? they have Dohc and Vvt.
I'm going to scrap the hard line I took there and just say that that's a wholly different ballgame altogether...damn, that post was made a long ass time ago! Still not a fan of OHC or VVT though.
deffenbaugh03
02-07-2006, 07:59 PM
makes sense, the idea behind most VVC/T systems are too give a mix of economy in easy driving and power in hard driving. If you modify your car, you most likely are gonna spend most of the time driving hard
It would make more sense to me if they just modified the VVC system. It's true most are made for a mix of economy and power (like honda's vtec) but it doesn't need to be that way. Like KnifeEdge mentioned, you can use VVC systems to get more low rpm torque, VVC's can help you make your engine better in specific rpm ranges. All valvetrain systems are designed for certain purposes and certain rpm ranges, but VVC could be very helpful in a performance application.