variable valve engine comparo

[orly_andico]

*m2,

thanks for the explanation. that clears up the stuff i'd heard that i-VTEC had less specific power output than DOHC VTEC, but at the same time has better economy and emissions.

does this also mean that even i-VTEC is an intake-only solution? and it doesn't have variable lift? kung ganun eh medyo stone age nga! and really doesn't justify the "i-VTEC is the shitz" attitude.

[mazdamazda]

Yup... i-VTEC is only applied for the intake valves only. Some VVT applications are applied to both intake & exhaust valves (like the VVTL-i).

Btw, it does have variable lift.

[parakitoJDM]

*m2,


does this also mean that even i-VTEC is an intake-only solution? and it doesn't have variable lift? kung ganun eh medyo stone age nga! and really doesn't justify the "i-VTEC is the shitz" attitude.

>>i-VTEC is an intake-only solution? currently yes. like what MZx2 said its for the Cam Phasing only - think real time adjustable CAM Gears! with upto 50deg. of adjustability.

>>stone age? i think u mis-understand. some mfg. even don't have it its pretty state of the art if u ask me.

>> variable lift? i think ur talking about varying Valve lift. Honda has it too. for the K20A3 (CRV, Civic in PH, Accord) this is implemented on the Intake side only. for the K20A2 exhaust side also gets it thats why it can crank out over 200horses fm. 2li of displacement. no other mfg. of NA engine can match that. but wait a few more years, Honda is coming up with even better VTEC engine, i heard something around 11% better fuel effi compared with the K20 series engines....

[niky]

Some manufacturers still don't use McPherson struts in the rear, or DOHC engines... but that doesn't make them state of the art.

Not many manufacturers can match 200hp from 2 liters, but Nissan and Toyota get similar power from their variable cam engines. Nissan's SR20VE is rated at 197 ps (same as the K20) and Toyota has 180+ ps from their 1.8 liter engine. Of course, this isn't to mention BMW's 340++ hp from their 3.2 liter engine, but that's too expensive to consider here.

[ferdine]

what i've heard (but i'm no expert) is that i-VTEC is actually inferior to the older VTEC in terms of performance, it'sreally more geared for economy.

although i don't see why people get all worked up about VTEC in general. VTEC is primitive technology! having only a few discrete cam profiles. Porsche Variocam and BMW VANOS are both far more sophisticated.

or maybe Honda fanboys are just.. Honda fanboys.

He-he-he-he... of course I'm a honda fanboy. My dad used to own a levin and big bro had a starlet for weekend races. I know they were the finest during their time. When i got a 94 civic and fitted it with a b16, it can still outran even the latest altisis I can find in hightways. How much more I think with the gen 8 and the soon type R gen 8 civic.
I'm just practical especially in the PHils. we've got only two popular vvt's technology to choose from Toyota and Honda. I do feel that Honda has the edge for people who are buying the gen 8 and and planning to tinker with their motors as the car ages. Mas richer ang resources sa i-vtec/vtec if you want to play with your engines. Widespread pa ang support sa Honda community through multitude of forums. Just my opinion.

From wikipedia...

i-VTEC (The i stands for intelligent) introduced continuously variable camshaft phasing on the intake cam of DOHC VTEC engines. The technology first appeared on Honda's K-series four cylinder engine family in 2001 (2002 in the U.S.). Valve lift and duration are still limited to distinct low and high rpm profiles, but the intake camshaft is now capable of advancing between 25 and 50 degrees (depending upon engine configuration) during operation. Phase changes are implemented by a computer controlled, oil driven adjustable cam gear. Phasing is determined by a combination of engine load and rpm, ranging from fully retarded at idle to maximum advance at full throttle and low rpms. The effect is further optimization of torque output, especially at low and midrange RPMs.

For the K-Series motors there are two different types of i-VTEC systems implemented. The first is for the performance motors like in the RSX Type S or the TSX and the other is for economy motors found in the CR-V or Accord. The performance i-VTEC system is basically the same as the DOHC VTEC system of the B16A's, both intake and exhaust have 3 cam lobes per cylinder. However the valvetrain has the added benifit of roller rockers and continuously variable intake cam timing. The economy i-VTEC is more like the SOHC VTEC-E in that the intake cam has only two lobes, one very small and one larger, as well as no VTEC on the exhaust cam. The two types of motor are easily distiguishable by the factory rated power output: the performance motors make around 200HP or more in stock form and the economy motors do not make much more than 160HP from the factory.

In 2004, Honda introduced an i-VTEC V6 (an update of the venerable J-series), but in this case, i-VTEC had nothing to do with cam phasing. Instead, i-VTEC referred to Honda's cylinder deactivation technology which closes the valves on one bank of (3) cylinders during light load and low speed (below 80 mph) operation. The technology was originally introduced to the US on the Honda Odyssey Mini Van, and can now be found on the Honda Accord Hybrid and the 2006 Honda Pilot. An additional version of i-VTEC was introduced on the 2006 Honda Civic's R-series four cylinder engine. This implementation uses very small valve lifts at low rpm and light loads, in combination with large throttle openings (modulated by a drive-by-wire throttle system), to improve fuel economy by reducing pumping losses.

With the continued introduction of vastly different i-VTEC systems, one may assume that the term is now a catch all for creative valve control technologies from Honda.

[squala]

For the K-Series motors there are two different types of i-VTEC systems implemented. The first is for the performance motors like in the RSX Type S or the TSX and the other is for economy motors found in the CR-V or Accord.

:evillaugh :laughbounce:

[basti08]

bakit hindi dinala ang mga engines na yan dito?

ang gagaling ng Japs when it comes to extracting power from NA engines.

[mazdamazda]

How much more I think with the gen 8 and the soon type R gen 8 civic.

There's already a Euro Type-R FD Civic. It is still using the old K20 197-hp engine.

we've got only two popular vvt's technology to choose from Toyota and Honda.

Err.. almost ALL car manufacturers / resellers here in the Philippines has a vehicle that is VVT equipped. Mitsu have MIVEC, Mazda has SVT, etc.

The world doesn't revolve around Toyota and Honda. :lol:

With the continued introduction of vastly different i-VTEC systems, one may assume that the term is now a catch all for creative valve control technologies from Honda.

Errr... the i-VTEC V6 is not about "valve control". It's about it having a multi-displacement system (which Chrysler pioneered).

it can crank out over 200horses fm. 2li of displacement. no other mfg. of NA engine can match that

Mazda RX-8... 1.3L... 238hp
Toyota Corolla Sport... 1.8L... 180hp
Lotus Exige... 1.8L... 190hp
BMW M3... 3.2L... 340hp
BMW M5... 5.0L... 500hp

[ferdine]

There's already a Euro Type-R FD Civic. It is still using the old K20 197-hp engine.

This is the reason why the "old" k20 is very nice to mod in the long run. You say 197-hp so it matches the A2. Not bad for a 2liter concept car. However K20A1 would be my ideal choice.


[/QUOTE]
Err.. almost ALL car manufacturers / resellers here in the Philippines has a vehicle that is VVT equipped. Mitsu have MIVEC, Mazda has SVT, etc.

The world doesn't revolve around Toyota and Honda. :lol:[/QUOTE]

He-he-he-he-he. See my word "popular". Everbody knows Mitsu and Mazda are just johnny-come-latelys in our market when it comes to VVT tech. And so who made the real headway? Lols:trampoline:

[ferdine]

This is the reason why the "old" k20 is very nice to mod in the long run. You say 197-hp so it matches the A2. Not bad for a 2liter concept car. However K20A1 would be my ideal choice.

Should have been K20A which can deliver much higher.