|
| My MDX is my first VTECH and Acura. I'm wondering if someone could explain it simple English. It sounds really good above 4000rpm, and I can't help myself from redlining my MDX whenever I can. Hehe. |
|
|
|
VTEC stands for Variable Valve Timing and Lift Electronic Control. VTEC was developed as a result of Formula 1 racing, and is now standard on many Hondas and Acuras. VTEC automatically adjusts how long the valves in the engine stay open, as well as how far they open, to give maximum high RPM horsepower without sacrificing low RPM torque.
VTEC combines these two characters by intelligently varying the valves' timing and lift according to the engine's revs.
So at low rpm, two small cam lobes are pushing the valves open quickly and narrowly for a lean burning mixture that results in economical driving, low pollution and plenty of low-down torque.
As the rpm rises, a hydraulic pin within the rocker arms locks in a high rpm cam lobe that forces the valves to open higher and for longer. With more fuel and air flowing into the combustion chamber, the engine can generate more power to move the car faster.
|
|
|
|
| Valves opening higher and longer.. got it. Thanks. It sure sounds good. Wish they had Sportshift option for MDX, then I would drive it at >4000rpm all the time (well, may be most of the time):D |
|
|
|
My great grandfather said a couple of things that have always stuck with me.
1. Nothing holds liquer better than the bottle.
2. Your gonna rurnt it boy.
|
|
|
|
| Does anyone know if the new version of V-Tech (reported on in the new issue of Motor Trend) that will premier in the new RSX, be added to the MDX '02? |
|
|
|
Correct me if I'm wrong, but isn't the V-Tec kinda long the old term positracton? It's just computerized now? When one wheel slips than the other wheel turns. Am I right?
Lmeans |
|
|
|
| a contradiction to the saying if it ain't broken don't fix it. Well Honda/Acura decided like the real innovators that they are to up the ante and develop the new version called i-VTEC (intelligent-Variable Valve Timing and Lift Electronic Control) The new design when mated with the Acura six speed(RSX Type S)does wonder to the engine's output and torque curve (200hp@7400 rpm)all that from a 2.0l 16 valve DOHC transversely mounted 4 cylinder engine. The difference from the old VTEC is the addition of an ECU-controlled camshaft with an actuator advancing or retarding the intake cam through a 50 degree range, optimizing power levels throughout the rev range(this is where the old VTEC fell short and got most of the complaints a lacke of low end torque). A steel chain-driven timing gears replace the venerable cog and belt set up from the previous VTEC. The transversely mounted inline 4's orientation has been changed so that the intake charge now enters the front of the motor leaving the crankshaft to rotate the opposite direction compared to the previous VTEC. The ligther weight block features a 2 piece construction w/ a seperate lower skirt carrying the main journals. The free-flowing stainless steel exhaust manifold escapes behind the motor under the firewall, shortening the path to the catalytic converter for reduced emissions. On the Type S the engine uses a short ram intake manifold, higher compression pistons, stronger rods, a revised exhaust system and VTEC cam profiles on both the intake and exhaust sides to yield the ultimate high-rpm power output. The new design also incorporates a new direct-fire ignition sytem providing a coil pack for each cylinder. Sorry for the long post but hopefully this will shed some light to your question. |
|
|
|
| From what I know the new RL will be getting the new engine so will the rest of the line down the road. This will be probably go on the MDX Type S, yes that's right a car enthusiast magazine(Super Street) also where I got the i-VTEC techno babble from, mentions that the whole Acura line according to Acura will be getting the S treatment including the MDX!!!!!!!! So I also have a question for people on the know here,will the Type S throttle body fit the MDX and will it work with the stock intake manifold and give me better throttle response? |
|
|
|
| I have a feeling that the throttle body on your MDX is finely tuned to work best, given the rest of the engine dynamics. Only on a poorly engineered system could you reap any great benefit by swapping out one part. |
|
|
|
| You are probably right, if I remember correctly the intake system in the MDX was based on the Type S design, so you are probably correct. I would probably get better results by simply swapping out the OEM air filter and adding a less restrictive exhaust. Throttle bodies cost about $ 300 or more, which would probably be close to what a good muffler and a K&N will cost. |
|
|
|
quote:
Originally posted by Xtreme MDX
This will be probably go on the MDX Type S, yes that's right a car enthusiast magazine(Super Street) also where I got the i-VTEC techno babble from, mentions that the whole Acura line according to Acura will be getting the S treatment including the MDX!!!!!!!!
XtremeMDX,
For 2002?
Thanks |
|
|
|
Would it be possible for Acura to release a Type-S so soon? They DID release the CL-S pretty quickly but it took em 2 years to get the TL-S out. Any idea?
|
|
|
|
I doubt you'd see it before 2003, at the earliest. (By the way, the "continuous VTEC" is similiar to the system that BMW has been using on both cams (their's is a DOHC six remember) for the past three years.)
quote:
Originally posted by rx7max
Would it be possible for Acura to release a Type-S so soon? They DID release the CL-S pretty quickly but it took em 2 years to get the TL-S out. Any idea?
|
|
|
|
quote:
Originally posted by Xtreme MDX
I would probably get better results by simply swapping out the OEM air filter and adding a less restrictive exhaust. Throttle bodies cost about $ 300 or more, which would probably be close to what a good muffler and a K&N will cost.
Here's my take on air filters.
http://www.acuramdx.org/forums/show...p?threadid=1741
I have a feeling even if we modified exhaust and intake, nothing great would happen without a new chip (new map) to take advantage of the new flows.
While this topic is open, I'll mention http://www.vtec.net again. |
|
|
|
