Gabkickshmm.. that reminds me, wasnt there a "Vtechless" Vtec on that vtec magic episode of best motoring? u know, with the high cams all the time? i think it was a the Jun prelude or something. It seemed to have plenty of power in the lower revs..
The tone on the JDM Type R seems dead on with the " VTEC tone " of my RSX.Ronnni dont' think you can hear Vtec kicks in in GT4
i mean, you can feel the car is going faster, has more power, and the engine sound....well louder...but that's not like Vtec kicks in.
Vtec kicks in...the engine tone will change as well, not only louder
Flip rSx driveRThe tone on the JDM Type R seems dead on with the " VTEC tone " of my RSX.I don't know why people always say VTEC kicks in, as if it will punch you in your seat like turbo lag or something. When I hit the gas on my car, all the car does is get louder. I think I'm going to have to jump on the highway later and just punch the gas in 2nd gear from 3000RPM.
That is, if this snow ever clears up.
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How far the valves open doesn't affect how much fuel you use, it affects how efficient your engine is. Having a high-lift cam (and also depending on the cam timing) will alter your torque curve (ie how much torque you have at so much rpm). So basically having an engine with a camshaft timed for lower revs and that doesn't open as far as a high-lift cam will rev a lot smoother down low but won't produce as much torque up high. However an engine fitted with a high-lift cam and the right timing won't rev very smooth at low revs but will have a lot more torque at high revs. That's where the concept of VTEC comes in; basically a VTEC engine switches camshafts as it approaches higher rpm's. This way you've got a camshaft timed for lower revs, allowing the engine to run smoothly at low revs, and also a high-lift camshaft timed for higher revs, to produce more power in the higher rev range and also maintain a high engine speed.Flip rSx driveRWell, think about it. If you have a valve opened really far, even at low RPM... what kind of gas mileage do you think you'd be getting.![]()
tha_conDefinately was NOT the Jun Prelude, lol, that is my baby though, love that car.
It was a highly tuned ITR, and if I remember correctly, the bottom end wasn't very impressive, but it was great with top end power. I already posted about this earlier in the thread, lol...I get ignored![]()
Thanks. I've learned something new.Trueno_SSHow far the valves open doesn't affect how much fuel you use, it affects how efficient your engine is. Having a high-lift cam (and also depending on the cam timing) will alter your torque curve (ie how much torque you have at so much rpm). So basically having an engine with a camshaft timed for lower revs and that doesn't open as far as a high-lift cam will rev a lot smoother down low but won't produce as much torque up high. However an engine fitted with a high-lift cam and the right timing won't rev very smooth at low revs but will have a lot more torque at high revs. That's where the concept of VTEC comes in; basically a VTEC engine switches camshafts as it approaches higher rpm's. This way you've got a camshaft timed for lower revs, allowing the engine to run smoothly at low revs, and also a high-lift camshaft timed for higher revs, to produce more power in the higher rev range and also maintain a high engine speed.
Haha. That's ok... I'm happy to help 👍Flip rSx driveRThanks. I've learned something new.![]()
neon_dukeIn all honestly, I own a car with V-tec and I have no idea what all the fuss is about. It's just not that great a thing. Mostly it just increases average fuel economy by keeping the cam lift and duration small at low and mid-range revs, rather than supplying some huge power boost over what a normal engine does (or could do). I see it as an economy feature, not a real performance feature.
Trueno_SSHow far the valves open doesn't affect how much fuel you use.
dreadfistOf course your base model accord (I'm taking a guess there) doesnt have any performance gain from vtec. If you've ever driven a honda with a tuned B series motor, you'll definitly hear and feel the change over.
Ride in a ITR with boltons and cams and you'll feel more than a small difference.
Yes I agree, but my point was that you're not going to start injecting more fuel into the cylinders because the valves are opening further. And yeah sorry I didn't explain it very well the first time, my mistake.Griffith500Opening the valves more is solely done to get as much fuel/air mixture into the cylinders over a shorter time (than at lower revs.) Exactly how it affects mileage depends on many things (base engine, cams used - its not a simple relationship) and can only be determined by measuring it.
Yeah they first introduced the 'clever electronics and variable valve timing' thing in the early 90's, it's called VANOS. I'm not 100% on how it works but it does something amazing with a whole lot of sprockets (instead of just chains and gears like normal OHC engines) to alter the timing of the intake camshaft throughout diferent engine speeds. In other words, at low revs the intake valves are opened just a little bit later so that the engine idles and revs smoother. In the mid rev-range, the intake valves open earlier so they can re-circulate some of the unburnt exhaust gases through the combustion chambers in order to improve fuel efficiency. Later on in the high rev-range the valves are opened later and wider to take in as much fuel and oxygen as quick as possible to increase power.Griffith500BMW's engines have had clever electronics and variable valve timing for the last 5 or 6 years... (E39 M5) I read somewhere (some car mag) that the new M3 under development will use a V8 engine with electronic valve actuation (no cams, just solenoid type things), and thus infinitely variable valve timing, similar to that used in F1 cars!
Flip rSx driveRWell, activating the VTEC at too low of an RPM can cause lower the low-end responsiveness of the engine because the VTEC cam lobe has too high of a profile. The " tuners " would probably lower the VTEC crossover a little bit, but never have it running all the time.
Also the standard VANOS system only alters the cam timing at 2 points in the entire rev-range whereas bi-VANOS is continuously altering the cam timing. The bi-VANOS system may be what you were talking about with the new V8 M3 under way, but I could be wrong.
Gabkickshmm.. that reminds me, wasnt there a "Vtechless" Vtec on that vtec magic episode of best motoring? u know, with the high cams all the time? i think it was a the Jun prelude or something. It seemed to have plenty of power in the lower revs..
Flip rSx driveRThe tone on the JDM Type R seems dead on with the " VTEC tone " of my RSX.I don't know why people always say VTEC kicks in, as if it will punch you in your seat like turbo lag or something. When I hit the gas on my car, all the car does is get louder. I think I'm going to have to jump on the highway later and just punch the gas in 2nd gear from 3000RPM.
That is, if this snow ever clears up.
![]()
bbq0801OK, this is slightly on-slightly off topic, but
1-Is the US version of the Lotus Elise in GT4?
2-That car has the Toyota 1.8L inline four with VVTi-L, apparenly in a car as light as the elise, the cam changeover is enough to put your head in the seat. Is the more significant push and sound changeover reproduced in the game?
Also, does the US elise sound any different from the celica/ others that use that engine?
neon_dukeIn all honestly, I own a car with V-tec and I have no idea what all the fuss is about. It's just not that great a thing. Mostly it just increases average fuel economy by keeping the cam lift and duration small at low and mid-range revs, rather than supplying some huge power boost over what a normal engine does (or could do). I see it as an economy feature, not a real performance feature.
Because it's not. It's nothing magic. With a properly profiled cam, the engine could make power like that all the time. Fuel economy would suffer, and the idle would get lumpy. Vtec - or i-Vtec - does nothing whatsoever to increase the peak power of the engine. What is does do is make the engine more economical and streetable to drive.draven6801How can you say that v-tec is not a real performace feature did you not read my post on page two of this topic. Not only that but my friend owns a daily driven 94 civic h/b with a fully built b20/v-tec that runs 11.6 1/4 miles on pump gas, so if its not a real performance feature how would that be possible.
It's an '04 TSX - 200 hp 2.4 DOHC i-Vtec. And I never said you couldn't feel the cams come in (though with the i-Vtec it is a much subtler feeling). Read my post above.dreadfistOf course your base model accord (I'm taking a guess there) doesnt have any performance gain from vtec. If you've ever driven a honda with a tuned B series motor, you'll definitly hear and feel the change over.
Ride in a ITR with boltons and cams and you'll feel more than a small difference.