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Yes, yes and yes.
Formula 1 cars used to have constantly variable valve timing through the use of 'cam-less' engines. Each valve is (was) controlled by its own hydraulic solenoid and suplemented by constantly variable intake trumpet lengths.
All these systems have been banned for the new V8s, which is why you will have seen an awful lot more photos of 'naked' F1 cars this year. Less technology to hide.
EDIT: oops, simultaneous posting.
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[QUOTE=sunk]Rather, its mostly the opposite. S2000s feel like lawn movers below 4000rpm and suddenly become a F1 car over that limit. Several other like Pontiac Lemans , which i had,(also a I4) have redline of 6500rpm and yet never feel as if they are struggling.[/QUOTE]
Cockandballs. You obviously never drove or rode in a S2K. That thing revs extremely free, it zips through the rpms rather quicky, then anything from GM. You could get great perfomance without even going above 6000rpms, the extra 2000rpm (3000 for me, in the old 2.0L one) is for that xtra punch. The i-vtec not only adjust the valve timers for high rpm, but adjusts for low end boost as well. Hense 3 cam phase
The GM Ecotech (2.2l) aren't half as flexable and lively as the H22, thats why its need forced induction like on the colbatSS.
EX. By the time a LS1 hits 2500 rpms the quickest it can, the S2k already broke its 8K red line.
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There are only two cam profiles in a V-Tec: 'torque' and 'high-lift' - it works via a small actuator that moves the cam across the head so the high lift cams are in contact with the valves.
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[QUOTE=MrKipling]There are only two cam profiles in a V-Tec: 'torque' and 'high-lift' - it works via a small actuator that moves the cam across the head so the high lift cams are in contact with the valves.[/QUOTE]
Oh, I thought there was a actuation for the change in the torque delivery for the mid-range . my mistake.:)
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2 Attachment(s)
I think the motor operates in 12V mode (rather than 16V) on light throttle apllications, but most (all?) sixteen valve cars do this.
These images show the internal differences pretty well (taken from asia.vtec.net), note the much closer spacing of the valve rockers to facilitate the cam switch.
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[quote=MrKipling]I think the motor operates in 12V mode (rather than 16V) on light throttle apllications, but most (all?) sixteen valve cars do this.[/quote]
Hmmm, not so sure on modern ones, but that wasn't the case on 16Vs before.
you got some examples ?
THe S2000 vtec is a "simplke" pin that locks the valve rocker into a high lift arm at higher revs. There is nothing else variable. THer eis the possibility that one of the valve pair is opening later/closing earlier in some pseudo 12V mode, but no evidence of that. ( and that can cause airflow and fule stall issues in the ports :( )
[quote]These images show the internal differences pretty well (taken from asia.vtec.net), note the much closer spacing of the valve rockers to facilitate the cam switch.[/quote]
This one of teh S200 vtec is easier to see ....
[IMG]http://www.canadiandriver.com/articles/jk/images/honda_s2000.jpg[/IMG]
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[QUOTE=henk4]apparently from what I heard, desulpherized and cleaner diesel will be available soon over there. Again this is a matter of perception, or "chicken and egg". As long as Americans associate diesel engines with "dirty and loud" there will be no real demand for them and the oil companies will not make the investments necessary to produce the right stuff from their refineries (which are very much geared to producing gasoline in the first place)[/QUOTE]
Sweet, I havent heard anything about it.
Its kinda a vicious cycle, we see big trucks with diesel spewing black smog, and cant help to think dirty.
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Matra, Yeah, that image is clearer! Ta :)
I believe the old Tipo 16v (Sedicivalvole?) worked in the manner of 12v/16v, although I think your 'psuedo' 12v mode with the later valve opening seems more feasible and I don't have any technical data to hand, just a piece of information kicking around the car bore's empty brain! :D
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[QUOTE=Matra et Alpine]]SO why the "weed whaker" nonsense ?
THAT's revline ... I was just taking what you repeat continuously about revving hard.
Sounds like you dont' like peaky OR revvy :D
Dont' know ANYONE who likes peaky and having competed in a tuned Imp I can assure you you haven't even been NEAR peaky till you try a Coventry Climax tuned out to it's max on twin Webers :([/QUOTE]
Do you have ears???
Revving has NOTHING to do with my complaint about the sound of the Honda engines. Listen to them! They sound buzzy/farty at any RPM.
Ferrari and lambo engines rev just as high, yet dont sound like trash. They sound smooth, throaty and powerful.
Do I have to post another comparison?
Good:
[url]http://videos.streetfire.net/search/murcielago/0/BCFD1B9B-1F90-46FF-BB72-D686B32133FD.htm[/url]
Bad:
[url]http://videos.streetfire.net/search/honda+civic/3/705BD27D-9C25-4314-BC7B-7CD273DF245A.htm[/url]
[url]http://videos.streetfire.net/search/honda+civic/4/B7071109-8DA9-46AA-8742-CD786721E770.htm[/url]
I already posted the WRX that sounded great, heres another 4 banger that sounds good.
[url]http://videos.streetfire.net/category/Dodge/10/0E09CD45-F170-496E-A0D5-1F2FE92946FE.htm[/url]
Notice how its throaty and not as buzzy?
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[QUOTE=zeta]Cockandballs. You obviously never drove or rode in a S2K. That thing revs extremely free, it zips through the rpms rather quicky, then anything from GM. You could get great perfomance without even going above 6000rpms, the extra 2000rpm (3000 for me, in the old 2.0L one) is for that xtra punch. The i-vtec not only adjust the valve timers for high rpm, but adjusts for low end boost as well. Hense 3 cam phase
The GM Ecotech (2.2l) aren't half as flexable and lively as the H22, thats why its need forced induction like on the colbatSS.
EX. By the time a LS1 hits 2500 rpms the quickest it can, the S2k already broke its 8K red line.[/QUOTE]
BAhahahah I can tell youve never driven any V8 car before... I barley touch the gas when in neutral and im at 2500RPMs. If I stomp on it it bounces off the limiter before I can blink(and feels like its doing no wrong).
BTW, If I remember right one of the mags C&D or MT did a 0-60 with the S2000 w/o going above 6000PRMS and it turned out to be like 11 seconds or something...
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[QUOTE=Slicks]Sweet, I havent heard anything about it.
Its kinda a vicious cycle, we see big trucks with diesel spewing black smog, and cant help to think dirty.[/QUOTE]
anyway, Mercedes is selling its 320 CDI (not in all states though) so there must be the right fuel available to run that engine....which is the same as used in the Chrysler 300 CRD, of which European testers say that is a close match to the hemi, (not in absolute power but under normal circumstances)
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[quote=Slicks]BAhahahah I can tell youve never driven any V8 car before... I barley touch the gas when in neutral and im at 2500RPMs. If I stomp on it it bounces off the limiter before I can blink(and feels like its doing no wrong).[/quote]
IN first, sure :)
[quote]BTW, If I remember right one of the mags C&D or MT did a 0-60 with the S2000 w/o going above 6000PRMS and it turned out to be like 11 seconds or something...[/quote]
That's as stupid a test as the EVO versus Fiat in top gear BS :D
Why not test a V8 and pull two of the plug leads off -- just as useful !!!
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[QUOTE=Matra et Alpine]IN first, sure :)
[/QUOTE]
no, slicks clearly said: [B]in neutral[/B]
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[QUOTE=Matra et Alpine]IN first, sure :)
That's as stupid a test as the EVO versus Fiat in top gear BS :D
Why not test a V8 and pull two of the plug leads off -- just as useful !!![/QUOTE]
EVO did the Megane (Clio?) Sport and the M6 in one test.
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[QUOTE=henk4]anyway, Mercedes is selling its 320 CDI (not in all states though) so there must be the right fuel available to run that engine....which is the same as used in the Chrysler 300 CRD, of which European testers say that is a close match to the hemi, (not in absolute power but under normal circumstances)[/QUOTE]
You sure that they just didnt "convert" their engine to run on our fuel?
Do you know what states they are selling them in?