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reppin 671
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Discussion Starter #1
how low does your rpm drop when you shift from 1-2?
when does vtech kick in? sorry kinda getting used to shifting in ss and wanna know where the perfect shift is for ss..
 

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iVTec on the exhaust switches at 2,200 RPMs. The intake runners change at 4,700 RPMs.
The Base RSX does not have performance iVTec.

The perfect shift is redline. Just put it in Drive and forget SS unless you need to downshift. SS is no faster than Drive if you have the pedal to the metal.
 

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barely, but it's hard to get it right, cuz u hafta account for the delay, which is different under different conditions.

when u shift from 1-2 in SS, it drop to about 5500 i think. i'll try to remember to check tonite, or tommorrow and post it up.
 

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No, you can't rev any higher with SS. You can keep it at a lower gear (i.e., my downshift comment), but you can't accelerate any faster. With the throttle wide open (gas pedal to the metal) the automatic transmission shifts optimally for speed. There are quarter mile times somewhere that shows that Drive is equal to SS.
 

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iVTec on the exhaust switches at 2,200 RPMs.
No Vtec on the exhaust, only the intake side @ the same rpm you mentioned (2200rpm);)
 

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James S said:

The Base RSX does not have performance iVTec.

I know that I've seen this before, but still it doesn't makes sense to me! when you get to 5.5-6rpm doesn't another valve open which lets more air in? Isn't this the whole point of V-tec?
 

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The K20A3 intake ports are smaller and have specially shaped aluminum cutouts in the port floor to enhance turbulence. This probably helps low end torque at the expense of top end power.

The VTEC mechanism differ significantly between the K20A2 and A3 head. The K20A3 uses only two cam lobe profiles on the inlet.

Under 2200 rpm, this engine is a effectively a 12 valve engine, and over 2200 rpm it is a 16 valve. There is no VTEC mechanism on the K20A3 exhaust valves.

Basically, this head does not breath well compared to the K20A2. It seems designed for low end torque, emissions and economy.

The K20A2 head uses three cams per pair of inlet valves on both the exhaust and inlet. The low lift cams on this head are probably very similar to the high lift cams on the K20A3. The high lift cams engage at 5800 rpm and disengage at 5600 rpm.

For more info..
http://hondata.com/techk20general.html

Later!
Carl :driving:
 

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So if I understand correctly on the base model the "Vtec" kicks in at around 2200rpm, and the engine performs the same all the way to the redline, right?
 

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that initial vtec at 2200 takes it from a 12V engine to a 16V engine, cuz it activates teh second intake valve.

then, around 4700, the intake runner switches to a shorter intake runner, allowing for better top end.

try to get a copy of the video of this, it's really interesting, and explains it very well. unfortunately, it's in japanese, so u onle get it from teh video, but it's still really good. if i can get it, i'll try to send it to u or something.
 

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yeah, the hondata website is great for explaining it.


i'm just saying that the video actually shows it, and it's completely different from what i thought. once i find the CD, i'll try to upload it and send it to whomever wants it.
 

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Relish then catch up
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Where do you get the CD?
 
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