4k miles, whoa..

[si02racerboi]

i noticed a real difference when i hit 4k. My friends 92 prelude who always use to pull on me hella bad before, cant do it anymore he use to just beat me by like a car lenght or two cars,but yesterday we were just driving around and i was going like 25 in second gear he was rollin next to me he started revvin his engine and than he took off as soon as he did i smashed also, we were almost side by side i was actually ahead of him, and iam like WTF shouldnt he be ahead of me by now?? but now i stay with him and beat him by like a foot! and i can actually feel the vtec kickin in, has anyone else noticed this?

[cj miller]

yeah i feel the i-vtec kick in. it isnt hard like vtec but its fast.

[S800Racer]

Originally posted by cj miller
yeah i feel the i-vtec kick in. it isnt hard like vtec but its fast.
You feel something at 2200 rpm? Because that is the only time the EP switches cam lobes (VTEC) from a low rpm/light load cam on the intake to the "normal" cam that operates the intake from 2200rpm to redline. There is no VTEC cam switch on the exhaust.
Hate to burst your bubble but that's the facts. What you probably feel is a jump in the torque curve at around 4800rpm that may be related to cam timing advance (VTC).

[si02racerboi]

all i know is my ep got quicker when i hit 4k

[Glix]

Originally posted by S800Racer

You feel something at 2200 rpm? Because that is the only time the EP switches cam lobes (VTEC) from a low rpm/light load cam on the intake to the "normal" cam that operates the intake from 2200rpm to redline. There is no VTEC cam switch on the exhaust.
Hate to burst your bubble but that's the facts. What you probably feel is a jump in the torque curve at around 4800rpm that may be related to cam timing advance (VTC).

I wish everyone would get their facts straight. The SI does not switch VTEC on at 2200 RPM unless the car is at or near WOT.

You can drive around at 5k rpm with a low throttle and not be in VTEC but if you punch it VTEC engages.

Think about it, it's the reason for the I in VTEC. It would be absolutely stupid to have the car in vtec all the time, fuel consumption would suck.

[quachster858]

Originally posted by si02racerboi
all i know is my ep got quicker when i hit 4k

I notice this too, well its either that or my friends car got slower .."snicker":D

[I-Vtec..DO-U (New name: SIxtacy)]

WERD:eek:

[rgGolf4]

Originally posted by Glix


I wish everyone would get their facts straight. The SI does not switch VTEC on at 2200 RPM unless the car is at or near WOT.

You can drive around at 5k rpm with a low throttle and not be in VTEC but if you punch it VTEC engages.

Think about it, it's the reason for the I in VTEC. It would be absolutely stupid to have the car in vtec all the time, fuel consumption would suck.

I completely agree. Just some common knowlege of even previous VTEC would lead you to belive this. If we were cruising in 4th gear at or around 3000rpm (my average speed, 40mph), we would always be in "VTEC". Not to state the obvious, but VTEC is not gas conscience. I haven't read up on i-VTEC yet, but i bleieve that it engages at WOT and only above a certain rpm....2300. So basically there are at least two conditions for VTEC to engage....WOT(or relatively close) and above 2300rpm.

I'm not staing fact, only things that I notice and have read about.

[rgGolf4]

Variable valve Timing and lift with Electronic Control. That's the official name - don't ask why.
VTEC uses an extra set of lobes on each camshaft. One set is optimized for low-rpm torque and emissions, the other set for high-rpm power. It switches between the two sets at a prescribed RPM (somewhere between 4000 and 6000rpm). The actual "switch" is done by engaging pins that lock the big lobes' followers to the small lobes' followers (which actually touch the valves). VTEC is traditionally used on BOTH cams of a DOHC engine; Honda's SOHC engines incorporate it for the intake valves.

Variations:
i-VTEC is used on the new K-series engines in the Civic Si, RSX, and CR-V. i-VTEC operates in three stages. Both small cams, intake small cam/exhaust big cam, both big cams. i-VTEC also incorporates cam phase adjustment on the intake cam. Toyota's VVTi and BMW's VANOS are cam phase adjustment systems.

VTEC-E is a special low-emissions, fuel-sipping version of SOHC VTEC that instead of having "big" and "small", will open only one or both intake valves. At low rpm only one intake valve fully opens, which creates extra swirl in the combustion chamber. The result is excellent economy. The Civic VX and HX models use VTEC-E.

http://asia.vtec.net/article/ivtec/index.html Explains it a bit more in depth

[S800Racer]

Originally posted by rgGolf4
VTEC uses an extra set of lobes on each camshaft. One set is optimized for low-rpm torque and emissions, the other set for high-rpm power. It switches between the two sets at a prescribed RPM (somewhere between 4000 and 6000rpm). The actual "switch" is done by engaging pins that lock the big lobes' followers to the small lobes' followers (which actually touch the valves). VTEC is traditionally used on BOTH cams of a DOHC engine; Honda's SOHC engines incorporate it for the intake valves.

Variations:
i-VTEC is used on the new K-series engines in the Civic Si, RSX, and CR-V. i-VTEC operates in three stages. Both small cams, intake small cam/exhaust big cam, both big cams.

There is a lot of good information on this site. But most people are like you and like to post what they think and give their opinion without doing the research first.
Contrary to what you think, the "VTEC" system on the Si operates ONLY on the intake cam. It operates the motor as a 12-valve (1 intake, 2 exhaust) under 2200 rpm, and a 4 valve above 2200 rpm. That's it. No high rpm cam. No VTEC on the exhaust cam. No third stage. It also has "VTC" that varies the intake cam timing +/- 25 deg. (the "I" in "I-VTEC")

Don't believe me? Go pop your valve cover and count your cam lobes. OR, hit the search button for "EP camshafts - pictures". Take a close look at the low RPM cam. The lift is really small. That's because it is a low rpm, light load only cam.
VTEC switchover point? Hondata confirmed it to be 2200rpm at WOT.
Could it be different at less than WOT? Nope. Not if you believe Modern-Perf who did a K20A2 swap and drove his car to the dealer to get his ECU reflashed to A2 specs. With the A3 ECU program still in place, he said it clearly switched at 2200rpm.

Next time, do some real research before you spew your "knowledge" on the people who actually know something about the K20A3 Civic Si engine.

[rgGolf4]

Originally posted by S800Racer


There is a lot of good information on this site. But most people are like you and like to post what they think and give their opinion without doing the research first.
Contrary to what you think, the "VTEC" system on the Si operates ONLY on the intake cam. It operates the motor as a 12-valve (1 intake, 2 exhaust) under 2200 rpm, and a 4 valve above 2200 rpm. That's it. No high rpm cam. No VTEC on the exhaust cam. No third stage. It also has "VTC" that varies the intake cam timing +/- 25 deg. (the "I" in "I-VTEC")

Don't believe me? Go pop your valve cover and count your cam lobes. OR, hit the search button for "EP camshafts - pictures". Take a close look at the low RPM cam. The lift is really small. That's because it is a low rpm, light load only cam.
VTEC switchover point? Hondata confirmed it to be 2200rpm at WOT.
Could it be different at less than WOT? Nope. Not if you believe Modern-Perf who did a K20A2 swap and drove his car to the dealer to get his ECU reflashed to A2 specs. With the A3 ECU program still in place, he said it clearly switched at 2200rpm.

Next time, do some real research before you spew your "knowledge" on the people who actually know something about the K20A3 Civic Si engine.

Whoa! Well, if you read my post, that was discussing VTEC, not i-VTEC. The little blurb under "Variations" is where i-VTEC was discussed. I just took the information from the web link I posted. Read that, before your spew your information.