I'm coming from an H22a1 with a very noticible and audible VTEC engagement (even stock). I just broke in the Si and it's no where near the same level as the H22a1 was. I realize that it's only a dual rocker on the intake cam, but shouldn't it feel like it engages? And maybe it does, and I'm just not used to the lack of umpf from 160bhp. Anyone?

 

http://www.hondata.com/techk20general.html

it engages at 2200rpm, also its only on the intake side

 

Thanks a lot. I'm wondering why the engagement is so low other than for economical reasons. I don't even think you can use the engine below 2200 unless you're immediately shifting from gear to gear. Strange, but thanks again.

 

This is still debatable.

Put an intake on the car and tell me you don't hear a changeover around 4800rpms.

Not sure if that is the 'i' in i-vtec, but nevertheless something happens around 4800rpms and it sure feels like a crossover to me.

 

I have a 2002 and it's broken in now, I have an aem cold air intake and it adds a lot to the car in my opinion. I also have a DC header but that didn't give me a really noticable performance gain.

 

You need to do an exhaust as well. All that air coming in, but it gets bottlenecked by the oem B-pipe. The restriction almost goes down to 1.5" in the resonator.

 

you said your car is broken in now...i just got mine yesterday and i was wondering when i can consider my car broken in...how many miles am i looking for here? i was just gonna wait until 1,000 miles or so...but im not really sure...its a 2002 with 74 miles right now...let me know thanks!

 

Your manual says to wait about 600 miles before starting to go full throttle. Also, according to tradition you should vary engine loads through this time. Your brakes also need to be broken in, so no real hard braking for the first 150-200 miles. On the other hand, some people suggest that breaking in really hard will yield better performance results. Either way, after about 3000 miles you should have your oil changed from the break in formula to a standard oil (or synthetic).

 

This is still debatable.


No it is not debatable, put a voltmeter on pin #B15 (grn/yel) and whatch it go active high at 2200 ish rpms.

 

What's going on at 4800rpms then? Is the cam timing being adjusted or is it just the sweet spot of the intake manifold?

I never said cam x-over happened then, but something is going on at ~4800 rpms.

 

What's going on at 4800rpms then? Is the cam timing being adjusted or is it just the sweet spot of the intake manifold?
I never said cam x-over happened then, but something is going on at ~4800 rpms.



most likely the resonance of the intake is the cause of this


the differential outputs of the VTC control part of the ECU make it a little harder to figure out where the cam retards and advances.......

 

good topic
ttt

 

Refering to the placebo "4800rpm vtec" switch, it would make sense if you were talking about a base RSX. That car comes with a dual intake runner (much like the one on the gsr) that switches to the short runner at roughly 5k rpm. However, the Si has a single intake runner, so there shouldn't be a reason why you should hear a switch at 4800rpm afaik.

 

Ok, the engine changes to 16 valve at 2200 for fuel economy. It actually kicks into vtec around 5k, or 4800 like above. And it does kick hard for me, I dont know why yours doesnt, but yeah its not as abrupt as previous honda vtecs, but it still hits hard.

 

It actually kicks into vtec around 5k, or 4800 like above


Uuuuuggh, NO. 12 valve below 2200ish, 16 after and above.

 

Guess you'd have to ride in my car to understand....

 

Dude, all of our cars do that. That's why we're trying to figure out if the motor/ecu is doing anything at that point, or if it's just the intake resonance playing tricks on us.



[Modified by Todd00, 1:40 PM 1/24/2003]

 

Mine doesn't. No discernable changeover.

 

below explains better what you guys are feeling


remember, the stock air box will not lend as much of a rise in power, CAI is the norm for this type of "4500-5000" pull that we are feeling.

 

I just want to know why i'm not FEELING the snail kick in on your buss yet ,kack..

nick, who says chains are for nissans/snow tires....not honda's....lol (j/k)

 

Basically you can engauge VTEC WHENEVER you whant to above 2200 RPM's
Also a great artical is here....http://asia.vtec.net/article/k20a/index.html

Enjoy!