OK guys, heres the thing. When i first bought the car it had 28,673 miles on it. It felt great as a driving car. Well i decided to punch it one day, and the i-VTEC engaged fine. As time went on, i noticed that i-VTEC was not engaging on a normal basis. While noticable in the sound of vtec b4, now the is no change over. Every now and then, it does engage, but i notice that it is usually when the engine reaches tempurature. Then after that, it goes back to not engaging. I've tested for i-VTEC engagment in gears 1 through 4. Any help is greatly appriciated. Thanks in advance for any feedback. By the way i have a base model RSX with a 5 spd tranny.

 

This motor does not use the conventional VTEC mechanism from the earlier B series motors but does have VTC. Instead it only has 2 cam lobes on the intake side and 1 on the exhaust lobe. This motor has no VTEC mechanism on the exhaust cam and runs on 12 valves before 2200rpm with the other 4 slightly opening. It also has smaller ports than the Type S and Type R.

Base RSX = K20A3 = K20 NON VTEC


Modified by HKS-EP3 at 6:48 AM 9/9/2005


Modified by HKS-EP3 at 6:49 AM 9/9/2005

 

I don't even know how you noticed your i-VTEC engaging. I don't feel any difference and it's just your throttle making the noise.

 

well i do notice a significant difference in the engine tone at the high rpm range. at 5900 rpms, i notice that there IS a drastic change in the tone of the engine. Was just wondering if any of the other base owners noticed this....or is it just me??

 

yeah i've got the K20a3 in my civic si and i've also recently discovered the "alledged" non vtec ... it's true the valvetrain on the a3 sucks ... from wat i've gathered you really shouldn't hear any vtec kicking in 5900 rpm's because wat little vtec we're getting out of the a3, it seems to kick in somewhere around 2000. this is because at 2000 rpm's the two rocker arms which otherwise work seperately are locked together. there is no high lift lobe on the a3 cams ... i'm just as bummed about this as i'm sure u are ... i'm currently exploring cam options, let me know if you come up with anything.

 

Well i am seriously debating a type-r motor swap. Reason being is that its different from anything anyone has done on the island that i live on. Another reason is.....ITS A FREAKIN TYPE-R!!! Still deciding tho, its a toss up between the type-r and the type-s. Imleaning towards the type-r, but any feedback would be apreciated.

 

Instead of putting money towards another engine, have you considered going the FI route?

 

its just you...i couldnt tell at all on my base. 2200rpm+ its working by opening 4 extra valves there is no high cam lobe change

 

I have thought about going FI, but if i go FI, i wanna go the supercharger route. I dont like turbo cars. I hate the lag, and the peakyness. If i were drag racing as most my time, i would go turbo, but i hate drag racing. I drive mountain roads where a nice even powerband is welcome. With a turbo, u get spooling and then a dramatic increase in horsepower. And then the reliability factor of the motor comes in. I have yet to see a turbo car hold its reliability better than a NA. Hence the reason i am swapping motors. Theres nothing that sounds better than a highly, mechanicly tuned motor at 9k rpms.

 

You're probably hearing the change in sound from the dual-length intake runners. The base RSX motor has a mechanism that uses longer runners for lower RPM's and switches to shorter ones for upper RPM's.

Hondata's got an interesting writeup.

 

Check your oil level if you haven't.

 

what??? help me out i was thinkin about getting a 03 SI which has the same motor as the base RSX...so your'e saying there is no vtec??? I had a 99 SI and after totaling that got a 98 EX and both screamed when the VTEC kicked in...I know its a different motor but I though the K20's from honda were like the greatest motors ever (from honda) So whats the case VTEC/NO VTEC?

 

There is VTEC, but it's a different VTEC.

The 02-05 Si's K20A3 motor does not have a high-lift cam lobe that engages at high RPM, so no, it's not the VTEC that you've known. As stated already, it runs as a 12-valve engine below 2200 RPM, and runs as a 16-valve engine above that.

Not only that, but the "i" in i-VTEC means "intelligent" -- which means that this motor constantly adjusts valve timing & overlap throughout the rev range. Adjustable cam gears, so popular on the B-series motors, are useless on any K-series engine, even if it's the top-flight JDM K20A ITR motor. If you're going to adjust timing & overlap, you'll do it by reprogramming the ECU -- and you can adjust spark & fuel while you're at it, too.

The Si's engine also shares its intake manifold with the Type-S RSX and CTR/ITR engines. Even so, it actually has just a bit more torque than those engines below about 4500-5000 RPM.

The 02-05 Si has a lower redline than the 99-00 Si, but again, it has more torque, and keeps it up through a broader powerband. Stock-for-stock, or mod-for-mod, the EP3 Si will beat the EM2 Si (been there, done that). It's faster, although the 0-60 time doesn't reflect it thanks to the 2-3 upshift at 57 mph.

If you're going to upgrade even further and boost it, the EP responds well, with its motor already having a lower 9.8:1 compression ratio that helps avoid detonation. Putting down over 250 whp at 10 psi is not unusual at all.

 

It must be the runners im hearing then. Because i hear a slight buzz, and then the motor gets louder. That would explain a lot. That system is similar to the RX-8 setup that they have on the rotary. Sorry for the dumb questions i've been asking. New to the K-series motor, and the RSX in general. Been looking for a site with the TOTAL specs of the car. Like the sway bar diameter and stuff like that. Call it technical if u will. Looking to get the car so it handles neutral, so this information would be greatly appretiated if anyone found a site like this. Sorry for going of topic.

 

No problem, dude -- new questions always seem like dumb questions, but everybody's gotta start at some point when learning info about their cars. I just answer within my knowledge; if I don't know, I'll still ask.

 

Does it sound like when a Type-S RSX or one of the B-series motors hits VTEC?

The EP really opens up at just under 5000 RPM, but it's still not a high-lift cam changeover like on the other motors. When I had a V2 on my EP, that's what I'd hear, but not a high-lift cam.

 

I also hear a change in tone when im in 5K and up on my EP. its not a high lift cam sound but you can tell the difference in engine sound. what does this sound come from then if not high lift cam?

 

The best that I can figure is that the intake section breathes better at upper RPM's, and that's when it picks up.

More about the A3 vs. A2:
http://www.superhonda.com/foru...unt=8

 

yea that makes sense

 

Plus, when I think about it more, I'll bet that the mechanism is changing the cam angle & overlap (even though it's the same cam lobe), and that's part of what we're hearing, too.

 

yea something like that. theres no crazy pull like a high lift cam would have but hey, it sounds good either way

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by qualitybelow &raquo;</TD></TR><TR><TD CLASS="quote">what??? help me out i was thinkin about getting a 03 SI which has the same motor as the base RSX...so your'e saying there is no vtec??? I had a 99 SI and after totaling that got a 98 EX and both screamed when the VTEC kicked in...I know its a different motor but I though the K20's from honda were like the greatest motors ever (from honda) So whats the case VTEC/NO VTEC?</TD></TR></TABLE>

The base RSX and Si basically don't have vtec, if you look a them from a technical standpoint. These are economy biased engines. The engine in the Type S is completely different than the base RSX, and has the evolution of vtec, but is different still from older Honda vtec motors.

 

for a great thread

 

When you say different, has the "economy bias" in the base and EP3 watered down the VTEC in the Type-S? Do you think that the VTEC in the DC5 is as good or better than in the past?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Teufeldog &raquo;</TD></TR><TR><TD CLASS="quote">When you say different, has the "economy bias" in the base and EP3 watered down the VTEC in the Type-S?</TD></TR></TABLE>
Nope -- they're very different systems. The only important things that the A2 and A3 engines have in common (from the factory, anyway) is the basic design of the block and the fact that the Si and RSX-S share the same intake manifold. The valvetrains are very different, and that's where most of the technical wizardry happens.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">Do you think that the VTEC in the DC5 is as good or better than in the past?</TD></TR></TABLE>
Better, definitely. The overlap & timing of both intake & exhaust cams are computer-controlled, so there's opportunity for good power production under many combinations of load, RPM, and throttle input. You'll never see adjustable cam gears on a K-series motor because there's no need for them. And, according to a short writeup in the most recent Honda Tuning, the NDRA is assigning K-equipped drag cars with up to 75 lbs of ballast just to try to slow them down.