Question about VTEC?

[CajunSi]

I saw a thread one time about the i-VTEC. I don't remember where I saw it though. It was saying something like the a3 is not a true VTEC. My brother in law has a 2000 Si and I noticed that his VTEC is a pretty loud. What could be done to fix that on the ep? Would a set of a2 cams fix that?

[FoReVaPmP]

IVTEC is constant, it engages at 2200RPM.... you wont feel it like your brothers 2000si.....

[Draw7Seven]

i-VTEC means we have the one that helps out with fuel efficiency, not power. If I remember correctly, A2 cams will NOT solve your problem, and putting real VTEC on an A3 might just be depressing anyway. Time for a swap, buddy boy :P

[FoReVaPmP]

A2 cams will not give you what your searching for..... only if you swaped heads......:mcool:

[CajunSi]

IVTEC is constant, it engages at 2200RPM.... you wont feel it like your brothers 2000si.....

Is there any way to change that? Would it even be worth it though?

[Kodeen]

Is there any way to change that? Would it even be worth it though?

You could change it through a vtec controller, but you wouldn't want to.

The only thing you can do really is to get a different engine.

[CajunSi]

A2 cams will not give you what your searching for..... only if you swaped heads......:mcool:

So what is better on the a3? An a2 head or a K24 head?

[FoReVaPmP]

You could change it through a vtec controller, but you wouldn't want to.

The only thing you can do really is to get a different engine.

vtec controllers for a A3 is pointless

[FoReVaPmP]

So what is better on the a3? An a2 head or a K24 head?

it all depends on what you want..... the K24a1 head flows better and can help make decent power.

The A2 head is the same..... it's like having a Ls/Vtec on a B-series.

[talonXracer]

Both the A2 and the A3 have I-VTEC. The "I" portion is the VTC, as in cam advance and it is the same for both engines.

The VTEC portion is where the difference arises. Both have VTEC, but different versions. The A2 uses a conventional VTEC like the earlier versions. The A3 uses a new economy version that reduces the primary intake valve under 2200rpm's to barely opening to create a massive swirl and improve combustion burn, lower emissions and increase torque production.

Again, both do indeed have I-VTEC.

[r_jones06]

IF I remember correctly.....

the a3 motor (2002-2005 Civic Si) engine has "diet VTEC" as I understand it. The a3 motor does not have an secondary "agressive" cam lobe for the exhaust side as it does for the intake side meaning that only the intake valves are held open longer. Our motors actually operate as a 12 valve motor up until 2200 rpm, at which all 16 valves are put into operation. VTC is really the deciding factor of performance in this motor (which is explained later on).

The a2 motor (2002-2004 Acura RSX Type-S) has a secondary "agressive" cam lobe on both the intake and exhaust sides which creates the "true VTEC" that the H and B series motors have. This motor actually has a set engagement point for the cams to switch over to the "agressive" lobes, whereas the a3 does not.

The I-VTEC is actually a mechanism called VTC. Its purpose is to change the cam angle to allow for better performance, better gas mileage, or both at the same time. VTC works in combination with the throttle body, intake manifold, and valvetrain to make the best performance with the best gas mileage.

Both of these motors have a VTEC soleniod and by defintion have "VTEC". Its just that the a3 motor has a more casterated version.

To answer your question about the swap, technically swapping an a2 head (valves, springs, cams, retainers, etc.) onto an a3 block will give you the "true VTEC" you are looking for; however, you will still be limited as to how far you can push the motor. The a3 motor is not built for 8k+ rpms due to its not quite as strong bottom end.

Simply put, you can put an a2 head on an a3 motor to get that true VTEC sound but you can't really SAFELY rev it past 7k rpm without risking blowing your motor.

I hope this helps and if any of it is wrong please feel free to correct me. I'm still kinda new to this but this is what I have gathered out of a few months of reading/research.

[talonXracer]

IF I remember correctly.....

Our motors actually operate as a 12 valve motor up until 2200 rpm, at which all 16 valves are put into operation.



WRONG !!!!

All the intake valves operate at all times! The primary intake valve is operated at a much lower lift below 2200rpm, but it still moves and opens!


This is one of my biggest pet peeves.

[JuicyJoint316]

IF I remember correctly.....

the a3 motor (2002-2005 Civic Si) engine has "diet VTEC" as I understand it. The a3 motor does not have an secondary "agressive" cam lobe for the exhaust side as it does for the intake side meaning that only the intake valves are held open longer. Our motors actually operate as a 12 valve motor up until 2200 rpm, at which all 16 valves are put into operation. VTC is really the deciding factor of performance in this motor (which is explained later on).

The a2 motor (2002-2004 Acura RSX Type-S) has a secondary "agressive" cam lobe on both the intake and exhaust sides which creates the "true VTEC" that the H and B series motors have. This motor actually has a set engagement point for the cams to switch over to the "agressive" lobes, whereas the a3 does not.

The I-VTEC is actually a mechanism called VTC. Its purpose is to change the cam angle to allow for better performance, better gas mileage, or both at the same time. VTC works in combination with the throttle body, intake manifold, and valvetrain to make the best performance with the best gas mileage.

Both of these motors have a VTEC soleniod and by defintion have "VTEC". Its just that the a3 motor has a more casterated version.

To answer your question about the swap, technically swapping an a2 head (valves, springs, cams, retainers, etc.) onto an a3 block will give you the "true VTEC" you are looking for; however, you will still be limited as to how far you can push the motor. The a3 motor is not built for 8k+ rpms due to its not quite as strong bottom end.

Simply put, you can put an a2 head on an a3 motor to get that true VTEC sound but you can't really SAFELY rev it past 7k rpm without risking blowing your motor.

I hope this helps and if any of it is wrong please feel free to correct me. I'm still kinda new to this but this is what I have gathered out of a few months of reading/research.

wrong. it does not operate as a 12 valve motor. all 16 valves are working. the secondary (small) lobe is cracked open just enough to prevent fuel from pouring into the combustion chamber but has shit loads of duration. at the same time the primary lobe (bigger) lobe is cracked at the same lift/duration as the secondary lobe to prevent it from stalling out. 2200 rpms both ride on the primary lobe and all are STILL working as 16 valves..

a3 CAN have agressive cams but it has to be aftermarket. and there is no such thing as "true/real" vtec all vtec systems operate the same function.

a2 head on a3 block can safely rev to 8k as i think anja did it on his ep3 at the time..jjust gotta check the V2P contact above 8k..

EDIT: talon u beat me to it about the a3 vtec operation foo:-)

[talonXracer]

EDIT: talon u beat me to it about the a3 vtec operation foo:-)


LOL,,,beat ya!

[r_jones06]

Thanks for the corrections like I said I'm still somewhat new at this. Hopefully soon I won't have to be corrected :mbiggrin:.

As far as the RPM's go... don't the different pistons, rods, crank, lack of oil squirters, etc not make it somewhat unsafe to rev a mostly stock a3 motor that high? I guess it really depends on how you do the swap and how its tuned and all... but I've heard many horror stories of people with the a2 head on the a3 block blowin the motor cause they were pullin it 8k+... maybe I've just been under the false impression that it's not safe especially without building the bottom end

[talonXracer]

I know of several A3's spinning to 8k(no higher).

There is no power being made up that high(unless FI) so why spin that high?

The rods/rod bolts(and A2/A3 valve springs) are the weak link that keeps the rev-limit lower.

[NatesSi04]

OK folks, I just bought my 04 Si, it came already modded with just about every bolt on possible. From what I'm reading on here, our A3 engines' VTEC is engaged from 2200 rpm's up, and there shouldn't be a noticeable surge or sound anywhere in the upper rpm range. My problem is that mine hits a very strong surge and very noticeable exhaust pitch change at approximately 6k rpm. (I don't know for sure, I'm too busy trying to keep it in a straight line)
No turbo or sc, just headers, short ram, catback, and high flow cat. I don't know if there's been any ECU work done, or engine internals. So everybody else's doesn't have that surge in power at high rpm?

[shanewdude]

OK folks, I just bought my 04 Si, it came already modded with just about every bolt on possible. From what I'm reading on here, our A3 engines' VTEC is engaged from 2200 rpm's up, and there shouldn't be a noticeable surge or sound anywhere in the upper rpm range. My problem is that mine hits a very strong surge and very noticeable exhaust pitch change at approximately 6k rpm. (I don't know for sure, I'm too busy trying to keep it in a straight line)
No turbo or sc, just headers, short ram, catback, and high flow cat. I don't know if there's been any ECU work done, or engine internals. So everybody else's doesn't have that surge in power at high rpm?

Sounds like it could have a different engine or head... check the stamp on the block. Doesn't sound like a normally tuned a3, but then again, I feel more power in my stock a3 when I get above 5000 rpm. Llisten to see what the pros here say... Talon?

[Draw7Seven]

OK folks, I just bought my 04 Si, it came already modded with just about every bolt on possible. From what I'm reading on here, our A3 engines' VTEC is engaged from 2200 rpm's up, and there shouldn't be a noticeable surge or sound anywhere in the upper rpm range. My problem is that mine hits a very strong surge and very noticeable exhaust pitch change at approximately 6k rpm. (I don't know for sure, I'm too busy trying to keep it in a straight line)
No turbo or sc, just headers, short ram, catback, and high flow cat. I don't know if there's been any ECU work done, or engine internals. So everybody else's doesn't have that surge in power at high rpm?

If it's incredibly noticeable, you just might have a swap of some sort, either with a full engine with VTEC (A2 perhaps) or a different head with a tune on it. Check the engine stamp, you may be in for a pleasant surprise...

[TheAmericanStig]

If it's incredibly noticeable, you just might have a swap of some sort, either with a full engine with VTEC (A2 perhaps) or a different head with a tune on it. Check the engine stamp, you may be in for a pleasant surprise...

If your valve cover says Honda Motor Co. Ltd. on the top, then its likely you have a head or motor swap.

[Jpax]

people change valve covers alot, so don't look at thatunless your taking it off! check the block stamp, and or pull the valve cover if it looks like this http://i41.photobucket.com/albums/e278/vietrice507/DSC00106.jpg

your golden with a swap

3 lobes on BOTH CAMS per cly.

[NatesSi04]

I haven't found the transmission code yet, but the engine tag matches the VIN. The head doesn't appear to have been swapped though, it looks tamper-free. Maybe that swirling effect I'm hearing about at 6600 rpm really does something.

[Emerica459]

I haven't found the transmission code yet, but the engine tag matches the VIN. The head doesn't appear to have been swapped though, it looks tamper-free. Maybe that swirling effect I'm hearing about at 6600 rpm really does something.

how high are you revving it to? I know that on my A3 when I had my intake it got noticeably louder in higher rpm's and that is due to the VTC operation, no real noticeable power gain there though. It is still very possibly you have a swap though.

[donkeygong64]

My A3 block also does sound a lot louder during the 6k+ revs but I'm 100% positive I don't have a swap. But maybe your lucky! :shocked:

[frm_808]

My A3 block also does sound a lot louder during the 6k+ revs but I'm 100% positive I don't have a swap. But maybe your lucky! :shocked:

if it doesnt crack then you dont have one