I-vtec vs. Vtec

[JoshSI]

Lets have a discussion on this. The pros and cons of both!

[yomamaInMySi]

Pros I-vtec:

chain driven, no worry about timing chain at 50K
new gadget for the motor to play with

Cons:
?? don't know

[02SilverSiHB]

pros of i-vtec:
sounds better
more torque
chain driven
easier to drive on the street (less high revving)


cons:
low rev limiter

[Gibhunter]

I-vtec and v-tec are identical save for I-vtec constantly adjusting your spark timing. That one is chain driven and another is belt driven is totally subjective. You could have chain driven vtec (like in a Maxima [yes, it does has variable valve timing]) and belt driven i-vtec if Honda chose to do so. V-tec in I-vtec still works the same as in original engines. All are activated by oil pressure that is proportionally higher due to the engine's RPM. A more valid comparison would be B-series versus K-series. Or GSR/00Si vs Type-S or Integra LS vs. Base RSX/02Civic Si.

[jaydub]

Con:

That fruity little 'i' on the sticker by the door. :mad: I hate that "i"

[Pradamuimui]

Pro's of I-Vtec;

1. Instant Vtec power all the way through ur powerband, unlike older Vtec motors like the GSR when you had to wait for 4400 rpms to hit before ur first runners would open up.
2. More torque!!! Our Si's have more torque then the older ones. Such as the 99-00 Si's!!


Cons;

1. Low redline (REALLY SUCKS) Because when you look at it hp matters, but torque and how high ur redline is matters MORE! Why?? Because the higher ur redline is, the more time you have to build up power...and the more torque, the quicker you will build that power!!!
2. Its a new beast, so its gonna take the aftermarket a while to tame it!!
3. Its a 2.0 liter, but yet with the same horse power as the 99-00 Si's!!!

[AJWUZHERE]

Originally posted by Pradamuimui
1. Low redline (REALLY SUCKS) Because when you look at it hp matters, but torque and how high ur redline is matters MORE! Why?? Because the higher ur redline is, the more time you have to build up power...and the more torque, the quicker you will build that power!!!


I'm sorry but the new SI lays down 160hp faster than the old b16a. and a lower redline helps out for a better gas mileage. And torque has nothing to do with you quick you can build up power, it's all in the tranny and the gear ratios. Witch the SI already has a close geared tranny.

[Pradamuimui]

Im sorry but a higher redline does help with building more power!!! Im not disputing that our Si's arent as fast as the 99-00's, because I know they are. As a matter of fact there FASTER!!! However I just think that with a 2.0Liter motor we should have more hp!! Torque does matter a lot, and a high redline is EVERYTHING...it lets you build power. ASK ANYONE!!!

[DJ Catchem]

I'm interested in the fact that no one has noted the difference between the Civic/base RSX VTec and the Type S VTec. Our VTec limits intake on select valves until 2500 RPMS, at which point all intake valves are run from the "normal" cams. Versus the Type S VTec which is the real-deal low to high cam fire-breathing VTec we all know and love.

We don't get the "high" cam. We end where the Type S starts.

Any thoughts there? It certinly makes me crave an engine swap...

[jaydub]

Originally posted by Pradamuimui
Im sorry but a higher redline does help with building more power!!! Im not disputing that our Si's arent as fast as the 99-00's, because I know they are. As a matter of fact there FASTER!!! However I just think that with a 2.0Liter motor we should have more hp!! Torque does matter a lot, and a high redline is EVERYTHING...it lets you build power. ASK ANYONE!!!

Why? Volkswagen's 2.0L motor puts out a ground punishing 115HP.

And btw, our cars aren't as fast as the previous Si, because we are carrying around about 200 more lb.

[Dallas2k2Si]

Originally posted by Pradamuimui
Cons;

1. Because the higher ur redline is, the more time you have to build up power

Unless the engine doesn't develop power at that rpm band. High RPM does not automatically equal more power. Pushing an engine past the RPM where the torque and hp are both falling off does not get you anywhere quicker, except last place.

[Cone Killer]

Originally posted by Pradamuimui
I just think that with a 2.0Liter motor we should have more hp!! Torque does matter a lot, and a high redline is EVERYTHING...it lets you build power. ASK ANYONE!!!

ok....the first thing I think of is a big block v8 and it's low red line and abundunt power and speed potential.

The only thing you get with a higher redline in our cars is a different peak rpm for hp. All one has to do is change the transmission gear ratios to take advantage of that. But this is all at a cost. More high rpm hp the less torque you can make. But will the new I-VTEC changes that a bit and allows for a more even torque distribution, not necessarily more torque. You have to realize that displacement whent up .2 from the 1.8 and .4 from the last civic, so of course it has more torque.

The whole premis behind VTEC is allowing the engine to get good gas mileage, and emmisions and when needed put out a lot of hp.

The current set up would not benefit from a higher redline much, as the hp and tq are dropping off on most dynos at redline.

So honda could have easily made more hp from our block, and they did, but they put it in a different car (RSX type-s).

So here are a revised list of pros for I-VTEC
-flater torque curve (read-more usable power at all rpms)
-regular unleded fuel

that's really it. The rest of the things you guys mentiond are things that have nothing to do with the I-VTEC system, but with the engine design as a whole.

[BlasTech]

Originally posted by Cone Killer


So here are a revised list of pros for I-VTEC
-flater torque curve (read-more usable power at all rpms)
-regular unleded fuel



Agreed, but also they do get decent gas mileage and cleaner emissions too- especially compared to the other hot hatches. Thats the one thing I'd add to that list.

[Cone Killer]

Originally posted by Cone Killer
The whole premis behind VTEC is allowing the engine to get good gas mileage, and emmisions and when needed put out a lot of hp.

I said it here

[Mr.02BlackSIguY]

Originally posted by Dallas2k2Si


Unless the engine doesn't develop power at that rpm band. High RPM does not automatically equal more power. Pushing an engine past the RPM where the torque and hp are both falling off does not get you anywhere quicker, except last place.

but isnt it proven from hondata chip that it DOES produce more horsies at higher RPM? it did for base RSX and i think it does for our EPs. so we shouldnt be last place.. we should be dirst place :D

[Cone Killer]

Originally posted by Mr.02BlackSIguY


but isnt it proven from hondata chip that it DOES produce more horsies at higher RPM? it did for base RSX and i think it does for our EPs. so we shouldnt be last place.. we should be dirst place :D

That is a bit different because the hp and tq are falling off as normal, but you have effectively moved the lines up a few more hp and tq. The trend of the curve is still the same. One could be better off changing gears and using lower rpm power instead of chasing less and less power at red line.

[Gibhunter]

There is a shitload of misinformation in this thread. I am by no means an authority on how engines work and how Si's engine works, but let me clarify some of your points.


Pro's of I-Vtec;

1. Instant Vtec power all the way through ur powerband, unlike older Vtec motors like the GSR when you had to wait for 4400 rpms to hit before ur first runners would open up.
2. More torque!!! Our Si's have more torque then the older ones. Such as the 99-00 Si's!!


Cons;

1. Low redline (REALLY SUCKS) Because when you look at it hp matters, but torque and how high ur redline is matters MORE! Why?? Because the higher ur redline is, the more time you have to build up power...and the more torque, the quicker you will build that power!!!
2. Its a new beast, so its gonna take the aftermarket a while to tame it!!
3. Its a 2.0 liter, but yet with the same horse power as the 99-00 Si's!!!

Pros:

1) Not true. Totally not true. For a good example of the new engines just look at RSX Type-S. You have to wait to 5900RPM untill you feel the V-tec punch. On our K20A3 engines the v-tec switchpoint is at 2200RPM and it only enable to second intake valve essentially switching the engine from a 12valve to a 16valve and is done to improve emmisions and gas mileage and not to increase performance. So you could say that K20A3 does not have a true form of Vtec.

2) Again, not really true. We have more torque because of 20% more displacement. The i in I-vtec probably gives us a bit more Torque though then a regular v-tec engine would.

Cons:

1) Not true. RSX Type-S redline is at 7900RPM (Japan's Type-R is even higher).

2) True, but the gains seem to be better with these new engines.

3) True, but only on this engine. The title of the thread was ivtec vs vtec and not K20A3 vs. B16A.

[Dallas2k2Si]

My statement holds true whether a mill is stock or modded. There is a point where any further RPM is a negative for continued acceleration (of racing quality).

I'm just tired of hearing that the 2k2 Si is a dog because it doesn't rev to 8k like the 99-00's. I had a '99, and traded for the 2k2. I ran them both on the 1/4 mile at Ennis, with me driving. Only mods on both at the time were/are AEM CAI. The 2k2 beat the '99 on all runs, ET and trap speed. I also head's up raced a 2000 Si with my 2k2, his only mod the AEM CAI, and beat it.

So, maybe I didn't rev to 8k down the track, but I got to the end firstest and fastest. Rethink the "high rpm" argument.

[02SilverSiHB]

Originally posted by Gibhunter
There is a shitload of misinformation in this thread. I am by no means an authority on how engines work and how Si's engine works, but let me clarify some of your points.



Pros:

2) Again, not really true. We have more torque because of 20% more displacement. The i in I-vtec probably gives us a bit more Torque though then a regular v-tec engine would.
But you just said it really is true :rolleyes: I'm getting dizzy

[02SilverSiHB]

Originally posted by Dallas2k2Si
My statement holds true whether a mill is stock or modded. There is a point where any further RPM is a negative for continued acceleration (of racing quality).

I'm just tired of hearing that the 2k2 Si is a dog because it doesn't rev to 8k like the 99-00's. I had a '99, and traded for the 2k2. I ran them both on the 1/4 mile at Ennis, with me driving. Only mods on both at the time were/are AEM CAI. The 2k2 beat the '99 on all runs, ET and trap speed. I also head's up raced a 2000 Si with my 2k2, his only mod the AEM CAI, and beat it.

So, maybe I didn't rev to 8k down the track, but I got to the end firstest and fastest. Rethink the "high rpm" argument.
yeah, I think I'm going to agree with you on this. I at first (from my previous first post on this thread) said it sucked not having a higher rpm like the 99-00 si. Now I'm beginning to think it isn't worth it. I ran against another si two days ago, he couldn't catch me, we were going as fast as possible and the guy wouldn't give up, he looked sooo pist. It was too funny.
I notice that when I get to 7k rpm (at least that's what it says on my rev limiter, I thought our max is 6800 but mine goes up to about 7200) that it sounds and feels like it's telling me..."okay, shift, I just gave the top end about 200rpm ago, you want more, shift!"