Turbo vs VTEC feel

TTRPGGeek

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So my Accord has a VTEC engine, and I've driven the 2016 Civic Touring for a bit. For the last few days I've been intentionally pushing my Accord when given the opportunity, which isn't often on my commute.

If I'm in "S" mode and I floor it there's some early get up and go that's ok, then a couple/few seconds later we get to around 6000 rpm, the engine howls and my head nudges back a bit. That, I presume, is the high RPM VTEC kick? Not a lot of long opportunities to push it to redline, so I haven't.

But, from what I remember a year ago driving the touring, the turbo lag was there but it was quite brief, and that kick, that nudge back into my seat, came a lot earlier - and then kept zipping a bit.

So, I reckon I anticipate the earlier torque in the SI to be a lot more handy on a day to day basis than what would have been happening in a VTEC.
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sfedai0

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I havent driven the SI yet, but I imagine the once the turbo kicks in, it will feel pretty similar to VTEC engaging....minus the changeover howl that everyone associates with VTEC. The beauty of the new engine is that the powerband is much more accesible, being in the lower portions of the RPM range. So I expect it to be pretty similar. The old one had you winding it up and staying up there, where as the new one has it around the 3-6k range.


Will I miss VTEC? Yes, but not all change is bad. I feel the new Si will be more fun to drive on a everyday basis.
 
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TTRPGGeek

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Yeah exactly. You have to work to get to the VTEC kick, something not happening much when tooling around town. Whereas the turbo with CVT felt zippy, at least compared to my accord, pretty much right out of the gate.

I expect my 12 year old daughter will miss the engine howl. I don't expect I will.

Looking forward to a test drive to find out how that turbo pairs with the manual. Come on kid at dealership, find that blue sedan that's on the way and get it here soon!
 

Milo & Miles

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Not sure about the Si, but in the Sport Hatch, the Turbo isn't designed to Kick you in the Pants like VTEC or Turbos of old, but it feels like a strong surge of power that kind of pushes you into your seat from about 3K to 5.5K. It definitely doesn't have any VTEC 'yo shenanigans going on.
 

Aero2001

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So, I reckon I anticipate the earlier torque in the SI to be a lot more handy on a day to day basis than what would have been happening in a VTEC.
Overall, I think this is correct, but IMO the turbo's torque curve is most advantageous on the highway for merging, passing, etc.

I now drive a 2010 TSX (6MT), and my previous car was a 2001 SAAB 9-5 Aero (5MT), so I have lots of experience with a powerful turbo four and VTEC. Around town and on back roads, I don't miss the SAAB's power at all, largely because the Acura's gearing is short enough to provide decent punch. It makes the most of its power. Plus, the NA engine has wonderful response, and we all know about VTEC on back roads.

On the highway, however, there's no comparison. In the range of, say, 50-90, the SAAB was unbelievable. Its fat torque curve provided awesome acceleration well past any sane speed, and downshifting wasn't all that necessary.

I know the new Si won't keep up with a beastly old SAAB on the highway, but the overall effect of its torque curve should be similar. In fact, it will probably be more linear, with less lag.

I can't wait to try it.
 


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TTRPGGeek

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Interesting! Honestly the 16 Accord LX feels best at straight line highway speeds vs around town. Ample get up and go on the on ramp, and when choosing to pass. Its one drawback, and a huge let down from my 2003 Accord LX that had double wishbone, is that I don't feel comfortable on certain highway curves without letting off the throttle. Sad that just this week i crept past a semi on a freeway bend at a bit over 70 whereas the previous car I'd have not thought about 80.

So if the new SI improves in town fun, enjoys freeway acceleration even more, while obviously enjoying the curves more, that'll be a bonus!
 

zroger73

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Turbochargers are "analog" devices. They provide no boost, full boost, and everywhere in between. A turbocharger is always on whenever exhaust gasses are flowing through it which is anytime the engine is running. It provides boost in a linear fashion depending the position of the wastegate and the speed of the exhaust gasses flowing through it. Unlike VTEC, a turbocharger doesn't suddenly "kick in" at an exact RPM - it provides varying amounts of boost over a wide RPM range.

VTEC is a "digital" device. It is either on or off resulting in a sudden transition and change in engine performance and sound at the engagement point. The degree to which VTEC engagement can be felt or heard varies by model and whether the intake and exhaust systems have been modified. In my stock Ridgeline, I can feel and hear it engage at 5,500 RPM if I'm paying close attention.

Think of turbocharges as a light with a dimmer switch - the light can be off, full brightness, or anywhere in between.
Think of VTEC as a light with a simple on/off switch - the light can be off or full brightness with nothing in between.
 

Aero2001

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Interesting! Honestly the 16 Accord LX feels best at straight line highway speeds vs around town. Ample get up and go on the on ramp, and when choosing to pass. Its one drawback, and a huge let down from my 2003 Accord LX that had double wishbone, is that I don't feel comfortable on certain highway curves without letting off the throttle. Sad that just this week i crept past a semi on a freeway bend at a bit over 70 whereas the previous car I'd have not thought about 80.
Your '16 Accord, with its direct injection, probably has a fatter torque curve than my TSX, so it could easily be better on the highway. I only have 172 lb.-ft., and I forget where it peaks.

I'm speculating here, but your lack of comfort on the curves might relate to lack of feedback through the electrically-assisted steering. Even though my TSX has vastly superior chassis dynamics than my old SAAB, the numb steering (especially on-center) makes me feel less comfortable with some maneuvers, like high speed lane changes. If you can't feel anything through the wheel, you might have a tendency to lift a little.

I'm positively thrilled that some reviews have praised the Si's steering feel/feedback, because the numb steering is, by far, my biggest complaint about my TSX.
 

totopo

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So my Accord has a VTEC engine, and I've driven the 2016 Civic Touring for a bit. For the last few days I've been intentionally pushing my Accord when given the opportunity, which isn't often on my commute.

If I'm in "S" mode and I floor it there's some early get up and go that's ok, then a couple/few seconds later we get to around 6000 rpm, the engine howls and my head nudges back a bit. That, I presume, is the high RPM VTEC kick? Not a lot of long opportunities to push it to redline, so I haven't.

But, from what I remember a year ago driving the touring, the turbo lag was there but it was quite brief, and that kick, that nudge back into my seat, came a lot earlier - and then kept zipping a bit.

So, I reckon I anticipate the earlier torque in the SI to be a lot more handy on a day to day basis than what would have been happening in a VTEC.
turbo lag is not related to RPM. It's the lag in throttle response from when you go WOT to when the engine starts developing power. Superchargers develop boost based on RPM, turbo chargers develop boost based on exhaust gas (throttle). So when you are cruising at low throttle, you have very little boost. When you open throttle you start developing more boost in a feedback cycle, but it takes a while. Larger turbos take more time to spool. Turbo lag is hidden in a large part by CVT/torque converter lag. It is much more evident on manual transmissions.

VTEC mechanically switches the overhead cams at a certain rpm, so you get an abrupt shift in power level which is RPM dependent, not throttle dependent. It doesn't effect throttle response.
 

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we get to around 6000 rpm, the engine howls and my head nudges back a bit. That, I presume, is the high RPM VTEC kick?
That's it. With my S2000, there's a real noticeable "something just changed" moment when the VTEC kicks in. With the turbo Civic, it's more of a "oh, the engine just got into its powerband" moment. Talking about when accelerating from a stop, that is.
 


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Turbochargers are "analog" devices. They provide no boost, full boost, and everywhere in between. A turbocharger is always on whenever exhaust gasses are flowing through it which is anytime the engine is running. It provides boost in a linear fashion depending the position of the wastegate and the speed of the exhaust gasses flowing through it. Unlike VTEC, a turbocharger doesn't suddenly "kick in" at an exact RPM - it provides varying amounts of boost over a wide RPM range.

VTEC is a "digital" device. It is either on or off resulting in a sudden transition and change in engine performance and sound at the engagement point. The degree to which VTEC engagement can be felt or heard varies by model and whether the intake and exhaust systems have been modified. In my stock Ridgeline, I can feel and hear it engage at 5,500 RPM if I'm paying close attention.

Think of turbocharges as a light with a dimmer switch - the light can be off, full brightness, or anywhere in between.
Think of VTEC as a light with a simple on/off switch - the light can be off or full brightness with nothing in between.
You might as well change your name to "Honda's Mad Scientist"

Best analogy ever on turbo vs vtec (dimmer vs switch)
 

zroger73

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I'm positively thrilled that some reviews have praised the Si's steering feel/feedback...
One concern is that those positive reviews were from automotive journalists who received early access, airfare, hotel accommodations, and other perks from Honda. They can't say too many bad things or they won't get the VIP treatment in the future.

Consumer Reports is the only professional review based on an Si they actually purchased with their own money from a Honda dealership. They said the steering "comes up a little short on feedback" and that the suspension "is a big letdown" and that the ride "is really stiff and choppy".

I'll reserve judgement until I pick up my Si tomorrow evening. :)
 

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You might as well change your name to "Honda's Mad Scientist"

Best analogy ever on turbo vs vtec (dimmer vs switch)
:agree:

Zroger73 brings so much knowledge and insight to this forum, and contributes to a wide variety of topics. :bow:

All threads benefit when he adds his contributions.
 

pukemon

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Hey ttrpg. One thing to consider though is the power available in NA engine. You still have accessible power when VTEC is not engaged. When you have a turbocharger it feels like your engine is severely underpowered then all of a sudden it's like OMG banner disappeared and Hulk is smashing it up. Something to put on the scale. Some people dig it, some people like me are meh and others will be like damn I miss NA engines for the response. Gotta get behind the wheel to know for sure. I just accepted reality knowing it will be turbos from here on out with most cars. I am still adapting. And yes, even though I miss that VTEC YO the turbo kicking in is pretty cool.
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