Vtech or no Vtech???

[Kable's2019Si]

So, when initially looking at this car I hard read, heard, and excepted that this engine does not have Vtech. But because I'm always curious I've been reading deeper and deeper, and though it is not the traditional Vtech we've grown up with, it does seem to be Vtech. Even Honda calls it a Turbo Vtech engine.

https://global.honda/innovation/technology/automobile/Vtec-turbo-picturebook.html

The engine does appear to have valve timing on both intake and exhaust but just isn't using the mechanics of a separate set of cam lobes. I get that to the purists it's not Vtech in the sense they know and love but it is variable valve timing done in a more thorough sense. I am constantly seeing the argument on here about how it's not Vtech like the K-series, but no discussions on why no one believes it to be Vtech. Technology changes, hell, I remember when Vtech was some crazy tech. I just see this as the next progression of Vtech.

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[amirza786]

VTEC basically changes the CAM profile to allow more air into the engine so that it can breathe at high RPM, as the the older gen engines did not reach peak power until they reached the higher rpm's. With a Turbocharger, VTEC in the traditional sense is no longer needed, as the power curve can now be placed in the lower rpm range, and they more efficiently pull air into the intake so the engine breathes better. Basically it is no longer needed, at least on the intake side

 

[Kable's2019Si]

VTEC basically changes the CAM profile to allow more air into the engine so that it can breathe at high RPM, as the the older gen engines did not reach peak power until they reached the higher rpm's. With a Turbocharger, VTEC in the traditional sense is no longer needed, as the power curve can now be placed in the lower rpm range, and they more efficiently pull air into the intake so the engine breathes better. Basically it is no longer needed, at least on the intake side

But it is using valve timing adjustment on the intake side, and the exhaust. It's just not using the cam profile to dictate duration. It's not adding lift, but it is variable valve timing, it's just not restricted to one area of the powerband, but to work in tandem with a turbo.
"
2. Dual VTC for Intake and Exhaust

Conventional turbo engines could not supercharge efficiently at low revs, causing slow engine response. With the VTEC TURBO, Valve Timing Control (VTC) changes the timing for intake and exhaust valves to operate, controlling the amount of time both types of valves are simultaneously open. This allows efficient supercharging even at low engine revs."

 

[amirza786]

But it is using valve timing adjustment on the intake side, and the exhaust. It's just not using the cam profile to dictate duration. It's not adding lift, but it is variable valve timing, it's just not restricted to one area of the powerband, but to work in tandem with a turbo.
"
2. Dual VTC for Intake and Exhaust

Conventional turbo engines could not supercharge efficiently at low revs, causing slow engine response. With the VTEC TURBO, Valve Timing Control (VTC) changes the timing for intake and exhaust valves to operate, controlling the amount of time both types of valves are simultaneously open. This allows efficient supercharging even at low engine revs."

Yes the Si is using Valve Timing Control, but it's different from the traditional VTech used in the older series engines where they needed a na engine to be able to cram in extra air at high rpm's where the power band is. I read somewhere that even though the CTR still has VTEC, it's not your 8th or 9th gen VTEC. Anyway someone who is more of an expert can weigh in

 

[jred721]

I always thought the CTR's VTEC works exactly the same but it's just kind of masked because of the turbocharger which changes how the engine delivers power. Interested to know the difference between the VTEC in the CTR and VTEC in a traditional Honda engine like the NA 2.0 in my Civic.

 

[Kable's2019Si]

Right and that's why I think it's just a new way of doing it. It may not be what WE want to call Vtech, but Honda says that it is. And it is using valve timing which is what Vtech's main advantage was minus the lift aspect. With forced induction they don't need the added lift to force it in, like you said. I always wondered why Honda waited so long to start implementing turbos after everyone else. I think they were just trying to figure out a way to work both together seamlessly.

 

[skorj]

Guys... it's VTEC

As for Honda being one of the last in the game to go the turbocharged, small-displacement route: my assumption is they had a lot of R&D money wrapped up in NA high-revving engines and were late to the game with turbocharging, probably attempting to keep the high-revving power traits they are known for while improving economy.

"VTEC" being utilized in their turbo engines is technically "VTC" (the "E" being lift electronic control) but Honda is probably just calling it VTEC due to brand recognition.

 

[sjd]

The Si doesn't have VTEC. Simple as that.

https://www.thetruthaboutcars.com/2...-drive-review-vtec-no-all-bout-that-turbo-yo/

"Peddling the coupe and sedan through the corners is the same non-VTEC 1.5-liter turbocharged engine seen elsewhere in the Civic lineup, as well as in the new CR-V and forthcoming Accord. But while the turbo mills in the “normal” Civics and CR-V only produce between 174 and 190 horsepower, the Si gets a turbo-boost bump to 20.3 psi to crank up output to 205 hp"

https://autoweek.com/article/car-news/2017-honda-civic-si-goes-turbocharged-first-time-ever

"However, with the new mill comes a new bit of technology that could make some hardcore Si fans upset. Gone is Honda’s VTEC variable valve timing and lift. The automaker’s camshaft variable timing control (VTC) technology, which is limited to the intake camshaft and is always active, optimizing engine performance and efficiency at any given rpm, replaces the VTEC technology."

The Type R does have VTEC.

 

[BogdanM]

The correct name for the 1.5 engine would be VTC Turbo. There is no VTEC anymore as there is no valve lift control (you don’t have the secondary set of bigger, more aggressive cam lobes). VTC is a similar system to Toyota’s VVT-I.
Honda kept VTEC in the name as a throwback to the older, more established engines and in this case it is just a commercial naming.

 

[sjd]

The correct name for the 1.5 engine would be VTC Turbo. There is no VTEC anymore as there is no valve lift control (you don’t have the secondary set of bigger, more aggressive cam lobes). VTC is a similar system to Toyota’s VVT-I.
Honda kept VTEC in the name as a throwback to the older, more established engines and in this case it is just a commercial naming.

You're right about the VTC Turbo but how it is a throwback when Honda in no way mentions VTEC at all in regards to the Civic Si? The Type R's 2.0 Turbo definitely has VTEC except it is implemented in a much different way.

https://www.wardsauto.com/engines/2018-winner-honda-civic-type-r-20l-vtec-turbo-4-cyl

"This intercooled, twin-cam 4-cyl. combines variable cam timing on the intake and exhaust sides with a revised version of Honda’s VTEC variable valve lift.
On earlier naturally aspirated Honda engines, VTEC provided additional valve lift by switching to a different cam lobe at high rpm. The execution is slightly different in the new turbocharged engine, which deploys VTEC only on the exhaust valves. Instead of doing its job at high rpm, the updated system operates at lower engine speeds, opening the exhaust valves wider to dump more exhaust into the turbocharger to spool it up more quickly."

 

[typemismatch]

The correct name for the 1.5 engine would be VTC Turbo. There is no VTEC anymore as there is no valve lift control (you don’t have the secondary set of bigger, more aggressive cam lobes). VTC is a similar system to Toyota’s VVT-I.
Honda kept VTEC in the name as a throwback to the older, more established engines and in this case it is just a commercial naming.

Partially true.

The 1.5T doesn't have VTEC. The 2.0L motors still do, but it's used differently than we're used to

 

[mvela]

This is just a thought but hear me out. The vtec in my lx model 2.0 NA is the traditional Vtec that we know and love. Trust me you can feel and hear when it opens up. It is port injected meaning that the injectors are behind the valves. So when Vtec engages the taller lobes it allows more fuel and air into the cylinders. Now a type R is direct injected so the injectors are spraying directly in the cylinders so would not benefit much from this other than a little more air. But it is a turbo so it’s already getting tons of air. So as far as having the taller lobes in the type R, I wouldn’t see the point really

 

[boosted180sx]

I always thought the CTR's VTEC works exactly the same but it's just kind of masked because of the turbocharger which changes how the engine delivers power. Interested to know the difference between the VTEC in the CTR and VTEC in a traditional Honda engine like the NA 2.0 in my Civic.

the CTR has it only on the exhaust side.

it's not activated at idle for a smoother idle, activated during cruising for fuel efficiency, not activated during turbo spool up, and active during high loads to push exhaust gasses faster.

 

[Design]

True VTEC is both valve timing AND electronic lift control.

Turbo VTEC is largely a marketing term, EXCEPT when it comes to the Accord/CTR's 2.0T, and the base Accord's 1.5T. In those specific configurations, variable lift is present on the exhaust side for improved throttle response and low end torque. It's cheaper than doing something like a variable vane turbo to help optimize airflow.

As mentioned above, turbo motors don't benefit from variable lift on the intake side. Which is why they use dual VTC to control the valves.

 

[BogdanM]

Partially true.

And which part is not true?

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