Does Vtec really kick in?

[MJinZ]

Having owned a VTEC-Yo mobile I'll have to chime in here. Yes 170 HP or even 200HP out of a 4 cylinder is nothing special, and laughable in anything but a super light performance car.

But the truth is the Prelude and Integra were two of the best performance cars produced in the late 80's and throughout the 90's. In terms of cheap performance there wasn't much better out there.

You could buy a POS DSM Eclipse with a turbo and it would be faster in a straight line, Mustang GT's were faster but a few mods here and there and it could get very close.

Back then, the GT's only made ~225hp and weighed ~3200lbs. Compared to 170/~2700 for the GSR.

Problem with light cars and small engines is that you load them up with fat asses and whoops, you're slow.

Heavier cars and bigger engines don't experience it to quite the same degree.

 

[Demon-Xanth]

Problem with light cars and small engines is that you load them up with fat asses and whoops, you're slow.

Heavier cars and bigger engines don't experience it to quite the same degree.

I don't have any problem with small and light cars as long as they are small and light. The Eclipse for example became neither small nor light once they went to the V6 platforms and started pushing more weight than the Camaros did until this current generation. "Smallish and heavy" is just a formula for slow.

Elise=good
Miata=doing alright
Ariel Atom=freaking amazing
Scion TC=meh

(and yes, I know my beloved Dakota is the poster child for porkers having grown from 2800LBs to 4600LBs)

 

[MJinZ]

I don't have any problem with small and light cars as long as they are small and light. The Eclipse for example became neither small nor light once they went to the V6 platforms and started pushing more weight than the Camaros did until this current generation. "Smallish and heavy" is just a formula for slow.

Elise=good
Miata=doing alright
Ariel Atom=freaking amazing
Scion TC=meh

(and yes, I know my beloved Dakota is the poster child for porkers having grown from 2800LBs to 4600LBs)

Uh, I meant people.

Like if you have a car that weighs 1000 lbs with a 150hp engine. FAST.

Seat 4 fat people in it, now it weights 2000lbs. SLOW.

 

[exdeath]

I should probably point out the chart I posted is from a gas V10 in a truck.



I prefer gobs of torque, preferably off idle. That means high displacement. When stomp on the accelerator, I want there to be a nearly constant acceleration from 2000 RPM to redline, not higher acceleration as redline approaches. Otherwize, you end up shifting a bunch (and losing time) to keep the engine in a very narrow powerband.

I prefer gobs of torque off idle too, but accompanied by increasing acceleration that would just never end if not for the rev limit to keep the engine from self destructing. Torque hit at 2000 RPM to pin you to the seat, and by 7000 RPM you are being launched to the moon.

You WANT the needle on the tach to move faster and faster as it sweeps left to right, regardless of how much torque you have down low.

 

[exdeath]

okay, someone's going to have to explain that one to me. The legend is saying that blue is torque and red is power. However the math says that if that were the case the red line should be below the blue until 5252RPM and then be above. Not above it the whole time. Should the key read blue=before supercharger, red=with supercharger?

That only happens when HP and torque are on different scales. The vertical scale on the left is set to show torque, it shouldn't be assumed that it's 1 to 1 with the HP scale. In order for the numbers to coincide, the HP curve was shifted up.

 

[exdeath]

Not many I'll agree but taking that little engine to redline in each gear with the vtec screaming definitely puts a smile on your face sometimes.

Until someone without vtec blows past you with their foot only 1/4 into it in 4th gear. :awe:

 

[exdeath]

I prefer motors that don't need gimmicks to increase their power. I also like motors that have more displacement than the .99C 2L bottle of soda I bought at Walmart last night.

Electronic fuel injection, more valves, more cylinders, and blowers/turbos are all just gimmicks.

Anything you can do to get more power out of a smaller engine will proportionally increase power in a bigger engine too.

If a turbo 4 cyl is making 400 HP to your 400 HP V8 would you still not need gimmicks or would you want a turbo on your V8 also and make 800 HP?

The only truth in your statement is with forced induction cars where the resonance tuning benefits of VVT on a N/A engine is mostly lost, as with many other N/A gimmicks.

 

[exdeath]

"JEEEEEESUS!!!!!"

http://www.youtube.com/watch?v=lMbaZzeKJC8

I can do that too, it's called hold at 5 percent throttle and stay in vacuum in first gear, then floor it at 4,000 and watch the needle shoot to 18 psi instantly. Holy shit, who would have thought Ford had VTEC! :awe: And like that Honda I wouldn't be going much faster either, I would slow down while making a ton of noise for nothing.

 

[exdeath]

In all reality, VTEC is NOT a performance modification, it's a fuel economy and driveability modification. You can stick a hot cam in any engine and have it perform like a VTEC engine with the same peak numbers. You would just have terrible idle and poor street manors with crap fuel economy with a very peaky high rpm power spike. VTEC lets you get away with a hot cam without that sacrifice and have a flat low end and mid range.

So when someone thinks VTEC is kicking in at 4000 RPM, it was actually benefiting them from 850 to 4000 RPM the most.

 

[TridenT]

On most of Honda's VTEC engines it seems to kick in at 4500rpm. It definitely makes the engine roar and gives a decent power boost.

I wouldn't mind flashing my computer chip so that my VTEC kicks in at lower RPMs so I get more power. I think it would be great at 3000rpm.

http://en.wikipedia.org/wiki/Honda_D_engine
It depends on what honda engine it is. They vary from like 2500RPM to 6000RPM+ for the VTEC switchover. And uh.. unless you have an Si, you're usually never going to hear the VTEC actually "kick in." I have a D16Y8(It comes in most 1996-2000 Honda Civic EX cars) and I can't tell when it happens. I've tried to tell the difference between the sound around 5000RPM to 6000RPM and there's no difference except from that of just going higher on the RPMs. (Which does start to sound lovely around 7,000RPM)

I lul'd

 

[DivideBYZero]

http://en.wikipedia.org/wiki/Honda_D_engine
It depends on what honda engine it is. They vary from like 2500RPM to 6000RPM+ for the VTEC switchover. And uh.. unless you have an Si, you're usually never going to hear the VTEC actually "kick in." I have a D16Y8(It comes in most 1996-2000 Honda Civic EX cars) and I can't tell when it happens. I've tried to tell the difference between the sound around 5000RPM to 6000RPM and there's no difference except from that of just going higher on the RPMs. (Which does start to sound lovely around 7,000RPM)

There is a night and day difference between the original and performance oriented VTEC and the system in your car, though. That's why you can't hear it. Drive an original VTEC CRX, Euro or JDM Civic Type R/Integra Type R or an S2000 and it is abundantly clear something has changed.

 

[DivideBYZero]

In all reality, VTEC is NOT a performance modification, it's a fuel economy and driveability modification. You can stick a hot cam in any engine and have it perform like a VTEC engine with the same peak numbers. You would just have terrible idle and poor street manors with crap fuel economy with a very peaky high rpm power spike. VTEC lets you get away with a hot cam without that sacrifice and have a flat low end and mid range.

So when someone thinks VTEC is kicking in at 4000 RPM, it was actually benefiting them from 850 to 4000 RPM the most.

Great post.

 

[lurk3r]

okay, someone's going to have to explain that one to me. The legend is saying that blue is torque and red is power. However the math says that if that were the case the red line should be below the blue until 5252RPM and then be above. Not above it the whole time. Should the key read blue=before supercharger, red=with supercharger?

Can't see it at work, but check the units, they will cross at 5252, if they don't either the graph is faked or the scale is off.

 

[Demon-Xanth]

Can't see it at work, but check the units, they will cross at 5252, if they don't either the graph is faked or the scale is off.

I think the graph is just mis-labeled and they're torque curves from two different runs. The bumps don't line up.

 

[DivideBYZero]

Can't see it at work, but check the units, they will cross at 5252, if they don't either the graph is faked or the scale is off.

Correct. Here's why:

Horsepower = torque X rpm / 5252

Below 5252 rpm any engine's torque number will always be higher than its horsepower number, and above 5252 rpm any engine's horsepower number will always be higher than its torque number. At 5252 rpm the horsepower and torque numbers will be exactly the same.

 

[vshah]

Not many I'll agree but taking that little engine to redline in each gear with the vtec screaming definitely puts a smile on your face sometimes.

not sometimes, always.

but feeling massive grunt off the line puts a smile on one's face too. always

 

[ayabe]

Problem with light cars and small engines is that you load them up with fat asses and whoops, you're slow.

Heavier cars and bigger engines don't experience it to quite the same degree.

Or if you hit any kind of incline, no TQ=weaksauce.

 

[reallyscrued]

http://en.wikipedia.org/wiki/Honda_D_engine
It depends on what honda engine it is. They vary from like 2500RPM to 6000RPM+ for the VTEC switchover. And uh.. unless you have an Si, you're usually never going to hear the VTEC actually "kick in." I have a D16Y8(It comes in most 1996-2000 Honda Civic EX cars) and I can't tell when it happens. I've tried to tell the difference between the sound around 5000RPM to 6000RPM and there's no difference except from that of just going higher on the RPMs. (Which does start to sound lovely around 7,000RPM)

You have a single over head cam engine, you will never hear a sound difference.

And great, a D16Y8 vs B16A2 is the perfect example to debunk this:

VTEC did not add the 40HP. It might have brought the peak up maybe 10HP. Look at that chart posted on the first page. The line stays in a 20 lb ft range, but not before dropping a good 20 lb ft. Even still, how many people are really going to use a 10-20HP increase at over 6000rpm? A flat curve from 1500-4000 is a lot more practical.

Yes speedy, it adds 40 hp at peak. VTEC is the only way a B16A2 makes 100 horsepower per liter. The D16Y8 is almost exactly like a B16A2 without a another camshaft and VTEC solenoid. The D16 puts out 127 horsepower, the B16 puts out 160-170 (depending on US/Japan).

The rest of your post is irrelevent. Whether you use it or not, what's more practical, yada yada. The title post asked, "Does VTEC really kick in?" And the answer is, "Yes....yo."



EDIT: Also...that graph is really weird. This is what a dyno graph of a b16 looks like:

http://asia.vtec.net/beystock/Civic/art5/index.html (scroll down to see the graphs)

It raises pretty steady after 5900 rpm. This is how it felt in my car. Don't know what's with all the hate, it makes the car a lot more fun to drive than a Civic DX.

 

[DivideBYZero]

To back up Mr Scrued, I have owned both the 130hp D16 and the 160hp B16 motors. VTEC kicked in hard in the B16.

The question in the original post is, "Does VTEC kick in?". The answer is a solid yes, no matter your opinion on it.

 

[speedy2]

You have a single over head cam engine, you will never hear a sound difference.

And great, a D16Y8 vs B16A2 is the perfect example to debunk this:



Yes speedy, it adds 40 hp at peak. VTEC is the only way a B16A2 makes 100 horsepower per liter. The D16Y8 is almost exactly like a B16A2 without a another camshaft and VTEC solenoid. The D16 puts out 127 horsepower, the B16 puts out 160-170 (depending on US/Japan).

The rest of your post is irrelevent. Whether you use it or not, what's more practical, yada yada. The title post asked, "Does VTEC really kick in?" And the answer is, "Yes....yo."



EDIT: Also...that graph is really weird. This is what a dyno graph of a b16 looks like:

http://asia.vtec.net/beystock/Civic/art5/index.html (scroll down to see the graphs)

It raises pretty steady after 5900 rpm. This is how it felt in my car. Don't know what's with all the hate, it makes the car a lot more fun to drive than a Civic DX.

How are you going to compare a SOHC and a DOHC and tell me the difference in power is only due to the VTEC?

 

[Zenmervolt]

Yes speedy, it adds 40 hp at peak. VTEC is the only way a B16A2 makes 100 horsepower per liter.

VTEC does not increase power per-se. VTEC allows two separate cam profiles.

If only the high-lift, high-duration cam were used without VTEC, the engine would still make 100 hp/liter. It would idle like crap and would be gutless at low RPM, but it would still scream just as much at high RPM as the VTEC engine and it would still make the same power at high RPM.

What VTEC does is allow the engine to run a tamer, low-RPM cam for more pleasant low-RPM operation and then switch to the more aggressive cam at high RPM. VTEC doesn't add power in and of itself, all VTEC does is swap cam profiles.

ZV

 

[speedy2]

Thank you Zenmervolt. lol

 

[reallyscrued]

How are you going to compare a SOHC and a DOHC and tell me the difference in power is only due to the VTEC?

*Sigh* Okay. Was really just using that as an example because someone said they couldn't feel it engaging. I guess it was a poor choice for comparison. How about this?

D16A8
Found in:
1988-1995 Civic/CRX/Concerto (UK/Europe/Australia)
1992-1995 Rover 216/416 GTi(UK/Europe)
1993-1997 Rover 216 SportCoupe (Europe)
Displacement : 1,590 cc (97 cu in)
Bore and Stroke : 75 × 90 mm (3.0 × 3.5 in)
Compression : 9.5:1
Power : 125 hp (93.2 kW, 127 ps) @ 6800 rpm
Torque : 108 ft·lbf (14.9 kg/m, 146 Nm) @ 5900 rpm
Valvetrain : DOHC (4 valves per cylinder)
Fuel Control : OBD-0 MPFI
ECU Code : PP5
Gearbox : L3

Similar bore and stroke of B16A2, same displacement, even two overhead cams..but only 125 horsepower.


In any case, it's still fun to make fun of VTEC.

 

[chin311]

LOLZ @ those

 

[speedy2]

How about head design? Throttle Body sizes? Cam profiles? etc. Are you really going to give VTEC all the credit of that power difference? If so, I guess other auto makers have no chance.