Carrera

I know this is probably one hell of a stupid question, but its a question nontheless, and its a question i do not know the answer to so here i go:

How come we cant have some sort of VTEC setup?

Ericy321

you could do it, but for the money and the pain in the ass it would be, turbo would be a better way to go. A lot more manufacturers are using the variable timing now so I wouldnt be surprised to see it on a Hyundai sooner or later

Alex01tib

you guys are crazy, havent you heard of the beta 2 engines with CVVT?

thats hyundais whack at variable valve timing.

Although it wasnt really to make gobs of power, it was for emissions purposes

Sousake Sagara

Vtec is not just a valve timing setup........

It has three different cam lobes per cylinder, at higher RPM a hydralic system engages the larger lobe for that valve giving more lift and duration, hence more power.

"VTEC stands for Variable Timing and Lift Electronic Control System. It was designed to resolve once and for all the usual compromise engine designers have traditionally been forced to make between low-speed torque and high-end horsepower. It lets the engine breathe according to its needs.

Engine breathing is analogous to the breathing of any living organism. At rest, the lungs take in the necessary amount of air for normal function. When running, the lungs and heart work faster to supply more oxygen to the system. Engines can't do that because their breathing apparatus (comprised intake maifolds, intake runners, valves, valve lift and throttle bores) is fixed. Not so with VTEC.

Using an innovative arrangement of three intake and exhaust lobes per cylinder, VTEC increases both valve lift and valve opening duration as the engine climbs through the rpm band. By varying valve lift and timing, the engine can aspirate more air when it needs it at high speed operation. It boosts power without resorting to the complex and sometimes overstressed system of turbocharging or supercharging.It's an elegant and organic solution to a problem that has plagued engine designers for generations, and exemplifies the Acura approach to engineering. Simplicity, elegance and function."

http://www.nsxprime.com/FAQ/Technical/VTEC.htm

Alex01tib

I didnt say vtec was only variable timing, but CVVT is. I also never said CVVT was in the same league as vtec, and i made it quite clear it wasnt for power gaining purposes.

But vtec just makes peak horsepower higher, id rather have something that increases torque

brian01tib

horsepower is a function of torque. I think a sig quote went: "VTEC is like waiting for bad sex"

Alex01tib

Horsepower is a function of torque and RPM, you could have the same torque (or less for that matter) at a higher rpm and still have higher horsepower, which is why the SI civic has 197 hp @ 7800 but the torque peak is only 139, and you still have to rev to 6100 to get it.

You see the horsepower number and your thinking driving it is going to be not too dissimilar to driving a wrx, "hey its only ~20hp less right?" wrong, not only does the wrx get its peak 227 hp at only 6000rpms it has 217 ft*lbs of torque at 4000rpms, which is where the fun starts.

What i was talking about in the last post was a power adder that increases your torque peak as significantly as your horsepower peak...

AS corky bell said 'horsepower sells cars, torque wins races."

Mad-Machine

Honda engines have a lack of torque because they are small stroke engines made to Rev. Torque is directly correlated to how big the stroke to bore ratio is. Large bore, small stroke engines like to rev and do not make much torque.

Having owned a couple of cars with radical high rpm cams (had a vdub that wouldn't even idle below 1500. and when it did it sounded like a harly-davidson, That car had no low end. Give it too much gas too early and it would buck, snort, and spit flame out the carbs.

Basically, VTEC is like having two different cams in your car. a low RPM to allow a smooth idle. low emissions, and easy drivability, and a high lidf/long duration cam to give the engine a screaming high redline and good HP numbers. The best of both worlds.

The only system that comes close is BMW's new double vanos system that has a near infinite valvetiming betweem two parameters. Instead of multiple lobes, it uses variable lifters to alter valve timing and duration. On some euromodels, the valve timing also works as the thottle butterfly. The engine and computer will adjust the timing to limit the amount of air coming into the engine.

There is a reason BMW can make 120hp per litre in their M cars.

Hyundai's system CWT only alters the timing of the intake cam. It does not change the lift or even the duration. It allows for a clean engine at idle and then it slightly advances the timing at higher RPMS for a little better breathing.

Carrera

Well that all makes good sense and all, I was actually expecting someone to call me a newb and shoot me down lol, however, with this CVVT, why cant we use this and some how modify it to be like a vtec, someone said earlier in this post its possible but hella expensive, but everything is expensive so is it worth it or not? I mean in the long run, when you do all the mods you can do, would it matter or no? Not that im saying im anywhere near having a 9 sec tib, if at all possible.... Im just saying, poweradders are fun, if theres a way, itd be interesting to see it happen

Mad-Machine

well, to actually add honda's Vtec would be impossible without redesigning the head and adding a lot of complexity to the wiring harness to enable the honda computer to run it.

Hyundai's system is sort of like an automatically adjusting timing gear.. it just depends on engine speed. Personally, I think you probably could use it with a rather longduration cam and have it retard at idle to allow a semi-smooth idle.

Anybody want to try it?