Why doesn't Honda put v-tec in their racing quad? My friend who's into cars says that v-tec is some solenoid thing that boosts motor performance. When I'm in his car, I can definitly feel the boost it gives. So why can't Honda put this in their performance quads?

 

Cost and complexity most likely.

I would figure if that technology was efficient overall for use in our market, that Honda would have included it in the design of the CRF450 engine. Or even the CBR line for that matter.

I know from owning an EFI quad myself that all those electrical componets add up to some serious weight.
What's a few horsepower by running a trick EFI and valve timing system if you end up with the same power to weight ratio you started with because you have all the extra weight??

I could be wrong and Honda introduce some exotic engine tomorrow, but that's my theory anyway as to why they haven't used it....
Yet anyway. [img]i/expressions/face-icon-small-tongue.gif[/img]

 

i may be wrong but i do believe that the V-tec is a high performance version of a honda 4cyl motor. its more than just one certain performance part.

 

i think v-tec is the variable valve timing system. It uses a solenoid that routes oil pressure to an auxiliary valve rocker that has the ability to open sooner the more oil pressure it gets. It helps boost the low end power of a 4-cylinder car engine, makes it so you dont have to wind them up so much trying to pick up speed.

 

pretty sure its Variable Valve Timing and Electronic Lift Control

Not sure if it would have a use on a utility quad, but it might on a racing quad someday.

Just like quicksilver said, it isn't to make a low RPM engine perform better at high RPM, but the other way around. It's to make a high rpm engine with radical cam grind able to perform down low by giving it another set of low RPM lobes.

 

It works well on cars, but they are fuel injected, since you need a computer to tell the v-tech solenoid to engage and to change the fuel maps to match, quads would also have to become fuel injected first. I dunno how effective it would be on a quad engine anyway, they dont rev out as high and already have alot of low end torque.

 

how does this low end thing work..on my friends 02 civic vtec doesnt kick in til 4500 rpm, revving til 7k rmp...and his computer is stock.

 

I'm not sure I'd say it isn't working until then, but the more aggressively profiled high rpm lobes aren't taking over until a certain rpm. Below that you just feel more power than you would if the cam was running on those lobes throughout the RPM range.

oh yeah, rather than me copying something down trying to sound like I designed it, read this

http://world.honda.com/history/chall...989vtecengine/

and this

http://world.honda.com/motorcycle-technology/vtec/


I have to say though, the last 500cc GP 2 stokes were 200 horsepower

 

propout is on par with what he said about vtec. I have a 91 crx that i swapped a dual cam (b16A1) into. Its vtec as well, it kicks in at 5200 rpm and pulls hard till 7250. It simply is the cams opening more.

 

VTEC is used in more than just Honda inline 4's.

Honda and Acura V6's are VTEC, (including the NSX) and the VFR motorcycles have VTEC with their V4's.


The CBR's dont have VTEC simply because they are a little heavier than the competition already.
(the benifits wouldnt be worth the weight gain/loss of handling)