Tirod

I recently bought the 3rd issue of TPR (Tuner Performance Reports) Magazine and I love it... They explain parts of the engine and upgrades easier than anything I've read so far. Anyways, after reading this issue I had to see what was in previous issue, so I got on their site (www.tprmag.com). The feature last issue was camshafts. Of course that's not the entire magazine but from what I see, the only thing on their site from last issue. At the end of the article he explained the advantage of VTEC. Here's that explanation:

"VTEC: Powerband Optimizer

Many bad explanations of the VTEC advantage have been given in the past. The advantage is simple: VTEC allows the engine to perform as if the cams were switched to a different profile at a set rpm. The low profile can optimize idle, meet emissions and provide good bottom-end torque. The high-profile lifts the valves higher and opens the valves longer to improve power at higher rpms.

VTEC does not allow for higher peak power to be made. If a set of non-VTEC cams were ground to match the VTEC high-lobe profile the same power would be made. However, the Non-VTEC cam would not have near the performance of the VTEC cam at lower rpms. Driveability, fuel efficiency and idle quality would all suffer.

The end performance result of VTEC technology is an engine that has an incredible broad powerband." - Michael Ferrara

and there it is, thought I'd share (for archived re-direction of riceb0is) and thought I'd advertise this awesome magazine that has grown from a quarterly print to a bi-monthly print by the 3rd issue. Good Job TPR!!

g2tegls

like duh

b00gers

who didnt know that/???? :thinking: h:

More&Faster

ya i hear a lot of misconceptions about vtec. some people think its like a turbo

a good friend of mine's mom owns an rsx and he trys to explain vtec to her by telling her its made to rev high and blah blah blah. basically he has no understanding of it.

its just like tirod said, its just two cam lobes, one optimized for low rps, and one optimized for high rpms. in my eyes, its a great system, specially for sports cars since it allows a small light engine to drive in a civilized way at low rpms, and still make power at high rpms. whenever people say stuff like 'vtec engines are great but they make no torque' i just get steamed. vtec engines are made for torque. so i took a second to illustrate how it works. this is the torque band of a non-vtec engine vs a vtec engine, with both lobes illustrated.

ideally the peak torques should be the same for all three lines, and the overall torque for the vtec lobes combined is more than the non-vtec.

S2Kev

Vtec engines rev high and thats where these small displacement engines make torque....at high rpms.

Tirod

re-read up top... the purpose of VTEC is not high revs, those come from honda's intelligence in putting together engines.. VTEC is there so that during normal everyday driving, you maximize on fuel efficiency and emissions while still providing enough low end tq.. when you're racing or utilizing higher rpms, the engine turns into a high rpm performer...

S2Kev

I'm just saying they rev high. I never said the purpose of vtec is high revs. Actually all Honda engines rev high. h:

Tirod

:chuckles: werd..

TPR also help me understand Rotoray engines, header[s], A/F, Venom's new nitrous kit, and such... its the best tuner mag i've read...

Dekz

Ok, here is a question that's been bothering me for a while.

What is the difference between an engine with VTEC and any other DOHC engine?

Tirod

re-read above :thumbup: and where they say take a cam with the non vtec profiles the same as vtec and the low end be notchy... tune down the entire range... less fuel economy at low rpms and less power at high rpms.. vtec utilizes the opposite (cause you just cant have both :chuckles: )