Vtec engines all the details please..

  • Thread starter Thread starter alex_gt
  • 9 comments
  • 931 views
A

alex_gt

Messages
2,123
Just purchased a tasty 98 1.5 ls vtec civic đź‘Ť this weekend for collection next week. Now whilst on test as expected after a certain rpm things got very exciting under the bonnet.

Wondering if some honda enthusiasts/owners or just people who know đź’ˇ could give me the info on how it does it :confused:, what parts of the engine are involved, what difference it makes in the real world driving etc.. oh yea and what is that little econ light mean?
 
Your civic is a '98? I don't recall Honda producing a 1.5 liter engine in 1998, let alone a 1.5 liter engine with VTEC at all. The last 1.5 liter engine Honda used was the D15 that was found in the 92-95 civics.

Anyway, some specific Honda engines have a VTEC system. When the engine reaches a certain RPM (like 5500), a special VTEC valve opens up and the VTEC lobe on the camshaft procedes to increase the amount of fuel coming into the engine. The engine becomes faster at higher RPMs to increase performance while remains normal at lower RPMs to conserve fuel. This is only a basic explanation, although the VTEC system is not that complex.

There is also i-VTEC, something which is kinda different from the traditonal VTEC. Its found on the K-series engines and does not have a set engagement RPM.
 
Essentially you can have a camshaft that is good at making power low in the rev range, or one that is good at making it high in the rev range. With VTEC you get both cams, and the engine switches from the low to high RPM cam once you get past a certain engine speed.

At least that's how the performance oriented VTEC system works. There are Civics with fuel economy ones too, either way the efficiency of the engine is increased, and you get either better fuel mileage or more power.
 
This is someone's sig on another board I'm on:
"VTEC: all of the lag, none of the turbo. It's like waiting for bad sex."
While it's better then nothing, it definatly isn't the best VVT system.
 
Emohawk
While it's better then nothing, it definatly isn't the best VVT system.
Click to expand...

Why do you say that? I recently tested a new Civic Type R and you could definitely feel it working, give it some right foot and when the revs build up it gives you a big kick up the arse.
 
BMW POWER
Why do you say that? I recently tested a new Civic Type R and you could definitely feel it working, give it some right foot and when the revs build up it gives you a big kick up the arse.
Click to expand...
I don't know what they've done with it recently, but last I read it was cam-changing only. This means it only changes when the valves open, not how long (cam-phasing).
Other VVT systems have more cam-changing profiles and the ability to change valve lift and duration. I think BMW's Double VANOS does that, possibly Toyota's VVT-i, and maybe whatever Porsche is using too. (My reference page is down, so I may have just buggered that all up)
 
producepete
Your civic is a '98? I don't recall Honda producing a 1.5 liter engine in 1998, let alone a 1.5 liter engine with VTEC at all. The last 1.5 liter engine Honda used was the D15 that was found in the 92-95 civics.
Click to expand...

All correct - Honda didn't have a 1.5 in 1998.
 

Latest Posts

Back