i have an 03 sir, and i have been redlining it and stuff lately but i cant hear my vtec cut in or anything like that. I drove my friends prelude and i could definetly hear it. wudup with that? Is there anything i can do to my car to get it revving to around 8000rpm and atleast hear the vtec cut in, because thats the whole fun part about driving these cars.
if yout talking about a new civic they really don't come with vtec. The version of vtec basically only operates the enging at 12 valves and at 2200rpm all the valves open to make it a 16 valve engine.
Mods: Determined to bring home the car that finally put a smile on my face like no other has...
someone posted about this a while ago. just because you cant hear it doesnt mean its not there. vtec is always "on" even in the preludes and such. it doesnt turn on... it just alternates lobes. between low and high rpm for fuel economy and power (respectively)
i took this passage from www.howstuffworks.com : "VTEC (which stands for Variable Valve Timing and Lift Electronic Control) is an electronic and mechanical system in some Honda engines that allows the engine to effectively have multiple camshafts. As the engine moves into different rpm ranges, the engine's computer can activate alternate lobes on the camshaft and change the cam's timing. In this way, the engine gets the best features of low-speed and high-speed camshafts in the same engine."
Mods: Determined to bring home the car that finally put a smile on my face like no other has...
also... they say that in the o2+ Si you normally cant hear the vtec switch lobes. maybe if you convert to the rsx type-S (not sure what exactly you need to change for this conversion) you might be able to hear the vtec "kick in" but ive never driven an rsx so i dont know about that. i - VTEC is a tad different from the older VTEC
Mods: H&R Springs, Short Shifter, CAI, Magnaflow exhaust, Iridium Plugs, NGK Wires, GSR Computer, Wheels, Power-adding Blue Engine Paint
Good point...my bad for not thinkin about the year of his civic
it's my understanding that on the newer hondas it's more of a progressive vtec, that it work in two stages, intake side then exhaust. Correct me if I'm wrong, but that's my understanding as to why th vtec isn't as abrupt as it is on most of the engines up to 2001 or so.
Mods: H&R Springs, Short Shifter, CAI, Magnaflow exhaust, Iridium Plugs, NGK Wires, GSR Computer, Wheels, Power-adding Blue Engine Paint
the new si (sir in canada)?
Nice little cars...I hated em but they drive well. Fairly tight, and I like where they put the shifter, even tho at first I thought i wouldn't get used to it.
(K20A3):
This system does not really conform to the "DOHC i-VTEC" nomenclature, as Honda would like us to believe. As I mentioned in my previous post, it actually should be called "i-VTEC-E," because it uses a VTEC-E mechanism rather than a standard VTEC mechanism. At low RPM, the VTEC-E system effectively forces the engine to operate as a 12-valve engine - one of the intake valves does not open fully, thus decreasing fuel consumption. At 2200RPM, the VTEC-E system engages the 2nd intake valve, effectively resuming operation as a normal 16-valve engine. There are no high-RPM performance cam profiles; this engine is tuned to balance fuel economy and power, rather than provide pure performance. On the intake cam, there is the VTC mechanism which basically is an automatic self-adjusting cam gear used to continuously optimize the valve overlap for all RPM ranges. This being a VTEC-E system - and not a true DOHC VTEC system - is the reason the K20A3 redlines at a measly 6800RPM, while the K20A2 is able to rev all the way to 7900RPM.
Here we see an image of the intake cam lobes of the K20A3. Notice there are only 2 lobes - there is a nearly round one used only for the low-RPM disabled intake valve, and then there is the regular lobe used by the other valve at low-RPM and by both valves at high-RPM:
This system is used in engines powering the USDM Acura RSX base, Honda Civic Si, Accord 4-cylinder, CRV, and Element.
Special note: The K20A3 engine used in the Acura RSX base has a slightly different intake manifold design from the K20A3 engine used in the Civic Si. The RSX engine uses a dual-stage manifold, similar in concept to the manifold of the B18C1 in the old Integra GSR. It uses long intake runners at low-RPM to retain low end power, and switches at 4700RPM to a set of shorter intake runners to enhance high-end torque. This accounts for the extra 9 ft-lb of torque in the RSX (141 ft-lb, vs. 132 ft-lb in the Civic Si).
Like you said you can hear it on your friends prelude because i guess you can say it has high output vtec while as stated above your engine doesn't have a high cam profile at higher engine rpm's.
At first i didnt like it, but once i started driving it is very fun, and i love my car. Which is better to go with the aem short ram, or cold air? thanks for all the good info guys.
Linear Mode
