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i have searched for an answer to this question and did not find anything, so. before i go taking off my valve cover to prove that i think is correct. Please correct me if im wrong here people but the K24Z3 in the 09-14 TSX (mine is a 2010) only has VTEC on the INTAKE camshaft correct? from my own research and findings that's what i have concluded. i just have several friends who work at a "mechanic shop" telling me im wrong/retarded/stupid/don't know what im talking about till they are blue in the face but im pretty sure im right. chime in guys, insert please.
keep reading Hondanews.com to find what you are looking for and print it out and show it to your buddies.
seriously, go straight to the source...Hondanews.com to look for your answer.
then you have proof.
what's the point of hearsay?
Plus, if I have to find it in Hondanews.com FOR YOU, you will owe me 200 million dollars because you are Richie Rich.
LOL I did read the whole article. and im convinced....lol let me give you the picture....im no mechanic....i graduated college with a business degree, but im a big honda guy....my "mechanic" friend who as a two year tech degree from a jr.college and works at a mom and pop shop fixing cars tells me im an idiot and i don't know what the hell im talking about....for me its easy....i go to hondas website and find what i need to know...end of story right? no, lol my friend tells me that:
"both cams have VTEC but only the intake is computer controlled because it can control low end torque. hence advancing and retarding the timing. there are two types of valve timing and you (talking about my tsx) has both and stop trying to read stuff you don't understand"
The 2.4L I-4 engine features Acura’s i-VTEC® "intelligent" valve control system that pairs Variable Valve Timing and Lift Electronic Control (VTEC®) with Variable Timing Control™ (VTC™). A patented VTEC® design uses three reduced-thickness aluminum rocker arms that operate a pair of valves for each cylinder. At low rpm, the intake valves follow low-lift, short duration camshaft profiles to help boost low-end torque. Above 5,000 rpm, the valves are operated by high-lift, long-duration camshaft profiles for maximum high-rpm horsepower.
To further refine the I-4’s operation, the engine features an "intelligent" element that adds Variable Timing Control™ (VTC™) to VTEC® which provides continuously variable, computer controlled camshaft timing. In total, the I-4’s i-VTEC® system provides performance, efficiency and emissions benefits by allowing the intake valve lift and valve timing to be continuously adjusted to suit the engine's operating parameters.
^lol so Honda's engineers are not good enough in print?
richie rich, you owe us!
believe me, it IS good enough for me...i coulden't find a picture of the K24Z3 exhaust cam on the interwebs...im trying to shut my buddy up who thinks he knows everything because he is a "mechanic", who works at a family owned shop, with no ASE certifications or anything....and im the idiot....smh...thank you UTAH for the pic!
my 2010 tsx engine cover does not say I-VTEC or anything on it....besides i took all the covers off after getting my powdercoating done....i hate engine covers....lmao
Iduno if this question has been answered yet....but:
VTEC and iVTEC are both controlled by the computer.
Traditional VTEC usually just means that there are 3 different cam lobes per valve. Two for normal operation, and one large one for high RPM operation. The cam has two different FIXED timing and lift profiles. This technology has been around in Honda vehicles since the late 1980's. Examples of engines with traditional VTEC:
-F20C (S2000)
-B18C (Integra)
-B16A/B (Civic)
-D16Y8 (Civic)
-C30B (NSX)
Note that single cam traditional VTEC engines only have the larger lobes on the intake valves. That's why you can't hear D series VTEC through the exhaust...no matter how much your local rice burglar would like you to believe that you can.
iVTEC means that the car has variable cam phase timing. Meaning that the cam degree is variable. iVTEC cars may or may NOT have the variable valve lift provided by traditional VTEC. But they all have variable cam phase timing. They call this portion of the system VTC. K24's have 25 degrees of VTC movement. K20A2's in RSX-S's and K20Z3's in 06-11 SI's have 50 degrees of VTC movement.
Cam phase movement allows the cam rotate out of its neutral timing by a certain degree. This advances or retards the valve timing in order to more accurately adjust valve timing to get the right overlap...or the lack of overlap, depending on whether the engine is trying to make power or get MPG...and is also RPM dependent.
Some iVTEC cars/engines only have VTC. They do not have variable lift. Examples:
-K20A3 (EP3/RSX base)
-K24A8 (8G? accord)
Some iVTEC engines have both, VTC, AND 3 lobe VTEC. Meaning that the cam phase can change to advance or retard cam timing...and there is a 3rd lobe to create higher valve lift at higher RPM. Examples of engines/cars with iVTEC with 3 lobe VTEC:
The TG TSX definitely has lift cams. You can hear the VTEC cam change over at 6K RPM, clear as day.
VTEC (lift) operation is tangible. You can feel it and you can hear it. The small cam runs out of breath...the power starts to drop...and then the big cam turns on and then engine has enough CFM to make tons of power in the high RPM range.
VTC operation is more seamless. It's going on all the time...constantly changing back and forth. This is advantageous because now the engine can maximize the potential of whichever cam profile it is on...whether the cam profile changes or not. So you can't hear or really feel a sudden change in VTC.
The 3 lobe operation should be on both cams since it's a DOHC engine. DOHC engines have always had 3 lobe VTEC on BOTH cams (if the engine came with 3 lobe VTEC at all).
Again...single cam engines only have the VTEC operation affecting the intake valves' lift.
iVTEC means that the car has variable cam phase timing. Meaning that the cam degree is variable. iVTEC cars may or may NOT have the variable valve lift provided by traditional VTEC. But they all have variable cam phase timing. They call this portion of the system VTC. K24's have 25 degrees of VTC movement. K20A2's in RSX-S's and K20Z3's in 06-11 SI's have 50 degrees of VTC movement.
Just in case you were not aware. The VTC's in our 2G TSX's are blessed with 45 degrees of advancement capability.. This is some great info in pretty much all your posts! You really know your Hondas, on an almost scary level..
Last edited by Jaheri_cbp; 04-30-2015 at 01:27 AM.
Just in case you were not aware. The VTC's in our 2G TSX's are blessed with 45 degrees of advancement capability.. This is some great info in pretty much all your posts! You really know your Hondas, on an almost scary level..
Ha! Didn't know Z3's had 45 degrees of movement. Thats awesome. Weird that they don't make a lot more power and torque compared to the A2. Maybe because of the crazy exhaust manifold design. Be nice to see a stock Z3 dyno graph.
The Z3 makes more low end torque. This is masked by naively looking at peak HP/TQ figures. In that case of peak power, the A2 and Z3 are more or less on par.
The 3 lobe operation should be on both cams since it's a DOHC engine. DOHC engines have always had 3 lobe VTEC on BOTH cams (if the engine came with 3 lobe VTEC at all).
Again...single cam engines only have the VTEC operation affecting the intake valves' lift.
k24z3 and z7 both only have 3 lobe operation on the intake camshaft. The exhaust is a single lobe.
The pictures are from the other day when I swapped valve cover gasket.
There's a picture of the turbo that people wanted to see so badly.
There it is. a turbo... strapped on the head.
Not only is it only a single lobe, it's only a single lobe driving both valves.
Last edited by optimusaccord; 05-05-2015 at 12:05 AM.
The Z3 is a strange engine. It looks like engine management and design has gotten good enough that stock 2.4's can make 200+ hp and good torque and good MPG without having 2 sets of lobes on each cam.
Maybe the weird exhaust "manifold" design can't handle the flow from a larger exhaust cam? Or maybe it's designed in a way to not need it.
Still though...I wonder how much power the Z3 would have been able to make with a normal header design and a 3 lobe exhaust cam.....
Real performance engines still have individual exhaust ports.
If you search google for white papers on integrated exhaust manifolds, the primary driving force is regs/emissions (IE the government), the close coupled cat reaches operating temps much faster. Some secondary benefits are minor weight savings, packaging and number of parts (IE cheaper).
Thus, the season became an endless mediation between two strategies: run at full steam and risk having the integrated exhaust manifold melt its casings, or turn down the wick and try to jog to a slow finish. It was a negotiation where no one won—literally.
...
cars that now feature reengineered cylinder heads. It's a departure from the stock piece, with the exhaust manifold moved to the outside of the engine and all water passages rerouted.
GM's just announced LT1 camaro and corvette also both still have individual exhaust ports and separate exhaust manifolds. The camaro even has a nice tuned header.
02-06-2014, 08:43 AM
please.
