k20a and k20z

[_CiVIC_]

Just curious to know if the engine configuration of a k20a (dc5r) is the same to the k20z (dc5s) in regards to the intake/ throttle body etc..

This question arises as I'm looking at getting an apexi power intake SRI for it, and they make one for the dc5r, just wondering if it will fit me typeS..

[AMS-89Q]

I'll say this straight out... DO NOT GET SRI(A'PEXi)! It's so f**king crap because, it sucks up all the hot air. Spend a bit more and get an Injen/GruppM/Mugen CAI. I've had A'PEXi and so with another guy i know we both agree it's rubbish. You can pick up an Injen CAI for around 500 - 600 mark if your lucky. NO to SRI, YES to CAI. My 2 CENTS anyways...
oh yeah the a and z are basically the same they both fit straight on.

[marcus]

From the forum of K series engine:

The K20A3 does not have a standard DOHC VTEC valvetrain as we know it from the B-series engines - the K20A3 should actually be called a "DOHC i-VTEC-E" engine, because it uses a VTEC-E cam setup. The K20A2 is the "real" DOHC i-VTEC engine, utilizing the standard DOHC VTEC cam setup we're all familiar with. To help you understand the differences between the K20A2 and K20A3 engines, I've included the following information from a post I made elsewhere:

Allow me to evaluate. Let's start out by defining some terms:

VTEC - Variable valve Timing and lift Electronic Control. At low RPM, a VTEC engine uses a normal cam profile to retain a smooth idle, good fuel economy, and good low-end power delivery. The VTEC mechanism engages a high-lift, long-duration "race" cam profile at a set RPM value (i.e., ~5500RPM on the B16A) to increase high-end power delivery.

VTEC-E - Variable valve Timing and lift Electronic Control for Efficiency. This system isn't really VTEC as we know it. At low RPM, the VTEC-E mechanism 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 a set RPM value (i.e., ~2500RPM in the D16Y5), the VTEC-E mechanism engages the 2nd intake valve, effectively resuming operation as a normal 16-valve engine. Note: in a VTEC-E engine, there are no high-RPM performance cam profiles; this engine is supposed to be tuned for fuel economy, right?

VTC - Variable Timing Control. This is a mechanism attached to the end of the intake camshaft only which acts as a continuously variable cam gear - it automatically adjusts the overlap between the intake and exhaust cams, effectively allowing the engine to have the most ideal amount of valve overlap in all RPM ranges. VTC is active at all RPMs.

i-VTEC - intelligent Variable valve Timing and lift Electronic Control. This is a combination of both the VTEC and the VTC technologies - in other words, i-VTEC = VTEC + VTC. Currently, the only engines that use the i-VTEC system are the DOHC K-series engines.

Now this is where things get tricky - Honda uses the term "DOHC i-VTEC" for two different systems: The first system is used in the K20A2 engine of the RSX Type-S. The second system is used in the K20A3 engine of the Civic Si.

The First System (K20A2):

This system is pretty close to the older DOHC VTEC engines. At low RPM, the K20A2 uses a normal cam profile to retain a smooth idle, good fuel economy, and good low-end power delivery. At 5800RPM, its VTEC mechanism engages a high-lift, long-duration "race" cam profile to increase high-end power delivery. The only difference between this i-VTEC engine and the older VTEC engines is the addition of the VTC system. The intake camshaft has the automatic self-adjusting cam gear which continuously optimizes valve overlap for all RPM ranges.

Here we see an image of the intake cam lobes of the K20A2. Notice there are 3 lobes; the two side lobes are the low-RPM profiles, and the center lobe is the high-lift, long-duration profile which engages at 5800RPM. Basically the same setup as the old VTEC engines we are familiar with.



Now here we see the VTC mechanism - the gear on the end of the intake cam that adjusts valve timing (overlap) automatically on the fly.



This system is used in engines powering the JDM Honda Integra Type-R, Civic Type-R, Accord Euro-R, and the USDM Acura RSX Type-S and TSX.

The Second System (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).

Here is an image showing just how this dual-stage manifold works. On the top, you can see the low-RPM (long) runners are in use, and on the bottom, you can see the high-RPM (short) runners in use.



Myths:

1. The i-VTEC engine engages VTEC gradually, and not suddenly like in the old VTEC engines.

Wrong. The i-VTEC engine "engages VTEC" at a single set RPM, like always. Whoever started this rumor is a ****tard. Read the definitions above.

2. VTC engages at a set RPM.

Wrong. VTC is always activated. Read under "VTC" above.

3. The K20A3 engages VTEC at 5000+ RPM.

Wrong. Technically, there is no "VTEC" (as we think of it) in the K20A3 engine - it uses a VTEC-E technology, which engages at 2200RPM. Read under "The Second Sytem" above

[marcus]

[[ " As Honda clearly stated in this K20A article, iVTEC is VTEC with VTC added. K20A uses a combination of VTEC-E and power-VTEC that switches between 12-valve economy mode and a 16-valve mode with a separate wild intake cam. VTC complements this VTEC variation. For the K20A engine however, outright power is not the sole objective of iVTEC, the other important parameters of fuel economy and emissions has been given equally important footing, a direction that Honda has always promoted in the past. "

"The VTEC mechanism on the intake cam remains essentially the same as those in the current DOHC VTEC engines except for an implementation of VTEC-E for the 'mild' cam." ]]

You can read the below link for a detail illustrated info on the K20 engine.
http://asia.vtec.net/article/k20a/

k20a3 or whatever the civic si uses has a totally different:
1) intake manifold
2) conrod + bearings + piston + camshafts
3) there is no mechanism to operate k20a camshafts should u install it
4) ecu does not handle k20a parts
5) si uses drive by wire and new air mass sensor

Just FYI, the new FD's 2.0 Si is running a K20Z3, similar to the K20A3, only difference is its running on a DBW system and changes to the some parts of the engine.

The engine is indeed a VTEC-E, built for Fuel Economy. Very different from its cousin, the formidable K20A2. Perhaps, some of you bros are thinking of swapping the head... unfortunately... sadly to say, both K20A and K20A3 or the K20Z3 may look similar on the outside, the internals are way different. Some workshop may claimed they can do that... the whole job may cost you few Ks ever to 10s of Ks. Reliability... uncertain.

The FD's K20Z3's DBW will be another big challenge for a lot of workshops, how are you gonna bypass that? Both K20As and K20A3s are drive by the coventional throttle cable. Pretty straight forward. In order to do that... the only way is to change your ECU... and not only that. rewiring the whole dame FD. Haha! Probably, by the time you are don't with the so-called "mod"... it'll sums up to 10 - 15 Ks. Worst still, the power you got cannot even beat a factory made DC5R.

No, Hondata does not work on Auto K20s... sorry man, Honda are only meant for K20A and B-series engines

[integral90]

... it would fit, but get cai

[_CiVIC_]

I'll say this straight out... DO NOT GET SRI(A'PEXi)! It's so f**king crap because, it sucks up all the hot air. Spend a bit more and get an Injen/GruppM/Mugen CAI. I've had A'PEXi and so with another guy i know we both agree it's rubbish. You can pick up an Injen CAI for around 500 - 600 mark if your lucky. NO to SRI, YES to CAI. My 2 CENTS anyways...
oh yeah the a and z are basically the same they both fit straight on.


arghh I just fitted the sri in this morning.... sounds alot better, but no real performance gain :thumbdwn: but i did fit in some piping to get direct cold air in from the front grill..

[FunkyR]

if it's for K20A2 dont get an Apexi SRI....

I've seen 2 seperate dynos of SRI with the *bonnet up* and the lost power....

[_CiVIC_]

fark that sucks... buttttttttt it doesn't feel like a loss of power though.

[integral90]

but if it doesn't feel like a gain either then it was a waste of $$$

[hui]

but if it doesn't feel like a gain either then it was a waste of $$$

you'd still benefit from the sound intake sound though?

[yourfather]

^^^^^^

noise isn't a benefit .

power is a benefit. that's such a rice thing to say. wow, it sounds better, great. doesnt make you go faster.

[timofytit]

What about the K&N Typhoon Intake? Any one know if they are any good?

[_CiVIC_]

I dunno about the K&N typhoon kits... I heard the oil based filters aren't entirely necessary, they work really well on carby motors but dunno about EFI's.. Plus you have to be really careful when oiling up the k&n's, only because if you put too much oil, you can even clogg up your throttle body..

i'd stick with dry based filters :thumbsup:

[locote]

i always thought the DC5R K20a was same as DC5S K20a?????

[_CiVIC_]

i always thought the DC5R K20a was same as DC5S K20a?????


they are very similar in setup, just the engine code is a bit different.. the dc5r has a k20a and the dc5s is a k20z, bit more power out of the S, but who really knows why haha

[locote]

similar code to the new civic sport too hey???

[_CiVIC_]

similar code to the new civic sport too hey???


yup.. the civic sport has the detuned k20z in it :wave:

[aaronng]

yup.. the civic sport has the detuned k20z in it :wave:
No it doesn't. The k20z2 and k20z3 have different head setups. It's not detuned. Detuned means same hardware but with different ECU to change the fuel/ignition maps to produce less power. In the case of the k20z3, the hardware is different. It has more aggressive cams as well as a full 3 lobe i-VTEC system on both intake and exhaust. The k20z2 on the other hand has only a 2 lobe i-vtec on the intake side. So it works in 12v/16v modes while the k20z3 is using all 16 valves all the time.

[aaronng]

they are very similar in setup, just the engine code is a bit different.. the dc5r has a k20a and the dc5s is a k20z, bit more power out of the S, but who really knows why haha
k20z3 has more aggressive cams as well as a different ECU map.

[aaronng]

if it's for K20A2 dont get an Apexi SRI....

I've seen 2 seperate dynos of SRI with the *bonnet up* and the lost power....
Both CAI and SRI sounds better than stock. SRI has better throttle response but less top end while CAI has worse throttle response and a loss of bottom end but more gains at peak power rpm.

[Tofu]

but in reguards to an SRI in the DC5...don't bother
the design of the DC5 engine bay really stuffs up the airflow for any improved performance, despite what dyno figures read. In real life terms, when the weather is hot, the SRI is useless.

I've had Injen SRI and Injen CAI on my DC5...it's night and day difference
the CAI throttle responce is neglectable

[AMS-89Q]

DC5R and perhaps DC5S are designed to be held at high rpms. Hence, you'd rather top end than initial response. If you can afford it get a Mugen CAI very good a bit pricy though but i heard GruppM is just as good but, with a more aggressive sound when the mid and high end rpms. Your choice, NA people have to be picky with mods to maximise power output unlike turbos.

Nice write up Marcus...

[FunkyR]

Mmmm what tofu said...

I went from top fuel power chamber SRI (prob one of the better designed SRIs as it directs the air filter away from the headers and engine) to Gruppe M.... there was soooo much difference it wasnt funny....

[R123]

so informative Marcus!! great work!!!

[Hullabaloo]

Sorry to bring up an old thread, but does anyone know where i can find some information about the difference between the k20z1 and the k20a2?

The closest i've found so far is : http://asia.vtec.net/Engines/K20Z/index.html
But they're the lower power variants and with auto boxes.

[Mst_Mugen]

in terms of motors.. there isnt that great a difference... its more to do with the combination of parts... eg. IM, H, lighter flywheel, lower final drive