The Difference of vTEC: EP3 Si, Type-S, s2000 and NSX
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The Difference of vTEC: EP3 Si, Type-S, s2000 and NSX Ok, as I learn more about VVT engines and my own (MIVEC), im trying to learn more about vTEC and i-vTEC aswell. My question is, what's the difference of vTEC across these 4 cars? When is the vTEC/i-vTEC cam profile (RPM), do you have videos of the vTEC change over? One of my 7thgen friends told me it's mechanical controlled is that true? MIVEC is oil controlled (a la celica GTS). How effective is a s-afc on these cars? Can you disengage vTEC or change the profile setting? Do you have a dyno of these car (stock) to show the vTEC cam profile switch?
Thanks.
P.S. Please keep this a disscussion topic and not a flamming or rambling thread.
Thanks.
P.S. Please keep this a disscussion topic and not a flamming or rambling thread.
s2k and nsx are the same ...
http://www.hondata.com/techk20general.html <--- k20a2 & k20a3
http://www.leecao.com/honda/vtec/index.html <--- same as s2k, nsx, b series, etc
http://www.hondata.com/techk20general.html <--- k20a2 & k20a3
http://www.leecao.com/honda/vtec/index.html <--- same as s2k, nsx, b series, etc
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vtec high cam profiles are activated by oil pressure. it locks the cam followers/rockers with the high lobe profiles on the cams.
VAFC can be used to not only do air/fuel but also lower/raise vtec engagement point. some SC'd S2000's benefit from a hi-cam crossover as low as 4200rpm.
VAFC can be used to not only do air/fuel but also lower/raise vtec engagement point. some SC'd S2000's benefit from a hi-cam crossover as low as 4200rpm.
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Originally Posted by S2000man01
vtec high cam profiles are activated by oil pressure. it locks the cam followers/rockers with the high lobe profiles on the cams.
VAFC can be used to not only do air/fuel but also lower/raise vtec engagement point. some SC'd S2000's benefit from a hi-cam crossover as low as 4200rpm.
VAFC can be used to not only do air/fuel but also lower/raise vtec engagement point. some SC'd S2000's benefit from a hi-cam crossover as low as 4200rpm.
The Si VTEC is not true VTEC in the traditional sense. It only has 3 cam lobes on the intake camshaft... the exhaust is a "normal" two-lobe profile. Also, the ECU and timing are not optimized for high-end performance but rather fuel economy. The RSX-S is a true tri-lobe VTEC and is as standard as it comes in the performance sense. This motor is comparable to the B18C1 from the Integra GS-R. It is geared for performance, is a true DOHC VTEC and is a horizontally opposed FWD engine. The "I" is a constantly variable cam gear (+/-25º) that will allow then engine to still get consideralbe performance as well as decent gas mileage.
The F20C and F22C from the S2000 is a traditional VTEC motor... it is basically an Integra Type R motor mounted longitudinally. There are variations (and it's very highly tuned from the factory) and hold nothing back as far as performance is concerned.
The C32 from the NSX is a far more complicated beast. It is basically two VTEC 3 cylinder motors welded together. It has 4 camshafts total... two for each side. This allows it the be a V6 that can spin upwards of 8000 RPM. It is still a tri-lobe camshaft for both intake and exhaust... but now there are two sets in the same engine.
Originally Posted by LogicWavelength
The Si VTEC is not true VTEC in the traditional sense. It only has 3 cam lobes on the intake camshaft... the exhaust is a "normal" two-lobe profile.
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Originally Posted by LogicWavelength
To elaborate on S2000man01's explaination... he is correct as to how the camshafts activate VTEC... Here is a breakdown of the cars you listed...
The Si VTEC is not true VTEC in the traditional sense. It only has 3 cam lobes on the intake camshaft... the exhaust is a "normal" two-lobe profile. Also, the ECU and timing are not optimized for high-end performance but rather fuel economy. The RSX-S is a true tri-lobe VTEC and is as standard as it comes in the performance sense. This motor is comparable to the B18C1 from the Integra GS-R. It is geared for performance, is a true DOHC VTEC and is a horizontally opposed FWD engine. The "I" is a constantly variable cam gear (+/-25º) that will allow then engine to still get consideralbe performance as well as decent gas mileage.
The F20C and F22C from the S2000 is a traditional VTEC motor... it is basically an Integra Type R motor mounted longitudinally. There are variations (and it's very highly tuned from the factory) and hold nothing back as far as performance is concerned.
The C32 from the NSX is a far more complicated beast. It is basically two VTEC 3 cylinder motors welded together. It has 4 camshafts total... two for each side. This allows it the be a V6 that can spin upwards of 8000 RPM. It is still a tri-lobe camshaft for both intake and exhaust... but now there are two sets in the same engine.
The Si VTEC is not true VTEC in the traditional sense. It only has 3 cam lobes on the intake camshaft... the exhaust is a "normal" two-lobe profile. Also, the ECU and timing are not optimized for high-end performance but rather fuel economy. The RSX-S is a true tri-lobe VTEC and is as standard as it comes in the performance sense. This motor is comparable to the B18C1 from the Integra GS-R. It is geared for performance, is a true DOHC VTEC and is a horizontally opposed FWD engine. The "I" is a constantly variable cam gear (+/-25º) that will allow then engine to still get consideralbe performance as well as decent gas mileage.
The F20C and F22C from the S2000 is a traditional VTEC motor... it is basically an Integra Type R motor mounted longitudinally. There are variations (and it's very highly tuned from the factory) and hold nothing back as far as performance is concerned.
The C32 from the NSX is a far more complicated beast. It is basically two VTEC 3 cylinder motors welded together. It has 4 camshafts total... two for each side. This allows it the be a V6 that can spin upwards of 8000 RPM. It is still a tri-lobe camshaft for both intake and exhaust... but now there are two sets in the same engine.
just to clarify, the F20C and F22C are the same type of VTEC as an Integra Type R motor. But as for the engine itself, the F20/22C are COMPLETELY different from that of the B18C engines. The F20/22 are a completely new type of engine designed from the ground up.
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Originally Posted by S2000man01
great explination.
just to clarify, the F20C and F22C are the same type of VTEC as an Integra Type R motor. But as for the engine itself, the F20/22C are COMPLETELY different from that of the B18C engines. The F20/22 are a completely new type of engine designed from the ground up.
just to clarify, the F20C and F22C are the same type of VTEC as an Integra Type R motor. But as for the engine itself, the F20/22C are COMPLETELY different from that of the B18C engines. The F20/22 are a completely new type of engine designed from the ground up.
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Originally Posted by HorrorSkopes
Yeah, great info... thanks all.
Quick Q: What about the Si coupe? Is that vTEC comparable to current rsx-s?
Quick Q: What about the Si coupe? Is that vTEC comparable to current rsx-s?
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Originally Posted by S2000man01
The Si coupe is the same VTEC as the S2000 and Integra Type R. The Si HATCH is the same as the RSX-S.
Si Hatch is k20a3. I thought you said its not true vtec like the rsx-s
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Originally Posted by HorrorSkopes
^^^ cool
so, what VVT is better? vTEC or i-VTEC? Doesnt vTEC work on both intake and exhaust and i-VTEC works just intake?
so, what VVT is better? vTEC or i-VTEC? Doesnt vTEC work on both intake and exhaust and i-VTEC works just intake?
k20a2 works on both intake and exhaust i believe. k20a3 vtec doesnt work on exhaust. correct me if im wrong
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Rep Power: 280 to answer QBoi... The Si coupe had a B16 which is similar in technology to the other B-series true VTEC motors. (GS-R, Type R, S2000) The only fake DOHC VTEC motors so far are the 03+ Accord and the Si/base RSX.
Heres a little guideline:
99-00 Si (B16) true VTEC
GS-R (B18) true VTEC
Type R (B18) true VTEC
S2000 (F20C, F22C) true VTEC
02+ Si/base RSX (K20A3) intake only I-VTEC*
RSX-S (K20A2) true I-VTEC*
NSX (C32) true VTEC
* - refer to my previous post where I explain what the "I" stands for.
Heres a little guideline:
99-00 Si (B16) true VTEC
GS-R (B18) true VTEC
Type R (B18) true VTEC
S2000 (F20C, F22C) true VTEC
02+ Si/base RSX (K20A3) intake only I-VTEC*
RSX-S (K20A2) true I-VTEC*
NSX (C32) true VTEC
* - refer to my previous post where I explain what the "I" stands for.
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Rep Power: 400 yeah i meant RSX not RSX-S when I said the Si hatch has ivtec like the RSX. doh! logicwavelength saves the day. 
oooo Indy 500 time!
horrorskopes as for what's better, i-Vtec is probably better. the K20 series engines were derived from the F20C, so it's probably the next step in technology. some day when they discontinue the S2000, it'd be interesting to see if they replace it with an i-Vtec powered beast.
oooo Indy 500 time!
horrorskopes as for what's better, i-Vtec is probably better. the K20 series engines were derived from the F20C, so it's probably the next step in technology. some day when they discontinue the S2000, it'd be interesting to see if they replace it with an i-Vtec powered beast.
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