I've heard that the 2.4L and the 2.0L in the RSX are 12 valve engines at low rpm. That is, 2 exaust and 1 intake valve per cylinder at low rpms.

Is this a function of the i-VTEC? Also, I think I visited a site that said the RSX was a 12 valve engine until 2,200 rpm. If this is the case, how does it impact fuel economy; should I cruise just below this low rpm threshold for optimization?

 

This is so wrong.

 

Please see:

http://www.honda-tech.com/zerothread?id=901865

The following is a quote from that thread:

"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. "

It appears this a "i-VTEC-E" system, not simply "i-VTEC". Thus, its probably not in the TSX. Seems its for the newest Civic's. Interesting though.

But....on: http://www.k-series.com/tech_search....ar=A_TSX_Intro

....it calls the TSX a: Valve Train: 16-Valve DOHC i-VTECÆ
..so I don't know?

 

It looks like what you pasted is a description of the new Civic engine. Is this correct? VTEC-e is a 12 culinder engine at low RPM, for increased swirl in the combustion chamber.

Honda uses the i-VTEC name loosly. The description you posted is not for the TSX, but I can see where the confusion comes from.

 

Wow the new Civic has 12 cylinders? No wonder that Si is getting rave reviews.

 

Hey, it was late....!