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Old 05-03-2009, 07:09 PM   #58 (permalink)
EcoModding Apprentice
Join Date: May 2009
Location: UK
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Rallye - '98 Peugeot 106 Rallye
90 day: 25.75 mpg (US)

Pesos - '96 Toyota Paseo ST
90 day: 39.8 mpg (US)

RX-7 - '94 Mazda RX-7
90 day: 18.68 mpg (US)
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Originally Posted by NachtRitter View Post
The SOHC VTEC-E (as it's called on the VX) works kind of the opposite direction as a typical VTEC... (again, explaining this as I understand it so apologies if I explain it poorly) The VTEC-E minimally opens the 2nd intake valve at low engine speeds to better help mix the air & fuel (and therefore allow leaner burning at those speeds) and then gradually goes to normal 4-valve operation at higher engine speeds (the ECU definitely can still allow lean burn even at the higher engine speeds). On the other hand, the standard (SOHC) VTEC opened the intake valves normally at low engine speeds and then opened them even more at higher engine speeds.

Apparently, there is also a 3-stage VTEC which combines both the economy of the VTEC-E as well as the performance of a SOHC VTEC... but that one was never made available in the US market.
Yep, all that sounds good to me. I've been looking into the VTEC-E engines a lot recently as one of the cars I'm considering replacing mine with is the UK market EK Civic 1.5 LS, which uses the D15Z6 engine and achieves very impressive economy despite the heavier and larger body than the VX that you have. I test drove one recently and it was an interesting drive - the way I naturally drive seemed to result in the "Eco" light being illuminated fairly frequently, so I reckon I could get some impressive figures out of it should I decide to settle on a Civic.

The 3-stage VTEC you mentioned was used in a few of the JDM/Far Eastern market models (D15Z7 engine). It must be an interesting car to drive, assuming the VTEC-E switchover point is at around 2500rpm like the others, and the performance VTEC switchover point is around 5500rpm like it normally is in the high-performance models. Must be a real Jekyll and Hyde car. Unfortunately, I think that engine was only available with a CVT transmission which must take some of the fun and some of the efficiency out of it

Congrats on hitting 50mpg
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