Quote:
Originally Posted by Mista Bone
VX in lean burn VTEC-E like the CX and HF are all 8 valve motors. With the smaller intake ports and runners as well are needed to keep air veolcity up because the engine is designed to operate in a lower powerband.
With a true 16 Honda, the "sweet spot" where the engine is happiest (PT BSFC) is at a higher rpm. I found it to be 2800-3200 rpm. Below 2800 rpm the engine more throttle input was needed to get up the hills. With Honda ECU's (OBD-1 and older) when you go below 10" of vacuum then engine mapping is more performance oriented. On flat ground I would be cruising at 15-16".....
Old Mech, are you old enough (I'm 47) to remember when you could play with the ignition timing? Add 2-4 degrees base timing as well and lighten the springs so the weights added timing at lower rpm, then tweak the vacuum advance canister????
Well I did all that with the help of a friends who tunes ECU's.
Here is a stock timing map....
Here is one with more timing, esp under light throttle, 11-14" vacuum
Also add that stock base timing was 16 BTDC and I was at 22 BTDC + the extra timing via the ECU.
The nice thing, that ECU tune was smog friendly enough to pass VX ULEV standards. I'll have to dig up that EPA printout.
Mind you this was all in 2000-2005 timeframe. 53 mpg on pure gas including two dyno pulls.
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You quoted us but didn't answer our questions.
I understand that you believe the motor has sweet spots and more gas will be used to get up a hill with a taller final drive, when compared with the same exact car and a lower final drive. But, how would a higher final drive return less mileage overall than the same exact car with a lower final drive? After all, we aren’t driving uphill everywhere we go. There are downhills that will help average out the uphills. We can clearly see by EPA ratings that a VX does better than a regular Civic. Even the personally added mpg’s are high with the VX.
I was not sure of your intent, but you are on an auto enthusiast forum. I think you'll find on here age isn't necessarily a factor in automotive knowledge. I am younger than you and have a timing light hanging on my wall in the garage. I know how a distributor works, to include mechanical and vacuum advance. Why did you only address Old Mechanic in a post with both of us quoted?