Which engine: D16A6 or B16A would be considered more fuel efficient in 'normal' driving conditions?

 

D16 since it is SOHC

 

my b16a can get up to 33 mpg and as low as 20 mpg it all depends on how much time you spend over 5krpms and in what gears heh

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 4Banger69 &raquo;</TD></TR><TR><TD CLASS="quote">D16 since it is SOHC</TD></TR></TABLE>

Number of cams has nothing to do with fuel economy. But now that we are on the subject, my B16A did quite a bit better on gas than my D16A6 did (about 33MPG highway vs 29MPG highway). But there is a catch: the B16A requires premium fuel.

 

Once I hit 5,000 RPM (VTEC) on my B16a gas sucks like crazy. My old D16a6 was far better in fuel economy with the same amount of driving

 

my zc dohc get about 40 mpg hw about 33 street ohc really doesnt change it

 

Based on personal experience....years ago when upgrading from a stock D16A6 to a DOHC ZC, i picked up mileage. I think the twin cam engine was able to get up to speed easier than the sohc resulting in better consumption.

 

More power= More gas.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 4Banger69 &raquo;</TD></TR><TR><TD CLASS="quote">D16 since it is SOHC</TD></TR></TABLE>

lol

Dohcs usually are more efficient. Especially if its variable timing.

 

My a6 used to get 30-34 mpg freeway.
My ZC w/ same Si tranny would get 38-40 mpg freeway
My B18b w/y1-LS 5th tranny gets 40-42(and even 46 once) mpg freeway

I can speculate why dohc gets better mpg, but I don't have any concrete answers. One of the biggest influences of mpg is driving style. I don't have to flail the dohc as hard to get up to speed so I think that helps. The dohc is supposed to flow better at higher rpms. Maybe this would be
help at freeway speeds. A lot of people claim the sohc is better around town...I just know what I've experienced on the freeway

 

Also keep in mind that the primitive electronics used by stock SOHC motors don't help fuel economy. If you are running 1992+ electronics, fuel economy will benefit.

 

D16 all the way.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by StorminMatt &raquo;</TD></TR><TR><TD CLASS="quote">Number of cams has nothing to do with fuel economy. But now that we are on the subject, my B16A did quite a bit better on gas than my D16A6 did (about 33MPG highway vs 29MPG highway). But there is a catch: the B16A requires premium fuel.</TD></TR></TABLE>



I thought for sure my MPG would drop when I did my B16 swap but, to the contrary, it went up.

side note: I was already burning premium fuel in my mini-me setup so that wasn't a factor for me

 

more mpg. another great reason to get a b16A setup

 

hate to say it but there is probably more efficiency in the DOHCs due to them having a larger head period. more room for air to flow through i guess.
but i dont think anyone could possibly say for certain.
i mean i would love to challange any b swapped motor CRX with a CRX HF for best fuel economy

 

Engine wise, there are a number of things that will effect mileage... VE efficiency at cruise RPM, friction loss, gearing, compression ratio, engine condition and state of tune, etc. If you were going for all out mileage, a VX motor will yield better mileage than a b16a, its 8 valve at cruise, lean burn, and has a 9.6:1 compression ratio, as well as tall gearing.. all which help achieve higher mileage.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NastyHabitzCRX &raquo;</TD></TR><TR><TD CLASS="quote">
i mean i would love to challange any b swapped motor CRX with a CRX HF for best fuel economy </TD></TR></TABLE>

Put a 5000 rpm rev limiter, a throttle cap at 50% open and skinny 13" tires on a B16 and it might be interesting

 

Then you could never go over 100mph... bah

 

...because 100+ mph would be the best way to practice fuel efficiency?

 

No need to lower the rev limiter, just drive sane.

 

just also depends on driving style

 

A USDM D16A6 probably would have a lot more miles on it vs. a swap.

 

my d16a6/z6 mini me gets 38 but I run premium.

 

This really depends a lot on the transmission. The D-series have tall gearing thus lower rpms at highway speeds. I think both engines under normal condtions will get the same gas mileage with the same tranny.

 

Fuel economy based just on engine setups goes like this.

Load, duty cycle, rpms, powerband.

-The heavier the foot, the more gas. This is plain and simple.
-The larger the injectors/bigger fuel curve, uses more gas. Even at the same load bigger inj/fuel map will use more fuel.
-Higher rpms use more gas. More duty cycles per min = more fuel.
-Depending where your at in your powerband at cruising gear can affect gas mileage. Making significantly more power at slightly higher rpms uses less fuel.

Plus you have to factor in mileage on the motor but we'll assume this is irrelevant.

My dohc zc got 33-35 all around, in my heavy 4dr ex.