Quote:
Originally Posted by Davo53209
(Post 121527)
In this post, I'm looking for those who've actually performed an actual D15Z1 engine into a CRX HF, while trying to determine both the actual city and hwy mileage that they've been able to achieved. If you've done this, please chime in. I like many others would like to hear about your results.
So far in my most recent post, I've been told that a realistic expectation could average somewhere in the high 40's for city mileage & somewhere over 60mpg consistently for hwy mileage. 60mpg on the hwy is impressive to say the least; but why such a disparity for city mileage? Is anyone able to confirm this? Given that the CRX HF is significantly lighter than the VX, plus having better aerodynamics, I would have presumed that such a swap would lend the city mpg closer to the mid 50's.
Thank You.
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Hi,
It is not possible for me to say what pure city driving is on my CRX VX because I have never done city driving alone nor have I ever recorded pure highway driving. All records on the CRX VX have been taken with an addition of 33% of the vehicle's weight added during the road tests. My gas log explains. I installed a 12 gallon CRX SI fuel tank that replaces the 10 gallon tank. On one tank of gas, under those conditions, I can drive in excess of 740 miles. This is why it is unrealistic for me to drive that many miles in city driving. I know that many people would say that you can fill up after driving only 50 or 100 miles but I have found large discrepencies in calculation under short driving conditions due to gas pump variations. And, at the mileage my car gets that is only three quarters of a gallon of gas to about a gallon and a half. That leaves large room for error. With the use of the A00 ECU I have never gotten below 55 miles per gallon under any condition. That includes racing other cars. :D
In the future I do plan on making a pure hypermiling trip to see how well I can max out with this vehicle. The reason there aren't any recent posts to my mileage log is because I am in the middle of aero mods so it is not driveable at this time. It has taken a long time because customer cars take precedence over my car.
I've been lax on the CRX VX because I also picked up a 1986 CRX HF and had to refurbish it first. It was in really rough shape. It even required rebuilding of the circuit boards that control some of the fuel management functions. It is a federal version HF and has both a wide-band five wire LAF sensor and a lean-burn feature even though it is carbureted. I know this sounds strange because it sure did to me. But, it is real, and I have an all-around-average MPG of 55. The lowest I've ever seen is 49 (local driving, many cold starts) and this one I did take on an all-out hypermiling trip--250 miles long--and received an awsome 68 mpg. This was with two adults on board. I have experienced in excess of 60 miles per gallon many times with this vehicle. Many of you might wonder why do the VX swap when you can get mileage like this out of a stock CRX HF. The answer is: The VX allows you to have your cake and eat it, too. In other words, with the VX you don't have to suffer the gutless woes of high mileage vehicles. It not only gives you superior over-all average mileage, but it climbs hills and accelerates effortlessly. Additionally there is not large descrepency in mileage due to cold conditions and short distance driving, as there is with a carbureted engine.
A couple of points I would like to make, because I've heard questions in the past regarding these areas: The VX does go into lean-burn in every forward gear. I know this because just by pure accident the installation of an external fuel pump in my CRX VX fuel system notifies me (with a sqwall) when the fuel pump meets the extra resistance of lean-burn conditions. This is evident even when I drive through town in the low load conditions and the D15Z1 engine leans out. The factory Honda service manual also states that the minimum speed requirement is three mph. The other thing I hear a lot is that the D15Z1 is weak on acceleration. I agree with this if you are comparing a Civic SI and a Civic VX in a drag race. But if you are installing a D15Z1 into a 1985 CRX HF, you are installing a 58% higher horsepower rated engine into a 400 lb lighter vehicle than a VX. That's a vehicle with an impressive 19 lbs per horsepower. Many of today's vehicles have much worse ratios and don't get anywhere near the mileage or performance.
My opinion is that the large variation in the advertised city to highway MPG was originally written on the window sticker to cover those individuals that like to accelerate from stop light to stop light in the manner of many teenagers (and some old folks, too).
In researching the CRXs and VXs I found that Honda had many variations of the seemingly "same" vehicle. That leaves a large range of personal experience by all of the different people driving in all of the different regions of this planet. For example: There are Japanese VXs, California early '92 VXs, California late '92 and '93 VXs, California '94 VXs, Federal A00 VXs, Federal A02 VXs, and even more variations on the first gen CRXs and
even additional variations on the 2nd gen CRXs, some of which are alterations in chassis design to meet safety regulations that increased the weight of the vehicle. I hope this helps answer some of your questions.