The "Sporty Accord" is back!

[Andyman]

I just figured out what my password was and logged in. Here is what it says at the top of my screen:

Welcome, Andyman.
Last online: 08-26-2013 at 03:18 AM

It's been over two years.

My car the Sporty Accord (1988 Honda Accord LX-i) was in a friend's garage for about six years. I was trying to conserve money by avoiding car insurance. I traveled mostly by bicycle. Then my friend told me he needed me to get my car out of the garage.

I put a good battery in it and it started up with really old gasoline. Unfortunately the alternator was stuck. I took it out and turned it with a wrench and then a drill. A lot of rusty powder came out and then it turned fine. I put it back and it worked. I also needed to fix a rim leak with some sealant. That worked fine too. I'm still having some other problems now that I'm driving it on the roads.

1) Sometimes when the engine is warm it resists cranking. I think the ignition timing might be too advanced. I also hear some knocking during acceleration.

2) The starter solenoid failed and I only get a "click" sound when I turn the key. I can start it by turning on the key and connecting a jumper cable from the positive battery terminal to the small solenoid terminal (through an alligator clip jumper wire) and then the motor terminal (through a wrench). I fixed it once by removing the starter and turning the contact terminal (connected to the battery) to a new position. It worked about ten times and then went back to clicking. I don't think the solenoid is meant to be disassembled. I might have to buy a new one.

3) When I hit a bump in the road, a warning beeper and light comes on to warn about a door not closed. I can shut it off by hitting the driver's door.

4) Something is rattling near the right front wheel. I think it is a strut mount.

Other than that, it is running well. It rolls very easily. I know I can fix the minor problems. Now I hope I can keep up with the insurance payments. It's about $800 per half year in New York City. I chose Safeco insurance. Most other companies wanted much more. I think they don't like old cars.

[MobilOne]

Would it be cheaper to rent a car in NYC when you really need one?

[Andyman]

It probably would be cheaper if I occasionally rent a car but I feel a lot more free to do what I want if I use my own car. Around here I see cars from Zipcar and Car2go. From the web sites I see that it costs at least $9.25 per hour (Zipcar Mon - Thurs). I have never rented a car. I use bikes, trains and buses. I bought a used trailer to connect to my bicycle but I don't have the proper hitch parts so it disconnects if I carry heavy things.

I'm hoping that having the car will allow me to earn more money by getting to some more distant jobs and carrying things (like tools) that would be too large or heavy to carry by bicycle. I think the insurance cost might go down if I keep my record free of accidents and violations.

[Andyman]

I just wrote some paragraphs in a Quick Reply box but it all got deleted when it said that I was not logged in. Apparently that is what happens if someone takes too long to write a reply. It would be a good idea to use a copy command to save the text before using the "Post Quick Reply" button.

Briefly, what I said is that I fixed a check engine light problem by tightening the coolant temperature sensor connector and retarded the ignition timing a bit to stop the knocking. I still need to fix the starter motor and sometimes the engine stalls.

I want to modify the automatic transmission so it will engage the torque converter clutch at 25 mph (in third gear) instead of 48 mph in fourth gear only. I need to find a hydraulic diagram to understand how it works.

[Andyman]

I found the hydraulic diagram for the 1989 Honda Accord transaxle. On this page from 3geez.com there is a message from HLW on 12/13/2013 which has a link to the PDF file of the manual.
http://www.3geez.com/forum/3geez-acc...updated-4.html

There is a description of the "Lock-up clutch" starting on page 15-7 and then on page 15-17 there is a hydraulic diagram of five valves that control the lockup clutch and a description of how they work. I still don't completely understand it.

I was playing with some formulas to calculate horsepower requirement and potential MPG at different speeds for my car. This is the result:

=================
Drag and MPG calculated for 1988 Honda Accord notchback coupe

mph hp (aero) hp (rolling) drag hp mpg if bsfc=0.5 lb/hp-hr
10 0.05 1.2 1.25 100
20 0.4 2.4 2.8 89.3
30 1.2 3.6 4.8 78.1
40 2.9 4.8 7.7 64.9
50 5.6 6 11.6 53.9
60 9.7 7.2 16.9 44.4
70 15.4 8.4 23.8 36.8
80 22.9 9.6 32.5 30.8
90 32.7 10.8 43.5 25.9
100 44.8 12 56.8 22.0
110 59.6 13.2 72.8 18.9
120 77.4 14.4 91.8 16.3
130 98.4 15.6 114.0 14.25
140 122.9 16.8 139.7 12.5
150 151.2 18 169.2 11.1

assumptions:

frontal area: 21 square feet
Cd: 0.32
loaded weight: 3000 lb.
rolling resistance coefficient: 0.015
BSFC: 0.5 lb/hp-hr
fuel density: 6.25 lb./gal
aerodynamic drag calculated using
http://gtechprosupport.com/support/AeroDragCalc.htm
=========================

These numbers might be close to being accurate if using a manual transmission and pulse and glide driving. After making this chart I discovered the Ecomodder tool to make a similar chart. Just click "Tools" on the menu.

For steady speed driving with my automatic transmission I estimated these results:

gear mpg speed range (mph)
1 11.25 0 - 12
2 19 12 - 22
3 27.5 22 - 32
4 40.33 32 - 48
4L 48.4 48 - 65

For this chart I'm assuming that the engine has a light load and the fuel flow is about 25% of full throttle flow. This might be close to accurate for the first three gears. For fourth gear and fourth gear with lockup the engine load is greater and the actual mpg will probably be lower unless I'm drafting a truck. Here is a formula I'm using:

mpg=4*v1k/d

v1k: mph at 1000 rpm
d: engine displacement in Liters

To take into account torque converter slip I multiplied the theoretical speed at 1000 rpm by 10/12 (0.833). This is about the usual slip for my car at low engine speeds. This formula seems to give good results for most V8 powered cars even at highway speeds up to 60 mph. It might not be accurate for unusual engines. To estimate the fuel economy at full throttle you can eliminate the 4x multiplier like this:

mpg(full throttle)=v1k/d

Sorry for the bad formatting. The tab characters don't seem to line things up except when the message is in the editing window. If you copy the chart and paste it into Notepad it will look better.

[Andyman]

I thought that the formula for full throttle fuel economy that I gave in the last message (mpg(full throttle)=v1k/d) gave results that were a little low so I did some more calculations. I remembered reading that one pound of gasoline makes 210 cubic feet of air and fuel mixture. From that I was able to calculate that one gallon of gasoline makes 2,268,000 cubic inches of mixture.

6.25 lb/gal x 210 cubic feet/lb x 1728 cubic inches/cubic foot
= 2,268,000 cubic inches

A one liter engine running at 1000 rpm at 100% VE (volumetric efficiency) would consume 1,830,000 cubic inches of fuel mixture each hour.

1 Liter x 1000 rpm x 61 cubic inches/liter x 60 min/hr x 0.5 intake strokes/rev
= 1,830,000 cubic inches of fuel mixture per hour

So a 1 liter engine running at 1000 rpm with 100% volumetric efficiency should use
1,830,000 cubic inches/hr / 2,268,000 cubic inches/gal
= 0.807 gal/hr

So the proper formula for full throttle mpg should be

mpg = v1k/(d x 0.807)
or
mpg(full throttle) = 1.24 x v1k / d

This assumes normal atmospheric pressure at sea level, normal temperature about 70 degrees Fahrenheit, and plain gasoline without alcohol and a chemically correct fuel mixture (14.7 parts air to 1 part fuel). The original formula might be close to correct if using a rich fuel mixture (about 12.5 to 1) and 10% ethanol mixed with the gasoline.

The formula I made for constant speed fuel economy (mpg=4*v1k/d) would imply a volumetric efficiency of 31%. If you think your car can cruise with the engine running at 25% VE (maybe you have a high compression engine) you can use this formula:

mpg = 4.96 x v1k / d