Hello group...
I have been thinking of a way to test my car for the benefits, if any, of certain modifications. Because of the expense & the time involved, visiting a dyno before & after every mod is out of the question. What I have come up with is a series of time tests. These time tests are simple & only require purchasing a stopwatch. It takes about 1/2 hour. The concept was tested yesterday with the help of a friend. My friend has a modded 1999 Miata. He autocrosses regularly & is a longtime car guy just like me. We found some minor design flaws & after some tweaking we ironed them out. This test is not “perfect” but works very well to test your modifications. It will also work to compare our cars against others. For now we are not going to worry about temperature & humidity affecting results. I will come up with a temperature “compensating” formula later. Rear end ratio will not considered yet.
The test consists of 3 sets of timed runs that each yield an average time. These 3 average times are what we are going to call the “BASE PERFORMANCE” Most of the human factor has been removed therefore there will not be any shifting or clutch starts. Although this test is designed for standard transmission cars, it should work for “hand shifted” automatics. The test has been designed so that most cars won’t redline or that you won’t have to go over or too far over the speed limit. If your car has a speedometer error it won’t matter in the test against itself….but it will in a test against other cars. Test 1 gives an indication of all-around acceleration. We are going to call this the “Autocross Test” Test 2 is the “Torque Test” Test 3 is the “Horse Power Test” These tests should be performed with a friend. One can’t drive, control the car, watch for traffic, work a stop watch, write down results and drive safely by himself. Besides, if you do it by yourself your results will not compare properly against our results.
I tested my car yesterday & got my “BASE PERFORMANCE” we also tested my buddy’s Miata. Next week end, I plan on doing my valve cover gasket, new ignition cables & spark plugs. I will then perform the BUTT DYNO PLUS test. After the test, I will install a chip & test again. We will then see just how well the BUTT DYNO PLUS test really works.
I have the whole test on one sheet of paper but it wont attach. Follow the directions or your test will NOT be realistic. You are only cheating yourself. If you get a time that is much different than the others just throw it out & do another run. I will add the test to the bottom of this post but the layout gets messed up. If anybody knows how I cansend it as a single sheet let me know. It would not go as a word document or a PDF... too large?
Here are the results of yesterday’s base run tests /1993 318is 5sp/no mods/60’ temp/full tank/copilot/30-32psi tires/speedometer error not noted (will check later with GPS)
AUTOCROSS TEST 7.06 SEC / TORQUE TEST 12.72 SEC / HORSE POWER TEST 10.95 SEC
BUTT DYNO PLUS
1. Copilot to read stop watch. 4. Write down outside air temperature
2. Find a low traffic 1 mile stretch of level road 5. Figure out speedometer error
3. Full tank of gas. 6. Tire pressure 30-32 PSI range
AUTOCROSS TEST (1,500RPM to 45MPH/72KPH) AVERAGE 4 RUNS_______ BASE_______RESULT______
In second gear roll at 1,500 RPM till stabilized. When stabilized at 1,500RPM floor it smoothly. Copilot start stopwatch when he hears accelerator being pushed. Diver just drives & watches out for traffic. Copilot, at 45MPH press stopwatch. You have to perform this test 4 times each way on the “same” road.
Initial direction Time ___________ Time ___________ Time ___________ Time ___________
Opposite direction Time ___________ Time ___________ Time ___________ Time ___________
TORQUE TEST (1,500RPM to 60MPH/96KPH) AVERAGE 4 RUNS________BASE________RESULT________
In second gear roll at 1,500 RPM till stabilized. When stabilized at 1,500RPM floor it smoothly. Copilot start stopwatch when he hears accelerator being pushed. Diver just drives & watches out for traffic. Copilot, at 60MPH press stopwatch. You have to perform this test 4 times each way on the “same” road.
Initial direction Time ___________ Time ___________ Time ___________ Time ___________
Opposite direction Time ___________ Time ___________ Time ___________ Time ___________
HORSE POWER TEST (3,000 To 6,000RPM) AVERAGE 3 RUNS________BASE_________RESULT________
In third gear roll at 3,000 RPM till stabilized. When stabilized at 3,000RPM floor it smoothly. Copilot start stopwatch when he hears accelerator being pushed. Diver just drives & watches out for traffic. Copilot, at 6,000 RPM press stopwatch. You have to perform this test 3 times each way on the “same” road.
Initial direction Time ___________ Time ___________ Time ___________
Opposite direction Time ___________ Time ___________ Time ___________
TEST No._______ DATE________ TEMP_________
MAKE___________MODEL__________ YEAR_______ ENGINE________ REAR END RATIO__________
MODIFICATIONS
Topic: Butt dyno plus (Read 2555 times)