On Sun, 23 Feb 2003, at around 07:11:18 local time, Greg Rowe <[EMAIL PROTECTED]> wrote: >>From: "William Davies" <[EMAIL PROTECTED]>
>>There are certainly too many variables to start pulling things apart - only >>calibrate against known measurrements. At the moment both of your >>calibration benchmarks are unknown variables, not a good starting point, > >I didn't see any mention as to whether you were running stock >tires; that could have an effect. Dear All, I bought a new toy this morning, and have been playing with it (and other things) earlier this afternoon. I can now confirm the following: My rev counter is not in need of recalibration - it is certainly much better than width-of-the-needle accurate, according to a Gunson electronic rpm tester. My diff is a standard 3.63:1 UK-spec 1500 diff (18.1/6 turns of the crankshaft pulley for 10 turns of the rear wheel). My tyres are standard (or at least I think this is standard) at 155/80 R13. They are running at manufacturer's specified pressures. This being the case, my speedometer *must* be accurate if it reads 18 mph per 1000 rpm in fourth - is this correct? Have I missed anything? However, I had to tweak the speedo needle by quite a bit to get it to read accurately. Even now, it is only absolutely accurate at around 60-70 mph, with accuracy falling off to about +10% at 30 (i.e., when I'm doing about 1650 rpm in fourth, my speedo reads 33 mph). > Do you have any measured miles >on the highways? I checked my speedometer on one of those once >and is seems to be dead on. The odometer, however is off almost >5%. We have very accurate mileage notices on our motorways - I checked the odometer against a fifty mile stretch of the M5 in Cornwall/Devon last week and found that it was reading about 8.9% low. All this being the case, I believe I can draw two conclusions: The Mazda's speedo is *very* over-optimistic. My speedo/odo drive gear has too few teeth. Am I right?? ATB -- Mike Ellie - 1963 White Herald 1200 Convertible GA125624 CV Connie - 1968 Conifer Herald 1200 Saloon GA237511 DL Carly - 1977 Inca Yellow Spitfire 1500 FH105671 /// [EMAIL PROTECTED] mailing list /// Send admin requests to [EMAIL PROTECTED] /// or try http://www.team.net/cgi-bin/majorcool /// Archives at http://www.team.net/archive /// Send list postings to [EMAIL PROTECTED] /// Edit your replies! If they include this trailer, they will NOT be sent.
