George, I think the figures that were originally posted pertain to Spiders. They would coincide with the early 4.56 rear end and the later 4.10 rear end.
The GTV6 and Milano were all over the place, with 3.41, 3.55, and 4.10 rear ends. Your GTV6 originally should have had a 4.10 rear end, but IIRC you now have a 3.55 Verde transaxle. That means your actual speed should be higher, not lower, than what's indicated on the speedo. Your stock tire size should have been a 195/60, on a 15x6" wheel. If you've got a wider wheel, I find that a 205/55 is pretty close in size, and works well on a 7" wheel. HTH, bs ________________________________ From: George Graves <[email protected]> To: Carl R. Davis <[email protected]> Cc: "<[email protected]>" <[email protected]> Sent: Mon, November 9, 2009 9:57:22 PM Subject: Re: [alfa] Info to share - Speedo check OK, My GTV-6 speedo says 80 MPH @ ~3600 RPM which is consistent with the 22.14 MPH/1000 rpm (which is what the specs on the GTV-6 says as well). BUT my GPS receiver tells me that when my speedo says that I am doing 80 MPH, and the tach says ~3600 rpm, I'm actually doing only 72 MPH. Since the GPS is going to be more correct than a Veglia speedometer, I tend to believe it over the Alfa instrument. Now, of course, as you say, this is with stock wheels and tires. Now, while my 15 inch wheels are stock, my tires are X50 aspect ratio, and I don't know what the car came with stock. Were they X50, X55 or X60? If they were of a higher aspect ratio, then that would explain the discrepancy between actual speed and indicated speed. Does anyone know what the proper factory tire aspect ratio was for the 86 GTV6 - I'm in the market for new tires and getting the proper ones would be nice. Thanks. George Graves '86 GTV-6 3.0 'S' On Nov 9, 2009, at 3:43 PM, Carl R. Davis wrote: > From Alfa technical service bulletin > > * 1971 - 1979: 19.71 MPH per 1000 RMP (3000 RPM = 60 MPH) > > * 1980 - 1993: 22.14 MPH per 1000 RMP (2700 RPM = 60 MPH) > > > > .. Of course this is with stock wheels and tires. > > > > Carl Davis > > Galena, Illinois, USA > > 750E, 750F, 101.21, 105.57, 115 > -- > to be removed from alfa, see http://www.digest.net/bin/digest-subs.cgi > or email "unsubscribe alfa" to [email protected] -- to be removed from alfa, see http://www.digest.net/bin/digest-subs.cgi or email "unsubscribe alfa" to [email protected] -- to be removed from alfa, see http://www.digest.net/bin/digest-subs.cgi or email "unsubscribe alfa" to [email protected]
