10-12-2007, 08:20 AM
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Correct RPM V Roadspeed? S4 Spider Please some quick advice
Sorry for such a banal question but can anybody out there who has a stock S4 Spider please tell me approx what RPM you are showing at 80mph? I used the very good thread (on this forum) to adjust my Tacho and just want to make sure it is close. At 80mph I am now showing 4100 rpm. Is that about what it should be?
PPS-to everyone with all the advice thanks you VERY much. I managed to fix the VVT issue and the entire flat spot issue on my S4. The low idle was in fact (I believe) an incorrect reading tacho!
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10-12-2007, 08:35 AM
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Join Date: Sep 2006
Location: Sharonville/Cincinnati Ohio
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 Quote:
Originally Posted by f512tr
Sorry for such a banal question but can anybody out there who has a stock S4 Spider please tell me approx what RPM you are showing at 80mph? I used the very good thread (on this forum) to adjust my Tacho and just want to make sure it is close. At 80mph I am now showing 4100 rpm. Is that about what it should be?
PPS-to everyone with all the advice thanks you VERY much. I managed to fix the VVT issue and the entire flat spot issue on my S4. The low idle was in fact (I believe) an incorrect reading tacho!
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 1990 Alfa Camaro Spider Super Sport Special American/Italian Edition. Pizza Burner with Pizzaz!
1974 Chevrolet Camaro
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10-12-2007, 05:13 PM
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But Mad North-Northwest
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Join Date: Sep 2003
Location: SF Bay Area, CA
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S4 Spider should be 22.14 MPH per 1000 RPM in 5th (Alfa TSB 40.93.03), so at 80 it should be ~3600 with stock tires as Douglas said. Did you set your tach using a digital tachometer and test it in the higher ranges? If so I'd get a GPS and verify the speedo accuracy.
How'd you end up fixing the VVT issue?
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Tom
1991 Spider
1987 Milano Gold
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10-12-2007, 07:36 PM
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Not sure if it adds to a significant difference, but if the S4 has the phonedial alloys, the stock size is 195/60 x 15. The starfish Campys are 185/70 x 14 if the S4 was not a Veloce model.
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-DMAC
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10-12-2007, 09:22 PM
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Quote:
Originally Posted by DMAC
Not sure if it adds to a significant difference, but if the S4 has the phonedial alloys, the stock size is 195/60 x 15. The starfish Campys are 185/70 x 14 if the S4 was not a Veloce model.
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1990 Alfa Camaro Spider Super Sport Special American/Italian Edition. Pizza Burner with Pizzaz!
1974 Chevrolet Camaro
Last edited by ddouglas77; 10-12-2007 at 11:26 PM.
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10-13-2007, 01:21 AM
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Quote:
Originally Posted by ddouglas77
With the car in 5th gear, 185/70R14 tires and a 4.11:1 rear end, your RPM should have been: 3594.900684123614
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Quote:
Originally Posted by ddouglas77
If he has the those tires, they are a little smaller in diameter and 80mph would put his car at 3609.7556456282577RPM
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Seems that your numbers would be affected a few zillionths by tire wear.
Could you please recalculate based upon the actual diameter of the tires .
Maybe you could do a detailed ANALysis taking into account each 0.001 of tire wear.
Thanks for your efforts. Details like this are so important, especially considering Alfa tachometers are known to be so accurate. 
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10-13-2007, 04:00 AM
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Thanks for the advice guys. My car has the original wheels, only ones offered on S4 here in the UK. I think they are what you call the phone dials. 3500/3600 is what I wanted, thats close enough anyway to tell me I need to adjust the back of the tacho again! Thanks for all the help.
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10-14-2007, 08:33 AM
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DDDouglas, if you could be more precise
Thanks man, this is great
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1992 Alfa Spider Green with Tan interior 
1989 Porsche 930S RUF 2008 Honda CRV EXL Green Tea with Grey Leather
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10-14-2007, 08:35 AM
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Quote:
Originally Posted by porsche935
DDDouglas, if you could be more precise
Thanks man, this is great
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__________________
1990 Alfa Camaro Spider Super Sport Special American/Italian Edition. Pizza Burner with Pizzaz!
1974 Chevrolet Camaro
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