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Re: Question. Posted by PGAero [Email]  (#1143) [Profile/Gallery]
(more from PGAero) on Mon, 20 Apr 2009 10:48:05
In Reply to: Question., moeman, Fri, 17 Apr 2009 14:36:49 Members do not see ads below this line. - Help Keep This Site Online - Signup |
Here are some numbers on your car (from your email)
Redline in your 2.8 V6: 6500 RPM
Final Drive: 3.53 (Auto)
First Gear Ratio (:1) 4.15
Second Gear Ratio (:1) 2.37
Third Gear Ratio (:1) 1.56
Fourth Gear Ratio (:1) 1.15
Fifth Gear Ratio (:1) 0.86
Sixth Gear Ratio (:1) 0.69
Redline in 1st = 3712 RPM in 2nd
Redline in 2nd = 4278 in 3rd
Redline in 3rd = 4791 in 4th
Redline in 4th = 4861 in 5th
Redline in 5th = 5215 in 6th
1st gear produces 258*3.53*4.51 = 4107 lbs.
2nd produces: 2158
3rd: 1420
4th: 1047
5th: 783
6th: 628
In order for shifting at redline to be a bad thing in first, the torque at redline would have to be below: (258)*2558/4107 = 158 lb*ft
So, shifting at redline in X gear would be goo donly if the torque is below Y
X : Y
1st : 158 lb*ft
2nd : 169 lb*ft
3rd : 190 lb*ft
4th : 193 lb*ft
5th : 207 lb*ft
Although you didn't give me info about the full torque curve on your engine, and I didn't find it quickly with a google search, I'd be willing to bet that you car makes more than 158 lb*ft at redline. I'd also bet that it makes more than 169 lb*ft. How fast does your car go in 2nd or 3rd gear? (6500 RPM /3.53 /2.37 = 777 RPM at the wheel. What are you running, 225/45 R17 = 6.54' per revolution, 777 RPM * 6.54'/rev = 5079'/min = 58 MPH in 2nd +/-, and 3rd = 88 MPH. +/-)
So, in a 0-60 run, depending on how close my calcs are on your tires, you shift either once or twice. If you have to shift twice, then you must actually consider the 2-3 shift, and the limiting factor in torque values becomes the 169 lb*ft figure for 2-3 shifts. I think your car makes more than 169 lb*ft, and redline shift is in order.
I think that JimBlake's assessment is right when he says that any factory car he's seen should be driven to redline. I'd argue that your car is no exception...
Hope this helps,
Peter
'93 9000 Aero, 5spd, 105K
posted by 71.137.213...
_______________________________________ Current: '03 9-5 Aero Wagon, 5spd, Polar/Black Past: '06 9-5 Combi, AT, Polar/Black '04 9-5 Aero Wagon, AT, Nocturne/Granite '03 9-5 Aero Wagon, AT, Steel/Charcoal '00 9-3 Viggen, 5D, Silver/Black '93 9000 Aero, 5MT, Cirrus/Black (Owned this one twice) '86 900 SPG, 5MT, Edwardian/Buffalo Grey
, Fri, 17 Apr 2009 13:11:48, Mon, 20 Apr 2009 10:48:05 <-- Viewing This Message, Mon, 20 Apr 2009 14:03:39, Mon, 20 Apr 2009 10:54:38
, Mon, 20 Apr 2009 09:40:52, Fri, 17 Apr 2009 15:25:50, Wed, 22 Apr 2009 10:10:36, Fri, 17 Apr 2009 12:14:27
, Fri, 17 Apr 2009 06:03:59, Sun, 19 Apr 2009 04:28:17, Sun, 19 Apr 2009 08:58:37, Sat, 18 Apr 2009 17:25:46
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