SuperMotors.net Forums
GCUbersoldat
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• Miami, FL, USA |
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• Registered on 11/2/2010 |
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• 2 posts |
• 1 Vehicle
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 Posted:11/5/2010 16:07 |
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Hello everyone, i was wondering whether it would be best to have overdrive on or off during a 1/4 drag race using a 1999 mercury grand marquis thats had some engine mods done to it along with the tranny. any input would be greatly appreciated, thanks  |
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jdmeaux
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• Lafayette, LA, USA |
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• Registered on 1/5/2009 |
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• 525 posts |
• 1 Vehicle
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Posted:11/6/2010 09:18 |
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The 4R70W is an electric/mechanical trans. By turning off the overdrive with the shifter button, you prevent overdrive from happening. However, it is possible to overrev the engine and trans by leaving it off, causing severe internal damage.
Most racers will program the trans for earlier shifter patterns and/or higher shift points. That is what they did with the P71 police versions of the vehicles.
If all you are doing is street racing, re-program the trans for higher shift patterns and earlier downshifts, and leave the overdrive turned on. You usually won't get overdrive to kick in until around 60-70 MPH when you need it.
Of course, this is MHO! 
*******************
PROUD MEMBER of www.crownvic.net
It's just a SUPER-DUTY Mustang GT Sedan. 198K miles and still rolling HARD.
1997 Crown Victoria P71 SVT *** ex-US Marshall service (the CAR)
STOCK?? I bet it was modified. 
13.26 @ 107.24 MPH 1/4 mi w/ me, tools, & full tank of 93 octane
I added CAI, NICHE 19 X 8.5 " wheels with 245/45ZR 19 rubbers, and completely rebuilt the front end with poly bushings, Kooks headers, 2 1/4inch exhaust, TCI 2200-2400 rpm Stall converter
.PLANS:: engine upgrade, 5.4L 2v stroker, rebuild interior in leather w/ buckets, thinking about turbos
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GCUbersoldat
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• Miami, FL, USA |
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• Registered on 11/2/2010 |
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• 2 posts |
• 1 Vehicle
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Posted:11/6/2010 13:18 |
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Would you recommend buying a performance programmer or having a jmod done to the car? i dont have that much experience with transmissions so i am very hesitant on whether to not to try and do the jmod myself |
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