Has anyone given any serious thought to changing the rear end to a 3.91 or 4.11 to sacrifice some top speed for low end insanity?
Rear end gear change
- Thread starter Kirby Vieira
- Start date
davefordgt
GT Owner
- Feb 10, 2006
- 302
once you mod the car you wish you had taller gears. i can spin 1st 2nd and 3rd gear. if i had 4.11's then the car would be useless. you can already run in the 10's with it.
AZGT
GT Owner
I brought up the topic before. Here is the link.
http://www.fordgtforum.com/forums/showthread.php?t=765
I would still opt for a lower ratio if it was available - hardly ever get to 6th. Around 3:90 would be wonderful. I think it would be a little more fun to be able to go through the gears without hitting 100+ on the 2 - 3 shift.
http://www.fordgtforum.com/forums/showthread.php?t=765
I would still opt for a lower ratio if it was available - hardly ever get to 6th. Around 3:90 would be wonderful. I think it would be a little more fun to be able to go through the gears without hitting 100+ on the 2 - 3 shift.
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Still my only complaint about the car's performance ... it is just not geared for the street. And remember to include rear tire diameter in any calculations ... those large diameters are not your friend for acceleration. I rarely leave third gear driving on the street :thumbsdow
What's the optimum rear gear? Don't know ... but my test is simple : I want to be able to stand on it in second and smoke those big meats :biggrin
What's the optimum rear gear? Don't know ... but my test is simple : I want to be able to stand on it in second and smoke those big meats :biggrin
Stock it could have probably lived with something that spins through the first 3 gears faster, but at that power level, I'll trade tractability for minimal acceleration gains. My Z06 has 3.90s and the 422c.i makes the car useless on hard street rubber. Spinning the tires at 1/2 throttle anywhere under 50mph gets old real quick. I'm sure 3.55's would be fine, or a 3.73 gear.
DBK, if I may ....DBK said:
What are the gear ratios in your Z06? And rear tire diameter? And motor torque? Sorry for the thousand questions ... I'd be interested in calculating the force at the road/tire interface in your Z06 in second gear, for example. And then we have to include the weight on the rear tires, to include the normal force ... to see why you're so prone to spinning.
It's my firm conviction that given : the purely marketing-driven need to get the GT to 60 mph in first, which, when including tire diameter as well as gear ratios, results in pitiful street gearing, plus the weight on the rear tires of a mid-engine vs. front engine car, that the GT is pretty far from a annoying wheel-spinning problem in second gear ... at least, in stock form.
Please take no offense ... not to be disagreeable, but I maintain that this car doesn't need more torque (or power) ... it just needs better gears! I'm only using half the gears in my transmission :frown
I think the best upgrade for the car (for ultimate acceleration on street tires) would be to change the 5th and 6th gear ratios. With a better ratio for these 2 gears you could get much more linear acceleration changing from 4th-5th, and 6th gear will actually be usable. Since most people will not see over 200mph, I would rather sacrifice some top end speed for blazing and linear acceleration in the 140-200mph range.
This worked wonders on a Viper. We lowered top end acceleration times by 3+ seconds.
This worked wonders on a Viper. We lowered top end acceleration times by 3+ seconds.
californiacuda
GT Owner
- Oct 21, 2005
- 919
If the rear tire diameter was reduced by 2". what would the rear end ratio become? Maybe this would be an inexpensive way to accomplish what is being discussed. Then if the front and rear were lowered a bit, maybe it would look ok?
yes ... reducing tire diameter has the same effect as shorter gearing. The rear tire diameter is 28.84", and the rear gear is 3.36:1. So a 2" reduction in tire diameter equates to about a 3.61:1 rear end gear.californiacuda said:
But lowering the car by 1" ... ?? Might at least be worth playing around, see how she feels :thumbsup
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AZGT
GT Owner
californiacuda said:
Just a quick calculation, but it looks like to get to an effective 3:93 (which I figure technically is ideal based on readings I did) would take about a 6 inch change. 2" looks like about a 3:55.
Six inches - can we say low rider :lol
MAD IN NC
Proud Owner/ BOD blah bla
Joe - one of these days I hope to mod my car to experience what you have with yours.... You're blazing a path that many are following....
Keep going! :cheers
Keep going! :cheers