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Discussion Starter · #1 ·
All this talk about all these performance mods.

The ONE mod this car needs is GEARS!!!!!!!

:AR15firin I want my 3.73's!
 

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Wouldn't you just stay in one place spinning the wheels with 3.73's? My car has 2.47 hooked up to 155hp and 4000lbs. 1/4 in 17 seconds at 80mph wooo hooo. I guess 2.47 would have made sense with the non-EPA certified 207hp engine. (just adding this note to throw things in perspective...and no the gears don't make up for the final drive ratio: top speed is achieved 1250rpms before redline.)
 

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Gears would def. help with takeoff, but you'd be running so high RPM's on the interstate your gas mileage would suffer.
 

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5point7 said:
All this talk about all these performance mods.

The ONE mod this car needs is GEARS!!!!!!!

:AR15firin I want my 3.73's!
My math says the SRT has 3.68:1 gear ratio and the C has 3.40:1 axel gears. Tranny's 5th gear is a 0.83:1
 

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Discussion Starter · #6 ·
Ratios in the 300C are 2.82 and in the SRT8 they are 3.06.

The Biggest bang for your buck driving around town is gears - by far. The car will get out of the hole much quicker and into the RPM's. Won't do much for 1/4 times, but it is a lot funner to drive.

As far as mileage and rpm's on the freeway - my experience says it won't change much.
 

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5point7 said:
Ratios in the 300C are 2.82 and in the SRT8 they are 3.06.

The Biggest bang for your buck driving around town is gears - by far. The car will get out of the hole much quicker and into the RPM's. Won't do much for 1/4 times, but it is a lot funner to drive.

As far as mileage and rpm's on the freeway - my experience says it won't change much.
Those numbers are correct but they are "final ratios" after a 0.85:1 5th gear is factored in. For the C is you take the 2.82/0.83=3.40 axle ratio.

Jack the car up, put car in N and count the number of times the drive shaft rotates for 1 rotation of the tire = gear ratio.
 

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bling300c said:
Those numbers are correct but they are "final ratios" after a 0.85:1 5th gear is factored in. For the C is you take the 2.82/0.83=3.40 axle ratio.

Jack the car up, put car in N and count the number of times the drive shaft rotates for 1 rotation of the tire = gear ratio.
Don't forget the effect of the spider gears!
 

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Discussion Starter · #9 ·
blingc -
This has nothing to do with final "axle" ratios, I'm talking about rear end gears. Last time I checked, GEAR ratio was calculated by the number of teeth in the ring/pinion.
 

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5point7 said:
Ratios in the 300C are 2.82 and in the SRT8 they are 3.06.

The Biggest bang for your buck driving around town is gears - by far. The car will get out of the hole much quicker and into the RPM's. Won't do much for 1/4 times, but it is a lot funner to drive.

As far as mileage and rpm's on the freeway - my experience says it won't change much.

The ring and pinion is indeed a 2.82 on the 300C. And by past experience, yes this platform definitely needs a better gear ratio. Getting 4000 lbs out of the gate with this motor is no easy task. The 5.7 litre just does not have enough "bottom end" torque.
On the SRT8 - the tranny gears are the same but they use a 3.06 ring and pinion and the gas mileage is just fine!! I cruise at 75-80 in my SRT8 and easily get 22 mpg on a regular basis.

This car (300C) could easily use 3.23's or even 3.42's and the highway milaege would still be in the range of 20 mpg's. By going to a 3.23 gear the approx drop in the 1/4 mile would be .4 or .5 tenths and easily 3-4 mph trap speed faster. -- That would be a BIG NOTICE in the every day driving of the vehicle!! Now the BIG ?-- Do they make such a Ring and Pinion for this platform???
 

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call jerry or devin at unitrax - www.gounitrax.com

they just need some interest to start selling gears for these cars.

not sure what the engine computer will do once wheel speeds start to vary, but you wont know until you try.
 
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