[Ripple]

OK, let's pretend that I was a goober that fell in love withy the looks of the Challenger, bought one, and didn't ask all of the questions I should have; let's just pretend. The Super Sport Package on my car includes a 3.06 rear axle ratio, what exactly does that mean? Let's also pretend that I am looking for more detail than just a technical explanation, but how this impacts the car and performance.

Thanks for playing.

 

[BPAG]

First, welcome to ChallengerTalk! Second, you chose wisely in my opinion, by going with the SS/T option group on the V6 Rallye.

To answer your question in laymans terms, the 3.06:1 rear axle ratio means your car will accelerate quicker than non-SS/T V6 models, and as a result will get slightly lower fuel economy.

Hope this helps,

 

[kenmer31]

Let me digress from the previous post. I believe you are 180 degrees off. A lower (numerically) axle ratio will give you better mileage and slower acceleration. A higher ratio 3:90 or 4:11 for example will increase acceleration and lower mileage and top speed.

 

[randycat99]

I think you guys are saying the same thing, as the 3.06 axle is shorter than the standard ratio that go on the v6 models (2.- something?). Tbh, the v6 would probably sing with an even shorter ratio than 3.06, but at the expense of effective overdrive ratio that is available on the 5-spd auto. Hence, it is not likely we would see Dodge equip any Challenger with anything beyond 3.06 for the auto's.

 

[proximo]

Hi Ripple and welcome! Everyone else has made good comments on the gearing and I'll add a little more here for you.

The gear ratio is your final gear ratio. 3.06:1 is (what I consider) a "normal" gear ratio. The shorter you get your final gear ratio (e.g. 3.73, 3.91, 4.11, etc) the faster your accelleration curve, but the lower your top end speed will be.

I don't have any correlation between gear ratio and gas consumption, but I would assume the taller your final gear ratio, the better your economy because your engine revs are lower. Dont' quote me on that though ...

You can change out your gearing for other versions for better track performance. Also, your tire sizes will also impact your speed and accelleration as it changes the effective final ratio.

There's a lot of math behind determining which will be best for you. For me, I will be doing a lot of track driving with short straights, so I like having a shorter gear. Cars like those in NASCAR have finals in the 3.5-4.5 range. If you're doing a lot of "normal" driving or long straights where your top speed will be a factor, you want taller gears (note, this is just generally said because there is a lot of factors that affect this).

For the math people out there, don't quote me on these numbers (tire sizes will change these numbers): Say you have a 3.73 final and running in 4th at 60mph -- your engine would rev around 3k-3.1k. If you have a 3.06 final, that same speed your engine would rev around 2.5k-2.7k.

Hopfully I said all that right and hope it's helped add to your information.

 

[sublime 781]

The input or driver gear in a gear train is the gear directly connected to the motor or other power source. Thus the driver is the gear that transmits power to the other gears in the gear train. In a simple 2-gear system, the second gear (the gear which is turned by the driver) is called the output or driven gear. In a gear train consisting of more than 2 gears, the final gear (the gear connected to a wheel axle or other rotating mechanical component) is the output gear.
gear ratio (gr) = (number of teeth on output or driven gear)/(number of teeth on input or driver gear)
If we assume that in the photo the smallest gear is connected to the motor, then it is the driver gear. The somewhat larger gear on the upper left is called an idler gear -- it is not connected directly to either the motor or the output shaft and serves only to transmit power between the input and output gears. There is a third gear in the upper-right corner of the photo. If we assume that gear is connected to the machine's output shaft, it is the output or driven gear.
The idler gear in this particular gear train has 21 teeth and the input gear has 13. Considering for the moment only those two gears, we can regard the idler as the driven gear. Therefore, the gear ratio is driven/driver = 21/13 = ~1.62 or 1.62:1.
The ratio means that the driver gear must make 1.62 revolutions to turn the driven gear 1 revolution. It also means that for every one revolution of the driver, the driven gear has made 1/1.62, or 0.62, revolutions. In practical terms, the larger gear turns more slowly.
Now suppose the third gear in the picture has 42 teeth. The gear ratio between the idler and third gear is thus 42/21, or 2:1, and hence the final gear ratio is 1.62x2=~3.23. For every 3.23 revolutions of the smallest gear, the largest gear turns one revolution, or for every one revolution of the smallest gear, the largest gear turns 0.31 (1/3.23) revolution, a total reduction of about 1:3.23 (Gear Reduction Ratio (GRR) = 1/Gear Ratio (GR)).
Since the intermediate (idler) gear contacts directly both the smaller and the larger gear it can be removed from the calculation, also giving a ratio of 42/13 = ~3.23.
Since the number of teeth is also proportional to the circumference of the gear wheel (the bigger the wheel the more teeth it has) the gear ratio can also be expressed as the relationship between the pitch circles of both wheels (where d is the pitch diameter of the input wheel and D is the pitch diameter of the output wheel):

Pitch circles have diameters that would give the same gear ratio, but with cylindrical surfaces that do not slip.
Since the diameter is equal to twice the radius;

as well.

and so

 

[BPAG]

Let me digress from the previous post. I believe you are 180 degrees off. A lower (numerically) axle ratio will give you better mileage and slower acceleration. A higher ratio 3:90 or 4:11 for example will increase acceleration and lower mileage and top speed.

I was comparing the 3.06:1 ratio to the standard V6 rear axle ratio of 2.65:1. The 3.06:1 gear is the lowest (shortest) rear axle ratio you can get in the V6, so there was no need for me to compare it to the R/T or SRT options.

 

[Carbon Hog]

OK, let's pretend that I was a goober that fell in love withy the looks of the Challenger, bought one, and didn't ask all of the questions I should have; let's just pretend. The Super Sport Package on my car includes a 3.06 rear axle ratio, what exactly does that mean? Let's also pretend that I am looking for more detail than just a technical explanation, but how this impacts the car and performance.

Thanks for playing.[/QUOT



they actually put the 3.06 rear behind the v-6?

i can tell you from my own experience, the 3.06 in my R/T auto won't spin,burn rubber, smoke'em, nuthin.. esp on/off, whatever....zero fun. But it does launch good and delivers killer fuel mileage!

 

[randycat99]

Something is up with your car or the way you drive it then, because you should be able to burn out in 1st gear on an RT until the moon comes out. Other gears, not so much, but that is mostly just the standard M-O for any automatic that is tuned for smoother shifts and long service life.

 

[Carbon Hog]

Something is up with your car or the way you drive it then, because you should be able to burn out in 1st gear on an RT until the moon comes out. Other gears, not so much, but that is mostly just the standard M-O for any automatic that is tuned for smoother shifts and long service life.

i tried the key trick last night, both the esp and bas lites lit...stopped the car and simply flat-foot nailed it in low 1..............................wait for it.............Nuthin!


tried an old school foot brakestand.......................................................


guess what happened?..................................................................Nuthin!


something has to be wrong,,,those 20 inch F 1's should spin right off the rims.


its rather embarrassing to have all the show and no smoke.....But! the car does HAUL!!! i still love IT!!:werd:

 

[polara71]

Yeah, something is not right, with ESP off the tires will spin for days......

 

[randycat99]

That doesn't sound right, at all! I was only speaking in the context of the base oem tire complement (all-season 235's), but I'm sure you should still be able to easily break'em lose on F1's, just as well. You shouldn't even need to do anything special with the traction-control button (technically, enabled-mode should allow a full-streaking burnout as long as you are heading in a straight line...this is a relatively new tidbit of info to me, but it is, indeed, true).

The only obvious exception where burnouts may be unusually elusive is when the weather is very warm and the engine has already taken a heatsoak for the day, after running a while.

 

[Keavdog]

shorter gears help keep the RPMS in the power band of the car also. I had 2.65s in my Charger. I swapped them out for 3.73s and the car is way more perky - accelerates like crazy.

 

[Carbon Hog]

the testing continued...i backed into a dirt driveway to turn the car around on a quiet road....esp/bas still engaged in OFF......nailed the gas to get the tires spinning in the dirt, came out of the driveway spitting dirt until it hit the tar...i figured it would just smoke'em silly................................WRONG!

2 FT rubber patch and off we went.....My Ranger would have done better.

the other night when it was cooler out, my wife DID manage to get it to do two posi spins about 5 ft long, then it wouldn't do any more....Really strange.

 

[Kean]

....really odd. I can break the tires loose on my R/T auto (STP/F1 equipped) with ESP fully on most times on dry pavement. With ESP partially or fully off, it's even easier. ....this is all by simply hitting the go pedal abruptly from a standstill (not doing a brake-stand).

However, I will say I had a hard time breaking the tires loose the first couple thousand miles or so. The car will also (from time to time) "dog" off the line if I get on it but that is probably do to heat soak (like mentioned) or perhaps the adaptive aspects of the vehicle. More times than not, I have no issue getting the tail squirrly.

 

[ptgarcia]

I was comparing the 3.06:1 ratio to the standard V6 rear axle ratio of 2.65:1. The 3.06:1 gear is the lowest (shortest) rear axle ratio you can get in the V6, so there was no need for me to compare it to the R/T or SRT options.

Don't know about the older models but the 2011 SE comes standard with a 2.8-something rear gearset. But I think something in the 3.3 range would be sweet. With the 2.8-something I find the car comfortable cruising at nearly 90 mph (too high!). Something around 3.30 would drop this closer to 80 mph and allow the car to get out of the hole much quicker.

 

[Carbon Hog]

....really odd. I can break the tires loose on my R/T auto (STP/F1 equipped) with ESP fully on most times on dry pavement. With ESP partially or fully off, it's even easier. ....this is all by simply hitting the go pedal abruptly from a standstill (not doing a brake-stand).

However, I will say I had a hard time breaking the tires loose the first couple thousand miles or so. The car will also (from time to time) "dog" off the line if I get on it but that is probably do to heat soak (like mentioned) or perhaps the adaptive aspects of the vehicle. More times than not, I have no issue getting the tail squirrly.

sorry about hi-jacking this thread, didn't mean to, but when i see "3.06" i get jumpy looking for answers.....My car only has 2400 miles on it, i hope it gets better as it ages!!

i will say, from a rolling start, it does surprise!!

 

[Ripple]

Thanks so much for all of your responses!

Sublime 781, I was a Business major, not a math major, but if I am understanding you and the majority right, the 3.06 axle ratio will create greater acceleration in the lower gears and lower RPM's in the higher gears.

Do I have it?

Thanks again to all!

 

[ptgarcia]

Thanks so much for all of your responses!

Sublime 781, I was a Business major, not a math major, but if I am understanding you and the majority right, the 3.06 axle ratio will create greater acceleration in the lower gears and lower RPM's in the higher gears.

Do I have it?

Thanks again to all!

Almost. It will create greater acceleration but the trade off is higher RPM in any gear.

 

[jcurrie]

To reply on the burnouts,,, some R/T cars like my '10 came with what was called Track Pak witch allows you to press the esp button once to fully remove traction control and stability control. Ive heard cars without this option will only remove one of these systems. And your cars computer will step in and apply the brakes if its starts spinning. Heres a vid of someone with a newer evic car then mine,,, maybe it can help you.