Which Getrag

[Bright White R/T 1]

hey all...

my vehicle is a 2012 Challenger RT with the Super Track Pack and the 3.92 limited slip Getrag differential.

I have recently stroked the motor from 345in^3 to 392in^3 and added a 2.9 Whipple.

I'm learning that the 3.92 is too low of a ratio for what I want to do for the amount of torque and power that I am now producing.

After lots of number crunching and investigating, I'm at the point where I feel like a 3.55 rear end ratio will work better for me than a 3.92 or 3.73.

When I look at different websites to acquire a new ring and pinion they list H198, H210, H215, H226, etc.

I am guessing that 198 is 198mm ring dia, 210 is 210mm ring dia, etc.....

My question.... how do I know or determine which I have in my 2012 R/T 3.92 Getrag?

thanks-

rich

[70Barracuda 25]

You have a 226 mm getrag rear. All manual transmission R/T's came with the 226 mm LSD getrag rear, only differences were the one's with 18" rims got 3.73's and the one's with 20" rims came with 3.92's.

[kbr577 5]

The Getrag's are 226, except the one's in the Hellcats, which are bigger 228 or 230mm I forgot, which wont fit without the hole H cat cradle.

[BayouTiger 88]

Should be an H226. I tried the 3.50 in my 9" and didn't like the results and went to a 3.70. The 3.92 and blower is a bit of a pain on the street.

Erik is THE MAN when it comes to the Getrag. Might want to reach out to him (Hemi31). From everything I've heard the original Richmond 3.55's were noisy as hell, but I've also heard that since Motive has bought them they have gotten better. Be prepared! the 3.55 is certainly more manageable on the street, but it does take a lot of the fun out of it. We only did it because we needed more top end at the mile as the 3.92 maxi out at in high 180's in 5th. Make sure you think about your goal before changing.

[70Barracuda 25]

The Getrag's are 226, except the one's in the Hellcats, which are bigger 228 or 300mm I forgot, which wont fit without the hole H cat cradle.

Starting in 2015 rear went to 230 mm LSD.

[kbr577 5]

Starting in 2015 rear went to 230 mm LSD.

That's right.

[Bright White R/T 1]

Should be an H226. I tried the 3.50 in my 9" and didn't like the results and went to a 3.70. The 3.92 and blower is a bit of a pain on the street.

I hear what you are saying.... with the 392 and blower I spin the tires off the line at the drag strip entirely through first gear regardless of tire pressure. (hoosier drag slicks 28x10/17)

Second gear is too tall and launches in second gear kill the 60' and ET....

When i do the math, it seems like the 5% difference between 3.73 and 3.92 isn't enough.... but the 10% difference between 3:55 and 3:92 will get me more inline with what I hope to accomplish..... not spinning completely in 1st gear on the launch and slightly faster ET and speed through the traps.....

would like to hear your thoughts...

rich

[nascarpat24 4]

3.23 ratio is another option.

[El Diablo 72]

3.23 ratio is another option.

In a 6 spd car, maybe for running the standing mile races but that's stretching it.

[nascarpat24 4]

your right I did not see 6 speed trans.

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[BayouTiger 88]

The differences between the relatively minor ratio changes are more dramatic that you would think. I believe 3.23 would take the life out of the car to a great degree. If you've got major HP you can make the 3.55's work. I'm guessing you're in the 675-700 ballpark and that might be on the lower edge for that gear.

Another option might be to look at the gearing in the tranny. I think Craig had his rebuilt using the gear sets from the CTS'V and was happier with them. If you do the GearClac chart, the gearing on the Tremec makes perfect sense, but add the blower and first and second can be hard to live with.

Getting the car to hook is certainly a challenge with a blower, but I've seen guys nearly lift the wheels with a 4.11 and the Hoosiers. 1.6 60ft's are repeatable with some practice. (Not me, I'm a 1.8-2.0 guy, but I make one pass a year or so).

I guess the main thing would be your goals. I can tell you that the 3.92 is perfect for the mile up to 180, but you ain't going far beyond that unless you move the limiter up.

[Bright White R/T 1]

The differences between the relatively minor ratio changes are more dramatic that you would think. I believe 3.23 would take the life out of the car to a great degree. If you've got major HP you can make the 3.55's work. I'm guessing you're in the 675-700 ballpark and that might be on the lower edge for that gear.

Another option might be to look at the gearing in the tranny. I think Craig had his rebuilt using the gear sets from the CTS'V and was happier with them. If you do the GearClac chart, the gearing on the Tremec makes perfect sense, but add the blower and first and second can be hard to live with.

Getting the car to hook is certainly a challenge with a blower, but I've seen guys nearly lift the wheels with a 4.11 and the Hoosiers. 1.6 60ft's are repeatable with some practice. (Not me, I'm a 1.8-2.0 guy, but I make one pass a year or so).

I guess the main thing would be your goals. I can tell you that the 3.92 is perfect for the mile up to 180, but you ain't going far beyond that unless you move the limiter up.

My first thought was regearing the the trans to ratios similar to the '13&up GT500...... 2.66:1 first gear, 1.82:1 second gear, 1.3:1 third etc vs the current 2.97:1 first and 2.10:1 second, 1.46:1 third .... I think the GT500 gearing is very similar to the CTS-V but I've never regeared a trans...I've rebuilt and re-geared rear ends... so that's why I started leaning toward the 3:55 rear end......

When you multiply the current trans ratios by (3.55/3.92) the resulting effective ratios (between the trans and the rear end) are very similar to those in the GT500/CTS-V with my current 3.92 rear end.....

yes.... my current power is right at 700 rwhp....

[Blue Blur 45]

I have a Gen 3 Viper Trans in my car with 3.91 Gears and 26" tires. It's the bomb IMO, it uses the 2.66 1st gear set but is .75 5th and .50 6th. It is way more capable than I have the balls in a 1972 Dart.