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Do you have an open differential in your LX/LC car? Do you have the 3.06 Gearing and looking for a bit more? Well, look no further! Speedlogix has the answer for you!!

We have built three kits that will convert your LX/LC car to a LSD and give you three choices in gearing! Using all genuine Mopar parts! These parts can be found on the 09-10 Challenger R/T and SRT8 6 Speed Cars. The 3.06 LSD is found on the 09 Challenger SRT8 as well!



Speedlogix 3.06 LSD Conversion Kit
http://www.speedlogixstore.com/product_p/bmcp-306lsd.htm

This kit is for those that want to keep the 3.06 gearing they have the same, but want to upgrade their open differential to a LSD. This is not the kit for any 2009-10 Challenger SRT8 Automatic owner. This is for 2005-2008 300, Charger, Challenger, or Magnum R/T and SRT8. This will also work for the 2009-10 Challenger R/T Automatic as well.

What this kit gives you is a Limited Slip Differential as well as the new 226MM Half shafts. This would be a good upgrade for those with the 215MM (SRT8 and 09 R/T Challenger) or 210MM (05-08 R/T) half shafts.

Speedlogix 3.73 LSD Conversion Kit
http://www.speedlogixstore.com/product_p/bmcp-373lsd.htm

This kit is for those that want a more aggressive gearing and also want to upgrade their open differential to a LSD. This will have the 3.73 gearing installed in the differential. This is for 2005-2010 300, Charger, Challenger, or Magnum R/T and SRT8.

What this kit gives you is a Limited Slip Differential as well as the new 226MM Half shafts. This would be a good upgrade for those with the 215MM (SRT8 and 09 R/T Challenger) or 210MM (05-08 R/T) half shafts.

Speedlogix Performance 3.92 LSD Conversion Kit
http://www.speedlogixstore.com/product_p/bmcp-392lsd.htm

This kit is for those that want a more aggressive gearing and also want to upgrade their open differential to a LSD. This will have the 3.92 gearing installed in the differential. This is for 2005-2010 300, Charger, Challenger, or Magnum R/T and SRT8.

What this kit gives you is a Limited Slip Differential as well as the new 226MM Half shafts. This would be a good upgrade for those with the 215MM (SRT8 and 09 R/T Challenger) or 210MM (05-08 R/T) half shafts.

Please note for 2008 and below SRT owners!
You will also need to upgrade your driveshaft to the correct driveshaft. Your current driveshaft has a 4 bolt flange on each side, while the Getrag Differential has a three bolt flange. By adding the Driveshaft kit to your purchase you will get a driveshaft that has the 4 bolt flange ono one side for the transmission and the 3 bolt flange on the opposite side for the differential.

Regarding Tuning:
You will need to also tell the car's computer that you have a different gear ratio if you are upgrading to the 3.73 or 3.92 (or 3.06 as well if you are upgrading from a 05-08 5.7L). This can be accomplished using either a Predator or a Trinity. PLease note, failure to tell the computer the correct gearing could result in making your vehicle go into Limp Mode.

Predator:
http://www.speedlogixstore.com/DiabloSport_Predator_5_7_6_1L_Hemi_p/u7135.htm

Trinity:
http://www.speedlogixstore.com/product_p/t-1000.htm

Fluids:
We also have the fluids you will need as well if you would like to order everything all at once.

Friction Modifier:
http://www.speedlogixstore.com/product_p/4318060ab.htm

Rear End Fluid:
http://www.speedlogixstore.com/product_p/5010320aa.htm

If you have any questions, post here, shoot one of the Speedlogix staff a PM or give us a call:
Toll Free (For US): 1.888.SPD.LOGX
Local (For Local US and International): 561.687.3712

Thanks!
 

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Discussion Starter #4
Can you explain the benefits? I know some things but not all.
As far as the gearing choices go, the higher the number, the quicker the car will get off the line. The sacrifice is top speed and mileage.

Here is a bit of information on the Limited Slip Differential

Limited Slip and positraction (posi) differentials are designed to "limit" the tendency of open differential to send power to a wheel that lacks traction and redirect the power to a degree to the other wheel of the axle. The Limited Slip and Positraction differential will send power to both wheels equally when traveling straight, however when one wheel spins due to a lack of traction, the differential will automatically provide torque to the other wheel with traction. Limited Slip and Positraction (posi) differentials limit the loss of torque to a slipping wheel through various mechanisms such as clutches, gears cones, and other methods dependant on the unit. The limited slip and positraction will not provide 100% lock up of the differential in extreme situations such as when a wheel completely looses traction. Limited Slip and Positraction (posi) differentials are recommended for daily driven vehicles and are used in many applications where traction is sometimes needed as in emergency vehicles.

Hope this helps!
 

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what would be the difference in mileage and top speed if going from the stock 210 halfshafts and 2.82 gears of an 07r/t, if you just went to the newer 226 mm halfshafts and 3.06 gearing.
I assume the halfshafts with this kit are from the newer cars and will just give you a stronger halfshaft, but how much better is the 3.06 gearing?
 

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i am in the same boat as Mik3y, I have been hearing for a long time a good all around gear for these cars would be in the 3.06 or 3.23 range. For my application a 3.73 and 3.92 is to much, but if I could be quite a bit better going to a 3.06 with the bigger and better halfshafts and using all mopar oem parts, that would be sweet.
 

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I just bought mine with 3.73 gears. can't wait to put it in.
 

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bmc- dont take this wrong- why such a huge price jump between 3.73 and 3.92? Why is a different ring and pinion tooth count so much more?

thanks.

mpg guys is gonna depend on the driver more than anything.
a little help for you guys on the ratio without stepping on bmc's toes . the ratio is a combo of ring and pinion teeth count. A higher ratio puts more teeth on both the pinion and ring gears thus allowing quicker acceleration but smaller gear length. You will bang through the gears quicker and launch better but the top end will be limited. Honestly i think mathmatically our cars can do 190 with diablo and proper tires but aerodynamically only in the 170's. Now without putting it to paper and doing the math i dont foresee a loss of 20-40 mph from 190, hurting anyone. The people that buy these setups are looking for better traction and good launching (aka track use) where, top speed will never come in to play. If your not going out and hanging with vipers a difference of 170, or 160 for a top speed probably wont matter to anyone.
 

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bmc- dont take this wrong- why such a huge price jump between 3.73 and 3.92? Why is a different ring and pinion tooth count so much more?

thanks.

mpg guys is gonna depend on the driver more than anything.
a little help for you guys on the ratio without stepping on bmc's toes . the ratio is a combo of ring and pinion teeth count. A higher ratio puts more teeth on both the pinion and ring gears thus allowing quicker acceleration but smaller gear length. You will bang through the gears quicker and launch better but the top end will be limited. Honestly i think mathmatically our cars can do 190 with diablo and proper tires but aerodynamically only in the 170's. Now without putting it to paper and doing the math i dont foresee a loss of 20-40 mph from 190, hurting anyone. The people that buy these setups are looking for better traction and good launching (aka track use) where, top speed will never come in to play. If your not going out and hanging with vipers a difference of 170, or 160 for a top speed probably wont matter to anyone.

That is a great question, and the only ones with an answer are the Mopar gods lol...Mopar has set the prices on these systems and for some reason the pricing is much higher for the 3.92's! Trust me we wondered the same thing.
 

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That is a great question, and the only ones with an answer are the Mopar gods lol...Mopar has set the prices on these systems and for some reason the pricing is much higher for the 3.92's! Trust me we wondered the same thing.
so honestly, what are going to be approximate differences all the way around when going from the stock gears in an 07 r/t which i think are 2.82 to 3.06? then to 3.73 and 3.92?
 

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I've had the 373's in since Oct.
With 265/35/22's
60mph is 2200rpm's
80mph is 3000rpm's

With a canned tune and cool weather in Nov. at Atco I ran a personel best.
13.007 and a 1.72 60ft
Previously 13.31 and 1.86 60ft with an RDP tune

BTW wickedchargerrt a Magnum has done 190mph on a standing mile:bigthumb:
 

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Here are some pics of the LSD Kit parts as well as pics of the kit installed in the car, taken from some recent installs we have done.







 

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i am very interested in going this route before working on my engine. but i am still torn between 3.06 or 3.73... any advise?? also i am thinking of purchasing a torque converter. install of these components..would it be the same price? or a separate install?
 

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i am very interested in going this route before working on my engine. but i am still torn between 3.06 or 3.73... any advise?? also i am thinking of purchasing a torque converter. install of these components..would it be the same price? or a separate install?
What other mods have you done to your car and what do you plan for the future?
 

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no mods as of yet... want to do a full exhaust, intake and predator tune.. from there ill see if im satisfied.. thing is doing the rear end is expensive and i rather start with beefing up the tranny rather than go backwards..
 

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no mods as of yet... want to do a full exhaust, intake and predator tune.. from there ill see if im satisfied.. thing is doing the rear end is expensive and i rather start with beefing up the tranny rather than go backwards..
If you plan on staying with mostly bolt ons the 3.73's will certainly give you great low end performance. You will lose some top end speed however, and also lower your mileage a bit. If you plan on doing serious mods like forced induction /stroker I would not suggest the 3.73's as IMO that is too much gear for most folks at that level for a daily driver.

Do you currently have and R/T or SRT? If you have an R/T the step to the 3.06 will be a nice jump over stock.
 
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