Looking for advice on diff. gears

2easy

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Gents,

Looking for some advice on gearing. 03 srt vert. with minimal mods. (08 exhaust and vipair intake) Reading other posts that seem to lean towards 3.55's for the street as I will never track the car. Future mods will be headers, throttle body, and a program. I was considering the mopar heads but the limited reviews on this add on report way less than the 150 hp claimed. Additionally, can the gears be handled by a weekend know-it all with a wrench like me, or should I throw some coin at it and leave it for the pros?? Your input please-
 
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FrgMstr

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I put 3.55s from PartsRack in my 2005. Best single upgrade I ever made. Car was a lot more driveable. Corsair catbacks with a tune and you could feel the seat of your pants HP.
 

AbsolutHank

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I have 3.55s, and don't plan to really mod other than bolt-ons/headers, and I regret not getting 3.73s.

I've done a few installs myself, but always have the gears setup from a pro. I then take he complete diff unit, reseal and install it to the existing rear diff cover/support brace, and reinstall it
 

AbsolutHank

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They are just a little quicker through the gears, and with the 5th and 6th gear in the Viper, highway cruising is still just fine
 

Sonoman

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Coming from old-school muscle cars with V-8s and 4.11 gears, I really missed the snappy/revvy feel when I drove my Gen III originally. It had what we used to call "freeway gears", and despite all the torque, I just felt like it was loping around all the time in normal driving (not track days). Once I changed the stock 3.08 gears for a Unitrax built ViscoLok with 3.73 ratio, it made the car rev quicker and feel like what I thought a high-performance car should feel like. With 20% lower rear end gears, torque multiplication is up 20% (boosting acceleration in a given gear)-- and you do go through the gears more quickly, so somewhat more shifting. Engine is mostly stock, with K&N/Corsa/DC tune. See the posts by 345s-bspinnin on Gears Vs Speeds Vs. RPM to track how different gear sets will perform.
 

cubican

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Like many others I did the 3;55 on my 03 and it was the wrong choice 3;73 is the way to go on a gen 3, on a gen4 3;55 is the way to go.
 
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FrgMstr

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I would suggest 3.73 in a Gen III is better for a straight line car where the 3.55 gears are going to give you a better experience if you intend to turn the car at speed be it on a track or twisty mountain road. Talk to JonB at PartsRack about it. I have not driven a Gen III with a 3.73 rear end so I am passing along information. But for all you that are saying 3.73, I would like to hear a bit more granularity on your driving experiences, not just cruising to Twin Peaks / ******* experience. :p
 

Viper Specialty

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IMO, I feel that 3.73's are too short for the Viper. Personally, I like the way the 3.07 drives through 1-4, but 5th and 6 are far too tall. I think the best approach is changing 5th and 6th gears- fix whats broken without breaking the rest. Of course, this can be done on Gen-4's... but 3's are not so easy with the T56. Given the lack of options, 3.55's are the most well rounded- but NOT for all applications. Near stock cars are fine, but SC & TT Cars STAY AWAY from gear changes. If you are just wanting the torque so you can "play" with sliding the rear around, have at it... but otherwise, make sure you do your homeworkon your intended application. Gears have both up and downsides.
 
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2easy

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Thanks all for your responses. Great info. It seems the gears of choice are between 3.73 and 3.55s, pending on personal preferance and final vehicle application.
 

Slithr

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Sonoman

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Looking at the charts by 345s-bspinnin, you'll notice that the stock 3.08 gears let the Gen III Viper hit 60.2 mph in first gear at redline. This makes a significant difference in the published 0-60 mph time compared to lower ratio gear sets which require a gear change to hit 60. I'm sure marketing was pushing for the 3.08's, and the small increase in EPA freeway mileage could be another reason, along with suitability for fast race tracks. The twisties here in NorCal are tight and hilly (perfect for a motorcycle!), didn't suit the stock gears IMO.
 

shooter_t1

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Looking at the charts by 345s-bspinnin, you'll notice that the stock 3.08 gears let the Gen III Viper hit 60.2 mph in first gear at redline.


I'm sure marketing was pushing for the 3.08's, .

When did Vipers come with 3.08's ?. Thought stock was 3.07.
 

Twister

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There has never been proof that a gear change will make a viper faster..

Nsx needs gears
Audi r8 v8 needs gears
Gtr hits third gear at 58 mph
Imports or ls1 powered vehicles need gears


When your in a viper with around 500 torque to tne wheels in stock form the last thing you need is steep gearing lol. You need steep gears or torque...having both is just asking for excessive wheelspin.

Not one person has documented proof of a viper being faster in th e quartermile with gears.

John b sold a lot of gears cas he said it feels like an extra 50 hp......well
Im sure in the dark Rosie Perez would still seem pretty hot.

But big diff between what feels like and what is
 

JoelW

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There has never been proof that a gear change will make a viper faster..

Nsx needs gears
Audi r8 v8 needs gears
Gtr hits third gear at 58 mph
Imports or ls1 powered vehicles need gears


When your in a viper with around 500 torque to tne wheels in stock form the last thing you need is steep gearing lol. You need steep gears or torque...having both is just asking for excessive wheelspin.

Not one person has documented proof of a viper being faster in th e quartermile with gears.

John b sold a lot of gears cas he said it feels like an extra 50 hp......well
Im sure in the dark Rosie Perez would still seem pretty hot.

But big diff between what feels like and what is

I'm sure you are right about 1/4 mile times but on the street the 3.55's give me better roll-on than the 3.07's did. You can drive in a higher gear and still accelerate as fast or faster than you could with stock gears. The biggest change is on the interstate. I can run 80 in 6th at a bit less than 2000 rpm. Before 6th gear was basically unusable. I know we could change transmissions to get "real" 5th and 6th gears but the 3.55 rear end works fine for me.
 

Silver04

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Im sure in the dark Rosie Perez would still seem pretty hot.

But big diff between what feels like and what is

Two great statements, Twister!!

I have 3.55s and like Joel, I appreciate them on i-state, as well. Otherwise, would've stayed stock, if I had a choice.
 

FLATOUT

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Two great statements, Twister!!

I have 3.55s and like Joel, I appreciate them on i-state, as well. Otherwise, would've stayed stock, if I had a choice.

This guy is a clown (Twister), please don't ever take his word on anything performance based. Look at 345's spinning data to understand how everything works and to help you make an educated choice.

For a gen 3 with boltons the 3.73's can make up allot of ground in a hurry with these cars. I run 3.73's with a couple small boltons and the car runs very well when compared to others from a roll. I have been extremely happy with the setup and would do it again in a heart beat.
 
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