Best Gear for Gen IV

[99FRC]

I'm tying to make a decision on what gear I would like to run. My car is mostly street with a 1/4 mile and Texas Mile thrown at it from time to time. I know 3.55 are a popular choice and know about the 5th and 6th trans mod (2010 settings) I would like as much feedback as possible from guys with 3.55, 3.33, 3.73 etc. Let me know the good and bad so I can make the right pick. Thanks for your help!

The car makes 600RWHP and 550rwtq

BTW I like to do 40-160+mph pulls!!!

 

[Sonoman]

One way to pick gearing is to take the max speed the car will pull and work out the ratios for approaching redline in top gear at that speed. A car that is faster in 5th gear than in 6th is not optimally geared (for performance). Obviously as you make changes to the engine this optimum final drive gear ratio changes as well. If you know what your Gen IV's drag-limited top speed is, you can pick a final drive ratio (or 6th gear ratio) to reach that speed just as the horsepower-peak rpm is occurring in 6th gear (a dyno graph helps here). If you plan to improve HP in the future you should go slightly taller in gearing. Guys that don't care about top speed (like me) prefer a lower final drive ratio (higher numerically) to make the car accelerate harder and feel snappier, though the number of gear changes required during driving will go up slightly.

 

[Paul Hawker]

Think a fantastic package for a street Gen IV would be one of the prototype trans with revised 5th and 6th with a 3.33 rear gear. Stronger gears should hold the extra torque

Won't overwhelm traction at higher revs while pulling strongly all the way deep into 6th gear.

Would also be a great open road event package.

 

[99FRC]

Think a fantastic package for a street Gen IV would be one of the prototype trans with revised 5th and 6th with a 3.33 rear gear. Stronger gears should hold the extra torque

Won't overwhelm traction at higher revs while pulling strongly all the way deep into 6th gear.

Would also be a great open road event package.

Didn't think of that...now I got another choice to make

 

[V10lover]

Think a fantastic package for a street Gen IV would be one of the prototype trans with revised 5th and 6th with a 3.33 rear gear. Stronger gears should hold the extra torque

Won't overwhelm traction at higher revs while pulling strongly all the way deep into 6th gear.

Would also be a great open road event package.

THIS!

 

[Hamrhead]

I'm not very interested in super-high speed runs, so 3.55's work well for my '08. Also had them in my '06. I would guess the car is still capable of 175 or so, which is way more than I'll ever need.

The only problem I can see in the '08 is traction in 1st gear - at ~3,800rpm when the cam kicks in, it struggles for traction. (My '06 never had too much of a traction issue with 3.55's) Otherwise, it's much better in slow speed areas such as in-town driving/parking lots, and 6th gear can be used at 55mph.

 

[99FRC]

I'm not very interested in super-high speed runs, so 3.55's work well for my '08. Also had them in my '06. I would guess the car is still capable of 175 or so, which is way more than I'll ever need.

The only problem I can see in the '08 is traction in 1st gear - at ~3,800rpm when the cam kicks in, it struggles for traction. (My '06 never had too much of a traction issue with 3.55's) Otherwise, it's much better in slow speed areas such as in-town driving/parking lots, and 6th gear can be used at 55mph.

What tire do you run...can you hook from a 40 roll?

 

[Hamrhead]

What tire do you run...can you hook from a 40 roll?

Stock PS2. My '08 only has 1,500 miles on it so far.

Hook at 40mph? If I'm in 2nd - Yep, no problem.

 

[99FRC]

Stock PS2. My '08 only has 1,500 miles on it so far.

Hook at 40mph? If I'm in 2nd - Yep, no problem.

Ha...that's what I thought. I think 3.55's will be to much for a 600+rwhp Gen IV. Do you think 3.33 is a good gear?

 

[Hamrhead]

Ha...that's what I thought. I think 3.55's will be to much for a 600+rwhp Gen IV. Do you think 3.33 is a good gear?

Dunno about 3.33's? If it were me, I might keep the stock gearing and see how it works with 600rwhp first.

Keep in mind w/ 3.55's, 1st gear doesn't go much faster than 40mph.(Not exactly sure how fast it'll go in 1st, but 3rd's only good for a bit over 100 )

 

[Viper X]

Keep in mind that as your rear gear ratio goes up numerically, you loose a bit of gear strength.

At 600 rwhp in a Gen IV, I'd stick with the OE 1 - 4 trans and diff gears and change 5th (to .8) and 6th (to .6 or .63) for all around.

FYI, 5th gear was lowered in the 2010, 6th gear was NOT.

If you track your car, there may be some tracks where a 3.33 or even a 3.55 would give you an advantage.

Dan

 

[SoCal Rebell]

Keep in mind that as your rear gear ratio goes up numerically, you loose a bit of gear strength.

At 600 rwhp in a Gen IV, I'd stick with the OE 1 - 4 trans and diff gears and change 5th (to .8) and 6th (to .6 or .63) for all around.

FYI, 5th gear was lowered in the 2010, 6th gear was NOT.

If you track your car, there may be some tracks where a 3.33 or even a 3.55 would give you an advantage.

Dan

Dan when I tracked the '08 ACR at Willow Springs I was able to keep it in 4th and the end of the front straight trapping at about 153 mph. do you think we'd bump off the rev limiter with a 3.33 gear in 4th?

 

[purplesnake]

Love... the 3:55! Did it in both the 05 and now the 08. Courtesy of the fine folks at RPM transmissions, Anderson IN. Of course after their micro-polishing, that made the gear like a piece of dinnerware!

 

[Viper X]

Dan when I tracked the '08 ACR at Willow Springs I was able to keep it in 4th and the end of the front straight trapping at about 153 mph. do you think we'd bump off the rev limiter with a 3.33 gear in 4th?

Haven't run the numbers but yes, I think you would hit the rev limiter with the 3.33's.

I know you would with Hoosier R6's, which are a bit shorter than the OE Cups.

Dan

 

[99FRC]

I love the performance level of the Viper, but I am looking to get as much as I can out of the GEN IV. I don't plan on adding turbos or nitrous (want to keep it NA).
Most of the time the car is used for 40-160 runs...would 3.33's help the performance in this area?

 

[utahviper]

It would hurt you because you would have to change in to 5th to hit 160mph.

I love the performance level of the Viper, but I am looking to get as much as I can out of the GEN IV. I don't plan on adding turbos or nitrous (want to keep it NA).
Most of the time the car is used for 40-160 runs...would 3.33's help the performance in this area?

 

[Viper X]

What Utah said .....

 

[Paul Hawker]

No matter what gear you run, your Viper will still put down the same total amount of torque. This is decided by the engine, not the drive line.

The Rear gear and transmission just breaks the torque thrust up into different size pieces.

You can have short, intensive torque thrusts, or l-o-n-g unbroken smooth torque thrusts.

The short thrusts are more violent, upset the driveline and suspension, but feel terrific and fun. The longer thrusts are not as exciting, but certaintly get the job done, just with less drama.

No magic here. Different gear sets are appropriate for different tracks and situations, as well as driving style.

Overall you do not want to have so much torque mulitplication that it overwhelms your traction or you get violent suspension tramping off the line.

It really depends on your personal preference and performance goals.

Generally as you go up in HP you go down in ratio.

As a side note, the stock 3.07 gear sets seem to be the strongest and quietest. Also run cooler than larger gears.

 

[Boxer12]

I have only run the 3.07 and currently have the 3.55 gear....road racing only. I have 607 rwhp. 5th gear STILL does NOT pull strongly...it changed the car from a 2-3-4 shifter (redlining a hundred yards from the end of back straight) to a 3-4-5 shifter (5th about the flagstand on back straight) and no real advantage in lap times at Mid Ohio which is a medium fast track. I will review some data and let you know about straightaway speeds, corner to corner times, etc., to see where the differences lie. My lap times were nearly identical (1.34's), although it took a while to get back down to where I was due to changed shift points etc. Need to review data to get more technical with it. I think that the added shifting combined with using 5th gear makes it more challenging to get good lap times. Due to this, I think the 3.33 would yield similar results. On shorter tracks like RPM and HPR, I get even more wheelspin coming out of slow corners so that slows me down. So far, not a big fan of the 3.55 for the track...maybe with the new 5th gear. Would be interested to hear from someone with the 3.55/new 5th gear combo. Mid Ohio experience preferred so we can compare apples to apples. If I had to vote without trying all the options, I would say the 3.07 (which isn't an option in the pole) bcz I am not a fan of using 5th gear. I would rather have a more usable 2nd. Just my 2c.

 

[Boxer12]

Here is video of the 3.55 geared car http://vimeo.com/29166380 and here is the 3.07 geared car http://vimeo.com/10880517. This is not exactly apples to apples as the 3.55 geared car also has ported heads/intake for an added 40 rwhp. Anyway, I note an 8 mph loss with the 3.55 on the back straight (due to using 5th gear) and wheelspin coming over Madness and at the entrance to Thunder Valley.

 

[Paul Hawker]

Higher ratio gears usually feel much faster than they are. (and are more fun)

3:07 is usually still the fastest around long road courses, runs cooler, requires less shifting, especially in the corner, better car placement and control.

Think Dodge is on to something with their stock rear gear, and revised 5th and 6th. (Believe better fuel economy with the later engines will allow better performance gearing with less gas guzzler tax expense.

 

[99FRC]

what would be the mph in each gear with 3.33's? I'm adding the Mopar PCM so my rev limiter will be raised to 6500 and I'm running 345-35-19 Invos.

I looking for the best striaght line acceleration 40-160+

 

[RCC]

what would be the mph in each gear with 3.33's? I'm adding the Mopar PCM so my rev limiter will be raised to 6500 and I'm running 345-35-19 Invos.

I looking for the best striaght line acceleration 40-160+

Using this info- and the new 5th and 6th gearing

Axle Ratio 3.33
Redline (RPM) 6500
First Gear 2.66
Second Gear 1.78
Third Gear 1.30
Fourth Gear 1.00
Fifth Gear 0.81
Sixth Gear 0.63

And using a 345/30-19

Results in this-

You must be registered for see images

You can use this calculator to try different ratios-

http://www.f-body.org/gears/

 

[99FRC]

Using this info- and the new 5th and 6th gearing

Axle Ratio 3.33
Redline (RPM) 6500
First Gear 2.66
Second Gear 1.78
Third Gear 1.30
Fourth Gear 1.00
Fifth Gear 0.81
Sixth Gear 0.63

And using a 345/30-19

Results in this-

You must be registered for see images

You can use this calculator to try different ratios-

http://www.f-body.org/gears/

3.33 look like a good meduim...not as aggresive as 3.55's and not as long as the 3.07's

What improvement would I see in the 1/4 with the 3.33? 2-3 tenths?