Why 3.07 gears in the Viper

MuscleJunkie · Nov 2, 2007

Have noticed after reading many posts on the site that some are changing to 3.55 gears and swear it improves gas mileage, etc.

Why did the SRT team decide to use 3.07 gears stock in the Viper?

JKVIPER · Nov 2, 2007

I don't beleive 3.55 gears improve gas mileage.

I had them in my GTS and have the 3.07s in my Coupe.

I don't race, but from a street standpoint, I think the 3.55 gears allowed you to use all the gears more, with the 3.07 you need to be going 70+ to use 6th gear.

redtanrt10 · Nov 2, 2007

There are numerous topics and posts regarding rear gears in the archives, take a look.

Also, I've never heard anyone say the gas mileage improves w/3:55's, it probably drops by 15%.

rcl4668 · Nov 2, 2007

I believe the reason for the stock 3.07 gear selection was fuel economy.

fqberful · Nov 2, 2007

redtanrt10 said:
There are numerous topics and posts regarding rear gears in the archives, take a look.

Also, I've never heard anyone say the gas mileage improves w/3:55's, it probably drops by 15%.

Actually my mileage got better with '06 coupe on the highway and a bit better in town if driven conservatively [well sometimes] because I can actually use 6th and don't have to open the throttle nearly as much to maintain speed. Less throttle, better manifold vacuum, PCM leans out the fuel -- and a side benefit of less noise in the cabin at cruise. Gen I-III are speed/density systems and that's the way they work. But if you go too deep then it will hurt you badly because you're simply turning too many RPM's. Going from 3.07's to 3.55's will raise your 6th gear cruise about 300rpm which is fine.

I believe the reason for the 3.07's is emissions.

MikeR · Nov 2, 2007

I would say its a combo of gas, emmissions and torque. We all know how fun a gear change can be. I think 3:55's would just get more people in trouble and we would have more single car wrecks. Id love to see a better gear ratio from the factory so that it would be warrantied.

Disturbed · Nov 3, 2007

It's a easy fix really, 3.07's are fine if you make about 550rwhp and 600rwtq

DEADEYE · Nov 3, 2007

I think it balances out the low RPM capabilities. It needs to stretch out the gear.

plumcrazy · Nov 3, 2007

id like to find a set of 332 gears. im pretty sure they make them. a local here had them and loved them. said he liked them over the 355's which he also had previously

Chuck 98 RT/10 · Nov 3, 2007

I never understood the complaints about 6th gear. The skip shift puts the car in 4th at idle speeds. Since that is the case then why not pop it into 6th when putzing down the road at 50 or 60mph? I use all the gears all the time. When I'm is "save" mode I put the car in 6th. I downshift when I need the power. JMO.

B767DRIVER · Nov 3, 2007

I'm with Chuck...I use 6th lots of times when above 50-55mph.

Bill Pemberton Woodhouse · Nov 3, 2007

I would agree on alot of points, yet the key reason from talking to engineers over the years, is that the 3.07s are the proper gear for the type of car the Viper is. Many switched to other ratios on the road course and all went back to 3.07s. It worked in the 90s and it works now, and of course the added benefit is better fuel mileage now, but on the track, the torque of the Viper works very well, geared the way it is.

VIPER GTSR 91 · Nov 3, 2007

Bill Pemberton said:
I would agree on alot of points, yet the key reason from talking to engineers over the years, is that the 3.07s are the proper gear for the type of car the Viper is. Many switched to other ratios on the road course and all went back to 3.07s. It worked in the 90s and it works now, and of course the added benefit is better fuel mileage now, but on the track, the torque of the Viper works very well, geared the way it is.

Well said Bill. I changed to the 3:45s and kind of wished I had not as too many shifts on the larger courses.

carguy07 · Nov 3, 2007

I have found that my gas mileage improved when switching to deeper gears on other cars. The reason as mentioned earlier is I was not having to put my foot in the throttle as far to get the same acceleration. It's more about gas mileage vs how you actually drive than ultimate theoretical gas mileage. IMO

JonB · Nov 3, 2007

MuscleJunkie said:
.....Have noticed after reading many posts on the site that some are changing to 3.55 gears and swear it improves gas mileage, etc.........
Why did the SRT team decide to use 3.07 gears stock in the Viper? .......

Many owners report that a 355 allows them to use 6th. Using 6th with a 355 produces better fuel economy than using 5th in 3:07.

Why: Gas Guzzler Tax. The 307 allows SRT to claim a higher hiway fuel economy, and therefore a lower gas guzzler tax. "Im From The Govt. and Im here to HELP You."

Chuck 98 RT/10 · Nov 3, 2007

B767DRIVER said:
I'm with Chuck...I use 6th lots of times when above 50-55mph.

Future member of the 100,000+ mile Viper club. More rpm means more wear and higher heat which increases wear exponentially. I hope to have 500,000 miles on my 98 someday without never having opened the motor.

JonB · Nov 3, 2007

plumcrazy said:
id like to find a set of 332 gears. im pretty sure they make them. a local here had them and loved them. said he liked them over the 355's which he also had previously

We have 3:33 in stock. New, hardened. Not old Buick 331 gears, NEW custom-made Hi-Perf gears.

Nader · Nov 3, 2007

John how much are they going for? What do you think is the cost of an average install?

Big Medicine · Nov 3, 2007

Gears multiply torque. A quick glance at the V10 torque curve should explain why long legs fit in the viper better. It has plenty of torque from low end rpms, so not much need to multiply. Once RPMs come up, the low gears just get in your way and make you shift more.

If you are towing heavy loads through the mountains, they are pretty handy.

Alexarz · Nov 3, 2007

I'm not so sure about that. When I bought my first Viper (2006), I was wondering where the torque was. I have a 454 in my '68 vette and right off of idle it pins me back. I think if I drag raced them, the vette would jump 4 car lengths on the Viper, based on low end torque and gearing. The vette has a 3.70 rear and a tremec TKO600 5 speed. At 3000 rpms the Viper's midrange is impressive but it takes too long to get there. The vette would be long gone. I think if the Viper had lower gears, it would come into the meat of the powerband sooner. Don't forget that with a solid roller cam, the 454 revs to about 6800 rpms, as well. By the way, I have raced a C6Z06 with the '68 and whipped him like a dog.

Hiss · Nov 3, 2007

Nader-I had the 3.55 gear installed in my 2006 and I really like the gear. I had a Dodge Dealer in Louisville Ky put mine in. The labor cost 800-900$. Dodge dealer told me they estimate 9-10 hours of labor.

FE 065 · Nov 3, 2007

I'm picking up my diff with the new 3.55 r&p installed early this week. Labor's about $125.

Same company doing mine that's doing all the Shelby Mustang diffs for Ford/Shelby btw..

Can't wait to put it back in the car !

:2tu:

MuscleJunkie · Nov 4, 2007

Thanks for the info on my question!

dave6666 · Nov 4, 2007

Big Medicine said:
If you are towing heavy loads through the mountains, they are pretty handy.

Could you post an AutoCad file on that bumper hitch? :crazy2:

RichieSRT10 · Nov 4, 2007

The 3.33 is a great gear in my opinion when you have less then 650rwhp. When I went over 800rwhp I had to go back to the 3.07. Friday I went to Ft Lauderdale with Bobby(Disturbed) & I find when cruising over 100mph for a distance the 3.33 is a perfect gear.

Once you get into the higher horsepower numbers there is no need for a different gear.

Doug Levin once told me that the 3.33 was his favorite gear so besides Jon B there are a lot of fans for this set-up

FE 065 · Nov 4, 2007

Doug is probably speaking of s/c set ups-which is what he's around most of the time.

Aside from one's gearing needs for the strip or specific track, I'd think a 3.55 and 3.33 ratio have to be close enough together for most people not to be able to tell or need the difference between the two in general driving.

- My 3.55 gears with 27.5" M/Ts will yield an effective 3.33 ratio right on the dot btw..

:drive:

caseyse · Nov 4, 2007

Big Medicine said:
Once RPMs come up, the low gears just get in your way and make you shift more.

Yes, shorter gears will likely require an additional shift (not good), and if traction is already an issue (as with the high torque V10's), shorter gears are only going to make traction worse. Once you hit your sweet spot in first, the gearing isn't going to make much of a difference, as you're going to remain in your power band for subsequent shifts. Now, if you can't smoke your rubber off the line, then shorter gears might be the ticket.

During the SRT Q&A, I thought they had implied the shorter gears would be better, which didn't make sense to me. For road racing, I see the shorter gears being a disadvantage for the V10.

Roadrunner · Nov 5, 2007

Another big reason for 3.07's was to ensure that 0-60 would be a one gear event... That is what the magazine push so hard as a "core" measure of performance. With 3.55's you have to shift to do your 0-60.

Vipermann · Nov 5, 2007

caseyse said:
Yes, shorter gears will likely require an additional shift (not good), and if traction is already an issue (as with the high torque V10's), shorter gears are only going to make traction worse. Once you hit your sweet spot in first, the gearing isn't going to make much of a difference, as you're going to remain in your power band for subsequent shifts. Now, if you can't smoke your rubber off the line, then shorter gears might be the ticket.

During the SRT Q&A, I thought they had implied the shorter gears would be better, which didn't make sense to me. For road racing, I see the shorter gears being a disadvantage for the V10.

I would say the 3.55s get in the way for road racing, but 3.33s do not. I had 3.45s, and switched them out for 3.33s -- perfect. But make no mistake, the car bogs down under acceleration with the stock 3.07s, which were chosen by Dodge for EPA ratings -- 3.07s are NOT the optimal gear for stock (not S/C) performance.

Viper X · Nov 5, 2007

I've tried 3.55's and 3.45's and gone back to 3.07's in both cases.

The 3.07's work very well on the street if you just add power. Don't get me wrong, 3.55's work great on the street too at lower power levels. They don't seem to hold up as well as 3.07's due to the torque multiplication of the lower gear and resulting wear and tear on the diff. This kinda' depends on how much and how hard you actually drive the car.

3.07's work great on the track. Just this weekend, one of our guys who had a set of 3.33's installed had to shift into 5th in the front straight due to the lower gears and shorter track tires while I could remain in 4th with my 3.07's, much to his disadvantage. His car is going back into the shop to swap back to 3.07's.

Dan :2tu:

Why 3.07 gears in the Viper

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