Review 3 07 or 3 73 or 4 10 final gears What are the differences

[Aevus]

Before I start, just a little context:

I have a Gen 3 with all the bolt-ons and tune, 494lbs of torque @ 4,300rpm (at the wheels) and all set of final gears were tested with 355-30-19 Kumho ACR tires.

Like many of us, I've been guided by JonB's (very convincing) article about gears:

http://www.viperpartsrack.com/gears-...al-dana-quaife

So, here I am. After a year of testing 3 different gears. From the stock 3.07 to the somewhat crazy 4.10.

Like anything, there is no black or white answer. It depends on many variables. That being said, i'll be short on the 3.07 topic: it sucks. It sucks almost as bad as the f*&* stock tie-rods. They had their reasons to put that into that car, of course, but that was downright stupid. The 6th speed is absolutely useless, and the 5th is not even fun to use. It's a big no. I wouldve put 3.33 as stock, at least. But we won't rewrite history here, won't we?

So, let's talk about 3.73. Or should I say 3.55? Yeah, because 3.55 seems to be the go-to. Never tried the 3.55. I sure can imagine, though ;-)
I jumped right to 3.73. I remember that I felt ''adventurous'' doing that bold move (lol). Well, I almost instantly regretted once installed. I remember saying to myself ''whatttt, that's it ?!?''.

Don't get me wrong, though: 3.73, it IS a major improvement over stock gears. It IS fun. But very very far from the dangerous-snake-that-will-bite-your-ass kinda feel I was warned about. Keep in mind that between 3.55 and 3.73, it's only a difference of 5% or so. So going to 3.73 probably won't make you hate your car, compared to 3.55... Both are probably decent choices for less than 500lbs torque at the wheels, with stock diff and 300TW tires.

Which brings me to the 4.10 gears.

Most probably NOT a wise choice with stock diff and not-so-sticky tires. If you have more than 500lbs of torque at the wheels and/or doubtful about your driving skills, just don't. I wouldnt even touch 3.91.

But. Yeah, there's a but, you saw that coming didnt you?

IF you made the diff upgrade, Wavetrac as I did or Quaife... And IF you have sticky 200TW tires... And IF you have 500lbs-ish of torque at the wheels (or less) ... Yeah, maybe you'll enjoy 4.10.

In fact, like me, you might LOVE those gears.

In case you don't know how ''gear torque'' feels compared to ''engine torque''... it is different. Any ''boost'' in engine torque is usually not constant everywhere on the curve. You might get 1% there and 10% elsewhere, or even lose some and gain some. It is not constant. But the ''gear torque'', it is constant.

4.10 means you have over 33% MORE torque than 3.07. From 0 rpm.

Needless to say, that's a lot.

In fact, it feels very much like an electric car. Instant. Somewhat brutal.

Is it dangerous? Then again: diff and tires.

Is it fun? Hell, yeah.

To be honest, I wasnt planning to try those gears with my stock engine. But since my racy high-rpm engine is not yet ready, I will have to live with that combo for few more weeks. I was a bit worried, but I'm not anymore. Quite the opposite. I sure don't feel it's any more dangerous than driving under heavy rain or with worn out tires. I'm not gonna lie: you DO feel the added torque. It PULLS. It's not the same feel as having more horses, but it's weirdly better, in some way... The car feels more agressive, more lively... and the SOUND! As you can expect, it revs faster. Not ''light flywheel'' kinda of faster rev, but under-load kinda rev. Which is extremely enjoyable.

Of course, the other big change is how you live with the 4-5-6th. Before, even with 3.73, I was always going from 4 to 3, 3 to 4 gears on the highway. Then cruisin' on either 5th or 6th...
But now, with those 4.10... It's very clear: your new best friends on the highway are the 4th and 5th. Both are fully enjoyable, plenty of torque for 110-135kmph (70-85mph) and the 6th is FINALLY useful....

So that's my review. That's my 2 cents. Hope that will help some Viper owners who are undecided about that (mandatory) upgrade from the poor 3.07 stock gears,..

[pokeyl]

I went with wavetrac and 3.73. Khumo's and Cam Heads exhaust...
Moton Shocks 400/800 and 250PSI in the dampers.
1.7 front - .8 in rear for camber.

All work together, lots of help from users VOA. Thanks to all

[Aevus]

also got rid of the low-frequency drone in 6th gear.

1,750 rpm @ 70mph cruising speed it's still there a little but at 75mph (1,900 rpm) it's completely silent. Perfect sweetspot.

It's the first time since I own that car that i'm really using the 6th.
Just below 2,000rpm like that I don't always feel the need to downshift now. Of course, with my other engine (+/- 10% less torque expected below 3,000rpm) my driving habits may change, but for now with the stock engine/cam it's fun to drive.

[Aevus]

Another thing I forgot to talk about: how close the shiftings are.

That's another price to pay with taller gears; you'll have to shift more often. To give you an idea:

(4.10 gears) 68mph max in 2nd gear ... 93mph in 3rd = 25mph
(3.07 stock) 91mph max in 2nd gear ... 125mph in 3rd = 34mph

It's a big difference, no doubt. And it feels short. It changes how you drive the car. Even from 3.73 to 4.10, it changes how you drive. A direct mod from 3.07 to 4.10, it would be downright shocking...

In real life driving, it's fun because it's more involving. You feel closer to the car, more in control. But if you're the type to enjoy automatic transmission, you may find that a bit annoying. Especially with a stock engine with rev limiter around 6,100rpm. I have a tune right now with 6,250 limit and I consider that fairly acceptable.

With my 6,800-,7000 racy engine, it would be fantastic, though. About 29mph differential between 2nd and 3rd. Probably the best balance between torque, faster rev and shifting gaps.

[Aevus]

Discovered another good point for the 4.10: Makes life easier in slow traffic.

You can stay in 2nd gear and even comfortably launch from a full-stop.

4.10 gears, that's officially in the ''Things-I-Should-Have-Done-Before'' bin.

[jpmst3]

Thanks for posting the great review. That definitely helps with knowing what to expect in all aspects. Nice.

I wanted to go from the stock 3.07 to 3.55/3.73. When I inquired, JonB said they were impossible to get at the moment.


Hopefully, supply chain issues will ease up by next spring.

[pokeyl]

My 3.73 Mopar gear was from Summit.

https://www.summitracing.com/parts/dcc-p5007043

Thanks for posting the great review. That definitely helps with knowing what to expect in all aspects. Nice.

I wanted to go from the stock 3.07 to 3.55/3.73. When I inquired, JonB said they were impossible to get at the moment.


Hopefully, supply chain issues will ease up by next spring.

[Old School]

My 3.73 Mopar gear was from Summit.

https://www.summitracing.com/parts/dcc-p5007043

Those are 4.10's these are the 3.73

https://www.summitracing.com/parts/dcc-p5007022

[Ramtuff]

I would choose the the 3.73 over the 4:10 any day. Traction is an issue even with the khumos. I daily drive the car and need 6th on the highway. 80 mph is about 1750 vs 1500 with the 3:55.
When you actually do get the new motor, you may regret the 4:10 and go back to a lower ratio as a lot do.

[jpmst3]

I think I would lean towards the 3.55 for my driving habits.
I do see something at Summit that may fit: https://www.summitracing.com/parts/m...iper/year/2004

What all is needed for the swap/install?

[Zubik]

What all is needed for the swap/install?

Ring gear plus bolts, pinion gear, crush sleeve, and diff cover sealant at the minimum. I ordered a kit from JohnB and got what I listed before and new bearings, shims and spaces. Very easy, open the box and have everything needed is in it.

[jpmst3]

Ring gear plus bolts, pinion gear, crush sleeve, and diff cover sealant at the minimum. I ordered a kit from JohnB and got what I listed before and new bearings, shims and spaces. Very easy, open the box and have everything needed is in it.

Gotcha, thanks!

Didn't realize he had a kit, that is a bonus.

[Aevus]

I would choose the the 3.73 over the 4:10 any day. Traction is an issue even with the khumos. I daily drive the car and need 6th on the highway. 80 mph is about 1750 vs 1500 with the 3:55.
When you actually do get the new motor, you may regret the 4:10 and go back to a lower ratio as a lot do.

I have zero traction problem, even though i'm in the worst case scenario: pretty cold weather (spring in Canada, eh) and less than 30-40% left on my one year old Kumhos.

You have a good point, though: If I have MORE torque under 3,000 rpm with my other engine than I have right now with that stock one, I might put back the 3.73 or go with 3.91.

But I highly doubt that since the (custom) cam will compared to the 294HR or 300HR, so totally high-RPM oriented.

https://www.compcams.com/dyno-graphs

[Aevus]

I daily drive the car and need 6th on the highway. 80 mph is about 1750 vs 1500 with the 3:55

I daily drive my car too and like I said it's the first time I'm really using the 6th gear. There's a lot of radar operation in Canada so 75mph is really the max you can go here and 70mph is the more common average speed around here. Using the calculator with 4.10 and 355 tires (27.39''):

1,762 rpm @ 70mph (112kmph)
1,887 rpm @ 75mph (121kmph)

That's exhaust-related but I got rid of the drone, which is a big plus for me. Also, from about 1,800 rpm it pulls decently without me wanting to downshift. I clearly feel that anything below 1,700 will make me want to downshift everytime. It just feels too lazy to my taste.

I've been ''warned'' by basically the entire Viper community to NOT install anything higher than 3.73 and I ended up wishing for 4.10 the very same day I got the 3.73 installed...

Anyway, at the end of the day it's clearly a matter of taste.

[Aevus]

Thanks for posting the great review. That definitely helps with knowing what to expect in all aspects. Nice.

I wanted to go from the stock 3.07 to 3.55/3.73. When I inquired, JonB said they were impossible to get at the moment.


Hopefully, supply chain issues will ease up by next spring.

For many reasons, 3.55/3.73 is the safest bet, especially with stock-ish car. Can't argue with that.

I've modified my car so much (and more to come) that it's basically a convertible race car (!) now, so the 4.10 gearing is just another layer added to the racy feeling I'm looking for.

In fact, 4.10 gears is easily in my top 5 mods so far.

[Aevus]

@Ramtuff

I'm surprised to hear that you had traction issues with the Kumho ACR tires. It's the stickiest (streetable) tire I ever had. And it seems I'm not the only one to think that, here is some comments on TR:

Excellent traction! 942HP Z-06 putting about 824HP to the rear wheels and this tire does as well as a drag radial and comes close to a drag slick. It has very good grip on the street, I mean I can turn the tires to smoke anytime I want but on good pavement and on a hot day, this tire is as sticky as anything out there

Amazing control on the track, very hard to break traction, you must force the car to in order for traction to be broke.

They grip like a drag radial and still corner like a hoosier. Randy is right holy cow.

I purchased these this spring to replace super sports. All I can say is wow. They stick like a drag radial yet corner like nothing I can explain. Short of a racing slick. The car went from mid pack with Michelins to one of fastest cars on course in the right hands. I am running a staggered set up with yokohama's on front.

(...) I have been autocrossing cars for 20 years. These tires made the largest single improvement I've ever seen. Outside of full on Hoosiers. They dropped 1/4 miles by .4 secs. When I get better at launching the car it will be more. Unreal tire kumho has made. Randy is correct holy cow!!!!!

The cornering and braking is every bit as good or better than the Toyo r888/r888r. Easy to see why the Viper ACR set so many records with these tires. So far, they are wearing very nicely, and I have no complaints about road noise or ride.

https://www.tirerack.com/tires/tires...m=53YR9V720ACR

Randy Pobst in the video seems very impressed by the tires too... That makes me realize that I probably enjoy the 4.10 gears because I have slick-like kinda traction...

[13COBRA]

Just so we can get this corrected for future generations not to be confused haha

3.55s are a HIGHER gear than 4:10s. The 4:10s are LOWER than 3:55s.

[usmcfieldmp]

After 700 miles of interstate driving over the weekend, I'm going to be eyeballing a rear end swap much harder.

I don't know that you've convinced me to go 4.10... but I'm confidently going with 3.73 over 3.55.



Also, for anyone debating this, I made this spreadsheet to calculate speeds at an RPM spread, etc: https://1drv.ms/x/s!AjjcCYuKiLfNgqNc...2kruw?e=ajITLm

Where I originally posted it: https://driveviper.com/forums/thread...l=1#post454490

Do me and everyone else a favor; download/save the Excel to your own computer before messing with it. This just ensures that whatever change you make doesn't get saved on the OneDrive version, screwing the next person to use it.

I threw this together fairly rapidly, but it checked out during my once over. If you see a mistake, let me know and I'll correct it.

Once saved on your own computer, all you'll need to do is change the tire size to whatever you are using and everything should auto-populate.
If you want to see a specific gearset ratio because you're doing something custom, all you need to do is change the "FINAL DRIVE:" of one of the tables.
Updating the "Gear Ratio" row in a table will auto-update the table, as well, in case you want to update for a TR6060 or a sequential/auto/etc.

Viper_T56_Rear_End_Ratios.jpg

[Old School]

Plenty of positives changing from 3.07 to 3.55, but a downside is you chew through back tires pretty quickly during spirited street driving.

[Ramtuff]

@Ramtuff

I'm surprised to hear that you had traction issues with the Kumho ACR tires. It's the stickiest (streetable) tire I ever had. And it seems I'm not the only one to think that, here is some comments on TR:













https://www.tirerack.com/tires/tires...m=53YR9V720ACR

Randy Pobst in the video seems very impressed by the tires too... That makes me realize that I probably enjoy the 4.10 gears because I have slick-like kinda traction...

If you can’t spin those with 4:10’s in first and second, you’re doing something wrong. (My car is basically stock) Especially in cooler temps.
Khumo is a good tire and works well. Obviously what you and I consider spirited driving are 2 different things.

[Aevus]

If you can’t spin those with 4:10’s in first and second, you’re doing something wrong. (My car is basically stock) Especially in cooler temps.
Khumo is a good tire and works well. Obviously what you and I consider spirited driving are 2 different things.

You can probably spin in first with 3.07 gears if that's what you want, but my point is: 4.10 won't suddenly make the car spin uncontrollably. Control is the keyword here. Spinning the wheels because that's what you want, that's one thing. But if the car breaks traction when you don't want it, that's a problem. Especially during cornering (lateral grip)... And that's what I was afraid of.

Straight line, unprepped, WOT, 2nd gear, I guess those Kumhos could spin a little. I'll push them more this week, just to see the limits. I have a fresh set anyway, so I'll be able to compare brand new v.s. worn.

FYI:

- Less than 30-40% tread left, a year old, many heat cycles
- Run them 27-29psi (cold)
- Always warming them up before I push the car
- Since I got the 4.10, weather temp averaged 15c deg (60f)
- Wavetrac diff

So, if I don't have traction issues right now... I sure will be OK with a fresh set of Kumho's and 80f outside temp, no?

[Aevus]

I don't know that you've convinced me to go 4.10... but I'm confidently going with 3.73 over 3.55.

I think it really depends on your torque curve. Especially below 3,000rpm and even below 2,500rpm... Since the more agressive gears are adding torque from 0 rpm, you feel it everywhere. And if you have lots of low-end torque, then you need sticky tires (200tw or better).

4-5-6th on the highway it's not a problem at all, it's fun (and usefull with the 6th) but 1-2-3 are pulling hard with the 4.10. And when you release the gas, you feel it engine braking a lot more too. Which I like, but not to everyone's taste.

As said previously, 3.73 is a very safe bet. But if you like your car to feel lively and racy, you might leave a lot of fun on the table, compared to 4.10...

[Aevus]

Thanks for posting the great review. That definitely helps with knowing what to expect in all aspects. Nice.

I wanted to go from the stock 3.07 to 3.55/3.73. When I inquired, JonB said they were impossible to get at the moment.


Hopefully, supply chain issues will ease up by next spring.

Since I'll keep my 4.10, my 3.73 are up for sale:


https://driveviper.com/forums/thread...han-5000-miles