Rear Gear Question

Greg-TT · Mar 8, 2007

My stock diff. was replaced at 9800 mi with Quaife. No drag radials, no drag racing, no road racing. My car is a daily driver and it was never been abused. However the stock spider gear had a 1/4" chip after 9000 mi and it started making a whinning noise. Took the car to the Unitrax to do the rear gear swap, and they strongly recommended the Quaife diff. I spent little over $2800 for the Quaife & 3.55. My car just passed 13K mark and no issues what so ever and I just love the way car drives now.

SmoknTires · Mar 8, 2007

We track our cars a lot in our club and don't have many problems at all with the spider gears, it's definitely not a pattern. We have many GenIII's with gear swaps on both the stock and the Quaife/comp coupe rear ends and it's an excellent upgrade in all cases.

GR8ASP hit it on the head. If you're a GenIII person you may be interested in the Q (especially if you track your car). But to others points, if you're just hitting the streets, it's probably not worth the money to upgrade to a quaife. One note, lots of folks went with a comp coupe rear end rather than a quaife. I've driven them both on the track and can't tell the difference between the two, they both are great options for track folks and keep that inside tire planted.

But in the end 3.55's are a good investment and not too extreme.

Flash1034 · Mar 8, 2007

Sounds like the 3.33s are the hot ticket for a normally aspirated SRT-10. I wonder if you could still pull a 0-60 without shifting to second with the 3.33s?

Flash :usa:

SmoknTires · Mar 8, 2007

Most people who I've talked to with 3:33's say it's too much. But I've raced with them and I get killed at higher speeds, it's amazing how much of a difference it makes compared to my 3:55's. I'm told 1st gear is near useless with a 3:33 though.

Flash1034 · Mar 8, 2007

1st gear should not be useless with 3.33s. It should be a little shorter/stronger to redline than the stock 3.07s. 3.55s would be even shorter to redline in 1st. Am I missing something?

Flash

Nader · Mar 8, 2007

Yeah something is odd. Given two equal cars one with 3.33 and another with 3.55 and a roll on race, wouldnt the 3.55 accelerate faster?

Flash1034 · Mar 8, 2007

I would think the 3.55s would make you have to shift out of first gear much quicker than the 3.33s would. With the torque of the Viper, I think you's lose the sprint race with a 3.33 car (all things equal) because he would have to shift before the car equipped with the 3.33's (Shifts=Slow). What do you think?

Flash

Vipermann · Mar 8, 2007

Sounds like the 3.33s are the hot ticket for a normally aspirated SRT-10. I wonder if you could still pull a 0-60 without shifting to second with the 3.33s?

Flash

Actually, they are hot with a n/a SRT, but they are even more 'the ticket' in higher HP SRTs ... either that, or stay with the stock 3.07s for anything over 550 rwhp

rcdice · Mar 9, 2007

Just a note on what the competition is doing:

Latest Z06 = 3.42
Ford GT = 3.36

Kenny · Mar 9, 2007

Just a note on what the competition is doing:

Latest Z06 = 3.42
Ford GT = 3.36

Apples and oranges comparison. Both of those cars have higher redlines and neither has the low end torque of the Viper. Even with the 3.42, the 06 Z06 can go faster in first than the 06 Viper.

Racer Robbie · Mar 9, 2007

Got to agree with you on this one Flash.

Vipermann · Mar 9, 2007

I would think the 3.55s would make you have to shift out of first gear much quicker than the 3.33s would. With the torque of the Viper, I think you's lose the sprint race with a 3.33 car (all things equal) because he would have to shift before the car equipped with the 3.33's (Shifts=Slow). What do you think?

Flash

That is correct -- an SRT with 3.55s moves up through the the rpms like a hot knife through butter -- seems like there's almost no load on the engine, which is kinda like leaving torque on the table -- you need to shift at the readline before you know it ... it's quicker than the stock 3.07s, but with something in between, and a little more load on the engine (as with 3.33s, using the torque) the SRT actually moves faster ...

johnk · Mar 9, 2007

In a straight line, the only way 3.33s accelerate the car faster than 3.55s is if there are traction issues, or you run out of rpm.

Flash1034 · Mar 9, 2007

I dont really agree with that. There are gears that keep the engine in its "happy place" longer AND you wont have to shift as early with the 3.33s compared to the 3.55s. Shifts=slow.

Flash

johnk · Mar 10, 2007

I dont really agree with that. There are gears that keep the engine in its "happy place" longer AND you wont have to shift as early with the 3.33s compared to the 3.55s. Shifts=slow.

Flash

Not sure about your motor, mine built peek power at the 6k redline, that's it's happy place for full throttle acceleration. No, you don't have to shift as early with 3.33s as with 3.55s, what does that have to do with acceleration? In a relatively high horsepower car, 2nd gear comes up quick, that's the point. Be ready for it. If traction becomes an issue, then it needs to be dealt with.

Best of luck...

Steve 00RT/10 · Mar 10, 2007

Quote:
--------------------------------------------------------------------------------

I dont really agree with that. There are gears that keep the engine in its "happy place" longer AND you wont have to shift as early with the 3.33s compared to the 3.55s. Shifts=slow.

Flash

--------------------------------------------------------------------------------

Not sure about your motor, mine built peek power at the 6k redline, that's it's happy place for full throttle acceleration. No, you don't have to shift as early with 3.33s as with 3.55s, what does that have to do with acceleration? In a relatively high horsepower car, 2nd gear comes up quick, that's the point. Be ready for it. If traction becomes an issue, then it needs to be dealt with.

Best of luck...

I don't agree either. When the 3:55 car shifts to a higher gear, the 3:33 car is still pulling at a better gear ratio. It will briefly start to catch the lower geared car. Each gear will be that way.. therefore the 3:33 car will out accelerate the 3:55 car in every gear for a split second. Where it really comes into play is when the 3:55 car shifts to .74 OD at 130 or so and the 3:33 car is still pulling hard at a 1:1 ratio. A race from 0-150 between a 3:07 car and a 3:55 car would have the cars about even. Once both cars were in OD at 150, the 3:55 will get to redline much faster than the stock rear end, but will also lose the race in the end when the 3:07 catches up and passes him.

Steve

johnk · Mar 10, 2007

Sorry I wasn't clear, my response was geared (LOL) toward straight line (1/4 mile) acceleration. With stock diameter Gen3 tires, top speed in 4th would be ~137 at 6k rpm. (well into the 10s) To that point, 3.55s would be quicker given ample traction. Beyond that, cases could be built for any higher gear ratio depending on the desired speed.

Steve 00RT/10 · Mar 10, 2007

Sorry I wasn't clear, my response was geared (LOL) toward straight line (1/4 mile) acceleration. With stock diameter Gen3 tires, top speed in 4th would be ~137 at 6k rpm. (well into the 10s) To that point, 3.55s would be quicker given ample traction. Beyond that, cases could be built for any higher gear ratio depending on the desired speed.

Seeing as the same transmission was used for GEN III cars, your effective rear end ratio is probably about a 3:40 given the 19" tires. That's why you show 137 MPH at 6K. An 18" GEN II runs out of steam at 130 or so with 3:55s.

Ample traction is the key. The see saw game will still apply, even in a straight line 1/4 mile.....with the higher gear catching(out accelerating) a little every time the 3:55 car shifts. I believe the torque tables which have been posted here several times show the main difference to be in 1st and 2nd. The advantage drops progressively in 3rd and 4th.

I'm not knocking 3:55s at all. I have 3:45s in my car. ...but there are tradeoffs for changing rear end gears. For example, I slaughtered a Honda CBR from 90-125 (4th gear) last year....after he jumped about 3-4 bikes on me from a 3rd gear start at 60. The race ended at around 125 MPH with me 2-3 cars in front of him. If it had continued, I would have been in OD instead of pulling at a 1:1 ratio. He would have easily caught up and passed me. Fortunately, He will only ever know that a Viper, which he egged on, put the boots to him

Steve

Fast Freddy · Mar 10, 2007

Just a note on what the competition is doing:

Latest Z06 = 3.42
Ford GT = 3.36

Click to expand...

Apples and oranges comparison. Both of those cars have higher redlines and neither has the low end torque of the Viper. Even with the 3.42, the 06 Z06 can go faster in first than the 06 Viper.

one must also take into account the differences in overall rear tire height that these cars have. the ford GT has the tallest rear tire height of any of these cars. therefore its 3.36 rear gear ratio faces up much more overdriven than it would in a gen-2 viper as a result of having an overall rear tire height that is more than 2" taller. my GT will do 180 mph in 4th gear at 6,500 rpm's

i just had 3:33 rear gears installed in my viper last week. this is gonna drop my mph in 4th gear from 145 mph at 6,000 rpm's on stock pilots to somewhere between 135-140 mph depending on which tires i use on my 18" wheels. pilot cups are a lil taller than stock pilots. so i am gonna say about 140 mph on them. hoosiers are shorter than stock pilots so it should be 135 mph on them. :2tu:

viperjim · Mar 10, 2007

Just a note on what the competition is doing:

Latest Z06 = 3.42
Ford GT = 3.36

Click to expand...

Apples and oranges comparison. Both of those cars have higher redlines and neither has the low end torque of the Viper. Even with the 3.42, the 06 Z06 can go faster in first than the 06 Viper.

Click to expand...

one must also take into account the differences in overall rear tire height that these cars have. the ford GT has the tallest rear tire height of any of these cars. therefore its 3.36 rear gear ratio faces up much more overdriven than it would in a gen-2 viper as a result of having an overall rear tire height that is more than 2" taller. my GT will do 180 mph in 4th gear at 6,500 rpm's

i just had 3:33 rear gears installed in my viper last week. this is gonna drop my mph in 4th gear from 145 mph at 6,000 rpm's on stock pilots to somewhere between 135-140 mph depending on which tires i use on my 18" wheels. pilot cups are a lil taller than stock pilots. so i am gonna say about 140 mph on them. hoosiers are shorter than stock pilots so it should be 135 mph on them.

Did you notice enough difference in the Vipers acceleration with the 3.33 to make it worth the gear change?

Fast Freddy · Mar 10, 2007

the reason for the gear change is because it puts my shifts points into a more advantageous spot on the road courses i race at. as far as acceleration is concerned yes the car accelerates quicker with the lower gears. the downside is that this puts more torque down to the ground when exiting corners. i am gonna ditch the pilot cups on the short tracks and go with hoosier slicks from now on. the pilot cups are still my tire of choice for long tracks like the silver state classic though. its a good thing i have 3 sets of wheels for my viper because i am gonna shoe em all with 3 different types of tires for different types of driving & racing.

Viper X · Mar 12, 2007

Steve,

I still have the stock GTS diff. I installed the Quaife because my GTS is my track car and the Quaife is superior on the track. Traction is better coming out of corners under power and at high speed.

The OE GTS diff gave me no issues whatsoever in over 20,000 miles of service. I'll likely put it back in if I sell the car.

Now, on to the Gen III diffs. I've been through 9 gear sets and 3 complete diffs so far, and I don't drag the car, abuse the car or dump the clutch. I do drive my cars and use the go pedal frequently, unlike some guys. The Gen III diffs just don't hold up very well for me.

There you go. Gen II diffs seem to be much stronger and more reliable than Gen III. This is likely why the 2008 Viper is changing their diff.

Dan

DR EVIL · Mar 12, 2007

I would think the 3.55s would make you have to shift out of first gear much quicker than the 3.33s would. With the torque of the Viper, I think you's lose the sprint race with a 3.33 car (all things equal) because he would have to shift before the car equipped with the 3.33's (Shifts=Slow). What do you think?

Flash

sounds like you should throw some 2.73's in your viper. Think about it EXTRA FAST and even LESS shifting!

Yes you will shift sooner with lower gears. You will also be accelerating faster with lower gears. In other words, the viper with the deeper gears will pull away then shift and the stock geared car will catch up a little until he shifts where the stocker will fall even further behind. Make sense?

DPViper · Mar 14, 2007

Now, on to the Gen III diffs. I've been through 9 gear sets and 3 complete diffs so far, and I don't drag the car, abuse the car or dump the clutch. I do drive my cars and use the go pedal frequently, unlike some guys. The Gen III diffs just don't hold up very well for me.

Stupid question: When you lose the Viper gears or diff, do they fail/break all at once or is it a "wearing out" over time? In other words, would I notice a problem while driving or would the rear just blow up? Thanks

Volltage · Mar 14, 2007

Mine just blew up when I was shifting hard from 1st to 2nd.

Steve 00RT/10 · Mar 14, 2007

Now, on to the Gen III diffs. I've been through 9 gear sets and 3 complete diffs so far, and I don't drag the car, abuse the car or dump the clutch. I do drive my cars and use the go pedal frequently, unlike some guys. The Gen III diffs just don't hold up very well for me.

There you go. Gen II diffs seem to be much stronger and more reliable than Gen III. This is likely why the 2008 Viper is changing their diff.

Dan

.....I wonder the reason they don't hold up? I see another one gone just above here. I thought the rear end and tranny was identical to the GEN IIs?

Steve

GR8_ASP · Mar 14, 2007

No, Gen 3 went to the hydralock differential.

Great for a Jeep. Does not belong on a sports car!

One reason for Gen 3 failures (beyond the inherent weakness and such) is a propensity to wheel hop. Very damaging. More related to tires, wheels and shock/springs than the diff. But the differential pays the price.

Steve 00RT/10 · Mar 14, 2007

Do you have a stock rear end Ron? If so, how are you managing to keep it together given your almost 700HP!

Steve

viperjim · Mar 14, 2007

Mine just blew up when I was shifting hard from 1st to 2nd.

I had my car for about a month and shifted "gently" into 2nd gear and destroyed the tranny. I ended up being #5 on a national waiting list for a new tranny. Took about a month for the dealer to get it. Happy it was still under warranty.

Flash1034 · Mar 14, 2007

To those guys who have changed to the 3.33s. Is the car noticeably faster out of the hole. Im looking for a quicker jump.

Thanks,

Flash

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