2.73 Rear Gears?

WESTCOAST JASON

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Anyone know if a lower (numerically) set of gears for the Viper is available? I have had 3.55's and am back at the stock ones now, but would like to get an even lower ratio....

thanks
 

Daffy Duck Viper

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Just curious. Is your reason for wanting a lower gear ratio than the stock 3.07 because your Viper makes such huge amounts of torque (731RWTQ)? I've been curious to know if anyone has ever gone lower than 3.07 because of having so much torque.

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WESTCOAST JASON

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exactly. I am unable to get satisfactory traction with my current gears to do performance testing. I am hoping that 2.73's would make as big a difference that going the other way does.....
 

onerareviper

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Poor you... Too much HP :rolleyes:

Have you considered Kuhmo's or Toyo's for increased traction on the street?

BTW - Let's see some more videos! That one you posted a while back with the chick laughing (passenger seat) was a classic. Your Viper is a freak'in rocket sled....
 

joe117

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You could get a 4.11 rear and start in second gear.
The final drive ratio will be the same for a 4.11 in second
as a 2.73 in first.
2.73 x 2.66=7.26
4.11 x 1.78=7.31
 

joe117

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If Jason has "697RWHP/731RWTQ", I don't see why he would want a 3.73 or 4.11 rear.
Do guys with that kind of power really run a 3.73 or 4.11 for 1/4 mile? I have no idea.
I don't know if the 2.73 will help him or not but a 4.11 in second gear is the same as a 2.73 in first.

The other thing to think about is that there is a fairly big ratio jump between 1st and 2nd in the trans,
If you used 2nd to start, you wouldn't have as big a jump on your fist shift.
Would that be good? I don't know.
 

Torquemonster

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Your best setup will be the one that drives how you like it best.

As for traction - although you may have problems with 3.55's, going to 2.73 is unlikely to go quicker. You'll do a bigger burnout with the taller rear gears than with lower ones because the tall ratio (2.73) will allow the rear wheels to spin faster than the 3.55's did in the same gear. With that much power you'll still easily break traction.... 5th and 6th will hardly be neck snappers tho with a 2.73 rear!

Want proof? Try a full power take off in second with a few rpm's up - it'll do a wicked burnout. Drop the rpm enough to not burnout - and it'll be soft until it can get going - not good for times.

Stick with your stock gear. I'd be focusing more on getting better tires and suspension tune/setup and learning to feed the power in better. A turbo car has the ultimate ability to feed power in because you can go from vacuum to boost by the load on your right foot - not rpm. Squeeze it in gently, watch the boost guage - it should be at eye level so you can drive on it without taking your eyes off the road.

Also 2.73 would make it drive like a diesel unless you altered the top 2 or 3 gear ratios on the 6 sp. Yuck, 6th is already ridiculously tall.
 
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WESTCOAST JASON

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Thanks for all the responses. The thoughts are really based on 'seat of the pants' and I will try the starting in 2nd thing before I do anything else.

unrelated:
There is a Ferrari/Viper club meet in a couple hours in San Diego. I will post pics from it later.
 

ElDiablo Viper

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If Jason has "697RWHP/731RWTQ", I don't see why he would want a 3.73 or 4.11 rear.
Do guys with that kind of power really run a 3.73 or 4.11 for 1/4 mile? I have no idea.
I don't know if the 2.73 will help him or not but a 4.11 in second gear is the same as a 2.73 in first.

The other thing to think about is that there is a fairly big ratio jump between 1st and 2nd in the trans,
If you used 2nd to start, you wouldn't have as big a jump on your fist shift.
Would that be good? I don't know.

I was talking about road racing and not 1/4 mile
 

Paolo Castellano

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Jason, I would not even consider going to a 2.73. Like Torquemonster said, it would be like driving a diesel. Going to a 3.07 from a 3.55 will be like having 15.6% less HP and TQ multiplication. Which should be fine for your level of HP. Besides going to a 2.73 from a 3.07 would be 2.73/3.07 = .88925

.88925 X 697RWHP = 619.8 correction factor
.88925 X 731RWTQ = 650 correction factor

Relative to a 3.07, you have 1.156 X 697RWHP = 805.97RWHP correction/multiple
Relative to a 3.07, you have 1.156 X 731RWTQ = 845.29RWTQ correction/multiple

The 3.55 is just too easy for the power level you have got. I also remember talking to Jerry @ Unitrax who said he would have to weld a collar of a larger diameter to the 2.73 to match that of the 3.07. That does not sound good to me either!
 
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WESTCOAST JASON

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(just once or twice Marv) ;)

I tried the 2nd gear thing and if that is truly how it would be with 2.73's than the issue is put to rest. yuk!
 

joe117

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Jason,
I don't know what you did to try "the second gear thing" but torquie wasn't telling you that your second gear is like your first would be with a 2.73 rear.
With a 2.73, your 1st gear overall would be 7.26:1
With a 3.07, your 1st gear overall would be 8.17:1
With a 3.07, your 2nd gear overall would be 5.47:1
You can't simulate the 2.73 rear with the gears you have now.
Like I said, a 2.73 in 1st will be just like a 4.11 in 2nd.
 

FE 065

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If someone was set on 2.73s, wouldn't Corvette gears work?
 
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WESTCOAST JASON

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Thanks Torquemaster & Jim. I am just going to stick with the 3.07's and work more on getting better control via my right foot.

As a point of curiosity, when SVSi did that awesome salt flat record setting run, what was the gearing setup on that car??
 

Torquemonster

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Not sure - hopefully someone from SVSI will chip in.

My guess is that they ran the stock rear gears. With well over 1000hp at the wheels - they'd have had the power to pull 5500rpm in 6th assuming that gear is strong enough (overdrives tend to be inherently weaker than underdriven gears).

Any any event - not see anything official about that speed run - there's a link on their website that doesn't work, nothing on the forum I've seen since I've been here other than a vague third party reference.

So if they did anything great it's almost a secret.... where's their marketing people?

How fast did they supposedly go?
 
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