3.33's did not make my car faster...

[jay01m]

To capitalize on what DJ has said, when it comes down to gears in the 1/4 mile, I'd rather have the rear gears that prevent me from shifting one extra gear than my opponent, because with two equal cars with different gears described above, that extra shift will likely cost me my race.

If your really looking to improve your 1/4 mile times using your gears, you should factor in your tranny gears. If you do the math between the gearing in your rear end and the gearing in the tranny, you can come up with a combination where your getting the most power out of each gear in the 1/4, but that involves regearing your tranny and rear end, and your overall driveability would likely go out the window.

 

[waheed_RT10]

My viper is paxton supercharged, michelin pilots, wide open exhaust and i just swapped to 3.54 ...

driving wise it is much more fun ... i just love the tirespin at 70 - 80 mph when i shift to 3rd gear, it is much much easier to do some drifts, even in high gears the car reacts more promptly, all of a sudden you can use the 6th gear for more that just autobahn ...

i think my swap was just the right thing to do ....

 

[RTTTTed]

I have a Roe sc'd Viper and the 3.54 gears slowed it down in the quarter mile. The 3.0's are back in.

With the Roe sc I have no problem driving in 6th at 55mph. I get 20mpg. Driving in 5th doesn't seem to make any difference except more Corsa exhaust noise.

Ted

 

[Paul Hawker]

I must be that rare exception. I could never break out of the 12's with stock 3:07. After changing to 3:54's the Viper did a 11.97 at Pomona. Thought it had to do with being able to change into 4th for the top end charge. (Strange as MPH did not change but 1 mph).

Real issue here is traction. If you are already having traction issues, the gear or more HP will not produce better times.

Get some new rubber on before the gears.

 

[Big Medicine]

Gears multiply torque, which is handy at low rpms when power is down. (unless you have a Viper with tons of torque already) Once rpms come up and power is available, the gears get in the way. That's when you want some gears with legs, not grunt.

 

[Tom F&L GoR]

My left tire was bald and my right side tire was 0.2" taller.... guys, you are focused on the bark of a tree. The forest tells you that a fixed energy producing unit (a 450 hp engine) can produce greater acceleration (0-60 or 1/4 mile) with more torque multiplication (gears) only if you have traction (sticky tires.) That is physics.

On a road course, street race, or any other instance where the wheels do not spin, you will not have an eternal advantage over another car if the comparison goes through more than one gear. (look at the graph when above 45 MPH.) In some cases (50 MPH) the 3.07 has the advantage.

You have to decide where you want the benefit, this is not an all-around "make it better" modification.

 

[REDSLED]

Well said Tom, but I will take my 3.55's over the 3.07's on a road course any day (given if 5th gear has to be used) I think SOTP or pulling out of a slow corner on a road corse is the only benefit. But you can't put a price on that SOTP feeling!

 

[TexasPettey]

Sounds like the question of 'What do I want to do with my car?' is important here or money is wasted.

SOTP = Pick the speed you want to feel the thrust and find the gearing ratio that puts you in the peak torque curve at that speed. BTW, traction had better not be the limiting factor.

Drag Racing = Look at the time spent in the power band for a given gear, as Tom has shown with the chart. Pick your distance you want to cover, and hope that traction isn't an issue.

Road Racing = Look at the courses you run and the speeds you can handle into and out of the corners. Make certain that you won't have to shift inside the corner to stay in the power band. Extra thrust is nice, but unless you're in 4th gear, you're probably traction limited at the apex of all your corners. Too much throttle, and say hello to the tire wall.

For what I do, DE track events similar to road racing, gears aren't worth it. There's too much variance in the courses to be able to pick an optimum RPM. The car has a ton of torque at WOT in power band in 3rd gear, which is plenty fast for most any track. So, staying with 3.07 works for me. Less shifting is always better, all things being equal.

 

[SingleMalt]

<hijack>
Sorry for sounding ***, but I love Tom! He's always got the best and usually irrefutable answers on here. I know I've learned a thing or two from him over the years.

Mike
</hijack>

This chart shows that a car will only be quicker (in a quarter mile) if you can plant the tires in first gear. After that, torque at the wheels is about the same.

Chart courtesy of the Northeast Viper club (I think.)

 

[Fred(DrivingSchool)Kinder]

I like 6th gear with the stock diff. Have read many post complaining about lack of 6th gear use. I use 6th all the time with stock gears. Had 3:55's and considered them a waste of money.

 

[Chuck 98 RT/10]

You have to decide where you want the benefit, this is not an all-around "make it better" modification.

As is many mods.

Often times if you are gonna upgrade part "A" you need to upgrade parts "B","C" and "D" to get the most out of part "A".