So Keith,
Would it be correct to say that this would be good only if you want to achive good times in 0-60 and 0-1/4 mile?

 

Yes....
They will hurt regular fuel economy and your car will be turning astronomically insane RPM's at moderate highway speeds, even in 6th gear.

It'd be like driving around in 4th gear all day long, even on the highway, but yet you're actually in 6th gear.

I think 5.1's should be just for track-only cars.

 

[QUOTE]Originally posted by munckee
Pardon my utter stupidity, but do these effect 1st or 6th?

 

Thanks, Rick. Good to know.
What mods are good for street and highway driving?
Thanks in advance.

 

as in everything, balance is required.

one of the reasons why the viper has such a low 0-60 mph time is it is still in 1st gear, i.e. NO SHIFTS and enough torque to pull it off the line and accelerate like a bat out of hell....

a higher rear end ratio means better acceleration, but a lower terminal speed in each gear.

if the car is geared to make terminal speed at redline in 4th at end of 1/4 mile and you go to a higher rear end, you will accelerate faster, but then need to make 1 extra shift, or, stay at redline for a short distance before the end of the 1/4. your trap speed would be the same as gearing before, but your ET might be lower if the time to accelerate was less than the amount of time you spent at terminal speed before crossing the line.

if the distance to end is great enough and you shift fast enough, time to shift (i.e. not accelerating during shift) is offset by the higher speed you can attain in the next gear.

if you drive a lot in tight twisties and short straights (like auto-x), a higher gear means you come out of corners faster and you are not worried about top end. if you drive on the open highway, gas mileage will kill you, putting more wear on engine, etc....

keith

 

I think it's so funny now how the 4.777s have gone from being the extreme option to "mid-pack". 5.1 seems useless to me though.

 

Thanks, Keith.
But let's take the dragon run for example. I was able to run all the twists with the 2nd gear (8-9K RPM). So If I had a higher gear set, I would have had to change gears or drive the red. Right?

 

K, I have kind of a dumb question... I understand that the higher gear ratio allows the engine to take a mechanical advantage, but at some point won't the car's lack of torque at the wheels become limiting? (i.e. does the car have enough power to turn a 5.1 from a standstill without dropping in at a higher engine speed)

 

Actually, the gearing is very important for the torque multiplication factor. You have 153 lb-ft of torque and then you get to multiply it by the gear ratio. Ignoring the transmission gearing (you just multiply it again with THAT gear ratio), the 5.1 would give you an effective 780.3 lb-ft while the stock 4.1 gives you 627.3 lb-ft. I'll take an extra 150 lb-ft of torque anytime...

 

at dragon staying in 2d entire time means no time shifting and possibly missing a shift, you get to concentrate on the turns themselves with both hands on the wheel the entire time. after getting used to it, might get a little faster doing left foot braking since you are not using the clutch to shift, but that could get confusing when you get a longer straight and actually do shift.

if you can pull out of corner hard and just about hit redline before next turn, your gearing is fine, since we all like the 9k stuff

if you are short of redline, you might go to a higher ratio, still have enough power to pull out of corner and get to a higher speed in 3rd all the time.

if 3rd pulls you out of corner too slow and you have to go 2d exit corner then 3rd, back to 2d, chances are you would be less efficient through the whole run.....

keith