Axle ratio 2.59:1 or 3.33:1 -- Which is faster in the quarter mile?
#1
Drifting
Thread Starter
Axle ratio 2.59:1 or 3.33:1 -- Which is faster in the quarter mile?
If a C4 has the same horsepower and is the same in everything else, which is faster in the quarter mile: an axle ratio of 2.59:1 or 3.33:1? What about in 0 mph to 60?
Someone told me the actual numbers represent the number of times the engine is turning in relation to the number of times the wheels are turning. Is that correct?
Of all the C3s, C4s and C5s that I've driven or ridden in, I was most amazed at the difference in a six-speed 1988 and a six-speed LT-4 1996. The 1988 coupe had an axle ratio of 3.07:1 and only 240 hp, while the 1996 coupe had an axle ratio of 3.45:1 and 330 hp. Yet, while test driving the cars and going 0 to 90 mph by flooring the pedal, it felt like the '88 coupe was beating the hell out of the LT-4. I had a passenger and he said the same thing. Maybe it was just my imagination.
Someone told me the actual numbers represent the number of times the engine is turning in relation to the number of times the wheels are turning. Is that correct?
Of all the C3s, C4s and C5s that I've driven or ridden in, I was most amazed at the difference in a six-speed 1988 and a six-speed LT-4 1996. The 1988 coupe had an axle ratio of 3.07:1 and only 240 hp, while the 1996 coupe had an axle ratio of 3.45:1 and 330 hp. Yet, while test driving the cars and going 0 to 90 mph by flooring the pedal, it felt like the '88 coupe was beating the hell out of the LT-4. I had a passenger and he said the same thing. Maybe it was just my imagination.
#4
Former Vendor
It all depends on traction and motor specs. Assuming that you can put the power to the road efficiently, more gears will tryically accelerate the car quicker. But its really something that needs to be trials and error tested.
More gear will make you feel that you are accelerating quicker.
I recently went from 4.10 gears to 4.56s and the acceleration difference is UNBELIEVABLE, also since my motor needed more gear to optimize it in the 1.4 mile, I ran about 2.5MPH quicker in the 1.4 and my 60' times dropped down a BUNCH.
More gear will make you feel that you are accelerating quicker.
I recently went from 4.10 gears to 4.56s and the acceleration difference is UNBELIEVABLE, also since my motor needed more gear to optimize it in the 1.4 mile, I ran about 2.5MPH quicker in the 1.4 and my 60' times dropped down a BUNCH.
#5
Burning Brakes
The stock TPI engine is all about low end torque and it fizzles out on power at around 4400 rpms. So it works well with the 2.59 because the engine stays in the fatty part of the torque curve longer.
Within the last year I removed my 2.59 gears for a 3.73 and the car actually slowed down slightly (et) in the quarter mile! I now have 3.07's and the car is the fastest and quickest it has ever been. I also have done a lot of engine mods, including SR, 219 cam, and Pete K converter which allows it to make power at higher revs.
Although the 2.59 gear lacks the "WOW!" factor, it is actually a pretty good ratio for its intended operating range. Even if the 3.33 is quicker, I doubt it will be so by much until you start making power in the higher rev ranges. Then its strength to handle increase power starts to come into play at (400+HP)
Within the last year I removed my 2.59 gears for a 3.73 and the car actually slowed down slightly (et) in the quarter mile! I now have 3.07's and the car is the fastest and quickest it has ever been. I also have done a lot of engine mods, including SR, 219 cam, and Pete K converter which allows it to make power at higher revs.
Although the 2.59 gear lacks the "WOW!" factor, it is actually a pretty good ratio for its intended operating range. Even if the 3.33 is quicker, I doubt it will be so by much until you start making power in the higher rev ranges. Then its strength to handle increase power starts to come into play at (400+HP)
Last edited by GeosFun; 11-02-2007 at 01:26 PM.
#6
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Can't answer that kind of question without qualifying statements. It depends on the power made across the band.
L98 and LT1/4 will react differently to gear changes because they have different power bands and peaks.
L98 and LT1/4 will react differently to gear changes because they have different power bands and peaks.
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#8
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The LT4 car is typically a full second quicker in the 1/4 mile so much for the good old s.o.t.p. dyno huh The 3.33 gear will get the car down the 1/4 mile quicker L98 or LT1/4. The LTX cars respond better to gear changes than the L98 cars with everything else remaining stock. A 3.73 is great for a LT1 and too much gear for an other wise stock L98.
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#14
Race Director
Generally the L98 would be faster with the 2:59's...3:07's is about the tallest gear you'd want in an L98..in an LT1 the opposite is true and you would be faster with the taller gear, the 3:33's...with the LT-1 you can actually go all the way up to 3:73's and see improvement...
As noted above, ET's are all about how effectively you transfer the power you have to the ground...gears won't do a thing for you if you spin off the line..neither will HP...I can't begin to tell you how many opponents I have put on the trailer with twice my HP because they spun out of the hole and couldn't get hookes up until it was too late...
#15
Drifting
Thread Starter
What about engine revolutions?
Thanks for all the insight and explanations about how peak power bands vary from the L98 and LT4 and the effect of the axle ratios.
But I still have this lingering questions. Does the ratio of 3.33:1 mean the engine is turning 3.33 times for each time the wheels turn?
Also, I remember the 4 + 3 transmission on the '88 coupe. I should have simply said manual transmission.
But please tell me what the 33.1 stands for. Maybe I'm dense in this area. My "Corvette Specs" book says the 1990 axle with a 33.3 ratio has 12 pinion teeth and 40 ring teeth and the ring gear outside diameter is 8.5 inches. The 2.59 axle ratio has 17 pinion teeth, 44 ring teeth and the ring gear's outside diameter is 7.875 inches.
But I still have this lingering questions. Does the ratio of 3.33:1 mean the engine is turning 3.33 times for each time the wheels turn?
Also, I remember the 4 + 3 transmission on the '88 coupe. I should have simply said manual transmission.
But please tell me what the 33.1 stands for. Maybe I'm dense in this area. My "Corvette Specs" book says the 1990 axle with a 33.3 ratio has 12 pinion teeth and 40 ring teeth and the ring gear outside diameter is 8.5 inches. The 2.59 axle ratio has 17 pinion teeth, 44 ring teeth and the ring gear's outside diameter is 7.875 inches.
#16
Burning Brakes
[QUOTE=Photomania;1562589439]Thanks for all the insight and explanations about how peak power bands vary from the L98 and LT4 and the effect of the axle ratios.
But I still have this lingering questions. Does the ratio of 3.33:1 mean the engine is turning 3.33 times for each time the wheels turn?
Also, I remember the 4 + 3 transmission on the '88 coupe. I should have simply said manual transmission.
But please tell me what the 33.1 stands for. Maybe I'm dense in this area. My "Corvette Specs" book says the 1990 axle with a 33.3 ratio has 12 pinion teeth and 40 ring teeth and the ring gear outside diameter is 8.5 inches. The 2.59 axle ratio has 17 pinion teeth, 44 ring teeth and the ring gear's outside diameter is 7.875 inches.[/QUOTER]
The ring gear teeth divided by the pinion teeth = ratio. (40/12=3.33) The ring gear diameter is exactly that. It is a Dana 44 rear. The other is a Dana 36. Yes, if the "input shaft" on anything with gears (an automotive rear end in this case) makes 1 full revolution, the output shaft or shafts will make as many revolutions as the gear ratio. (2.59 or 3.33 or whatever the ratio in this case)
But I still have this lingering questions. Does the ratio of 3.33:1 mean the engine is turning 3.33 times for each time the wheels turn?
Also, I remember the 4 + 3 transmission on the '88 coupe. I should have simply said manual transmission.
But please tell me what the 33.1 stands for. Maybe I'm dense in this area. My "Corvette Specs" book says the 1990 axle with a 33.3 ratio has 12 pinion teeth and 40 ring teeth and the ring gear outside diameter is 8.5 inches. The 2.59 axle ratio has 17 pinion teeth, 44 ring teeth and the ring gear's outside diameter is 7.875 inches.[/QUOTER]
The ring gear teeth divided by the pinion teeth = ratio. (40/12=3.33) The ring gear diameter is exactly that. It is a Dana 44 rear. The other is a Dana 36. Yes, if the "input shaft" on anything with gears (an automotive rear end in this case) makes 1 full revolution, the output shaft or shafts will make as many revolutions as the gear ratio. (2.59 or 3.33 or whatever the ratio in this case)
#17
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No ya don't.
Any car, bike, boat, sewin' machine, anything, is gonna be faster (quicker off the line) with higher gearing.
That ain't no guess.
YUP.
YUP.
Any car, bike, boat, sewin' machine, anything, is gonna be faster (quicker off the line) with higher gearing.
That ain't no guess.
Assuming that you can put the power to the road efficiently, more gears will tryically accelerate the car quicker.
I recently went from 4.10 gears to 4.56s and the acceleration difference is UNBELIEVABLE, also since my motor needed more gear to optimize it in the 1.4 mile, I ran about 2.5MPH quicker in the 1.4 and my 60' times dropped down a BUNCH.
I recently went from 4.10 gears to 4.56s and the acceleration difference is UNBELIEVABLE, also since my motor needed more gear to optimize it in the 1.4 mile, I ran about 2.5MPH quicker in the 1.4 and my 60' times dropped down a BUNCH.
YUP.
YUP.
Last edited by schrade; 11-03-2007 at 12:40 PM.
#18
Burning Brakes
Car will pull harder with lower (higher numerically) gear ratio. It's basic leverage. They will be quicker off the line if you have infinite traction. Nobody does have infinite traction. (Ski_down_it is obviously close to infinite traction by watching his videos!!! ) If by quicker you mean 1/8th or 1/4 mile runs, then one does need to know what C4 you have and what mods you have to make a gear suggestion. 4.56's in a L98 and you will NEVER get traction. And if you do, you will run through your powerband so fast that a 2.59 geared car will smoke by you probably before the 1/8th.
#19
Former Vendor
A very basic rule of thumb is you want your car to be crossing the finish line at your maz power RPM.
THe problem is most cars can't plant the power at the launch, which costs much more ET than not having the gears optimized at the finish line. More ET can be gained or lost in the 60' time that will effect your ET, than at the end of the track.
As a result most people undergear their cars to bandaid the traction problem and feel their cars are quicker with less gear. However optimized you want it at the start and at the end of the track. This requires a GOOD working suspension.
THe problem is most cars can't plant the power at the launch, which costs much more ET than not having the gears optimized at the finish line. More ET can be gained or lost in the 60' time that will effect your ET, than at the end of the track.
As a result most people undergear their cars to bandaid the traction problem and feel their cars are quicker with less gear. However optimized you want it at the start and at the end of the track. This requires a GOOD working suspension.
#20
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Car will pull harder with lower (higher numerically) gear ratio. It's basic leverage. They will be quicker off the line if you have infinite traction. Nobody does have infinite traction. (Ski_down_it is obviously close to infinite traction by watching his videos!!! ) If by quicker you mean 1/8th or 1/4 mile runs, then one does need to know what C4 you have and what mods you have to make a gear suggestion. 4.56's in a L98 and you will NEVER get traction. And if you do, you will run through your powerband so fast that a 2.59 geared car will smoke by you probably before the 1/8th.
In fact, in the quarter, you'd probably have to pit for re-fuel, with 4.56:1