3:54's or 3:75's?
Thread Starter
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Joined: Sep 2001
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From: Houston, TX
3:54's or 3:75's?
I would like for some of yall to educate me in how 3:75 gears would effect the whole spectrum of driving for me.
Im concerned that it will be too much gear.
1. What kinda gas mileage will i lose going from a 2:59?
2. What will my rpm be at 70 mph?
3. Will I lose my ability to race effectively from a 70 mph roll?
4. How much does it affect top speed?
Im really concerned that in the long run it may not be the gear for me. The most i will ever mod is maybe a torque convertor and headers. pros and cons?
Im concerned that it will be too much gear.
1. What kinda gas mileage will i lose going from a 2:59?
2. What will my rpm be at 70 mph?
3. Will I lose my ability to race effectively from a 70 mph roll?
4. How much does it affect top speed?
Im really concerned that in the long run it may not be the gear for me. The most i will ever mod is maybe a torque convertor and headers. pros and cons?
Team Owner
Joined: Dec 2000
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From: SE NY
Cruise-In II Veteran
Re: 3:54's or 3:75's? (Torquem)
Since 2.59/3.73=0.69, the RPM in 4th gear with 3.73 gears is about the same as in 3rd gear with 2.59s. So you can get most of your answers by driving in 3rd gear on the highway.
1. Compare instentaneous/average highway mileage.
2. Check RPM.
3. You will gain torque in each gear but come out of each gear earlier; most drag racers show a drop in 1/4 mi ET.
4. Top end will be limited to 140-170 mph at 5,000-6,000 rpm; so depends on your mods.
1. Compare instentaneous/average highway mileage.
2. Check RPM.
3. You will gain torque in each gear but come out of each gear earlier; most drag racers show a drop in 1/4 mi ET.
4. Top end will be limited to 140-170 mph at 5,000-6,000 rpm; so depends on your mods.
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Re: 3:54's or 3:75's? (65Z01)
for an auto id say go with 3.07s or 3.54s. I personnally think that 3.73 is too much for an auto w/o serious mods. But the LT1 sure does love gear. I get 2000rpm in mine and about 19mpg (mix of city and hwy driving though) and i have 3.07s, after i make all my mods i'll go up to 3.54s and a new TC. Have you thought about a new high stall TC?
65Z01, i thought LT1 owners gained ET with lower gears, is that just the 6spd's?
65Z01, i thought LT1 owners gained ET with lower gears, is that just the 6spd's?
Le Mans Master
Joined: Dec 2000
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From: San Angelo TX
Re: 3:54's or 3:75's? (vader86)
65Z01, i thought LT1 owners gained ET with lower gears, is that just the 6spd's?
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From: Houston, TX
Re: 3:54's or 3:75's? (IcemanZ06)
This car will see a track MAYBE once a year
the most mods it will ever see are my exhaust..cut lid with K&N, and possibly farther down the road a stall convertor.
I am not a hardcore drag racer but i DO want something better than 2:59's. Most of my perf needs will be minor street scuffs. not head to head track racing with stickies over and over. Are 3:73 what i really need? i just dont want a car that is useless past 80 mph
the most mods it will ever see are my exhaust..cut lid with K&N, and possibly farther down the road a stall convertor.
I am not a hardcore drag racer but i DO want something better than 2:59's. Most of my perf needs will be minor street scuffs. not head to head track racing with stickies over and over. Are 3:73 what i really need? i just dont want a car that is useless past 80 mph
Burning Brakes
Joined: Oct 2000
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From: Tulsa OK
Re: 3:54's or 3:75's? (Torquem)
I say go with the 3.54s. This is what I plan on getting. Mine only sees the drag strip once or twice a year. I don't need 3.73s, I just want an extra kick sometimes :yesnod: 2.59s are way to high for a corvette.
Burning Brakes
Joined: Aug 2000
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From: Warrenville IL
Re: 3:54's or 3:75's? (Torquem)
Honestly I think you'll be happy with either gear in your car. Part of the reason I went with the 3.54 instead of 3.73 was because I knew I would be putting in a good converter as well. Since you only plan on heading to the track once a year you're probably not going to be putting a converter in so you might consider going with the deeper 3.73. If the car is your daily driver and/or you do alot of highway driving then you might want to consider staying with the 3.54. I don't think it would be worthwhile to go with a 3.07 gear. just my opinion.
Going from the 2.59 to 3.54 I gained 5-6 tenths and 5 mph at the track on street tires.
Don't forget you'll need a Hypertech III to recalibrate the spedo gear after the ring & pinon goes in.
Going from the 2.59 to 3.54 I gained 5-6 tenths and 5 mph at the track on street tires.
Don't forget you'll need a Hypertech III to recalibrate the spedo gear after the ring & pinon goes in.
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From: SE NY
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Re: 3:54's or 3:75's? (IcemanZ06)
IcemanZ06, indeed a drop in ED means a quicker car.
I think the 6-speed guys gear a little higher since they have more OD than the A4s and 1st isn't quite as deep. Since the A4 has a pretty deep 1st gear and only a .70 OD maybe 3.73s would be a little steep for only street use. Put your shifter in "D" and take her out onto the highway and see what you think.
Of course my preference for the street/highway is to release more HP and keep my 2.59s. If I need a little more highway pickup my modified A4 shift gate allows me to confidently select 3rd or even 2nd. With 2.59s out back I can hit 90mph out of 2nd and 145mph out of 3rd at 5,250rpm.
I think the 6-speed guys gear a little higher since they have more OD than the A4s and 1st isn't quite as deep. Since the A4 has a pretty deep 1st gear and only a .70 OD maybe 3.73s would be a little steep for only street use. Put your shifter in "D" and take her out onto the highway and see what you think.
Of course my preference for the street/highway is to release more HP and keep my 2.59s. If I need a little more highway pickup my modified A4 shift gate allows me to confidently select 3rd or even 2nd. With 2.59s out back I can hit 90mph out of 2nd and 145mph out of 3rd at 5,250rpm.
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Safety Car
Joined: Sep 2001
Posts: 4,095
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From: modland CT
Re: 3:54's or 3:75's? (Torquem)
i put 375's in my car & blew my transmission (rebuilt with 2200 stall & shift kit)3 days later. you better hope your tranny is in tip top shape. :yesnod: i love my 375's! :D thay woke my car up!good luck! :cheers:
Safety Car
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From: Southern California
Re: 3:54's or 3:75's? (Torquem)
http://www.smokemup.com/utilities/calc/mph_range2.cfm
Plug it in. There is a very small rpm difference between the 3.73 and the 3.54. If you are swapping to a lower gear get the best one for the LT1. Get the 3.73's.
[Modified by Raysur, 10:29 AM 1/17/2002]
Plug it in. There is a very small rpm difference between the 3.73 and the 3.54. If you are swapping to a lower gear get the best one for the LT1. Get the 3.73's.
[Modified by Raysur, 10:29 AM 1/17/2002]
Le Mans Master
Joined: Apr 2000
Posts: 5,713
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From: Manassas VA
Re: 3:54's or 3:75's? (Torquem)
The one down side to the gear change is if you do a lot of highway driving the fuel mileage will suffer. Mine used to get 29 on the highway and now gets about 23.5 or 24mpg. Now this is on a trip running a steady 70mph. Stop and go traffic, I didnt notice such a loss. For me the loss of MPG were a good trade off for the additional power the car now has. But I only drive it about 4 or 5 thousand miles a year. Good luck with your decision
Drifting
Joined: Aug 2001
Posts: 1,407
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From: Houston TX
Re: 3:54's or 3:75's? (Torquem)
Sorry I got so excited that I did not answer your questions:
1. 16 mpg
2. 2600
3. no
4. I don't think you want to go that fast anyway.
5. You will stay in third gear in the quarter mile.
:smash:
1. 16 mpg
2. 2600
3. no
4. I don't think you want to go that fast anyway.
5. You will stay in third gear in the quarter mile.
:smash:
