3.15s or 3.42s?
Thread Starter
Drifting
Joined: Aug 2004
Posts: 1,519
Likes: 0
From: Bedford TX
St. Jude Donor '06-'07
3.15s or 3.42s?
I am trying to determine which way to go....
I will be doing my H/C upgrade with 21st Century Musclecars next month and I anticipate about 400 rwhp/rwtq on my 98 A4 coupe. I currently have 2.73s. This is my DD and weekend toy (no 1/4 mile, but definitely auto-x and now HPDE) that I drive on 700 mi. roundtrip business meetings monthly (the company pays per mile) and rack up about 15k miles per year.
Gas mileage is a concern (I don't think prices are coming down), but not the biggest. Driveability and durability are #1. I have a freeway commute every morning and I don't want it continuously running at 3500 rpm all the time (alot of wear and tear).
I can easily stick with the 2.73s, but gears + tq =
Thanks in advance.
I will be doing my H/C upgrade with 21st Century Musclecars next month and I anticipate about 400 rwhp/rwtq on my 98 A4 coupe. I currently have 2.73s. This is my DD and weekend toy (no 1/4 mile, but definitely auto-x and now HPDE) that I drive on 700 mi. roundtrip business meetings monthly (the company pays per mile) and rack up about 15k miles per year.
Gas mileage is a concern (I don't think prices are coming down), but not the biggest. Driveability and durability are #1. I have a freeway commute every morning and I don't want it continuously running at 3500 rpm all the time (alot of wear and tear).
I can easily stick with the 2.73s, but gears + tq =
Thanks in advance.
Race Director
Joined: Mar 2005
Posts: 14,440
Likes: 3
From: MD
St. Jude Donor '11
Originally Posted by mcintex
I am trying to determine which way to go....
I will be doing my H/C upgrade with 21st Century Musclecars next month and I anticipate about 400 rwhp/rwtq on my 98 A4 coupe. I currently have 2.73s. This is my DD and weekend toy (no 1/4 mile, but definitely auto-x and now HPDE) that I drive on 700 mi. roundtrip business meetings monthly (the company pays per mile) and rack up about 15k miles per year.
Gas mileage is a concern (I don't think prices are coming down), but not the biggest. Driveability and durability are #1. I have a freeway commute every morning and I don't want it continuously running at 3500 rpm all the time (alot of wear and tear).
I can easily stick with the 2.73s, but gears + tq =
Thanks in advance.
I will be doing my H/C upgrade with 21st Century Musclecars next month and I anticipate about 400 rwhp/rwtq on my 98 A4 coupe. I currently have 2.73s. This is my DD and weekend toy (no 1/4 mile, but definitely auto-x and now HPDE) that I drive on 700 mi. roundtrip business meetings monthly (the company pays per mile) and rack up about 15k miles per year.
Gas mileage is a concern (I don't think prices are coming down), but not the biggest. Driveability and durability are #1. I have a freeway commute every morning and I don't want it continuously running at 3500 rpm all the time (alot of wear and tear).
I can easily stick with the 2.73s, but gears + tq =
Thanks in advance.
Drifting
Joined: Dec 2004
Posts: 1,937
Likes: 1
From: Tempe Az
Originally Posted by mcintex
I am trying to determine which way to go....
I will be doing my H/C upgrade with 21st Century Musclecars next month and I anticipate about 400 rwhp/rwtq on my 98 A4 coupe. I currently have 2.73s. This is my DD and weekend toy (no 1/4 mile, but definitely auto-x and now HPDE) that I drive on 700 mi. roundtrip business meetings monthly (the company pays per mile) and rack up about 15k miles per year.
Gas mileage is a concern (I don't think prices are coming down), but not the biggest. Driveability and durability are #1. I have a freeway commute every morning and I don't want it continuously running at 3500 rpm all the time (alot of wear and tear).
I can easily stick with the 2.73s, but gears + tq =
Thanks in advance.
I will be doing my H/C upgrade with 21st Century Musclecars next month and I anticipate about 400 rwhp/rwtq on my 98 A4 coupe. I currently have 2.73s. This is my DD and weekend toy (no 1/4 mile, but definitely auto-x and now HPDE) that I drive on 700 mi. roundtrip business meetings monthly (the company pays per mile) and rack up about 15k miles per year.
Gas mileage is a concern (I don't think prices are coming down), but not the biggest. Driveability and durability are #1. I have a freeway commute every morning and I don't want it continuously running at 3500 rpm all the time (alot of wear and tear).
I can easily stick with the 2.73s, but gears + tq =
Thanks in advance.
11.63@121.14mph 1.80 60ft with 2.73's, 3000 stall and 400rwhp.
Just get a stall.
Team Owner
Joined: Apr 2001
Posts: 54,204
Likes: 180
From: S.W. Ohio. . . . . . NRA Life Member
Originally Posted by army2000
Personally I don't see anything wrong with the 3.42's. With your specifications I wouldn't recommend going higher. Good luck and enjoy your car.
Pro
Joined: Jan 2004
Posts: 749
Likes: 0
From: Las Cruces New Mexico
John and friends will take care of you at 21st CMC. They did a H/C and 2800 stall TC for mine with my factory 3.15 gears. I came back later for the 3.42 gears which John suggested the first go round - Should have listened! Highway cruising is not an issue - still getting 23 -25 mpg on the open road. Tires will be an issue - those back ones just keep wearing out!!!!!!!!!!!!
Good luck on your choice.
Good luck on your choice.
Team Owner
Joined: Oct 2000
Posts: 39,939
Likes: 61
From: From San Diego to Bentonville, AR.....WTF was I thinking?!? Oh yeah, that free state thingy!
St. Jude Donor '15-'16
On my first Vette, I also had a 2.73 & A4. I installed a SuperYank 3500 TC and 3.42s with programming, of course (have to when going higher than 3.15). I loved it!! It was my daily driver and there were no issues with it whatsoever. Mileage did drop 1.5-2 mpg, but it was absolutely worth it. Of course, it could have been 'cause I was enjoying driving it so much more. 
I woulnd't worry about wear-and-tear, it doesn't run at that much higher RPM,. Personally, I like running it at higher RPM because that's where they really perform. Definitely go with the 3.42s over the 3.15.
Hope this helps. Good luck with the mods.
I woulnd't worry about wear-and-tear, it doesn't run at that much higher RPM,. Personally, I like running it at higher RPM because that's where they really perform. Definitely go with the 3.42s over the 3.15.Hope this helps. Good luck with the mods.
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Drifting
Joined: Nov 2002
Posts: 1,644
Likes: 0
From: Sparta NJ
I have 3.73s and a Yank SS3600 TC. Since you do a lot of highway miles, go with the 3.42s and a 2800 stall TC. You won't lose any driveability and it will feel like a beast compared to your 2.73s and stock TC.
Drifting
Joined: Jun 2002
Posts: 1,847
Likes: 1
From: Iowa
Cruise-In IV Veteran
Cruise-In V Veteran
Originally Posted by BiggieBoy
Go w/ the 3.42's, you'll not be sorry.... 
Small cam, headers, Yank 3200 converter.....goes like a raped ape when I want it to, and gives me 30 mpg when I want it to.
3.42's do not without some sacrifice in fuel economy. In my previous Vette, the jump to 3.42 gears cost me 4 mpg....it does add up over a few miles.
It was mentioned there is a lack of torque with 2.73's. Tell you what, with this mild cam/header setup, I can fry those tires from a dead stop clear up to 65 mph. THAT'S torque!
I say get the H/C and torque converter job done and see how you like it, before committing to the added expense of gears and whatnot.
Le Mans Master
Joined: Aug 2000
Posts: 5,294
Likes: 2
From: Suffolk, Long Island NY
I'd go with the 3.42's, I don't miss my 3.15's one bit!
As for reving to 3500 rpms on the parkway, I'm only at 3000rpms at 80mph with 4.10's(yes A4), so don't be afraid to go to 3.42's.
As for reving to 3500 rpms on the parkway, I'm only at 3000rpms at 80mph with 4.10's(yes A4), so don't be afraid to go to 3.42's.
Le Mans Master
Joined: Aug 2003
Posts: 9,298
Likes: 4
From: American Canyon Lethal Injection
Originally Posted by MagikDraggin
I stuck with the 2.73's (I do a lot of highway driving too) and am not sorry I did.
Small cam, headers, Yank 3200 converter.....goes like a raped ape when I want it to, and gives me 30 mpg when I want it to.
3.42's do not without some sacrifice in fuel economy. In my previous Vette, the jump to 3.42 gears cost me 4 mpg....it does add up over a few miles.
It was mentioned there is a lack of torque with 2.73's. Tell you what, with this mild cam/header setup, I can fry those tires from a dead stop clear up to 65 mph. THAT'S torque!
I say get the H/C and torque converter job done and see how you like it, before committing to the added expense of gears and whatnot.
Small cam, headers, Yank 3200 converter.....goes like a raped ape when I want it to, and gives me 30 mpg when I want it to.
3.42's do not without some sacrifice in fuel economy. In my previous Vette, the jump to 3.42 gears cost me 4 mpg....it does add up over a few miles.
It was mentioned there is a lack of torque with 2.73's. Tell you what, with this mild cam/header setup, I can fry those tires from a dead stop clear up to 65 mph. THAT'S torque!
I say get the H/C and torque converter job done and see how you like it, before committing to the added expense of gears and whatnot.
I'm doing a mild cam, LS6 intake, underdrive pulley and headers, but going from 2:73 to 3:15. Want to keep decent gas milage.Rsty
Race Director
Joined: Apr 2004
Posts: 16,135
Likes: 5
From: Newberry FL
Cruise-In VIII Veteran
St. Jude Donor '07
Originally Posted by Sully C5
I had 3.15's on my 427 & switched to 3.42's. Going from 2.73's to 3.42's would be sweet!
I am going to go from 3:15s to 3:42s hopefully this summer. I just think that is the perfect gearing for these cars.
