40 mph sucks for a 3.23 car as well. 
Question - Modding an 04 C5 Auto 2.73
Thread Starter
Staging Lane
Joined: Aug 2004
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Question - Modding an 04 C5 Auto 2.73 I raced my 98 stock Z28(MN6 3.42) the other day in the vette. It was from a 40 roll and the camaro pulled strong and consistently on the car (lead was at least 3 car lengths) till we let off at about 120. The vette has some minor mods.....borla duals catback, vararam and tune.
So what's the next step to go much faster in a straight line? Gears or heads and cam on the vette. Which is more expensive? FI is not an option. FYI, I'm a rolling start kinda guy.
All opinions welcome.
So what's the next step to go much faster in a straight line? Gears or heads and cam on the vette. Which is more expensive? FI is not an option. FYI, I'm a rolling start kinda guy.
All opinions welcome.
Question - Modding an 04 C5 Auto 2.73 The next step should be a 3.42 differential and 3000-3500 stall convertor. Many use this combo as a daily driver with great results. Your car will feel totally different and run much quicker.
Thread Starter
Staging Lane
Joined: Aug 2004
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Originally Posted by DBN
The next step should be a 3.42 differential and 3000-3500 stall convertor. Many use this combo as a daily driver with great results. Your car will feel totally different and run much quicker.
I'm considering the 3.42 diff.. Ecklers has one for 1K which is not a bad deal. Don't know if a new stall is all that important to me at this point since I don't plan on launching the sucker.
TECH Apprentice
Joined: Nov 2001
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From: Long Island
A high stall will help from a roll, it'll keep you in the powerband. I'm looking for a rematch against a procharged MN6 Camaro. He pulled on me a little with my SS4000, now with my YPT4400, it should be close. 
11 Second Club
Joined: Nov 2001
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From: NE PA
As I'm sure you already know, your 2.73 gears are killing you. However, I wouldn't waste my time going to 3.42's. There's a reason serious M6 guys get rid of them in a hurry. They just aren't enough. If you're going to spend the time and expense for a gear change, I'd highly recommend getting 3.73 gears. After a lot of research and getting the opinions of those that had already made the swap to various gear ratios, the 3.73's became the clear choice. I couldn't be happier with them.
Of course, racing from a roll you are giving away all the advantage you have with your A4 car which is from a dead stop. For you to be really competitive from a roll, you'll not only need deeper gears, but, as already stated, a higher stall torque converter in the 3500+ stall speed range.
Of course, racing from a roll you are giving away all the advantage you have with your A4 car which is from a dead stop. For you to be really competitive from a roll, you'll not only need deeper gears, but, as already stated, a higher stall torque converter in the 3500+ stall speed range.
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Formerly MagRedC5
Joined: Dec 2002
Posts: 235
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From: San Antonio, TX
Originally Posted by DBN
The next step should be a 3.42 differential and 3000-3500 stall convertor. Many use this combo as a daily driver with great results. Your car will feel totally different and run much quicker.
ITS NO SECRET... get rid of the 2.73 rear diff, ASAP!Swap out for a 3.42 rear diff / Vigilante 2800 [flashes to 3200] and you will be very pleased with the much quicker performance, as well as the retained drivability.
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Verdad Gallardo Formerly MagRedC5
Joined: Dec 2002
Posts: 235
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From: San Antonio, TX
Originally Posted by XTrooper
Or a 3500 with 3.73 gears and it'll still be totally streetable and feel nearly stock. 
Your definitely a reliable source, yet just wanting to compare... thanks.
11 Second Club
Joined: Nov 2001
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From: NE PA
Originally Posted by MagRedC5
What is your tach showing cruising down the hwy at 70mph?
Your definitely a reliable source, yet just wanting to compare... thanks.
Your definitely a reliable source, yet just wanting to compare... thanks.
FWIW, I only lost ~2 mpg highway going from 3.15 to 3.73 gears.
Teching In
Joined: Mar 2005
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From: Davie Fla.
Originally Posted by MagRedC5
What is your tach showing cruising down the hwy at 70mph?
Your definitely a reliable source, yet just wanting to compare... thanks.
Your definitely a reliable source, yet just wanting to compare... thanks.
Formerly MagRedC5
Joined: Dec 2002
Posts: 235
Likes: 0
From: San Antonio, TX
Originally Posted by XTrooper
At 70 mph my engine is taching at ~2300 rpm. Even at 80 mph, I'll still under 2700 rpm.
FWIW, I only lost ~2 mpg highway going from 3.15 to 3.73 gears.
FWIW, I only lost ~2 mpg highway going from 3.15 to 3.73 gears.
However, no more major mods anytime soon.
I found out the hard way my homeowners insurance does not insure slab leaks. My wife & I had to take out a home equity loan to cover the repair cost of a recent hot water slab leak in one of our bathrooms. We could use the extra $$$ for other house touch ups, too. BTW, my wife made me promise not to use any of the $$$ leftover for mods. 
11 Second Club
Joined: Nov 2001
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From: NE PA
Originally Posted by MagRedC5
As you know, I went from 2.73 to 3.42, which was a noticeable improvement. Now, I suppose a 3.73 rear diff would have been a better choice
However, no more major mods anytime soon. I found out the hard way my homeowners insurance does not insure slab leaks. My wife & I had to take out a home equity loan to cover the repair cost of a recent hot water slab leak in one of our bathrooms. We could use the extra $$$ for other house touch ups, too. BTW, my wife made me promise not to use any of the $$$ leftover for mods.
However, no more major mods anytime soon.
I found out the hard way my homeowners insurance does not insure slab leaks. My wife & I had to take out a home equity loan to cover the repair cost of a recent hot water slab leak in one of our bathrooms. We could use the extra $$$ for other house touch ups, too. BTW, my wife made me promise not to use any of the $$$ leftover for mods. Regarding the gears, I was dead-set on going to 3.42 gears and when I started in inquire about the install, I was told by two major tuners here in the Northeast (East Coast Supercharging and The Vette Doctors) that I should definitely skip them and go with 3.73's. Now that I have them, I'm glad they convinced me to go with them.
Originally Posted by XTrooper
As I'm sure you already know, your 2.73 gears are killing you. However, I wouldn't waste my time going to 3.42's. There's a reason serious M6 guys get rid of them in a hurry. They just aren't enough. If you're going to spend the time and expense for a gear change, I'd highly recommend getting 3.73 gears. After a lot of research and getting the opinions of those that had already made the swap to various gear ratios, the 3.73's became the clear choice. I couldn't be happier with them.
Of course, racing from a roll you are giving away all the advantage you have with your A4 car which is from a dead stop. For you to be really competitive from a roll, you'll not only need deeper gears, but, as already stated, a higher stall torque converter in the 3500+ stall speed range.
Of course, racing from a roll you are giving away all the advantage you have with your A4 car which is from a dead stop. For you to be really competitive from a roll, you'll not only need deeper gears, but, as already stated, a higher stall torque converter in the 3500+ stall speed range.
3.73 3800 vigilante and LG headers
Get the tranS done by
Rodney(crashed 94) my choice ) then ,FLP,ROSSLER at this point you're mid 12's
Now you're ready for the HP mods
mild H/C
11.61 119 1.67 60'
Want more ,I do! (Stroker ) thinking 402 for 10's Still a corvette and not a race car
These opinions for ET 'S are in Michigan (800ft ) not on the east coast
Our cars are faster! (at sea level)
John Sr.
Last edited by Blktie8; May 20, 2005 at 07:21 AM.
Originally Posted by z28nbr1fan
I raced my 98 stock Z28(MN6 3.42) the other day in the vette. It was from a 40 roll and the camaro pulled strong and consistently on the car (lead was at least 3 car lengths) till we let off at about 120. The vette has some minor mods.....borla duals catback, vararam and tune.
So what's the next step to go much faster in a straight line? Gears or heads and cam on the vette. Which is more expensive? FI is not an option. FYI, I'm a rolling start kinda guy.
All opinions welcome.
So what's the next step to go much faster in a straight line? Gears or heads and cam on the vette. Which is more expensive? FI is not an option. FYI, I'm a rolling start kinda guy.
All opinions welcome.
TECH Senior Member
Joined: Nov 2001
Posts: 10,341
Likes: 1
If you are going to change gears I'd go 3.42's (cheaper and plentiful)
Personally I have a 2.73 geared C5 with TCI 3000 stall converter.
Runs 12.50s@111mph with marginal traction. (BONE stock internally. Just headers, converter and halltech)
From a stoplight and on a roll with the converter the car is deadly. (I can hit 60mph in first gear and downshift to second at ~95mph)
I have thought about 3.42s but there'll be a problem with traction (DRs will be a must)
Just another perspective for you to chew on
Personally I have a 2.73 geared C5 with TCI 3000 stall converter.
Runs 12.50s@111mph with marginal traction. (BONE stock internally. Just headers, converter and halltech)
From a stoplight and on a roll with the converter the car is deadly. (I can hit 60mph in first gear and downshift to second at ~95mph)
I have thought about 3.42s but there'll be a problem with traction (DRs will be a must)
Just another perspective for you to chew on
Thread Starter
Staging Lane
Joined: Aug 2004
Posts: 71
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Update.....Yank Stealth 3000, B&M Cooler, and Z06 3.42 diff. purchased and waiting to get installed.
I think these upgrades will help to overtake my Z. BTW, I recently ported the MAF housing, did the coolant bypass, 160 stat, and the FRA mod on the Z. Still using the stock lid though. Car runs great. I'm thinking about porting the throttle body to pick up some extra air flow. Still running a stock exhaust system. Thinking about pulling the trigger on a cheap TSP exhaust and a lid since it's long overdue.
Thanks for the advice.
I think these upgrades will help to overtake my Z. BTW, I recently ported the MAF housing, did the coolant bypass, 160 stat, and the FRA mod on the Z. Still using the stock lid though. Car runs great. I'm thinking about porting the throttle body to pick up some extra air flow. Still running a stock exhaust system. Thinking about pulling the trigger on a cheap TSP exhaust and a lid since it's long overdue.
Thanks for the advice.
I wouldn't mess with anything under a 3.73 gear. I know how expensive those C5 differentials are
I'd get the upgraded output shaft as well. The labor on the diff replacement is rated around 10 hours.
No need to do it twice.
Mike
I'd get the upgraded output shaft as well. The labor on the diff replacement is rated around 10 hours.
No need to do it twice.
Mike