3.90 vs 4.10 rear end
Thread Starter
Burning Brakes
Joined: Jun 2002
Posts: 1,055
Likes: 0
From: Troy MI
3.90 vs 4.10 rear end
I ordered a 4.10 rear end, but am now second guesing myself.
I was talking to a friend who drag races a caprise, he has an auto with a 4.10 and said it is a steep gear for the street.
I have a 6 speed, so I know it is a different animal, but what are forum member experiences with these two gears on a MN6?
See sig for mods.
He also told me with his rear end he had to heat cycle it to break it in, ie drive 10 miles, cool it off, repeat 10 times.
He also said that with his he can't run it on the express way at 70-80 mph for extended periods of time because it will overheat the gears. This especially sounded wierd to me.
I am not too concerned about the fuel mileage, I think it will still be fine for what I use the car for. I assume that the 4.10 will make 6th gear more usuable on the streets, and only reduce my fuel mileage to the mid twenties on the express way.
What will 4th gear top out at say around 6500 rpm?
If I run a 125 wet shot, for a total of 525 rwhp will I be at a disadvantage in 4th gear at the traps?
A lot of questions, but a gear swap in a C5 is big $$$
I was talking to a friend who drag races a caprise, he has an auto with a 4.10 and said it is a steep gear for the street.
I have a 6 speed, so I know it is a different animal, but what are forum member experiences with these two gears on a MN6?
See sig for mods.
He also told me with his rear end he had to heat cycle it to break it in, ie drive 10 miles, cool it off, repeat 10 times.
He also said that with his he can't run it on the express way at 70-80 mph for extended periods of time because it will overheat the gears. This especially sounded wierd to me.
I am not too concerned about the fuel mileage, I think it will still be fine for what I use the car for. I assume that the 4.10 will make 6th gear more usuable on the streets, and only reduce my fuel mileage to the mid twenties on the express way.
What will 4th gear top out at say around 6500 rpm?
If I run a 125 wet shot, for a total of 525 rwhp will I be at a disadvantage in 4th gear at the traps?
A lot of questions, but a gear swap in a C5 is big $$$
Le Mans Master
Joined: Jul 2000
Posts: 7,758
Likes: 0
From: Fort Worth Texas
Cruise-In II Veteran
Cruise-In III Veteran
Re: 3.90 vs 4.10 rear end (msuc5vette)
I made a spreadsheet a while back that will help with some of your math questions...
http://www.vetteguru.com/apps
gforce.xls
http://www.vetteguru.com/apps
gforce.xls
Instructor
Joined: Sep 2003
Posts: 145
Likes: 0
From: Scottsdale Arizona
Re: 3.90 vs 4.10 rear end (msuc5vette)
http://www.smokemup.com
this site will help you calculate your trap speeds based on tranny, tire size and gearing. After thoroughly researching this and reading the hundred's posts here I decided on the 4:10 but I run N/A no power adder and expect to hit the trap in fourth gear at 6600 rpm (fuel cut off at 6700) and 120 mph. If I had NO2 I would have gone with the 3:90 which will get you 124 mph @6500 rpm. This is based on a 26.1 inch diameter tire.You may want go with the 3:90 and bump the fuel cut off to 6800. You could get about 127 or 128 mph out of that set up at 6700 rpm. This of course assumes you are running the N02. With the 4:10's in there and 525rwhp you will have to shift out of fourth gear or severly over rev the engine. I have about 415 rwhp and with my current 3:73's my trap speed is 117 mph.
:cheers:
[Modified by goodhands, 8:15 PM 2/4/2004]
this site will help you calculate your trap speeds based on tranny, tire size and gearing. After thoroughly researching this and reading the hundred's posts here I decided on the 4:10 but I run N/A no power adder and expect to hit the trap in fourth gear at 6600 rpm (fuel cut off at 6700) and 120 mph. If I had NO2 I would have gone with the 3:90 which will get you 124 mph @6500 rpm. This is based on a 26.1 inch diameter tire.You may want go with the 3:90 and bump the fuel cut off to 6800. You could get about 127 or 128 mph out of that set up at 6700 rpm. This of course assumes you are running the N02. With the 4:10's in there and 525rwhp you will have to shift out of fourth gear or severly over rev the engine. I have about 415 rwhp and with my current 3:73's my trap speed is 117 mph.
:cheers:
[Modified by goodhands, 8:15 PM 2/4/2004]
Melting Slicks
Joined: Jun 2001
Posts: 2,743
Likes: 3
From: Davie Florida
Re: 3.90 vs 4.10 rear end (98VETTEC5)
The M6 is an entirely different animal than an A4 with 4.10 gears. IMO 4.10s are not too much for an M6. Your final drive ratio will only be 2.05 in 6th gear on the highway.
Thread Starter
Burning Brakes
Joined: Jun 2002
Posts: 1,055
Likes: 0
From: Troy MI
Re: 3.90 vs 4.10 rear end (Mitch C)
I believe my rev limiter is set at 6900 already, I'm probably not going to end up at the track that often, or use the N2O very often.
Are long trips on the e-way at 80-90mph an issue for the gears?
What is the breakin if any?
Are long trips on the e-way at 80-90mph an issue for the gears?
What is the breakin if any?
Collections Hold
Joined: Aug 2002
Posts: 2,899
Likes: 6
From: Fort Wayne Indiana
Re: 3.90 vs 4.10 rear end (goodhands)
When a differential is built properly, break-in procedures are not/should not be complex and are very easy to follow.
Our differentials carry a 300 mile break-in schedule and no additional fluid changes are necessary after the initial fill w/ our supplied lubricants, abiet regularly scheduled maintainace. That's it! :thumbs:
No special heating.....no special cooling.....waiting around for cool-down, high speed-low speed run around....... :rolleyes:
Just follow our easy break-in schedule with our differentials and it will live a long happy life! :) :auto:
HTH's :)
Regards,
Phil
DTE
Our differentials carry a 300 mile break-in schedule and no additional fluid changes are necessary after the initial fill w/ our supplied lubricants, abiet regularly scheduled maintainace. That's it! :thumbs:
No special heating.....no special cooling.....waiting around for cool-down, high speed-low speed run around....... :rolleyes:
Just follow our easy break-in schedule with our differentials and it will live a long happy life! :) :auto:
HTH's :)
Regards,
Phil
DTE
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Melting Slicks
Joined: Mar 2001
Posts: 2,372
Likes: 51
From: New Milford CT
Re: 3.90 vs 4.10 rear end (DynoTech Engineering)
I have 3.90's, if I did it again, I would go with the 4.10's. After a month or so you will not even remember what it was like with the 3.42's, the new gears will feel so natural.
Team Owner
Joined: Apr 2001
Posts: 26,794
Likes: 614
From: Elmhurst, IL (West Suburb of Chicago) & Home of MEGA Horsepower
St. Jude Donor '06
Re: 3.90 vs 4.10 rear end (98VETTEC5)
I honestly think your friend is a little bit :crazy: :crazy: ! I have 4.10s in my z06 and love it and NOBODY that i have seen after many many posts here never had anything but RAVE REVIEWS after putting in 4.10s in their M6 car. That having been said, if your planning to drag race you may have to bump up your rev limiter a bit so that you will not have to shift out of 4th gear going through the traps as that will probably be a problem if you stay stock with the rev limiter with 4.10s!!! Something to consider! OOPPs, now i see you rev limiter is set to around 6900 or so so you are GOOD TO GO BROTHER!!!!!! ;) :D
GOOD LUCK! :cheers:
[Modified by MTI 427 Roadster, 10:15 PM 2/4/2004]
GOOD LUCK! :cheers:
[Modified by MTI 427 Roadster, 10:15 PM 2/4/2004]
Supporting Vendor
Joined: Mar 2002
Posts: 2,073
Likes: 0
From: Loveland CO
Re: 3.90 vs 4.10 rear end (Mitch C)
I ordered my gears from DTE about a week and half ago. I have a 6 speed also and decided to go with 4:10's with the hardened output shaft. Fed Ex says they are on the truck for delivery right now. I don't think that the 4:10's will be to much of a gear for you. With the 4:10's you 5th and 6th gear will be more usefull. Kaley
Drifting
Joined: Mar 2003
Posts: 1,817
Likes: 0
From: Pacific Beach CA
Re: 3.90 vs 4.10 rear end (kewlbrz)
I made a spreadsheet a while back that will help with some of your math questions...
http://www.vetteguru.com/apps
gforce.xls
http://www.vetteguru.com/apps
gforce.xls
Le Mans Master
Joined: Apr 2001
Posts: 8,133
Likes: 144
From: Ex-SF Bay Area; now happily Denver area
Re: 3.90 vs 4.10 rear end (Cobra4B)
4.10's + mn6 = perfect
4.10's + mn12 = no traction
3.73's + mn12 = perfect (but not worth the cost to me)
4.10's + mn12 = no traction
3.73's + mn12 = perfect (but not worth the cost to me)
Team Owner
Joined: Apr 2001
Posts: 26,794
Likes: 614
From: Elmhurst, IL (West Suburb of Chicago) & Home of MEGA Horsepower
St. Jude Donor '06
Re: 3.90 vs 4.10 rear end (FunDriver)
The mn12 with 3.42's is similar to an mn6 and 3.90's---so I think that an mn12 with 4.10's is like going from 3.42's to 4.68's on an mn6. That's a lot of gearing. :yesnod: [/QUOTE]
And TRUST me when i tell you that ALOT of GEARING makes for ALOT OF FUN!!!!!!!!!!!!!!!!!!!! :party: :steering: :chevy :auto:
And TRUST me when i tell you that ALOT of GEARING makes for ALOT OF FUN!!!!!!!!!!!!!!!!!!!! :party: :steering: :chevy :auto:
Pro
Joined: Sep 2003
Posts: 564
Likes: 0
From: Cary NC
Re: 3.90 vs 4.10 rear end (msuc5vette)
Here is one vendors installation instructions/breakin procedure. http://www.westcoastcorvette.com/ins...nstruction.jpg
Moderator
Joined: Jan 2001
Posts: 17,139
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From: Charlotte NC
Cruise-In IV Veteran
Cruise-In V Veteran
St. Jude Donor '08-'25
Re: 3.90 vs 4.10 rear end (goodhands)
http://www.smokemup.com
this site will help you calculate your trap speeds based on tranny, tire size and gearing. After thoroughly researching this and reading the hundred's posts here I decided on the 4:10 but I run N/A no power adder and expect to hit the trap in fourth gear at 6600 rpm (fuel cut off at 6700) and 120 mph. If I had NO2 I would have gone with the 3:90 which will get you 124 mph @6500 rpm. This is based on a 26.1 inch diameter tire.You may want go with the 3:90 and bump the fuel cut off to 6800. You could get about 127 or 128 mph out of that set up at 6700 rpm. This of course assumes you are running the N02. With the 4:10's in there and 525rwhp you will have to shift out of fourth gear or severly over rev the engine. I have about 415 rwhp and with my current 3:73's my trap speed is 117 mph.
:cheers:
[Modified by goodhands, 8:15 PM 2/4/2004]
this site will help you calculate your trap speeds based on tranny, tire size and gearing. After thoroughly researching this and reading the hundred's posts here I decided on the 4:10 but I run N/A no power adder and expect to hit the trap in fourth gear at 6600 rpm (fuel cut off at 6700) and 120 mph. If I had NO2 I would have gone with the 3:90 which will get you 124 mph @6500 rpm. This is based on a 26.1 inch diameter tire.You may want go with the 3:90 and bump the fuel cut off to 6800. You could get about 127 or 128 mph out of that set up at 6700 rpm. This of course assumes you are running the N02. With the 4:10's in there and 525rwhp you will have to shift out of fourth gear or severly over rev the engine. I have about 415 rwhp and with my current 3:73's my trap speed is 117 mph.
:cheers:
[Modified by goodhands, 8:15 PM 2/4/2004]
BTW: Unrelated point...N02 is Nitric Oxide which a supplement used for fitness athletes...N20 is Nitrous Oxide ;) :yesnod:
Guest
Posts: n/a
Re: 3.90 vs 4.10 rear end (msuc5vette)
Don't agree with other posts: I'd go 3.90s in the M6. I've had 3.73s and 3.90s in my C5 M6. Can't see how anyone would want 4.10s unless they were a drag racer. The 3.90s are almost too tall for my taste, but still OK, and quick. With 4.10s, say goodbye to using 4th gear on the highway. JMO.
Good luck.
Good luck.
