For the non-mechanical guy some times the forum sends me in different directions. One posts says that I absolutely need to do... and then the very next post says absolutely no way should you do...

This is what I think I want to do. I'll never be on the track, just want a little more zip/get up and go. I have a 00 M6 Vert. I have a Blackwing and 160 thermostat. Instead of buying a ton of bolt of modifications which are often suspect in "do they really add a gazillion HP" I've decided to just get the rear gears changed to 4.10. Based on the reading I've done, I think this is the "single best" modification that I can do for the bucks. I also intend on doing someting for the exhaust (Corsa Indy) just for the sound and not necessarily for the HP.

Am I heading in the right direction or am I barking up the wrong tree?
Be kind because I don't know what the hell I'm doing!!

 

Get the 4:10's, you'll love em. One of the best mods I've done, I'll probably never go to the track with mine either but just makes it a lot more fun to drive. I started out with a exhaust and an intake. Then the gears and now headers. The car has a sound that is just awesome and my normal shifting has moved from 2000 to 3000 just to hear the exhaust. You won't regret the change.

 

ttt

 

4.10's got my vote. SOTP feel is just awesome. Go for it. You won't be sorry.

 

There is nothing quite as thrilling as the SOTP response and difference you will feel when you upgrade the rear gears.

 

What does SOTP stand for? Also do 4.10 gears hurt gas mileage in a M6?

 

Seat of the pants = SOTP

I just put 4.10's & LS7 clutch in my car last Friday. Still babying it to break them in, but I'm already likeing them. You won't even be able to tell much difference cruising at 80 mph in 6th, but the lower 5 are much closer. Seems the car moves out of the hole much easier with less effort. I can't imagine there wil be much difference in gas mileage, maybe 1-2 mpg at most, however I expect it to stay the same. Again, cruising in 6th, there is not that big a change.

I have another 3-400 miles before I get on it, but I can tell the car feels quicker. If you break them in right, they wil be as quiet as stock, and nobody will be able to tell a difference except you. After just 100 miles, I'm already used to them.

I bought mine through Xtreme Motorsports, they are made by DTE. Figure on ~$1200 for a complete diff, even comes with fluids. I bought a diff with 2.73's from a forum member as a cheap core, and will sell my 3.42's in a months or so. Figure $1200 for gears, $150 for core, sell your 3.42's for $500, your out $850 for the gears. If you can't do the labor, figure on $3-400 for the install.

There are some really good guides on doing this, and it's really quite easy. If you can turn a wrench, you can do this. Took me and a friend 7 hrs for this and a clutch install. Gears should be 3-4 hrs.

 

SOTP=Seat of the pants

Yes, the 4:10's will hurt the gas mileage just a little depending on how you drive it. I still get 17 to 20 around town and that's getting on it a little every now and then. On the road 27 to 28.

 

Seat Of The Pants - you know, the force you feel when accelerating much too quickly.

It can lower gas mileage depending on how you drive. It's not significant either way, though - or so I hear. I don't yet have my 4.10s installed, but it is coming.

 

Gas mileage change will be approximately 3.42/4.1 (assuming you started with 3.42 gears). 3.42/4.1=83.4%, in other words if you were getting (non-specific round numbers now) 30 mpg on the highway you will likely get 25 on the highway. If you were getting 15 in the city, you will get 12.5 in the city. This also assumes that you don't change your driving habits. In fact your driving habits will change, but could go either direction!

 

It will drop the mileage THAT much? That's crazy. I heard that it could change it by up to maybe 1mpg, but 5 is totally insane. That means it will cut around 100 miles off how much you used to get per tank! Looks like I won't be getting this mod.

 

20% reduction in gas mileage, no way.


I suggest that you listen to those that actually have them in their car.

 

I think you are headed in the right direction, and it sounds like you have done some homework.
A couple of things, and pardon me if you have already thought this through, but I did not see it in your post. One of the things people tend to forget when they mod, is how will this effect other parts of the car, or how will this mod effect other mods.

Switching to 410 gears is a great mod, and will change the SOTP feel quite a bit. I did this mod to a few of my F-body Camaros.

The thing to watch is TRACTION...think how easy it is to spin the tires with the stock 342 gear, and then multiply that by say 4 times (just generally speaking)..you will need to learn to shift a drive a bit more conservatively, otherwise you will be just putting on a nice Smoke Show with your tires

2nd- what are your future mods? If you plan on ever doing some big horsepower mods like Nitrous or a SuperCharger, Big Cam/heads then 410 gears maybe to much, even if you don't track the car.

that's my .02 cents. Only downside to this forum is that lots of people jump on the "band wagon" just because, and they don't think what is best for them, and their car, might not be so good for someone else's car or driving style.

have fun and good luck with your gears I am sure you'll love them

 

I have had the 4;10s in for about a year on my Silver coupe they are great all around the factory should put them in as a standard ratio. Last year I drove to the cruise in up in KY averaged 29 MPG at 80MPH she is only turning 2100 RPM and as for a 1st gear pull if your tires bite hang on You will feel the diff

 

I was talking to a local tuner today, and he recommended 4.10 gears also. I have a 2004 mn6 vert, modded with a Honker, QTP lt headers, hi flow cats and Corsa Indy's. I had asked about an intake manifold and bigger throttle body, since I don't want to do heads/cam, and he said gears were the best thing to do.

If I go with 4.10's, should I do hardened shafts at the same time? Also, what other secondary effects would there be with 4.10 gears, other than even more fun?

 

4.10:1 gears make you feel like you did something...

good idea...

no more hp just seat-of-the-pants response

..just right for a 00 m6 vert

 

Uh, WRONG! You can not linearize and extrapolate the mileage that way. Your assumptions are incorrect. Sorry.

 

Sorry, but have to disagree. The above assumes that the MPH/GEAR will remain the same after the gear change. If the you drive by RPM per MPH the mileage should not change.

 

Do it! Best mod you can do with a 6 spd. unless you plan on upgrading beyond 400 rwhp someday. Then traction becomes a serious issue. I love my 4.10's, and gas mileage is a non-issue. You still cruise at 1800 rpms at 70 mph. Make 6th gear a useful ratio.

 

Obviously I can't go wrong with the 4.10 gears. I'm sure I'll have to learn how to come off of the clutch now. I'll suck up the difference for the gas mileage if it is truely an issue I feel good with the advice provided. I'll let you guys know what happens.

VETSTYL
27 YEAR ARMY VET