darkoctave99

i have an 02 m6 z28 with all boltons(after next week). i will eventually be going inside for a h/c swap. looking to get close to 425-430 rwhp before its all over. i was wondering, since i have a 3.43, what gear i should go to. i want to feel a harder pull, but i want to maintain somewhat of a daily driver. what would be the pros and cons of the 3.73 vs. the 4.10?
also, after that is answered, where is the best place to buy the gears from?

42NightZ28

with that kind of power you will destroy 4.10s before to long. DO your self a favor and wait till you can afford a new rear and get 4.10 then

Mike K.

I was thinking of getting 4.10's myself, they are weaker unless you have a 12 bolt so be careful.

darkoctave99

why are they weaker?

1ScrudeDude

Allow me........

Size Matters
January, 2000
When ever the gear ratio in a differential is changed pinion diameter changes. There are two things that must change in order for the gear ratio to change. First, the gear ratio is determined by the tooth combination. The number of teeth on the ring gear divided by the number of teeth on the pinion (eg: 41/11 = 3.73) equals the gear ratio. Second, in order for the teeth to have the proper mesh and contact, the relative size of the two must be changed to match the ratio. If the gear ratio is 3.00 to 1, the distance from the pinion shaft centerline to center of the pinion teeth must be 1/3 the distance of the center of the ring gear teeth to the ring gear center line. This means that the pinion shaft is roughly 1/3 the diameter of the ring gear for a 3.00 to 1 gear set. This also means that the pinion size for a gear set that is 5.00 to 1 must be only about 1/5 the size of the ring gear. The ring gear diameter is generally constant for any particular differential design regardless of the ratio. This means that the pinion size changes with the ratio and for lower gears (higher numerically) the pinion teeth are smaller.

There are a few problems that go hand in hand with a small pinion head. The first are the facts that there are either smaller pinion teeth or fewer of them. The smaller teeth have less material supporting the load surface and it is a lot easier to break them off. In cases where there are fewer pinion teeth, there are fewer teeth contacting the ring gear teeth at once. In taller gears (lower numerically) such as 3.08's, there are about two pinion teeth contacting the ring gear at any time....etc....

camarossdn

iTrader: (1)

I personally would go with the 4.11 in a m6. If you cannot afford a 12 bolt.

Proud2bSS

iTrader: (2)

Depending on your driving habits.......you might, you might not.

IF you are going to run a soft street tire, ie ET Streets, Drag radials, Nittos, etc., AND you are going to dump the clutch AND/OR you are going to launch hard at high rpms....in other words, IF you are going to want to hook the tires and get maximum traction, then you DO NOT want 4.11's in the 10 bolt rear end.

I went with 4.11's, an Eaton posi, and a TA gridle and carrier studs in the stock housing. I DO NOT run a soft tire, NOR do I do clutch dumps, Nor do I try to launch above 2500 rpm. I feather the clutch on hard acceleration; once I'm rolling above 3500 rpms, and I want a little fun, I go WOT, hit second, maybe third, and enjoy the show. I personally like the lower gears; wakes up the car in a rolling start; and are just plain fun.

I will invest in a 9" WHEN I go to a ATI Procharger.

Mike98WS6

iTrader: (5)

I would go with 4.10's instead of the 3.73's IMO.

SMOKIN01TA

iTrader: (10)

yea, what he said
he mike, nice times, look kinda familiar