What gears with Procharger?
What gears with Procharger? Trying to figure out whether or not I should swap out my stock 3.42 gears for something bigger like 3.73s, 3.90s, or 4.10s....this is a STREET CAR. The car will also have a procharger pushing around 500whp on no more than drag radials and possibly street tires for awhile.
What do you guys think?
What do you guys think?
Do you do a lot of highway driving?
As a rule of thumb six speed cars tend to do very well with 4.10 gears, and automatics do well with 3.73 gears to keep the rpm's in a good range for highway use. The gear change will make a noticeable difference. With your six speed, be prepared to be breaking your 10 bolt rear, as they are quite fragile. Bob
As a rule of thumb six speed cars tend to do very well with 4.10 gears, and automatics do well with 3.73 gears to keep the rpm's in a good range for highway use. The gear change will make a noticeable difference. With your six speed, be prepared to be breaking your 10 bolt rear, as they are quite fragile. Bob
8 sec potential, 12 sec slip
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From: Savannah, GA
Don't bother putting a set of gears in your 10 bolt. Just save the money and put it towards a 9" or 12-bolt. You WILL break your 10 bolt with 500rwhp, its only a matter of time. You'll most likely break your driveshaft too... So save the money and when the time comes invest in a solid driveshaft and rear end and a good torque arm. If you can't get a body mount tq arm, at least get a trans cross member with a torque arm mount on it to take the load off the tailshaft of the tranny...
But with all that said, I am running 3.73's in my M6 car...
But with all that said, I am running 3.73's in my M6 car...
Don't bother putting a set of gears in your 10 bolt. Just save the money and put it towards a 9" or 12-bolt. You WILL break your 10 bolt with 500rwhp, its only a matter of time. You'll most likely break your driveshaft too... So save the money and when the time comes invest in a solid driveshaft and rear end and a good torque arm. If you can't get a body mount tq arm, at least get a trans cross member with a torque arm mount on it to take the load off the tailshaft of the tranny...
But with all that said, I am running 3.73's in my M6 car...
But with all that said, I am running 3.73's in my M6 car...
I bought a new 9" after reading a lot about other people experience, and went with 4.11 on the m6. Many says it to high for my tt setup, 1 and 2 gear will be useless but 3 and up will be a lot of fun. A 9" with aluminum center is 8lbs lighter then a stock 12bolt 
buy the 9" 
buy the 9" 
Teching In
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I have always been told to stay in the lower 3.xx range with a blower or turbo unless you are only running 1/8th mile tracks. With a forced induction setup you will have plenty of torque for a good 60 foot and won't have to rev the guts out at the top end. My buddy went from 3.73's to 3.23's in his Grand National and still has too much torque off the line and it's just a V6 . 
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3.73 should be probably just about a best of both worlds gear. It shouldn't be too high of a gear or too low of a gear. If you go with a 4.10 there's a slight chance you may need 28" tall tires for the track, but that's not so bad,I guess, I do it.
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From: Somewhere Between Mild Insanity and Complete Psychosis
Even with a stalled a4 and street tires, my only regret with this car is the 3.42.
I may switch to 4.10 or 3.90 some day.
3.42 are enough to spin from a stop or slow roll, but that is what drag radials are for. On the highway, I would like a little more SOTP.
I may switch to 4.10 or 3.90 some day.
3.42 are enough to spin from a stop or slow roll, but that is what drag radials are for. On the highway, I would like a little more SOTP.
I have 4.10's and I think that they are too much gear for a FI setup. Before I went FI they were great, I would go through the traps hitting off the rev limiter at 6800 in 4th. If I were to try it now with the blower on the car, I would have to shift to 5th. On the other hand, a friend of mine with about 200 more rwhp has 3.90's on the street and they are fine. My 4.10s on the street can't hook up worth the sh$%......I am going back to 3.42's or 3.73's.
I started out with 4.10s when I installed my s/c, and they were too deep. I now run 3.70s and they seem just about right for the track & the street. With a 6 sp, maybe 3.90s would be best?
I had some 2.70s in it for an open road race to drop the sustained rpms down but those were WAY too sluggish for street drivng. Tho I would have liked to take it out on the salt flats with those once (top speed calculator said 260mph )
I had some 2.70s in it for an open road race to drop the sustained rpms down but those were WAY too sluggish for street drivng. Tho I would have liked to take it out on the salt flats with those once (top speed calculator said 260mph
) 
