rear ends
rear ends i thought i heard someone say one time that it takes less power to turn a 12 bolt than a 9 inch. and that with the same car the 12 bolt under it ran a better time than with the 9 inch under it. first off is this true? 2nd how is the sd60 compared to them. as far as power to turn them. i know its heavier than both of them.
Originally Posted by ls1transam346
i thought i heard someone say one time that it takes less power to turn a 12 bolt than a 9 inch. and that with the same car the 12 bolt under it ran a better time than with the 9 inch under it. first off is this true? 2nd how is the sd60 compared to them. as far as power to turn them. i know its heavier than both of them.
Furthermore, your increased ability to leave like a bat out of hell will make you forget about the slight differences in absorbed power from the larger rear end. You have a M6, so your logical choice is 9 inch or S60. The 9 inch is tried and true, and lighter than the S60, so there ya go.
Originally Posted by keliente
There are far more things that will influence your timeslip instead of just changing rear ends. Driver, modifications, density altitude, suspension & tires; the difference between 9 inch/12 bolt/S60 is the least of your worries when it comes to track day imo.
Furthermore, your increased ability to leave like a bat out of hell will make you forget about the slight differences in absorbed power from the larger rear end. You have a M6, so your logical choice is 9 inch or S60. The 9 inch is tried and true, and lighter than the S60, so there ya go.
Furthermore, your increased ability to leave like a bat out of hell will make you forget about the slight differences in absorbed power from the larger rear end. You have a M6, so your logical choice is 9 inch or S60. The 9 inch is tried and true, and lighter than the S60, so there ya go.
Teching In
Joined: Dec 2006
Posts: 34
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From: Bastrop, Texas
When we were racing econo dragsters you could get a tenth or so (1/4mi) from the reduced friction, rotating mass & lighter weight of a 12 bolt over a 9". We had a 9", but of course knew what our competitors were up too. That's talking about an 800hp motor in a 1350lb car.
So much easier to setup a 9" than a 12bolt + you can setup a spare with a different gear ratio & have it changed out in 30min or less, if you're so inclined. That easier setup's gonna be worth a whole lot more to you than that negligible reduction in ET you'll gain. Plus you're only gonna be able to make some use of that small gain after you've exhausted at least another 100 more important issues.
So much easier to setup a 9" than a 12bolt + you can setup a spare with a different gear ratio & have it changed out in 30min or less, if you're so inclined. That easier setup's gonna be worth a whole lot more to you than that negligible reduction in ET you'll gain. Plus you're only gonna be able to make some use of that small gain after you've exhausted at least another 100 more important issues.
