How can I tell what rear end I have?
01-13-2003, 09:25 PM
#2
Melting Slicks
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Re: How can I tell what rear end I have? (68350hp)
Use a large mirror!!! :eek: :eek:
If you tell us what rpm and rear tires you have, we can probably come close.
I have a 3.36 with 255x60's and am doing about 2800-3000 at 70mph.
Terry
If you tell us what rpm and rear tires you have, we can probably come close.
I have a 3.36 with 255x60's and am doing about 2800-3000 at 70mph.
Terry
01-13-2003, 09:30 PM
#3
Melting Slicks
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St. Jude Donor '08
Re: How can I tell what rear end I have? (trw)
Put the rear of your car on jackstands and put it in neautral. Turn the drive shaft 1 full turn, and have someone count how many times the tires turn. Easiest way. Use soap stone or chalk to mark the wheel and drive shaft so you know. Will be approximate. Or you could tell us the RPM you are at in top gear on the freeway doing 65 mph. :)
01-13-2003, 09:37 PM
#5
Team Owner
Re: How can I tell what rear end I have? (68350hp)
01-13-2003, 09:38 PM
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Re: How can I tell what rear end I have? (trw)
At 60 MPH - 2100 RPM. At 70 MPH 2500 RPM. 255/60/15 rear tires.
Anyone want to guess?
[Modified by OHSIXX, 9:38 PM 1/13/2003]
Anyone want to guess?
[Modified by OHSIXX, 9:38 PM 1/13/2003]
01-13-2003, 09:43 PM
#8
Team Owner
Re: How can I tell what rear end I have? (OHSIXX)
At 60 MPH - 2100 RPM. At 70 MPH 2500 RPM. 255/60/15 rear tires.
Anyone want to guess?
Anyone want to guess?
:cheers:
Olivier
01-13-2003, 09:44 PM
#9
Team Owner
Re: How can I tell what rear end I have? (Chris O')
Or post the stamp on the bottom of the housing.
:cheers:
Olivier
01-14-2003, 07:41 AM
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Re: How can I tell what rear end I have? (Darkness)
Yes 2100 RPM @ 60 MPH. I have always marveled at how low the RPMs are in relation to speed. :confused:
01-14-2003, 11:03 AM
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Re: How can I tell what rear end I have? (88'Cubka)
Put the rear of your car on jackstands and put it in neautral. Turn the drive shaft 1 full turn, and have someone count how many times the tires turn. Easiest way. Use soap stone or chalk to mark the wheel and drive shaft so you know. Will be approximate. Or you could tell us the RPM you are at in top gear on the freeway doing 65 mph. :)
01-14-2003, 11:37 AM
#14
Team Owner
Re: How can I tell what rear end I have? (Chris O')
Thing is, doing by math just will not work....the speedo gears in the tranny come with 1-2 tooth variations around what you think may be correct for your rear ratio...to include for tire diameter...which can vary a LOT these days....
the only way to know for sure is doing the chaulk on tires/driveshaft and do a very careful revolutiion count, and of course make damn sure the posi is locked so the rear tires spin together...if not...all manner of looking/tackling the problem in that manner is useless.....
second off, reading your speedo or tach on a 30 years old car is a bit wishful...even IF the things do not wobble all over the map.....
the best way to determine ratio is pull the whole damn thing apart, and look at the ring gear for the ratio on it.....should say something like 11-41 or 13-39 something like that.....divide the two for the mechanical ratio....
then knowing the tire diameter, and hopefully with a good accurate tach...you can know the speed of the car.....to check the speedo....
the best tach is of course an oscilloscope....measure the time between ignition pulses....that tells you exactly the engine RPM's....then you just do math for tranny gears, rear gears....and tire diameter, and then you know....
over the decades, I been there done all that on a variety of cars....
GENE
the only way to know for sure is doing the chaulk on tires/driveshaft and do a very careful revolutiion count, and of course make damn sure the posi is locked so the rear tires spin together...if not...all manner of looking/tackling the problem in that manner is useless.....
second off, reading your speedo or tach on a 30 years old car is a bit wishful...even IF the things do not wobble all over the map.....
the best way to determine ratio is pull the whole damn thing apart, and look at the ring gear for the ratio on it.....should say something like 11-41 or 13-39 something like that.....divide the two for the mechanical ratio....
then knowing the tire diameter, and hopefully with a good accurate tach...you can know the speed of the car.....to check the speedo....
the best tach is of course an oscilloscope....measure the time between ignition pulses....that tells you exactly the engine RPM's....then you just do math for tranny gears, rear gears....and tire diameter, and then you know....
over the decades, I been there done all that on a variety of cars....
GENE