Gear swap

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DERICKS

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CLINTON TOWNSHIP,MI
Got my 4.56 swapped in today and compared to my 4.30 the thing feels like its wound tighter that a watch spring! I didnt think it would make that much difference until I got on it a bit and really just cruised in high gear down the road. Now I have to wait until Spring to see what it'll do for me. Its about time I gave that weak knee'd 340 a little help :)
 
mullinax95 said:
At 60mph between the two gears there should be about 200rpm difference.
Click to expand...

You know, thats what I hear....but thats not what I felt. I felt a car that from a trip to the gear shop, a three hour swap, and a drive home that felt way more responsive. The mid range response in any gear was much more "attentive" and when I launched the car it didnt seem to drag itself to the top of first...it got there in a hurry. We calculated more like 350-400rpm at the shop and next to my wifes Jeep it was 300rpm on my tach so I'm not sure what to think about the calculations. I'm just excited becuase its the gear I wanted and I got it in an even swap my 4.30 to a 4.56 and a friend put it together with my help for a grand total of.....$0 :)
 
DERICKS said:
You know, thats what I hear....but thats not what I felt. I felt a car that from a trip to the gear shop, a three hour swap, and a drive home that felt way more responsive. The mid range response in any gear was much more "attentive" and when I launched the car it didnt seem to drag itself to the top of first...it got there in a hurry. We calculated more like 350-400rpm at the shop and next to my wifes Jeep it was 300rpm on my tach so I'm not sure what to think about the calculations. I'm just excited becuase its the gear I wanted and I got it in an even swap my 4.30 to a 4.56 and a friend put it together with my help for a grand total of.....$0 :)
Click to expand...

Oh yeah you will feel a difference. The formula for RPM at a giving speed is

Gear x MPH x 336 / tire diameter = RPM

4.56 x 60 x 336 / 28" = 3283 RPM
 
Yea I used that one before and the guys at the shop had another way of figuring it out. After I drove it I went back and made him double check the gear we took out and the figures on the gear we put in because I didnt expect such a seat of the pants change!
 
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