Author Topic: Transmission ratio question.........  (Read 5287 times)

Offline afaulk

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Transmission ratio question.........
« on: March 06, 2017, 05:03:59 PM »
It's time to upgrade my stock case PowerGlide with a new aftermarket unit.  I have a blown alky SBC making about 800 with current tune. I may bump it up, sometime in the future.  I have 33" tires, 4.30 gears and a converter that stalls 5400 on the brake. My current trans. has a 1.76 low gear. I'm wondering if I should get the 1.80 or 1.69 low gear.  My trans builder says the 1.80's are stronger but I'm wondering if that will be a factor in such a light car.

Offline wideopen231

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Re: Transmission ratio question.........
« Reply #1 on: March 06, 2017, 05:40:58 PM »
lots of big power guys going with 1.69 and even going to 1.58. A big name  FED bulder told not to go with 1.80,was more about shake than strength thing. If not for deal I would have gone with Ried  or other.Differance of 350 and about 1300 for case, hemi bell and another flywheel setup.
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Offline George

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Re: Transmission ratio question.........
« Reply #2 on: March 06, 2017, 05:42:17 PM »
We run a similar setup with a 31" tire.  The 1.80 in a Reid case is where we started. The 1.80 was too aggressive. The 1.69 has worked well.

Here is some video that you can slow down to see the car work:
« Last Edit: March 07, 2017, 01:52:42 AM by George »

Offline masracingtd1167

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Re: Transmission ratio question.........
« Reply #3 on: March 07, 2017, 11:53:56 AM »
I went from a 1.80 to a 1.69 in my car and it is better with the 1.69 . I had a 4.56 rear with the 1.80 and when I The trans to a 1.69 I also went to a 4.86 rear . Same starting line ratio but the car is .003 and 2 mph quicker to the 1/8 .

Offline afaulk

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Re: Transmission ratio question.........
« Reply #4 on: March 07, 2017, 05:50:10 PM »
Thanks guys, looks like the consensus is the 1.69s.  I can change the rear gear easier than planetaries.

Offline JrFuel Hayden

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Re: Transmission ratio question.........
« Reply #5 on: March 19, 2017, 02:33:53 AM »
We also changed from a 1.76 to 1.68 [ small carrier] about 10 years ago to help control tire spin and there is a smaller RPM drop shifting into high gear. And started running in the 7.0's.

Jon
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Offline afaulk

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Re: Transmission ratio question.........
« Reply #6 on: March 25, 2017, 09:50:45 AM »
I got a 1.69, Reid case, etc..... thanks for the input everyone.