What's the gear ratio???? - Team Camaro Tech
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post #1 of 19 (permalink) Old Jul 16th, 19, 03:42 PM Thread Starter
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Frank
 
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What's the gear ratio????

Ok math guru's

70 mph @ 2750 rpm's

Tires are 255/45-18's
Diameter inches 27.04"
Circum. inches 84.93"
Revolutions per mile 745.99

'68 Camaro 454, 4sp
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post #2 of 19 (permalink) Old Jul 16th, 19, 03:53 PM
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Re: What's the gear ratio????

...ah not a math wiz but if you jack up rear of car, put a mark on DS, with trans in neutral rotate tire 1 revolution and cound how many times the DS rotates.

just a little over 3 turns is 3:08, 3 1/2 turns 3:55, 3 3/4 turns 3:73, etc

looks like you would have 3:08's

use this calculator and enter your 411

https://spicerparts.com/calculators/...rpm-calculator
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post #3 of 19 (permalink) Old Jul 16th, 19, 04:47 PM
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Re: What's the gear ratio????

2.73's or 3.08's I'd guess.
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post #4 of 19 (permalink) Old Jul 16th, 19, 05:02 PM Thread Starter
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Re: What's the gear ratio????

I was figuring 3:08's.. going to be a big change when i do the 3:55's

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post #5 of 19 (permalink) Old Jul 16th, 19, 06:04 PM
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Re: What's the gear ratio????

Just a few hundred rpm more (500 or so)

68 Camaro~LSx ~all motor
1.54 60'--6.95 @ 98.45 660'--10.96 @ 121.53
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post #6 of 19 (permalink) Old Jul 16th, 19, 06:15 PM
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Re: What's the gear ratio????

Yes. Calcs to 3.08

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post #7 of 19 (permalink) Old Jul 17th, 19, 04:07 AM
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Re: What's the gear ratio????

26" tire, 3:55 rear at 60 mph I am turning 2600 rpm in 4th gear. BUT, when I shift into 4th overdrive I can run 80 mph at 2600.
sorry I don't have any records for 70 mph in 4th, but 4th in OD is 2300
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post #8 of 19 (permalink) Old Aug 28th, 19, 01:46 PM Thread Starter
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Re: What's the gear ratio????

Quote:
Originally Posted by DOUG G View Post
Just a few hundred rpm more (500 or so)
Quote:
Originally Posted by flat tire View Post
26" tire, 3:55 rear at 60 mph I am turning 2600 rpm in 4th gear. BUT, when I shift into 4th overdrive I can run 80 mph at 2600.
sorry I don't have any records for 70 mph in 4th, but 4th in OD is 2300
It jumped to 70 mph @ 3170 rpm from the 70 mph @ 2750 rpm's so not quite 500rpm but definitely a noticeable difference .. Now I need a GVOD

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post #9 of 19 (permalink) Old Aug 28th, 19, 03:54 PM
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Re: What's the gear ratio????

Quote:
Originally Posted by Just 1 More View Post
It jumped to 70 mph @ 3170 rpm from the 70 mph @ 2750 rpm's so not quite 500rpm but definitely a noticeable difference .. Now I need a GVOD
420rpm....so close
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post #10 of 19 (permalink) Old Oct 12th, 19, 02:16 PM Thread Starter
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Re: What's the gear ratio????

Quote:
Originally Posted by Just 1 More View Post
Ok math guru's

70 mph @ 2750 rpm's

Tires are 255/45-18's
Diameter inches 27.04"
Circum. inches 84.93"
Revolutions per mile 745.99
Quote:
Originally Posted by Just 1 More View Post
It jumped to 70 mph @ 3170 rpm from the 70 mph @ 2750 rpm's so not quite 500rpm but definitely a noticeable difference .. Now I need a GVOD
Anyone have a good guesstimate where I would be with the Gear Vendors over drive?

'68 Camaro 454, 4sp
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post #11 of 19 (permalink) Old Oct 12th, 19, 05:28 PM
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Re: What's the gear ratio????

Quote:
Originally Posted by Just 1 More View Post
Anyone have a good guesstimate where I would be with the Gear Vendors over drive?
$2800 lighter in the wallet.
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post #12 of 19 (permalink) Old Oct 12th, 19, 07:37 PM
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Re: What's the gear ratio????

Quote:
Originally Posted by Just 1 More View Post
Anyone have a good guesstimate where I would be with the Gear Vendors over drive?
Tired of shifting gears ? I have a 4L80e in my Camaro with no tunnel cutting.

68 Camaro convertible, 6.0 LQ4 with LS3 heads, Vintage Air, 750 street demon carb, eddy perf rpm, GM hot cam, Hooker headers, 4L80e, 12 bolt, 3.55 gears
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post #13 of 19 (permalink) Old Oct 13th, 19, 04:26 PM Thread Starter
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Re: What's the gear ratio????

Quote:
Originally Posted by Vega$69 View Post
$2800 lighter in the wallet.


Quote:
Originally Posted by NashvilleCat View Post
Tired of shifting gears ? I have a 4L80e in my Camaro with no tunnel cutting.
I may ultimately end up with an automatic since my daughter will be inheriting the car but for now, I want to row this boat

'68 Camaro 454, 4sp
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post #14 of 19 (permalink) Old Oct 13th, 19, 04:28 PM Thread Starter
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Re: What's the gear ratio????

From a facebook reply ..
Quote:
Your rpm's will be 2402 at 70 in over drive with a Gearvendor.

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post #15 of 19 (permalink) Old Oct 14th, 19, 01:14 AM
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Re: What's the gear ratio????

Quote:
Originally Posted by Just 1 More View Post


I may ultimately end up with an automatic since my daughter will be inheriting the car but for now, I want to row this boat
My now 43 year old daughter loves rowing gears, and looks forward to driving my LS3-T56-3.73 rear-440hp to the tires '68 Camaro when I shuffle off this mortal coil - although she's willing to wait for as long as it takes.
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