top speed 160mph observed
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by crkemppainen
The question is this- What is my rearend gear ratio?
160mph observed
275/40/zr17 tires
6000 RPM observed
overdrive in 4L60 trans is .70
160mph observed
275/40/zr17 tires
6000 RPM observed
overdrive in 4L60 trans is .70
RACE ON!!!
Melting Slicks
Joined: Jun 2000
Posts: 3,215
Likes: 6
From: Tampa Florida
CFI EFI: I ran another gear calculator and your are right...~4.09 is what it spit out for those numbers provided.
www.f-body.org is a good one to use.
My mistake...not a 3.07...just surprising someone did the swap and didn't tell you prior to you purchasing it as 3.07 and 2.59 were the only gears you could get with an automatic.
www.f-body.org is a good one to use.
My mistake...not a 3.07...just surprising someone did the swap and didn't tell you prior to you purchasing it as 3.07 and 2.59 were the only gears you could get with an automatic.
Last edited by No Go; Feb 6, 2005 at 03:17 PM.
Safety Car
Joined: Sep 2000
Posts: 3,524
Likes: 4
From: Hinckley Ohio
[QUOTE=crkemppainen]The question is this- What is my rearend gear ratio?
160mph observed
275/40/zr17 tires
6000 RPM observed
overdrive in 4L60 trans is .70
QUOTE]
These numbers don't really make sense..
With this size tire it takes about 801 revs to go one mile, at 160mph you are going 2.67miles per minute, so the tire is turning 2136 rpms..
If the motor is turning 6000 rpm, then the drive shaft is turning 8571rpm.........
So rearend ratio is 8571/2136=4.01
If you were actually in 3rd gear..1:1 driveshaft would be turning 6000rpm
So rearend ratio is 6000/2136=2.81.....
My guess is you have 2.59.....the tires grew at speed and/or you were actually going a little less than 160 and/or you were actually a little less than 6000 rpms...
OOPS!!! 801 rev per mile is for 285's......810 rev per mile is for 275's
So tire at 160mph is turning 2160 rpm....
So axle ratio is 8571/2160=3.96 if in 4th gear
160mph observed
275/40/zr17 tires
6000 RPM observed
overdrive in 4L60 trans is .70
QUOTE]
These numbers don't really make sense..
With this size tire it takes about 801 revs to go one mile, at 160mph you are going 2.67miles per minute, so the tire is turning 2136 rpms..
If the motor is turning 6000 rpm, then the drive shaft is turning 8571rpm.........
So rearend ratio is 8571/2136=4.01
If you were actually in 3rd gear..1:1 driveshaft would be turning 6000rpm
So rearend ratio is 6000/2136=2.81.....
My guess is you have 2.59.....the tires grew at speed and/or you were actually going a little less than 160 and/or you were actually a little less than 6000 rpms...
OOPS!!! 801 rev per mile is for 285's......810 rev per mile is for 275's
So tire at 160mph is turning 2160 rpm....
So axle ratio is 8571/2160=3.96 if in 4th gear
Last edited by LT4BUD; Feb 6, 2005 at 09:02 PM.
Melting Slicks
Joined: Apr 2003
Posts: 2,150
Likes: 6
From: NS
Originally Posted by USAsOnlyWay
Are you sure that wasn't Km/hr, there are very few cars who can actually pull the true 200mph, let alone many cars passing.
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by LT4BUD
OOPS!!! 801 rev per mile is for 285's......810 rev per mile is for 275's
So tire at 160mph is turning 2160 rpm....
So axle ratio is 6000/2160=2.777
You had to have been in 3rd gear not 4th....
So tire at 160mph is turning 2160 rpm....
So axle ratio is 6000/2160=2.777
You had to have been in 3rd gear not 4th....
Originally Posted by atok
I've never seen a European car with MPH on the speedo.
RACE ON!!!
Safety Car
Joined: Sep 2000
Posts: 3,524
Likes: 4
From: Hinckley Ohio
Originally Posted by CFI-EFI
That, or he WAS in 4th, and he has 4.11s. Like my post says, "ASSUMING all of the above is correct"
RACE ON!!!
RACE ON!!!
The axle ratio then is 8571/2160=3.96
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
Melting Slicks
Joined: May 2001
Posts: 3,014
Likes: 18
From: Raleigh, NC
I come up with 4.09's on www.f-body.org/gears
Why not mark the driveline and the tire? Put the car on stands and see how many revolutions the tire makes for each revolution of the driveline.
Why not mark the driveline and the tire? Put the car on stands and see how many revolutions the tire makes for each revolution of the driveline.
Thread Starter
Racer
Joined: Apr 2004
Posts: 298
Likes: 1
From: Springfield Missouri
Originally Posted by neat
I come up with 4.09's on www.f-body.org/gears
Why not mark the driveline and the tire? Put the car on stands and see how many revolutions the tire makes for each revolution of the driveline.
Why not mark the driveline and the tire? Put the car on stands and see how many revolutions the tire makes for each revolution of the driveline.
really?
I didn't know that a D-36 carrier could accept that ratio!
other info-
1st gear top speed is 60mph (apprx)
2nd is 100
3rd is 145
4th is 160
and to my knowledge, the gearset has NOT been changed.
and that includes dynos!!! 
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by LT4BUD
Yep, I screwed up.......in 4th if the motor is going 6000rpm, the driveshaft is turning6000/0.7=8571rpm....
The axle ratio then is 8571/2160=3.96
The axle ratio then is 8571/2160=3.96
Originally Posted by crkemppainen
really?
I didn't know that a D-36 carrier could accept that ratio!
I didn't know that a D-36 carrier could accept that ratio!
RACE ON!!!
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
I'm not convinced the data supplied was accurate. The answers ARE correct for the input. Are you POSITIVE you were in 4th (OD) gear? Like I said, G.I.G.O.
You might take the advice from neat, and count turns.
RACE ON!!!
You might take the advice from neat, and count turns.
RACE ON!!!
Instructor
Joined: Jun 2001
Posts: 132
Likes: 0
From: Monroe Washington..the State
Originally Posted by sniperdiver37
I have a nice stretch of I-5 in washington you are more then welcome to run that fast on. Our Crown Vic's only do 135 MPH so they tell me 
so they tell me Naw but there radios and spike strip catch up fast
I was "clocked" at 145MPH slowing down from a run on 18. 14Psi boost 3.42 and 6,200 RPMs in 4th (A4) Speedo was pegged LONG after I let up before going into a three car trap
Thread Starter
Racer
Joined: Apr 2004
Posts: 298
Likes: 1
From: Springfield Missouri
The info supplied is correct, unless I mistook 3rd gear for 4th and then when i took it to the top or 3rd again, a week later, the speedo was 20mph off.
but for the sake of argument, lets plug in the numbers- IF i was to be going 160mph in 3rd gear at 6000 rpms, what would the gearset be?
another interisting problem.... I tried to top end last weekend and it would not stay in OD. it shifted back and forth between 3rd and od and acted retarded untill i stuck the selector in "D" and put it to the wood. I pegged the tach out at 145mph and got out of it. the tranny would not let the car go any faster. so WHY, when on tuesday night, it pulled OD clean to redline at 160mph?
but for the sake of argument, lets plug in the numbers- IF i was to be going 160mph in 3rd gear at 6000 rpms, what would the gearset be?
another interisting problem.... I tried to top end last weekend and it would not stay in OD. it shifted back and forth between 3rd and od and acted retarded untill i stuck the selector in "D" and put it to the wood. I pegged the tach out at 145mph and got out of it. the tranny would not let the car go any faster. so WHY, when on tuesday night, it pulled OD clean to redline at 160mph?
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by crkemppainen
but for the sake of argument, lets plug in the numbers- IF i was to be going 160mph in 3rd gear at 6000 rpms, what would the gearset be?
RACE ON!!!
Safety Car
Joined: Sep 2000
Posts: 3,524
Likes: 4
From: Hinckley Ohio
[QUOTE=crkemppainen]The question is this- What is my rearend gear ratio?
160mph observed
275/40/zr17 tires
6000 RPM observed
overdrive in 4L60 trans is .70
QUOTE]
Since there seems to be some question as to whether you were in 3rd or 4th gear and your question is what is your rearend ratio, why not repeat it to be sure what gear you are in....
Actually why not just take it up to say 60, be sure which gear you are in, and get a tachometer reading.........
or 80mph would be half of 160, so check tach at 80 in 4th and if necessary again in 3rd......one of should be taching 3000 rpm..
160mph observed
275/40/zr17 tires
6000 RPM observed
overdrive in 4L60 trans is .70
QUOTE]
Since there seems to be some question as to whether you were in 3rd or 4th gear and your question is what is your rearend ratio, why not repeat it to be sure what gear you are in....
Actually why not just take it up to say 60, be sure which gear you are in, and get a tachometer reading.........
or 80mph would be half of 160, so check tach at 80 in 4th and if necessary again in 3rd......one of should be taching 3000 rpm..