a) Wanted to know and
b) To have a nice gear ratio for high speed highway cruising without too high RPM
Drivetrain 5th Gear Ratio
- Thread starter PonyGTrider
- Start date
b) To have a nice gear ratio for high speed highway cruising without too high RPM
If you want do 70 mph at red line while cruising on the Hwy be my guess… Peanuts
manicmechanic007
5 Year Member
The 6 speed in my 1990 corvette has a .50 6th gear
fifth is .73
It's a helluva bog under 120 mph in 6th when racing
I'd leave a 5 speed around .7 for optimum performance like Ford and Chev did
Road racing is another story where close ratio vs wide ratio comes in
Note: I've had my Boss 302 doing 140+ in 1:1 fourth gear with .275 rear gears at the time IIRR
fifth is .73
It's a helluva bog under 120 mph in 6th when racing
I'd leave a 5 speed around .7 for optimum performance like Ford and Chev did
Road racing is another story where close ratio vs wide ratio comes in
Note: I've had my Boss 302 doing 140+ in 1:1 fourth gear with .275 rear gears at the time IIRR
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I can totally see going through all the fuss if you're trying to cross the line at peak HP in the quarter.
Otherwise... I'm here:
In my 86, I run the stock 2:73s and a T5 (Not sure WC or Z. I bought it new to replace the one I broke). What is the top speed on the highway with that combo? Faster than I am comfortable taking it. I have no idea except that when I got to somewhere around 130, that was enough.
In my mind, I envisioned my Cooper Cobras flying apart like a Slurpee out the car window.
Now, for city/highway driving all around? It's awesome.
Stoplight Warrior wise? I do pretty well with the 2:73s, a stroker, and PD blower. Care must be taken in the first three gears as it will peel if you let it.
Better gripping tires at this point could spell the end of the T5. It's on the list.
Otherwise... I'm here:
In my 86, I run the stock 2:73s and a T5 (Not sure WC or Z. I bought it new to replace the one I broke). What is the top speed on the highway with that combo? Faster than I am comfortable taking it. I have no idea except that when I got to somewhere around 130, that was enough.
In my mind, I envisioned my Cooper Cobras flying apart like a Slurpee out the car window.
Now, for city/highway driving all around? It's awesome.
Stoplight Warrior wise? I do pretty well with the 2:73s, a stroker, and PD blower. Care must be taken in the first three gears as it will peel if you let it.
Better gripping tires at this point could spell the end of the T5. It's on the list.
I hear you! I replaced my 2.73’s about 14 years ago and never looked back after I installed the 3.55.I can totally see going through all the fuss if you're trying to cross the line at peak HP in the quarter.
Otherwise... I'm here:
In my 86, I run the stock 2:73s and a T5 (Not sure WC or Z. I bought it new to replace the one I broke). What is the top speed on the highway with that combo? Faster than I am comfortable taking it. I have no idea except that when I got to somewhere around 130, that was enough.
In my mind, I envisioned my Cooper Cobras flying apart like a Slurpee out the car window.
Now, for city/highway driving all around? It's awesome.
Stoplight Warrior wise? I do pretty well with the 2:73s, a stroker, and PD blower. Care must be taken in the first three gears as it will peel if you let it.
Better gripping tires at this point could spell the end of the T5. It's on the list.
Those 2.73 make a nice road runner!
Here are the speed/rpm comparison in between the 2.73 with .68 ratio 5th gear and the 3.55 and .584 ratio 5th gear at the same given rpm.
My 83 I am working on came with a SROD 4 speed ( .070 OD 4th gear) and according to the tag on the 7.5" rear, had 3.07 rear end gears...
My sister bought this car in 84 and I drove it occasionally in that time frame.... I can't remember any RPM settings but my mechanic friend and I used to joke it would probably go 150 mph .... It cruised at 90 - 100 effortlessly when I drove it from Oregon to California a few times....
My sister bought this car in 84 and I drove it occasionally in that time frame.... I can't remember any RPM settings but my mechanic friend and I used to joke it would probably go 150 mph .... It cruised at 90 - 100 effortlessly when I drove it from Oregon to California a few times....
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Yeah I drove my 90 GT 2k miles with the configuration I described but I didn’t know what was my final 5th gear ratio to find out that I have it a bit too high at .584 versus the .68 stock and .63 with the Z specs T5.My 83 I am working on came with a SROD ( .070 OD 4th gear) and according to the tag on the 7.5" rear, had 3.07 rear end gears...
My sister bought this car in 84 and I drove it occasionally in that time frame.... I can't remember any RPM settings but my mechanic friend and I used to joke it would probably go 150 mph .... It cruised at 90 - 100 effortlessly when I drove it from Oregon to California a few times....
I wonder if I can replace the stock 27/59 With the 25/51 gear set to get .63 without taking the transmission down by just removing the tail housing.
Those high ratio OD gears were meant to be for fuel economy at least at cruising speeds
Thats all they were after..... Going through 2 gas shortages 73 & 77 while having the government tell us we were running out of gas, Hondas and Datsuns became the top sellers.. Diesel VW Rabbits were selling for 1K over list price ( that was alot of money then ) with a year waiting list...
3-4 hour wait lines for gas, then sometimes just as you get to the pump the gas station ran out... Thats why you got in line with 1/2 a tank.....
1/2 of the gas stations shut down and were bull dozed over in the small Oregon town I grew up in....Amazes me to see them sprout up every other week here in Florida the last few years..
My ‘86 GT had the stock 2.73 rear end and T-5 when I took it to be tuned on the dyno. The dyno run showed it went to 149 MPH!I can totally see going through all the fuss if you're trying to cross the line at peak HP in the quarter.
Otherwise... I'm here:
In my 86, I run the stock 2:73s and a T5 (Not sure WC or Z. I bought it new to replace the one I broke). What is the top speed on the highway with that combo? Faster than I am comfortable taking it. I have no idea except that when I got to somewhere around 130, that was enough.
In my mind, I envisioned my Cooper Cobras flying apart like a Slurpee out the car window.
Now, for city/highway driving all around? It's awesome.
Stoplight Warrior wise? I do pretty well with the 2:73s, a stroker, and PD blower. Care must be taken in the first three gears as it will peel if you let it.
Better gripping tires at this point could spell the end of the T5. It's on the list.
Bill
Back in 99 bought a 92GT from my brother, put all boltons LTs,Dr Gas X, March cold air 75mm bullett, pulleys 3 chamber flows. On slicks ran 4 times 13.37-13.40 slowest with 2.73s 60 fts 1.92s 5000K launch. Put a D1 14lbs of boost, 11s. TW heads and Holley Systemmax 2 500RWHP. Still had 2.73s. Car was beastley on the highway. Like pull a big turboed Supra beastley. It pegged the speedo with just boltons. Speedo was probably a little on the high side, but still. I always got picked on by C5s, Supras, LS1s. D1 is kinda quite at 70, exhaust super quiet. Untill... WOT and there I went.
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