Hey 2.73 5-speed guys...

The reason I ask is that I'm likely going to swap out my 3.27s, and they're right at 2k rpm at 60. I would have expected the 2.73s to be a bit lower.

And SCchick, how's your clutch doing after the Shootout?
 
It's doing ok :rolleyes: Still don't know whats going on with it because of more issues (power steering explosion) but it made me home ok! :D
 
308 is better on a late trans. Stock on an early trans. I got 24 mpg on the way home this time after tuning. I dont drive at 60 though.
 
on my 93 with 275-40-ZR17 rear tires on 17" wheels I would see around 1800rpm in 5th going 60. This picture says 60, but it's more like 56 according to my gps.

Taken driving down the highway light touch on the throttle to maintain speed.
5thgearcruise.jpg
 
I couldn't imagine any other gear than a 2.73 even in a late trans once you've acquired some horsepower. I got 25 mpg on the way to and from the shootout and I was mostly going 75-80. I played around some too.

I'm not too sure what rpm I turn at 60 but I'll check tomorrow.
 
At 60, I'm running around 1900rpm in 5th, according to the factory gauges.

Actually, you know, I think I am a little lower than this - maybe it is around 1800. I must have been thinking of the 95 auto. :eek: I know that 70mph was 2k though.

I think 2.73's are perfect for an upgraded 5-speed car. Better gas mileage, less shifting, cross the 1/4mi finish in 3rd... :cool:
 
3.08's are fine on the street. 1800rpm at highway speeds, 3rd gear around town (mostly my choice) and the car traps in 3rd comfortably.

2.73's will do pretty much the same but they will let you use 4th more effectively around town. The primary difference you will feel is the power range in 2nd gear. The 2.73's will seem to pull harder and further on the butt dyno.

Ira
 
Regardless of what your tach or speedo say (they are both notoriously incorrect), with 275/40/17's and 3.27 gears @ 60mph you are turning 1920rpm. With 2.73's at the same speed you are turning 1600rpm.

Will, with your cam 1600rpm is going to be about absolute minimum rpm for cruising. Anything less than 60mph and you'll find yourself running in 4th and the other thing is you'll find that the car is much happier running 70mph than 60. 70mph with those tires will equal 1860rpm.

The biggest thing you'll find is that with the amount of torque the car has (Will's car) currently 1st and 2nd both result in -0- traction. With 2.73's you'll find it marginally possible to hook up in 2nd gear. The fact that 2nd gear will pull all the way to 70-75mph without shifting is another nice bonus.
 
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We just did a late model M5R2 and 2.73's in a local member's SC, and he likes it.

Car feels so much better than with the early model M5R2 and 3.27's, even with the super light aluminum flywheel.

Jeramie
 
...

The fact that 2nd gear will pull all the way to 70-75mph without shifting is another nice bonus.
headbang.gif



math is good. as torque goes up gear needs are less.

Autocrossing, 2nd seems about right for most of the course, with a shift down to 1st only being needed once due to a mistake on my part at a hairpin turn.
 
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A stock car will for sure be shifting to 4th with 2.73's though

2.73:1 in 3rd at 5,000 rpm

89-93 M5R2 = 102 mph
94-95 M5R2 = 108 mph

Assuming stock diameter wheel/tire combo.

I don't know of any stock SC that does over 100mph in the quarter :p

Jeramie
 
I dunno, if I switch to a 3.08 in my car I'm pretty sure I'll have to use 4th in the quarter, or stretch the revs more than I want to. On the other hand, with shorter gears, the engine braking effect is stronger (thinking autocross and... errr... other things here).

My snapshot at 60 mph looks the same as Mike's pretty much so I won't bother posting.
 
I liked the way my '93 pulled in 3rd all the way to 110+. Just cruzin' 4th to 65 then 5th. She was very happy at 70-75 mph in 5th cross-country.
Now I get to try out a whole new trans gear set with the T56 and 2.73's. I have a 3.27 in the auto car if the they're too steep.
I don't think I'll ever use 6th with 2.73 and oem tire size while cruzing on the freeways in this part of the country;)
MikeH
 
My tach and speedo are pretty close to what you said, David. At 60 mph indicated on the speedo, the car is right around 2000 rpm. As it stands, I don't shift into 5th before 55, but freeway RPM seems a little higher than it needs to be. And yes, first gear is totally worthless, and the car will spin the tires pretty easily from second in a roll. So come winter, I plan on putting in the 2.73s.

What do I need to correct the speedo for the new gears? I've done it on the 4R70W, but not the M5R2. If it's a new speedo gear, where can I find one?

And who sells 2.73s? I'm having a hard time finding a new set.
 
I liked the way my '93 pulled in 3rd all the way to 110+. Just cruzin' 4th to 65 then 5th. She was very happy at 70-75 mph in 5th cross-country.
Now I get to try out a whole new trans gear set with the T56 and 2.73's. I have a 3.27 in the auto car if the they're too steep.
I don't think I'll ever use 6th with 2.73 and oem tire size while cruzing on the freeways in this part of the country;)
MikeH

My buddy drove a T-56 Camaro (LT1) with 2.73 gears and a big cam once (it was a free temporary diff). It was weak for the most part, but the car made great power up top, and thusly, they were branded "great gears for racing bikes." :D

If you have a stock cam, you might be able to use 6th at 80+ mph.

Actually, I still run a stock cam and 2.73s and I use 5th at 46+ mph nowadays. I used to deny 5th until I was going 52+ or so. Sure, 46 punches my tach down to ~1,100 rpms or so, but she handles it with little effort.
 
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