Could I possibly have 3.73s????

[Jay 02 TA ws6]

raro, the gear calculator is here: www.f-body.org/gears/

I was talking with raro last night on AIM when he said he hits 50 mph in 1st gear in his car. That puzzled me, because we both have M6s and 3.42 rears... but I rev a couple hundred RPMs higher, and I shift at 45 mph.

So, I found that gearing calculator site, used a 98 f-body M6 as my reference... 275/40/17 tires... and used a 3.42 rear with a 6000 RPM redline.

Max speed in each gear was:

50, 75, 103, 134, 181, 268...

Keeping everything the same, I used a 3.73. Max speed in each gear was:

46, 69, 94, 123, 166, 246...

I realize 46-50 mph discrepancy is splittng hairs and maybe the speedo just isn't quite keeping up... BUT... I am 100% positive I don't stretch 2nd gear past 70 mph... and i am 100,000% sure that I don't stretch 3rd gear over 100 mph. In every case, the 3.73 seems to be a dead-on description of how my car behaves on the street.

Now... I bought my car "brand new", completely stock, off a dealer lot, never titled. There were 137 miles on the clock when I drove it off the lot...

What do you all think about this? If this was in fact modified and sold to me as new, where do I go from here? And is there ANY chance I may have gotten a 3.73 from the factory???

[Craig 94 TA GT]

Have you tried to clock it at a high (numerically low) ratio? i.e. Hold it at 80 mph in 5th or 6th then compare the RPM with what the calc says.
My friend's 30th Anniv. Z has 3.73s...I thought he had 4.10s because it seemed "dead on" to the calculator, but with a bit of tach & speedo error, and a not clocking at a high gear, it took awhile to figure it was 3.73s.

[Rob B (shoebox)]

Not likely that they came from the factory, since it was not an optional set for these cars.

[beachbum86]

Hey Jay... Try this, it might help. I found this on another forum and I thought it was interesting. Might give you the answer you are looking for.

Mark the driveshaft with a very small piece of tape or a stripe of paint, just as you would a timing mark on a harmonic balancer. Then, turn the wheel (or axle shaft if the tire is off) one full turn, counting the number of times the marking reaches the twelve o'clock position.


If the driveshaft turns:
The gearing is:


2 3/4 times = 2.73

3 times = 3.08

3 1/4 times = 3.27

3 1/2 times = 3.55

3 3/4 times = 3.73

4 times = 4.10

4 1/2 times = 4.56


Hope this helps bro...

Got any plans for your 23rd???

Later

[fastTa]

Hey birthday boy, get on AIM tonight!

[wolfdogs]

no chance of 3:73 from the factory.. at all... those gears are not even close to that assembly line. that car does not meet CAFE without the 3:42's, which is what its certified to. That would be a healthy fine for GM if they delivered that car from the factory with those. They wouldnt even let thier Tier 1 suppliers do that as an option.

[darkz711]

6100 47 70 96 125 169 250

those are my numbers and i do have 3.73s.Based on that calculator, my speed is about 3 mph off in each case, except for the 125 and above since ive never taken it above 115 before. but that isn't a factory option, so i dont see why you would have them in your car, you probably have some speed error, although you numbers are quite close to mine

[Kevin - Blown 95 TA]

46/50 = .92
3.42/3.73=.91
46-50 mph (diff of 4 mph) is all the difference it takes for the two different gears. You have a 3.42 gear.

[smokinstangs]

if you have a stock rear end, call a GM dealer and they will be able to tell you what ratio you've got by code in glove box also if you have locking rear differential or not the code is G80 for a locker

[Jay 02 TA ws6]

46/50 = .92
3.42/3.73=.91
46-50 mph (diff of 4 mph) is all the difference it takes for the two different gears. You have a 3.42 gear.

Yeah, i know that's a small difference... that's why I mentioned that in 3rd gear, I AM POSITIVE that I shift before I hit 100 mph.

[raroZ28]

Well, went to test it out today. Once I hit 4k rpm my car lost tons of power, nose dipped down, like it had slight hesitation to keep revving. Looks like my optispark is crapping out or something. Glad I found it now, I'll put a new one on with the cam.

[Jay 02 TA ws6]

Well, went to test it out today. Once I hit 4k rpm my car lost tons of power, nose dipped down, like it had slight hesitation to keep revving. Looks like my optispark is crapping out or something. Glad I found it now, I'll put a new one on with the cam.

Went to test what? The cam? Boss, you ain't gonna have nothin' if you put in a cam and don't tune it.

[raroZ28]

Went to test what? The cam? Boss, you ain't gonna have nothin' if you put in a cam and don't tune it.

LOL, No, not the cam man. Test my top speed in first gear. I'm assuming it's optispark, I'll have to test it. I'm taking that cam back anyway for a diff. one.