What a difference a gear makes!

[XfireZ51]

Got Roza Nero back from Al's with now 3.73 gear installed. It's a real improvement over the stock 3.45s BUT 19" wheels.
Some observations:

1. Speedo error cut in half. Haven't changed anything else yet.

2. 6th gear now usable cruise gear under 80mph.

3. 4th and 5th now feel like passing gears.

4. MPG improved due to better rpm band. Also more accurate MPH and ODO.

5. RPMs don't drop as much between gears so it feels like you are staying closer to the power band. Better acceleration coming out of curves and ramps.

6. Much reduced exhaust drone at cruise due to higher rpm.

I can see now why something like a 3.90 would have been the preferred gear by LPE. With the Z06 wheels, I would do that next time. But for now, the 3.73s translate to something like a 3.60 gear on 19s.

[mike100]

I had a chance to talk to a C6-Z06 owner who used to have a ZR-1 and he said the 3.73's was one of the better mods he did (stock tire size).

[902066]

OK, just to be a party pooper, [because I probably do it well]. I have stock tire sizes and 3:73 gears. I wish I had gone with a 3:90 or 4:10 gear. 3:73 is a small improvement over stock, but not enough to justify the effort and cost.

[Blue Flame Restorations]

I have no experience driving any ZR-1 except my own but I LOVE my 4:10's!!

[XfireZ51]

OK, just to be a party pooper, [because I probably do it well]. I have stock tire sizes and 3:73 gears. I wish I had gone with a 3:90 or 4:10 gear. 3:73 is a small improvement over stock, but not enough to justify the effort and cost.

With only 113 posts, I get the party pooper!!
With the additional power and torque from the mods on my motor, I can easily tell the diff. Maybe stock is a different matter. I'd probably do 4.10s in that case and could see your point.

[Hib Halverson]

I've always wanted to put 3.73s in my 95. I math'ed that out one time and with the wider rpm range of my engine with its Automaster "Streetskinner" package of mods, the car would still do 180-mph in fifth but would accelerate just a little quicker.

Some day....

All I need is time...


Well, money, too.

[RICKYRJ1]

Thanks to WAZOO I also run 3.73's. I am very satisfied with them, I roll on a 19" wheel. I do feel I would also be happy with 3.90's or 4.10's as well :proud:

[Paul Workman]

Got Roza Nero back from Al's with now 3.73 gear installed. It's a real improvement over the stock 3.45s BUT 19" wheels.
Some observations:

1. Speedo error cut in half. Haven't changed anything else yet.

3.73/3.45 ≈ 1.08 (or approx 8% increase in torque in all gears) is nice.

2. 6th gear now usable cruise gear under 80mph.

3. 4th and 5th now feel like passing gears.

4. MPG improved due to better rpm band. Also more accurate MPH and ODO.

5. RPMs don't drop as much between gears so it feels like you are staying closer to the power band. Better acceleration coming out of curves and ramps.

Well, technically, the ratio between gears (in the ZF) did not change, so all things being equal, the rpm would drop the same amount as before.

However, I can see the grin factor coming from the fact the rpm would be higher up the torque curve of the LT5 after shifting, which when combinded with the higher ratio ring gear would definately affect the "seat of the pants!"

6. Much reduced exhaust drone at cruise due to higher rpm.

I can see now why something like a 3.90 would have been the preferred gear by LPE. With the Z06 wheels, I would do that next time. But for now, the 3.73s translate to something like a 3.60 gear on 19s.

If that is true, then your speedo would register higher than it did with the 3.45 gear for a given speed. I get the impression from what you said that the speedo is still reading low compared to distance/time calc or GPS, no?


;)

P.

[XfireZ51]

Paul,

Yes the speedo was reading 10mph slower at 70, now it's 5mph. The speedo gear is set up for 4.10s I believe. I checked my speed using the GPS of the
AVIC-D2.
As for the rpm drop, if what you are saying is the the change in rpm would stay constant, I'd agree. It's happening at higher rpms however.

[-=Jeff=-]

My plan is for 4.10s to be installed in the Fall

[XfireZ51]

My plan is for 4.10s to be installed in the Fall

In time for 5th Annual Corvette Challenge?

[-=Jeff=-]

In time for 5th Annual Corvette Challenge?


No

[Anniv88]

I have 4.10's and love them. :)

[pantera1683]

I really like my 4:10s too, especially the way 6th gear feels on those long Texas highway cruises.

[WVZR-1]

I can see now why something like a 3.90 would have been the preferred gear by LPE. With the Z06 wheels, I would do that next time. But for now, the 3.73s translate to something like a 3.60 gear on 19s.

The gear is a 3.73 - not "something like" X.XX! your wheel/tire choice was a "known" and is something that needs to be considered when "selecting" axle ratio.

It seems originally the gear change was to be a "dual purpose" install, performance (you've accomplished) and speedometer/odometer "correction" (you missed it seems). What now? Speedo/odo was slow?

SPEEDO CORRECTION:

If your car actually had Marc's 4.10 drive/driven you're in good shape. You've got three driven gears available to you before you would need to change the VSS 40, 41, 42. I see your reference earlier to the error so I'd probably attempt a 41 tooth (25513048) first.