BJ67

Nice 60 ft times, hard to do that with a M7

RPOC7R

The performance data I referenced was published by General Motors in their 2016 Corvette brochure. (A Z51 A8 Stingray was reported by General Motors to be 3/10's of a second quicker from 0 to 60 MPH [3.7 seconds] than a Base A8 Stingray [4.0 seconds].)

The data I've seen on this forum and elsewhere indicates that a Z51 A8 Stingray is as little as 60 pounds and as much as 100 pounds heavier than a Base A8 Stingray.

According to data published by General Motors, the performance advantage of the Z51 A8 Stingray's 2.73 axle ratio, electronic limited-slip differential, larger rear tires (1/10 of an inch wider tread), performance exhaust and dry sump engine oil system (less drag on the crank than a conventional oil pan) more than offsets the weight penalty of the Z51 Performance Package.

That said, for those who have no intention of racing their Corvette, a Base Stingray is a better choice than a Z51 Stingray. The Base Stingray is still an awesome performer, and it has a more comfortable ride than a Z51 Stingray.

C2367

I Have heard that if I run in sport with the Traction control on I would get faster / quicker response WOT. I well try next time Sport traction Control off for heating -up the tires and roll up and run with the TC on to see if helps.

BJ67

Chevrolet doesn't publish any HP difference between a dry and wet sump. My combo is base 1lt, NPP, Zf1, M7. I think a Z51 manual would have no advantage in a 1/4 mile sprint.

BJ67

With drag radials nice and hot, pressure down to at least 20lbs (hot), after a good burn out, you should be able load the converter and floor it without spin on a prepped track. Your best 60 ft will always be without nannies. You are already getting 1.7 60ft time's , Low 1.70's or high 1.60's should be the best you can expect with out mods like a converter or more gear.

C2367

Yes that's what I would like. The next time they are running here is I think is February.

RPOC7R

The Base M7 and Z51 M7 Stingrays both have 3.42 axle ratios, but the ratios of all 7 gears in the Z51 M7 transmission are lower than those of the Base M7 transmission.

The 2016 Corvette brochure reports 0 to 60 MPH ET of 4.0 seconds for a Base Stingray with either an M7 or A8 transmission, 3.8 seconds for a Z51 M7 Stingray and 3.7 seconds for a Z51 A8 Stingray, and quarter mile performance of 12.0 @ 119 MPH for a Z51 M7 Stingray and 11.9 @ 119 MPH for a Z51 A8 Stingray. (Quarter mile performance is not reported for a Base Stingray with either an M7 or A8 transmission.)

Density Altitude (a measure of track elevation above sea level, temperature, humidity and barometric pressure) has a significant effect on an engine's power output, and that coupled with track prep can result in quarter mile performance variation of 4/10's and 4 MPH in the same car raced at different tracks, on different days and under different Density Altitude conditions. Hence there are Base Stingrays that have turned quarter mile ET's of well into the 11's with good (low) Density Altitude and track prep conditions. However, if a Base Stingray and a Z51 Stingray are raced at the same track, on the same day and at the same time of the day, if the skill level and weight of the drivers are comparable, the Z51 Stingray should always be 2/10's to 3/10's faster than the Base Stingray in the quarter mile.

It's understandable that some Base Stingray owners would like to believe that the Z51 Stingray offers no performance advantage. However, the performance data achieved by Corvette engineers and reported in the 2016 Corvette brochure confirms that a Z51 Stingray is faster than a Base Stingray. But there is a trade-off for the better performance the Z51 offers - ride comfort. That said, a Base Stingray is still an awesome performer!

DAFFYDRUNK

I wouldn't put much weight in a GM brochure that's most likely geared (pun intended) to up sell people to the more profitable Z51.

KWC6

Thanks for the link. Great write up..

Always Red Dave

Zymurgy I was thinking about the 2014 C7 base A6 which had 2.56 gears and the A6 Z51 has 2.73 gears.

Skyhawk27

I am purchasing a new 2017 Grand Sport with the Automatic 8 speed trans. I have a choice of 2.73 or 3.42 rear axle ratio. I am not a racer but use it for fun and touring. Which ratio should I have put in at the factory?
Skyhawk

NSC5

You don't have a choice, the A8 comes only with the 2.73 rear axle in the GS, 3.42 is only for the 7 speed. The days of being able to choose from a wide range of rear axle ratios has gone away with CAFE and EPA emissions regulations. Compared to older vehicles the axle ratio for automatic transmissions seems odd but the extremely low first gear in current multi-speed automatic transmissions compensates. My Z06 has the A8 and it comes with a 2.41 rear axle.

DickieDoo

3.42 will make the car much more responsive... dropping in a lower ratio ( numerically higher number ) is the cheapest performance improvement that can be made to a car!.

If fuel economy is your main consideration then 2.73. With 8 forward speeds you have so many overdrive gears you'll still be spinning a nice low cruising speed.

Hopper12

As others have said, not a choice - from the factory - in this day and age.

But if you're comparing how the car will 'feel' with the options you do have - 2.73 with an A8 or 3.42 with an M7 - you should look at Zmurgy's post #2 at the multiplicative effect of combined transmission and rear gear ratios. As you work your way up the transmission gears, you'll note that the A8 multiplicative effect - and therefore the impact of the combined gearing on the ability of the car to accelerate (all things being equal) is slightly in favor of the A8. This is one reason that the A8s may be a bit faster on acceleration than an M7. But the difference is very small and should not be a factor in deciding which transmission to get - you should get the one that you want because all C7s are awesome. And let us know when you order and post pics when it arrives!!

JoesC5

The Z51's 20" tires are actually smaller in diameter(0.2 inch), thus does not help to compensate the difference, In fact the smaller diameter of the Z51's rear tires actually lowers the effective gear ratio even lower vs the taller gearing on the base C7 with it's larger diameter rear tires.

Mike Mercury

exactly.

The seat-of-pants potential needs to be assessed by the percent of difference, not solely by the ratio number itself.

lakemg

Not my car, not my video, but this is pretty impressive for a stock A8 Z51:

https://www.youtube.com/watch?v=UEpuJ_JdOoM