Suns_PSD

I am considering putting some lower gears in my 08 Corvette z51 as I know for the money it will result in the most acceleration increase. My understanding is the z51 has really close ratios in the first three gears? And I'm wondering if I'll be shifting so much that it will just become annoying and may be ineffectual. Can anyone offer any insight into this? The gear ratio I am considering is a 4.11. Also will high-speed cruising at 75 or 80 miles per hour become flat annoying? Thank you!

timd38

I went with 3:73 gears, but a ton of people are running 4:10's and love them.

Joe_G

I love my 4.10 gears and z51 transmission. No concerns as you raise, the car is great. I had 3.90's as well and I much prefer the 4.10's. Still get over 20 mpg combined city/highway. If you go to the track the 2.97 first and 4.10 gears help you get off the line very well, that's my secret to my 1.4 60 foots and 80,000 OEM clutch life.

This thread has a lot of discussion as to why gears are a great mod.

https://www.corvetteforum.com/forums...ast-heads.html

Suns_PSD

Thanks Joe!

09_BSM_Z51

I'm interested in this as well. Everyone that has them, loves them. I'm thinking this may be my first mod next year. Since I put on new tires and getting headers, my major mod finances are tied up lol.

Joe_G

It's one of my favorite mods. Great on the street and on the track. Check my link above for more discussion.

Suns_PSD

Joe, I'm pretty close to breaking down and getting the 4.10 gears as they appear to be the best bang for the buck for me.

You broke a 3.90 before correct? Is that just because naturally the smaller pinion is prone to breakage? If so, it surprises me that you went even smaller on the pinion with the 4.10 next time!

Did you do any cryo treating or anything else to make it live?

Thanks

Joe_G

No, the gears didn't break, my rear end cracked in half like 05's do if you race long enough. I got 301 passes out of mine so that was a pretty good life.

When the case cracks in half and spits out the pinion the gearset is ruined. So is your transmission mainshaft by the way.

Back out of wheel hop at all costs.

The gears you buy will be as strong as they need to be and your case is a lot stronger than my 05, GM fixed it with the 06's.

BTW you don't have a Grand Sport manual do you? Those use the C6Z06 rear which is even stronger, but nobody makes any aftermarket gears for their 9" career. You'll have to downgrade to the smaller c6 carrier and rear. But your rear is a very good core and worth a lot to a A6 guy looking to get gears.

Here's what can happen to 05's: Mine looked just like this.

Suns_PSD

No, mine is an '08 Z51. It has 345s in the rear because it has a Ligenfelter mini-tub.

I'm close to breaking down and buying them but I've had a real rough start to the year here at work (commission only) and that has been my only pause.

Thanks.

Pitufina

Don't fear the gear! Look at 11+ mustang 5.0 tranmission and rear end gears. That's what I call aggressive. Gearing is another reason why the 10-15 camaros are so slow. Their weight makes it even worse. The 16 camaro even though it has a stronger powerband and weights less, now it comes with 3.73s standard. GM knew they had to step up the game, although I still think that considering the long tr6060 gears, 3.90s should've been standard like the 1LE.

GARY2004Z06

We run 4.10s in my buddy's '08 Z51 and he thoroughly enjoys it. Car is a pleasure to drive. This car is a H/C setup and has run 10.37.

I ran 4.10 in my C5Z and it was perhaps the best mod that was performed on that car. You still have OD to cruise at 80 mph. No throttle was needed to start off in first. Car woke up down low.

SpinMonster

I had posted so many times on this topic and I will forego the long typing session to say that Subfloor ran 3.42's on his A6 auto which is like the manual having 5.xx gears and it netted him a 0-60 at the track of just under 2 seconds. Gears are Tq multiplication and it comes down to the tire you run. I tell people to gear for redline at the traps and stop adding power when you can't get it to the ground any more. I ran 4.10's on my z51 with over 800rwhp and with Mickey Thompsons on the street, I'd leave AWD cars like the shifted into reverse. My 0-60 was 2.2 seconds. Enjoy the mod.

Suns_PSD

Spinmonster, what is your take on the "lower gears IMPROVE hook up" notion? That just seems so far fetched to me as much as I trust Joe.

I'm afraid I'll just make 1st gear (more) useless than it already currently is, and that's with 345 R888s in the rear and only 500 rwhp. What say you?

Please advise.

Joe_G

Use this calculator to see what I'm taking about. I have the 2.97 first gear tranny, Magnum XL they call it as do you.

http://www.tremec.com/calculadora.php

My first gear with 4.10 gears, 28" tires and 6500 redline tops out at 44 mph

With 3.42 gears 28" tires and 6500 redline it tops out at 53 mph.

It's easier for the car to "catch up" to the spinning tire when the spinning tire is going slower. If you're not brake torquing, you're accelerating, and the car accelerates faster with the 4.10 gears and the speed of the car catches the spinning tires more quickly with 4.10 gears as the tires are spinning slower.

Any car with street tires with 500 rwhp will spin street tires on the street in first and second gear if you want to spin your tires. It's easier to control with 4.10 gears.

I can't explain this any other way. I suggest you go ride in a car with 4.10 gears before you spend your money.

I'm not as quick as Subfloor, my 0-60 is only 2.59 seconds (on the track with drag radials). On the street, who knows what it would be. At the track on street tires, I can only get 1.8 60 foots vs 1.4 with drag radials so the common denominator here for traction is drag radials, not gears. Gears do feel a lot faster for the reasons I previously posted along with the dyno sheet which shows why that is.

Suns_PSD

I've been holding off on ordering the gears for a couple of reasons. One reason is I just received the Corsa exhaust and got it installed over the weekend. But I haven't even driven the car yet because it's flooding here in Texas. I'm going to try out 5th gear at 75 miles per hour on the highway and verify there is no drowning with the corsa. Droning would be a deal-killer on road trip for me.

Joe_G

Corsa prides themselves on "no drone", I suspect you'll be fine.

You could use that gear calculator website link to see what your cruising RPM will be with 4.10's at 75 mph and with 3.42's then cruise at the 4.10 Rpm at 75 mph to see if you have drone. If you drop a gear you won't have to go so fast.