RomanNYC

I am mostly reading people who add cams or heads want to upgrade to the 3.9 or 4.10 , would it make sense to add these gears to a z that has only cai,headers,tune?

Drewstein

I see it in reverse, people adding gears so the car feels quicker without more power. With my cammed Z, there's no way I need more gear, instead I rip through the gears I have just fine.

RomanNYC

i also thought about a cam, not sure what i want to do as in get gears or get cam, i dont know how i feel about switching more frequent. will the PAUNCH be worth it with the gears? or just go get a cam and sink into the seat

GARY2004Z06

Many of us who have ran only bolt-ons, went with a gear change. Perhaps gears are one of the best mods for these cars whether it be street and/or strip. If you are considering a cam, gears work well with that also. It will provide optimum performance in the 1/4 mile.

RomanNYC

im trying to get an idea of how the change will be with gears... how much time would i shave off the 1/4 mile?

zeevette

May be no gain at all in ET, depending on shift points, traction, and other factors. (just gears) OTOH, the right cam will shave tenths, and give you a nice rush in the mid-range that's really fun on the street. Sounds cool, too. A cam installation also is a good excuse to attend to the stock harmonic balancer, timing chain, oil pump, etc. for very little added expense.

RomanNYC

well lets say your not doing ET, from light to light or highway pulls what would be the difference between stock gears and 3.90, because a cam is like $3k installed... and the gears are around $1300

zeevette

Well, light to light racing is hardly a way to benchmark your performance. You're gonna end up regretting revving that AWD fart can, and losing badly.
I did all my own wrenching, so I've changed cams three times...NBD. Lots easier than replacing a clutch. Put it this way; tall gears get the revs up faster, but you run out of the first two gears pretty fast, assuming you have any traction. More shifting, more time lost, and you don't want to end up shifting just before the lights. I don't race, but it's just common sense. Highway pulls; gears make almost no difference, but the right cam sure will.

grantv

Agree with this. Gears mostly affects off the line acceleration. 3.42's with a deep 1st gear is all I need, and also agree that deeper gears might even hurt 1/4 mile times (if it incurs an extra shift, or a shift at the wrong time). Highway pulls it might help, might hurt; just depends on the exact MPH you hit the gas at, and what gear is best at that speed with what rear gears.

Acid666

Like Grantv said, that extra shift can hurt you for quarter mile racing. For zipping around town and light to light pulls, it'll yank harder and quicker, but when you're at the track if you're BARRRRRRRRRRRELY redlining in 4th by the end of the line now, you'll have to shift to 5th with shorter gears so the time that you add doing that slows you down.
It really boils down to what you're interested in. Fun in the streets, drag racing, roll racing, tracking, autocross....
For me, I'm holding out on gears because 2nd is perfect right now for autocross. Going shorter might really hurt me on the pad.

GARY2004Z06

That depends on the driver. A novice may see several tenths while a seasoned driver may only see a tenth or thereabout. With the OEM 3.42s, you will have to leave at a higher launch rpm than you would with 4.10s. In general, it is easier to produce better 60's with a higher numeric ratio.
As for shifting into 5th, that will not be necessary with either a bolt-on car or H/C car which is properly setup. You would need to choose a gear ratio and tire combination that works for your projected rpm and trap speed. Here are several examples:
My Bolt-On C5Z- 4.10s, 275/40R17 DRs, trap speed of 126.32 mph
Robz's H/C C5Z- 4.10s, 26x11.50x16 ET Streets, trap speed of 138.80 mph
Robz's 388 C5Z- 4.10s, 275/50R15 DR, trap speed of 148 mph
My Bolt-On C6Z- 4.10s, 315/35R17 DR, trap speed of 138.81 mph
My Bolt-On C6Z- 4.10s, 28x11.50x16 QTP, trap speed of 138.70 mph
Note: Besides needing to meet the race rules for the race we entered, I elected to jump to a 28" tall tire to reduce my engine rpm through the traps for my last example. The key is good analysis and projection of your setup.

RomanNYC

good info

Dennis Wilson

Yes.

ApexerER

I only have headers, cai and tune and feel the 4:10's were the best investment I have made hands down. Upgraded to C6Z outputshafts while I had it apart. Much easier on the driveline when launching. Awesome on the street, makes 6th gear usable. I can't think of one single downside. Fuel mileage has suffered....

acroy

Shorter gearing makes a street-driven car a lot more fun to zip around town. Makes a cammed car a bit little easier to baby around as well.

RomanNYC

how much did this all cost you? including install

ApexerER

I purchased the gears and C6 Z shafts and had a buddy of mine set up the diff. I honestly can't remember how much it cost. It was at least 4 maybe 5 years ago. Don't listen to the people giving opinions that don't have gears. The guys saying you will require an extra shift in the 1/4 mile don't know what they are talking about. In the 1/4 mile before hand I was shifting into fourth gear just before crossing the finish line. Now I am crossing the finish toward the top of fourth gear. To be perfect i would actually need a lower gear than 4.10 for the quarter with the power my car is making. (assuming my purpose would be to cross the finish line just as 4th gear 1:1 was running out) My purpose was to build the drive train before adding more power. I build the rear end, added an LS7 Clutch, slave and aluminum flywheel. Added the Tick master cylinder. I never added more power because running below 11.50's at my track the car needs a cage. I have crossed that threshold and have been warned a few times when the air is right. Generally car runs in the 11.50's. My first ever pass with the car was 12.6 and the car had CAI, Longtubes and catless x pipe...Driver mod and gear change made the majority of the difference!

NosLaser

At the track on a sticky tire with a good prep gears will only help you.

On the street however, they could easily render 1st and 2nd pretty useless. It is a give and take in my opinion. I know that none of us street race, but in that 1st or 2nd gear roll scenario, you don't have the advantage of launching from a dig and getting the suspension loaded and making the car hook. Rolling and punching it with a lot of torque and a lot of gear and you will likely just blow the tires off.

justin.

I actually did the opposite. I am a heads/cam car and I had 4.10s and went back to factory 3.42s. If your cam is aggressive the 4.10s made the car not as enjoyable to drive. With 3.42s the car is much more fun on the street and a million times better on the highway. All depends on your long term goals

dork

I agree with Justin but my 'experience' is strictly "academic"--that is to say, I don't have any H/C/I + 4.10 experience. I did a lot of research and came to the conclusion that for my needs and situation adding 4.10s was the best option. There are lots of advisories that adding 4.10s to an H/C/I set up will almost omit the use of first gear; the combination is just too torquey to make the gear useful since tire spin will be problematic. This was my situation: I only had bolt-ons when I added 4.10s --just LT headers, Calloway Honker CAI and Chuck CoW tune.

I waited until the clutch died and replaced it with a McLeod RST, new slave, TOB, etc., add a Lwt flywheel (@12lb), had the torque tube bushings replaced and an RPM 4.10 box installed all at the same time. (The entire drivetrain has to come out anyway to service the clutch, so the labor to R&R the differential was "free".)

I did a gear swap instead of an H/C/I because I didn't want to commit to having to trust any (regionally well-known) speed shop to get the H/C/I combination and accompanying required tune correct the first time. There are so many stories and queries in our Tech/Performance section of each model Corvette about "my H/C/I installation doesn't run right; how do I fix it?" that I was leery that closest "local" speed shop (250 miles away) would/could get the correct combination of heads, cam, intakes, and tune configured correctly in one attempt, that I chose the brain-dead option of R&R'ing an RPM gearbox.

If all you ever do is swap the rear gears, nothing else in the drivetrain or the electronics (BCM) needs alteration. That's another benefit if gears are a consideration.

RomanNYC, I forgot to add... I don't remember where, but I saw a thread somewhere listing "best 1/4 times" sorted by add-ons. Someone using drag radials with my exact bolt-ons (except no Lwt Flywheel) posted he did an 11.4 qtr. I dunno if that's "fantasy" or not. I'm sure mine would be easily <12sec. in qtr, but I don't know if it's "11.4-fast".