I was looking into upgrading my gear from a 3.15 to a 3.73, i have a z51, auto. Does any one know where i can get a descent price on a 3.73?

 

Call chris at East Coast Supercharging. They can get it turned around to you fast. I had no complaints about the build of the rear....quiet and tough.

 

Anyone with the experience of changing out the rear gears? How much is the install? Any warranty issues with this mod?

6 speed people...what are you using? 3.90's? 4.10's?

 

Im putting 3.90s in on Tuesday. I dont expect to find anyone in a chevy service deptartment that is smart enough to figure out I changed gears. I was told I can expect about 5 or six hours on labor. This at a viper/vette shop. I found gears going from $350 and up. I sprung for the cryo, shot-peened, polished, etc. Not all that much more money in the grand scheme of things and gives me a warm glow. Some gear sets are going to be noisier than others. A good shop that does this kind of work should be able to help you out with choosing what gear to get if your like me and your not knowledgeable about the different choices.

 

Please PM me and give me an update on how you like the 3.90's....THanks

 

Do you plan to have your speedometer recalibrated? Is there a way to do this other than taking it to a dealer...

 

You only have to recalibrate the vette speedo when you change tire size. It reads the ring gear speed, not the pinion speed (driveshaft) like a traditional speedo.

 

Mine's a stick so I dont have to worry about recalibrating for the shift points either. I have not researched what the dealer can do in terms of programing. First of all though, some dealers wont want to touch it. Others dont have a problem with doing stuff like reprogramming for a tire change. When I was down to get reprogrammed for the speedo on my truck the guy could not find it in the menu. I had to download a step by step map to take in so he could navigate to it and make the change. I know the guy and he is a good tech but this is stuff they dont normally have to mess with and it was seriously buried in the menu tree. At any rate a tuner can fix you up.

 

Since your car is an Auto you will need to have the transmission shift points reprogramed. The trans controller is different in the C6 then the C5 and there are only two shops on the board that I know of who can reproigram the C6 trans controller, Ron Zimmer from Z industries and Lingenfelter Performance Engineering. DO NOT swap the gears without getting the trans controller reprogrammed or you will set all sorts of transmission codes and probably hit the rev limiter on the shifts at WOT.

Jersey

 

I installed a 4.10 gear in my MN6. It works great and no noise.
At 74 m.p.h the r.p.m's are at 2000 in 6th gear. It cost me $1000.0 for the gear set and installation in Michigan. I know gear sets can sell for up to $600.00 alone. You do have to install the TM module from Cartek in order to feel the full affects of the gear. Torque Managment kicks in sooner with the new gear.

 

I have changed gearing a number of times and had quite a few cars with various gears in them and I know what I like. I wouldnt reccomend changing gears on a lark to someone who doesnt have a pretty clear idea of what they want and what to expect from a change in gearing. Not trying to scare anyone off but its not something you want to throw at a car to see what will happen.

 

What do you expect to get from changing to a 3.90 and any pros and cons you could share with us. Thanks.

 

I hope your not expecting advice from an expert cause your not going to get that from me. Cons, milage will go down and top end is reduced. Pros, acceleration is improved. You can calculate optimal gearing for performance in various venues but you dont need me to tell you any of that. I was refering to how the car feels out on the road. I have been through a fair variety of gears and changed a number of times so I have a handle on what I like and how a car feels gear wise on the road with different gearing. This is not to say whats right, just what I like. I find the gearing on the base car to be a little highway gearish feeling. I find the Z51 to be just about right. Andy at A&A told me he felt the Z51 trans was better with 3.73s but 3.90s were a little low. He was referring to how the car felt out on the road btw, not what gives the best performance. So its different strokes for different folks. What I expect in this case however is pretty easy to call. The 3.90s put the base car very near the Z51 in the lower three gear. The base car has slightly closer ratios from 1st to 4th but Im not expecting to be able to feel the difference SOTP. 4th will be 15 percent lower than 4th in any of 6 speeds and I will be able to feel this as both being lower and pulling harder during acceleration. I cant find my little sheet where I had the numbers crunched out but if I recall correctly 5th will end up being about 12 percent lower and expect it will also feel lower and pull harder. 6th ends up being about the same as with the Z51 thanks to the huge drop on our base or F55 cars. A forum member ran the numbers and told me I can expect about the same et and 1 mph higher trap speed than a Z51 car. Im not really concerned with that but some folks might be interested. At any rate one cool thing about the non Z51 cars and 3.90s is you have a pretty good idea of what to expect just by having driven a Z51. I guess my point was that gearing really changes the way a car feels on the road and its not something you want to do unless you know where your going with it and that place is where you want to be. Of course if you dont mind and can afford experimenting then no worries. Wish I could be more helpful. I'll post my impressions when I get em in.

 

I have the Z51 and I too feel that 4th and 5th are a little long winded. I think I would appreciate a little more zip, particularly in 4th gear. I'm thinking about the 3.73's but don't want to be rowing through gears 1-3 too much in town. I'm all about the acceleration and really don't care if the car goes above 160. I look forward to your impressions. Thanks.

 

Who is the maufacturer of your new gears? Where did you buy them? If I can get my dealer to say that he'll still honor the warranty with the 4.10's, I think that I'll try this next. I have the Cartek TM module scheduled for delivery next week and the Callaway Honker for the following week. I already have long tube headers and cat backs. I am really looking forward to the effects of the TM module. If it does what I think it will, I won't need more power, for the time being. I'll need more traction! My experience with 4.10's, as a kid, was very positive. They might be an excellent next step for this car, too.

 

With the Z51 it's taking a little getting used to, seems to run out of gear in 1st 2nd and 3rd as compared to my 02 with 3.42's. Haven't done the ButtonWillow road course yet but last year with the 02 with 3.42's, four corners were 25 to 50 yards long and had to coast or waste two shifts. that means it'll be a 35 to 60 yards long now, even worse.