If you are not going to track your Vette and you have 3.15 gears already, (like I do, and I drive my Vette only on public road, no racing) then save your cash and don't bother with gears or a torque converter.

Here some info on torque converters for you:

http://auto.howstuffworks.com/torque-converter.htm

 

i find the car lacking, needs some more punch forsure! thanks for the article!! i get it now.i guess the stock converter wont do the job.how much are these converters??

 

I totally disagree.

3.42 gears and a converter (even when starting out at the 3.15 ratio) can make a day/night improvement; and still keep the car controllable. Best money I ever spent.

a LOT of added fun on the street

and no added stress on the engine or torque tube

here's my inexpensive converter swap:
http://forums.corvetteforum.com/show....php?t=1715694

 

ok guys if i go with 3.72 and its only for street use.do i need a converter?? if so which one ( brand and model) do you recomend?

 

Vigilante and Yank seem to be popular. Check out this converter selector on the Yank site....

http://www.converter.cc/converter_se...ector_main.htm

 

Both are excellent, and we have personally used the Yank in our brack cas for years, but we designed our Extreme line after selling & installing & using both lines....we ended up with the intial hit of a Vig & the down track efficiency of a Yank...and each one is built to the customers application, nothing off the shelf. $799 retail, 1 free install, full year warranty, and quick turnaround.

 

Went from 3'15's to 3.42's and I could not be happier. REALLY woke up the performance. VERY SATISFIED!

 

If this shop has done a lot of gear swaps maybe the owner can put you in touch with one of his customers that had it done. They would probably be willing to take you for a ride in it (or maybe even drive!) so you can really feel the differance.

If not, then see if there is a local Vette club. Someone there might have done the swap.

 

Here are your options:

You have a 3 series carrier with 3.15's (unlike the guy's who have stock 2.73 and 2 series carriers). With that, you can either pay for a new GM pumpkin. There are 2 flavors, standard(~1000) and Z06 (~1200), both in 3.42 gear ratios. Or, you can have someone reputable disassemble your diff and put in any gear ratio you want, 3.42, 3.73, 3.90, 4.10, or even 4.56. This option is slightly cheaper, and you do have option of choosing any gear you want.

Automatics only have 4 gears, and first is much lower than a manual. As such, they should be gear'd differently. The most popular upgrade for manual cars is either 3.90 or 4.10. This produces a final 1st gear drive ratio of 10.374 or 10.906. For automatics, 3.42/3.73/390 first gear final drive ratio's end up being 10.465/11.414/11.934. So you see, 3.90's in a automatic are way overkill. Some here love them, but you will roast tires very easily. 3.42's fall in between, and that's why many love them. 3.73's are also a good choice for first gear. Now, when manuals get to 4th gear, or auto's in third, the transmission ratio is 1:1. Final drive ratio equals the gear ratio, so if you want highway passing ability, where your already in 3rd gear, 3.73's will pull harder. You would have to be more careful in bad weather, since the increased torque can definately cause the tires to spin pretty easy.

You certainly don't need a converter, but it is a signifigant performance upgrade. Most converters can take a full half-second off your 1/4 mile time.

A torque converter is the device on the car that enable's automatics to work at all without stalling. When the engine is at low RPM's, the fluid spins around the converter in a way that doesn't spin the output shaft (very simplified explanation). As RPM's increase, the fluid imparts more energy to the output shaft, and the driveshaft turns. At higher speeds, modern torque converters "lock up" meaning they couple the input and output portions to increase efficiency (like a clutch). A high stall converter, actually transfers less energy to the output shaft until engine RPM's are higher (hence the name, high stall). This allows the engine to be in a much better powerband, and hence more power is delivered seemingly instantaneously, vs the slower build up of power with the low stall. Yank 3200 are very popular, and Vigillante as well. I suggest you do your research and talk with them, as well as reputable tuners for your best options.

3.90's with a high stall, and standard tires may never be able to hook up. I'd say this combo would only be useful for strip use with drag radials. 3.73 and 3200-3600 would be (IMO) the max for careful street performance. For casual street performance, 3.42's with 3200 stall. MikeMercury's excellent writeup give's you details on why he did what he did. He also bit the bullet and went to a higher stall, I think like 2200. Some people like the high stall TC's, other don't. I stand by my original advice, if you plan to add power in the future, you should probably go 3.42's. If you don't, then I'd seriously consider going 3.73's and call it a day.

You have to make the decision on what you want, so I'd recommend hooking up with some local guys who will be more than willing to show you what they have. Be warned though, because what you think you want may change radiacally when you see what other have done.

I'd suggest filling in your profile so we can see where your located. You'd be surprised how many CF members are right next door.

I'm sure your aware, that changing gears has the effect of slowing the tires down to correspondingly increase rear-wheel torque. As a consequence, to do the same speed, your engine RPM's increase, and you gas mileage will decrease.

 

Excellent write up.

 

GREAT wirghtup

 

great write up!!! thanks..

 

I don't know if you've already made a decision - but tuners make a big difference with automatics. They can change when the tranny shifts, tranny pressure, etc.

They're not too expensive - especially if you have a friend... to try out. The 1/4 mile difference can be significant just based on tranny tuning...