54inches

iTrader: (4)

That is mounted totally different that we are mounting out 8.8s. I think it makes a difference as we are sandwiching the front mount.

I am not worried about it.

In fact if you read the thread that you posted above, they mention that it is mounted wrong.

Moot point.

Sweet. I am thinking mounting the whole cradle/subframe and diff in Aluminum.

Yes, we are doing that, so did CS. I have yet to hear of a failure of this sort when mounted properly.

54inches

iTrader: (4)

http://s184.beta.photobucket.com/use.../Lincoln%20IRS

FuzzyLog1c

iTrader: (4)

Anyone else thinking about going with 3.27 gears on the back end?

If you look at the variants of the T-56 that shipped with the CTS-V, the GTO, Viper, Corvette, etc...you'll note that there's a 2.97 wide ratio and a 2.66 close ratio. I have a problem with the way the CTS-V is geared. We have too much gear and too little tire. Unfortunately, because of the weird, bastardized version of the T-56 we have, we can't shift worth a damn, and we can't change our gears without buying a whole new transmission from G-Force for $5000 (I called five T-56/TR6060 specialty shops to confirm).

First: 2.97 (CTS-V and GTO), 2.66 (Corvette and Viper)
Second: 2.07 (CTS-V and GTO), 1.78 (Corvette and Viper)
Third: 1.43 (CTS-V and GTO), 1.30 (Corvette and Viper)
Fourth: 1.00 (CTS-V and GTO), 1.00 (Corvette and Viper)
Fifth: 0.84 (CTS-V and GTO), 0.74 (Corvette and Viper)
Sixth: 0.57 (CTS-V and GTO), 0.50 (Corvette and Viper)
Differential ratio: 3.73 (CTS-V), 3.46 (GTO), 3.42 (Corvette), 3.07 (Viper)

See anything wrong here? We have the worst differential, subframe, transmission, and the least ability to carry wide rubber, and yet we have (by FAR) the shortest gears. Even with a 3.27, we're still carrying about 10% more gear than the stock Corvette. And for those of us who are planning on building 416+ CID LS3s and supercharging them, that gear ratio will really come in handy.

There are also some positive side effects. First, you can buy that $900 DSS aluminum driveshaft that has a critical speed of 150 mph and run it up to 172 mph instead of paying for their $1500, 250 mph carbon fiber model. That's $600 saved. Second, first gear suddenly becomes a little more useful, and you can finally get great fuel economy at some of the more typical cruising speeds (e.g. 45 mph in urban environments and 80 mph on certain highways).

The following is based on a little worksheet I put together that takes the minimum possible speed that you can run the engine in Gear X before it starts lugging and identifies the speed that you can hit at 2000 RPM before you need to shift to conserve fuel. Before you go off and yell at me for saving fuel, note: I either drive like I'm in an autocross event, or I cruise to save fuel. There's no middle ground. This is just an example of the conservative extreme.

================================================

T-56 2.97 wide gear ratio with 3.73 differential

900 RPM = 6 mph
2000 RPM = 14 mph in first

1150 RPM = 12 mph
2000 RPM = 21 mph in second

1225 RPM = 18 mph
2000 RPM = 30 mph in third

1325 RPM = 28 mph
2000 RPM = 43 mph in fourth

1375 RPM = 35 mph
2000 RPM = 51 mph in fifth

1375 RPM = 51 mph
2000 RPM = 68 mph in sixth

DSS Aluminum $900 Driveshaft: 150 mph critical speed (7000 RPM in 4th gear??)

================================================

T-56 2.97 wide gear ratio with 3.27 differential

900 RPM = 7 mph
2000 RPM = 16 mph in first

1150 RPM = 13 mph
2000 RPM = 23 mph in second

1225 RPM = 21 mph
2000 RPM = 34 mph in third

1325 RPM = 32 mph
2000 RPM = 49 mph in fourth

1375 RPM = 40 mph
2000 RPM = 58 mph in fifth

1375 RPM = 59 mph
2000 RPM = 85 mph in sixth

DSS Aluminum $900 Driveshaft: 172 mph critical speed (7000 RPM in 4th gear??)
================================================


Based on hand calculations, and by using various calculators, I think that we have a chance of breaking 10 seconds in the first generation CTS-V with a 416 CID LS3 and TVS2300 making above 700 RWHP (825 crank horsepower), provided that we can keep the transmission and differential from exploding and the wheels on the ground.

GulfM3

iTrader: (14)

Fuzzy, My 3.31 gears were just delivered yesterday. My reasoning was a little more "simple" than yours in that I can't build boost in 1st and can't reach full boost in 2nd. It takes third gear to load up the motor enough to reach full boost. On top of the inability to load up the turbos I plan on running the car in the Texas Mile again, at my current power I was able to redline 5th and forced to shift to 6th. I'm nervous putting down big power in 6th and wrecking the transmission.

FuzzyLog1c

iTrader: (4)

Have you considered doing a Stage 2 T-56 rebuild? Should let you do 600 ft-lbs of torque, as opposed to 400 ft-lbs of torque. The owner of The Gearbox indicates that they're out of stock on the 1-2/3-4 CTS-V T-56 synchros, and they're not going to get more until around April. I'm hoping to do a group buy to drive the $950 price of the rebuild kit down. As I said earlier, the only "bigger" option is the G-Force 850 ft-lbs option at $5000 a pop.

FoD

Fuzzy, Tick Performance also offers a Trans rebuild, and they state it is able to withstand 700RWTQ. It is a bit pricey, but another option. I know there was another shop near me, in South Carolina somewhere that was doing TR6060 retro's out of your T56. Wanna say the price was somewhere in the $2500-$3K mark for that, but that is a new trans, upgraded for extra power. I'll try to find info on that.

On topic- This thread is starting to make me want to upgrade my Gen 4 Diff. Damn you guys! This bug is hard to get rid of.

Dmax/04V

Pricey but here's an option that may allow more flexibility down the road.....

http://forums.corvetteforum.com/c5-g...ansmisson.html

I8URSVT

iTrader: (2)

I've talked to this guy before:

http://washingtondc.craigslist.org/m...519653410.html

Pretty sure hes on Ls1tech as well. I talked with him on the phone a year or so ago about rebuilding/upgrading a viper t-56 for my mustang. He seemed like a pretty cool guy and had reasonable prices at the time, although from talking to another trans builder, alot of the parts have gone up in price so not sure what it would cost now. Just an option, maybe more so for the guys in MD/DC/VA


Keep up the good work guys!

FoD

Yup, that's the one I was talking about.

FuzzyLog1c

iTrader: (4)

Fod, they're all selling the same parts. The only thing that differs is their "marketing strategy," as opposed to a rating, because a rating implies a warranty, and there is none on these parts.

Frankly, any continuous-time torque number thrown out there is pretty much baseless, because what usually breaks a transmission is shifting it under load (causing stress transients several times greater than the continuous torque rating). These shops admit that they haven't done qualification testing of their rebuild kits, so what you get is basically a "this guy runs our kit and he makes 700 RWTQ" statement that doesn't account for the driver, his shifting style, or the "grab" characteristics of his clutch (permutations include organic/ceramic/carbon fiber, single/double/triple, and sprung/unsprung friction disc or discs).

Bowtie70SS

iTrader: (10)

I always thought of my clutch as a fuse...it doesnt always work out like that though.

FoD

Okay, so you, deciding to use the one above, are basing this off of what? Their claims, just like everyone else, are unfounded, right? Are you going with The Gear Box rebuild because it is the cheapest you've found?

FuzzyLog1c

iTrader: (4)

Correct. All of these kits include the exact same parts acquired directly from Tremec. Setting up a group buy feels like a scavenger hunt for the cheapest individual parts and the most amenable distributor.

Fuzzy_Wuzzy

iTrader: (8)

I think the conversation has changed topics a little bit...

That is the nice thing about having an 8.8 that we finally get that option to choose gear ratios as we please.

DACTARI

iTrader: (1)

I agree completely with Fuzzylogic's logic on gear selection. Finally we would be able to choose optimal cam setups without having to worry about grip.

54inches

iTrader: (4)

Which one would you like kind sir?

I too have been thinking about going a different gear ratio, but had not put pen to paper yet as I would like to see final drive ratios (1:1) just for ***** and giggles.

I really don't mind these kinds of off-topic discussions as I think they are healthy and promote open discussion that in turn really is on-topic.

As stated before, WHEN this becomes reality, I will start a thread, hopefully have it stickied, that has info and no q&A per say.

But we still have work to do, so keep up the chatter.

FoD

If I do decide to upgrade, I'd want the fully welded design, paint or no paint doesn't make a difference to me.

Schitzo

iTrader: (6)

Hi that's my car. Those stubs are not from DSS and were under $250 each.

54inches

iTrader: (4)

Well don't leave us FN hanging; please expound.

54inches

iTrader: (4)

Hello?