graebz28

iTrader: (5)

Just wondering if anyone is running lower gears with an m6.

I am trying to get the same take off that I had with the 700R4 which if I remember the 1st gear correctly would be:

3.08(1) * 3.42(rear) = 10.533 (final drive ratio)

Motive just released a 3.90 for 7.5 rears. Those of you running 3.73s, are you still lagging some out of the hole? Those with 4.10s, is it too much?

Wondering why the made the 3.90. Maybe alot of t-56 LS1 guys were asking for.

2.68(1) * 3.42 = 9.165

2.68 * 3.73 = 9.996

2.68 * 3.90 = 10.452

2.68 * 4.10 = 10.988

BMmonteSS

You have to remember you are loosing the torque multiplication of the torque converter when going to a manual, I would go for the 4.10's. You'll still be around 2000 rpm on the high.

If you have plans for over 300 hp at the wheels I would save up your money and try to swap in a 9" or 12 bolt. I've broke more 10 bolts than I care to think about and a 6-speed is just going to speed things up a bit.

graebz28

iTrader: (5)

The torque converter is a 1:1 ratio, right? If anything, it slips in non-lockup mode to reduce the effective 1:1 ratio. How can it increase your final drive ratio if there are no gears?

BMmonteSS

It's kinda complicated but this explains it pretty well.

Most torque converters will multiply your torque by 2.4 to 2.8 times as you come off the line, but this quickly tapers off as the tranny side of the converter comes up to speed.

swerve-driver

I didn't know how a torque converter works and why until reading that. Cool article.
I'll stick with the stick, though.

I believe 1st gear in a T56 is either 2.68 or 2.97. I wasn't able to find a 2.66 listed. I have the 2.97 1st and 4.10 gears out back. I chose the numerically higher gear so I could actually get some use out of 6th gear on the highway without going 90mph.
As far as racing, I haven't been to the track yet, working too much. I suspect the 3.90 would be a nice middle ground. That is why I bought a 12 bolt with a 3.90 gear. I wound up installing another 10-bolt with a 4.10 gear instead as the 12 bolt would have been overkill for my driving habits. Not saying I couldn't break the 10bolt, though.
Edit- I should add that, given the 2.97 1st on my trans, I would have gone with the 3.90 gear if it was available at the time. Oh well...

Best-
S-D

BMmonteSS

The 93 f-body trans had the deaper 2.9x first gear, the later tranies had the 2.6x first gear.

Damon

I was this close -><- to installing 4.10s in my 94 Formula with that trans. Eventually they went into my wife's 92 Camaro with 700R4. On the highway with the MONSTER .5:1 6th gear in your trans 4.10s ain't really all that steep (like 2.05 rear rear gears without overdrive).

In any case, any of those gears will require a better driveshaft. Just becuase the engine isn't spinnign it's guts out doesn't mean the driveshaft won't be on the highway. A typical skinny factory stock steel driveshaft should be vibrating pretty good at only 80 MPH with anything approaching 4:1 in the rear. At 100+ MPH through the traps at the dragstrip you'll know what I'm talking about. My wife's Camaro would do over 105 through the traps and it was obvious the driveshaft was in over it's head. Never let go, but when you can actually feel and hear the vibration throughout the car over the engine and wind noise you know you're living on borrowed time with the stock shaft.

graebz28

iTrader: (5)

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graebz28

iTrader: (5)

BMMonte, I know that a torque converter slips out of the hole to allow the engiine to spin faster than the trans in order to spool up the motor faster. Similar to if I let the clutch out at 2500RPM, but it does not really increase the torque of the motor or effect gear ratio. In actuallity, you lose some gear from the slip factor. See this link: Calculate Speed for an RPM Range - SMOKEmUP.com

Also, there are several sub 11 sec cars running 10 bolts. I'm keeping mine, adding a cover that preloads the bearings and that's it. Different story if you were running slicks at the track constantly.

I recently drove the Hertz Mustange GT-H ( yeah, I know, but it was 325hp with a 5spd auto and 3.55 gears.) It was really a fun car to drive and was a perfect balance of performance and comfort. My friends and I put over 500 miles on it in two days.

Point is that it had a 3.22 1st and a 2.29 second gear in the trans. Anyway that equates to a 11.43 final dive in first and 8.13 in 2nd. The car was quick off the line and hit second high up in the power range when shifting at WOT. After driving that , I want my car to match that feel. Since I have the new t56 with a 2.68, a 4.10 would be slightly lower that that. a 4.56 puts me at 12.22, which is way to high. It is still lower than a 700R4 with 4.10. That equates to 12.68 ist gear final drive. I drove in a stock tbi with that set up and 1st gear was way too quick. With a stock set up, it just did not feel right.

Damon, how do you like your girls car with that set-up?
The new t-56 has such a numerically low 1st gear, it need at least 3.73s to be strong out of the whole. I read a bunch of post by 4th gen guys who swear by 4.10s, so I think that is where I am heading. Luckily, I got a carbon-fiber d/s used so I do not have any concerns with shaft speed.

I also read some mustange posts of guys running 4.10s and they hated it. Makes sense since the final drive with a t-5 1st gear is 13.86!

Damon

With the 700R-4 trans the 4.10s were too much. 1st gear was rediculously short. Unless you have a trans that shifts lightning quick it'll take as long for the trans to do the 1-2 shift as it will to run all the way through 1st gear to begin with. And even in OD the RPMs on a long highway cruise are too much. For racing, great. For the street, I wouldn't go beyond a 3.73 with that trans.

With the 2.66 1st gear in the T-56 a 4.10 would be about perfect. And 6th gear FINALLY becomes usable as something other than a pure fuel economy gear. With stock 3.42s in my Formula 6th gear was worthless. I never used it unless I was just steady cruising on the interstate at 75 MPH. It was so outrageously tall you couldn't even count on it unless the interstate was very open and free of traffic- doing even mild cut-and-thrust highway commuting was a 5th gear-only activity unless you felt like having Kia Rios and fully-loaded 18 wheelers beat you to the next hole in traffic.

BMmonteSS

graeb,

Your correct in that a converter has some amount of slip, but it's not a centrifigal clutch. Read the link I posted it explains it pretty clearly. Converters are tricky little devils, it's all a balance of slip, torque multiplication and fitting everything inside the cover.