T56 magnum vs TCI 6x
 

Guys,

These two transmissions are up for consideration for my project.

I know one is manual and one is auto, but what are the real world pros and cons off one over the other in terms of perf, driving feel etc?

I like the idea of paddle shift and have also always wanted a rally car style sequential shift with a little kick when changing gears and I think I can simulate that with the 6x. Also for track use, the 6x will be able to shift faster than me.

But I have always hated auto boxes with TC because they feel slow to bite on launch compared to a regular clutch, or a DCT trans.

Then there is also the extra parasitic power loss with an auto trans?

How much of my fears are justified with the 6x? On paper it looks great!

Cost aside, what would you choose? And why? Not worried about missing rowing gears, more interested in scientific/factual reasons

Cheers
Amit

I think you'll be hard pressed to find 6X feedback.

As I seemingly spend half of every day helping people with their 6L80E/6L90E installs, that might be a possible explanation. The GM 6L is awesome. Clutch to Clutch operation for super quick shifting, internal TCM, and readily available. ...And if you want 6L feedback, just go drive a TAPshift vette, then imagine it shifting and launching more quickly after custom calibration.

The 6X is bolt in, the 6L requires that you apply your thinking cap and have your ducks in a row. The 6X is expensive. I've heard reports of 6L's for $1500 with TCM. You'll then spend money on the right harness and, to achieve your listed goals of low parasitic loss and snappy launches, the right torque converter. :hello:

I cant really drive a vette as I am in the UK.

Not many about :D

Can you give me some pointers on the 6L ?

Will it take the 800bhp I have planned?

What do I need and where can I get it?

What do I need to install it on an LS9?

How do I choose the right TC?

If I understand the concept correctly, the 6x is a regular 4L80E that they just do creative things with locking and unlocking the torque converter. If that's the case, I wonder how long the converter will last? And because it is still a regular 4L80E I don't think it will have quite the sequential manual feel you are wanting.

I'd go with the manual if it were my car.

No, TCI re-engineered the gear train hard parts to achieve different gear ratios, then re-programmed the valve body to achieve six forward gears by applying distinct planetary combinations. The converter is actually quite ordinary.

The thing I like about the TCI is the programmable TCM.

You can program it to do soft shifts for street use, and hard and fast shifts for track use. I am hoping the hard and fast shifts will give me the rally car feel.

Just been doing some reading on the 6L80E and it still seems a little to unknown.

Lack of aftermarket TCM, the need to active torque management of the engine, all sounds like a ballache for now benefit?

I'm guessing this thread has become too technical for the open section? I like to speak to the public record, so some responses might not apply to your specific application.

I cant really drive a vette as I am in the UK.

Not many about :D
That's terrible! Caddy dealer?

Can you give me some pointers on the 6L ?
-It's a very tall transmission, so the tunnel needs to be raised. Less than an inch.
-It cannot, at this time, be used with non LS engines. (Soon)
-For best results follow the Corvette programming and wiring scheme.
-ECM/TCM should be of similar vintage.
-Tailshaft conversion kits are available, though two piece driveshafts tolerate lower mounting.

Will it take the 800bhp I have planned?
-Mechanically, the 6L can be enhanced to handle 800HP, though ANY 800HP-capable transmission is expensive. T56, 4L or 6L. 800HP = $$$
The torque management software is a different matter. 800Hp will require a radically altered calibration. Spend your time researching a reliable tuner with references that can provide a 6L tune to suit your engine. As you are in the UK, that can be a challenge. Or lower your input torque goal.

What do I need and where can I get it?
Trans, Tail shaft conversion or 2pc driveshaft with carrier bearing, Corvette style harness and calibration (where the BCM is excluded), converter tuned for your specific application, 6L compatible paddle shifter.

How do I choose the right TC?
The stock converters are actually quite efficient. It's more a matter of tuning for your specific application along with some light upgrades to excise the bean-counters.

Based on all that, the 4L based solution looks pretty good in terms of installation, but the performance driving experience may not suit the requirements listed in your original post.

In the interest of objectivity, I won't discuss where to buy publicly, other than we're having success with Howell Engine Development for harnesses. That has been the biggest challenge--getting the harness right.

The 6L's TCM is programmable, just more complex. And as it's built into the trans, it is essentially free. Find a good tuner or lower your input torque expectations. At 600HP, you utilize an almost stock calibration. Torque management is awesome, just sophisticated. The 4L based 6X, as it is a step-gear design, is an absolute no-brainer from an install standpoint.

You asked about shift speed, rally style performance, parasitic loss and DCT style functionality. To that end, the 6L has the performance benefit, by far. Except for the tunnel mod and 800HP cal, the process has become surprisingly straightforward. I personally am a little shocked at how many people are going 6L.

Go t56. alot more entertaining to drive. My father in law had a 67 chevy II that had a ls9/6l80e combo. It was fun, but after numerous issues with programing etc switched to a t56 magnum. The car ran so much better, was alot more entertaining to drive and no programing issues to worry about. The engine felt alot more responsive and revved alot more freely. just my .02

here is a video of my tci 6x trannyed dodge charger 572 all aluminum hemi with kenne bell 4.2L .. tranny does the job well even on over 1k hp range. 60mph at 1800rpm :)

https://www.youtube.com/watch?v=RGvUs..._4CNig&index=5

This is just my opinion based on my own experience with automatics and road racing. You'll never get one to live long term, they generate way too much heat.

The electronic stuff is absolutely surviving. They just need to be built right -- just as with any other system on the car. ...And the right converter, cooler and fluid is everything.

BEAUTIFUL Charger!

Thanks :thumbsup:

I'm sure with enough effort, money, and time you could make anything work. The sump on the pan with need to be right because it will suffer the same slosh/starvation issues as an engine. The cooler will have to be well thought out as well. Imo that's an awfully expensive trans to be experimenting with.

The third pedal......the one on the left. That's the man pedal.:lol:

I prefer to row my own gears because it shifts EXACTLY the way I want it to, every single time.

I hear yah..

Always been a manual man.. just starting to accept autos can shift faster than me lol

Yup. The "slush box" term doesn't really apply to e transmissions unless they are specifically calibrated slushy or built wrong. But hey, the stigma persists.
They also launch better, yield torque multiplication and offer zero power interrupt between gears.

The GM 4L design is not as good on the road course, but its just as good for auto-x. As for heat, the wrong torque converter will literally shear fluid and quickly turn it into smoke. It should be tight, efficient, and locked up when appropriate.

The more we learn, the converter is the key to a successful pro-touring automatic. There's an 8 yr old survey thread on this board showing a 60/40 split between manual and auto. It's not as crazy or unpopular as some people think.

Where can I find more info on TCs?

I dont get all this stall speed and locking stuff?

Need a dummies guide lol.

Hi have driven an Audi S4 with a traditional box and was more than happy with that.

I will defo need 6spd as I want to keep the fuel costs down too.

good thing with the automatic is that you can drive with the paddle shifter and dont need to take the hands from the steering wheel and with cruising just put it on D dont worry about anything.. tci has 3 modes: automatic ecomonic, automatic performance and full manual with paddle shifter. you can also adjust the shift points and firmness for differend modes and lock up setups.

One thing that has always steered me away from an automatic in the past when choosing transmissions has been the ability, or lack there of, of the automatic transmissions to effectively downshift on a road course. Most don't seem to rev-match. Can the 4L and 6L units do this well?

They all have multiple modes. From our real world experience, use that capability wisely. You have 100 modes under your right foot relative to TPS. Build a calibration that is mild at 0-30% TPS, then aggressive from 30%-100%. There is no logical reason to have a calibration that's soft at WOT (bad), or harsh at 10% TPS (also bad).
A/B modes are best reserved for applications like trucks that might have significantly varied weight (i.e. towing) or applications where traction conditions vary greatly such as snow or mud.

When road racing a 4L based trans (including the TCI 6X), run a bit more rear brake bias and instead of downshifting as you approach the corner, downshift at the apex to power out of the corner and rocket down the straights. Three pedal cars have steadily increasing rpm curves down the straight. Auto cars see a vertical spike, then a much more horizontal curve.

The 4L design is just not as good going into the corner, but better coming out. With the wrong converter and lock up calibration, acceleration will be sluggish, and the drivetrain will feel like it's in neutral every time you lift.

As for rev matching, the torque converter is a fluid coupling and therefore largely unnecessary with the 4L design. And no none of the available trans controllers ask for a blip from DBW throttle pedals. It would sound cool though.

Now the 6L has 3 pedal style engine braking AND torque multiplication under acceleration.

Sorry for geeking out.

Amituk,

I am currently running a 6L80e/Built LS3 set-up in my 67 Camaro. I am using a ProTorque converter, Twistmachine Paddles, and a Tranny tune from Zero Gravity Performance in Arizona. I originally intended to go with a T56, but an now very happy with my 6L80.

Here is my build thread on Pro-touring: (please excuse my initial reference/misprint to the tranny as a 6L90.....I have a 6L80)

http://www.pro-touring.com/showthrea...ro-Build/page2


Driveline specs:
Gear Ratio: 3.70
Rear tire size: 18" x 10" x 4.75" BS, 285/40 Tire (Toyo Proxies)
Car weight: 3200 #'s est.
Torque converter: 3000 stall, 10" Pro-Torque
The car has a fairly aggressive cam from COMP cams, along with headers and a tune. The car produces 420 HP at the tires.


Hope this helps!
Thanks,
Bobby

My personal opinion is that if I'm building a car with intentions of driving it on a road course there is no other option than manual.

I believe a 6x and 4l80 are both .75 overdrive ratio. As a comparison, 5th gear in a T56 is .74 and 6th is .50.

Think again, tuning it to perfection can be nightmare..

Have you seen this: http://www.mastershift.com/p_street_manual.html

Look at the vids , really cool!

Gosh, the first pic on that page looks awful familiar. They used to be good customers of ours, then copied our part almost exactly. Didn't even bother to change the design in the slightest. Beware.

You know what else Steve...I saw this in action @ SEMA. Sure seemed like a very slow shift to me. No idea if it was just the demo unit, but I was thinking I could shift manually in less than half the time.

Keep Geeking out! Your knowledge of the 4L and 6X are great. I like reading your in-depth post about the 4L. Keep it up.

Great thread!:popcorn2:

Sorry Steve, i had no idea. My point was only post best of both world's imho.

Can you tell me how quick it shifts ?

I would not recommend anything other than Twistmachine's set up. I did research all of the other products prior to my purchase; and the customer support, quality, and knowledge of relating components was of no comparison with the other brands. Steve was always willing to help when I was setting up my system.

That's alright. Hasn't hurt us a bit. As for shift time, it's irrelevant since the system lacks proper clutch integration, it needs to shift slow in order to avoid tripping over the clutch.

The modern torque converter, as a semi viscous coupling, is forgiving. With a mechatronic manual, the clutch is the challenge. It must be applied and released with finesse.

Thanks Bob!!!

As good as the new automatics are, I would go with a T56. I have a new CTS-V w/ the 6 spd auto, its fine for a that type of car but to me, it will never "feel" like a manual transmission car. The only other transmissions better are the F1 in a Ferrari Scuderia or the new double clutch systems in BMW, Ferrari ect. Even the E-gear in my Turbo Lamborghini is slow in comparision to the dual clutch trannies.

Lambo
https://www.youtube.com/watch?v=IErRo6L-5bc
turbo Scud
https://www.youtube.com/watch?v=iKT8y...layer_embedded