T56 magnum vs TCI 6x

[Amituk]

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

[Steve Chryssos]

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.

[Amituk]

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

Not many about

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?

[JsTA]

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.

[Steve Chryssos]

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.

[Amituk]

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?

[Steve Chryssos]

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
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.

[Steve Chryssos]

Originally Posted by Amituk

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?

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.

[hifi875]

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

[Studio57]

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