LS / T56/ diff info for non-GM guys.

[734i]

So I thought I'd offer some insight, for you guys who know GM about as well as I know BMW.
LS info is all over the internet, good info on the T56 not so much.
Most of the demand for cheap used LS engines is easily met by all the different vehicles the LS has been offered in, but the T56, the only versions of use to an E36 M3 or similar are going to be the '98-'02 Camaro / Firebird version, for which the demand is extremely high, the '04-'06 GTO version, and the CTS-V version.
You're not going to find any of these, in any condition, for less than $1500. Then you'll need a rebuild kit with new synchros and stuff.
If you shop well, you can find a few NOS versions in warehouses for $2500, but those are nearly gone.
For most, it's either shell out for a new T56 Magnum directly from Tremec, or try something else, like the similar TR-6060 from the '10-up Camaro SS.
Then there's the Tremec TKO-600. It's not quite as strong as the Magnum, but it's stronger than the production T56s. It's also lighter than any T56. It doesn't like high-RPM shifts, it'll do better with forced induction and a lower redline than it will with the opposite sort of build.
Most of the popularity of the LS, in the GM world, is for how they take forced induction, especially Chinese turbos. The RX-7 community doesn't bother, and it seems like why even go LS if you're not going to boost it? And it seems you BMW guys are the same way. Strange.
Here's an engine that you can pull out of a 150,000-mile work truck for $250, add a turbo, and make 1200+ HP without having to waste money on forged pistons and all those other high-dollar parts. So why add all that mass, bulk, and hassle for just 300 HP?
Ok, back to the transmission. A production T56 can be built to hold as much as a Magnum, a Magnum can be built to hold 1200 HP and 1000 TQ ( Rockland Standard Gear calls their version Tranzilla, but it's even more $ ) And for anything over that, your only option is a built 4L80E from Jake's, unless you want an SM465. Which you don't. But it is the only transmission on earth that can hold 1500 HP for under $500. If you want details, PM me.
'98-'02 Camaro pullout LS1/T56 combos are in high demand, but that particular version of the LS is developing a reputation for throwing connecting rods. The '07-up rods are stronger.
You're better off with an aluminum-block 5.3L than an iron-block 6.0L.
And unless you want 7200 RPM with no forced induction, you're better off with 243 or 799 heads than any of the non-cathedral-port heads. If you can afford better, the best cathedrals are AFR's 205s, and if you want the absolute best non-cathedrals, it's Mast Black Labels.
Chevy's own race block is rated to 2500 HP, and they got there with a pair of T88 turbos. The only transmissions that can hold that are either adapting a big-rig transmission, which weighs more than your BMW, or a Rossler TH400, or a max-race-only, Powerglide-based. Those last 2 are both automatics, neither has an overdrive, but GearVendors makes a 0.78:1 OD that can bolt to the back of a TH400.
If you're new to boosting an LS, plan on starting with a 5.3 and an E-Bay GT45. Add a set of 80-pound ( of fuel per hour ) injectors, every chassis dyno shop out there can download a baseline tune for that combo, then go from there. That'll get you around 550 HP to start with, you can push it as far as 1300 before needing any major changes. To go from 550 to 1300 will require a pair of T76s, a turbo cam, CNC-ported heads, better head gaskets, ARP head studs, and fuel delivery upgrades. But any Junkyard 5.3 will suffice if you keep the tune on the safe side.
Your 210-mm diffs aren't strong enough for 1300 HP, and I doubt your halfshafts are, but The Driveshaft Shop can upgrade those, and change the inboard ends to match a '90s Ford Thunderbird-sourced iron-case 8.8" IRS diff assembly. This version came as 28-spline, but is a much stronger case than the aluminum version from the Mustang Cobra, which used stronger 31-spline parts. The strongest option is a 33-spline, you can get a 35-spline spool, but in 33 you can get 3 different limited-slip choices. The Wavetrac is the best, and is priced accordingly. The Auburn is great for daily commuting, even in snow, but wears out, and as it does so it accelerates the wear of the gears. Plan on frequent fluid changes if you get one. The Truetrac doesn't wear so much, and isn't really weak, but It's not as strong as the Auburn. Unlike the Auburn, the Truetrac was developed for off-road 4x4 Jeeps.
More later.

[unnatrl]

I can't completely argue with you, but you make it sound so easy!

[734i]

I can't completely argue with you, but you make it sound so easy!

If you have the $, then it is that easy. Vorshlag makes all the BMW-specific parts you need to get it into a few different models according to your tastes. Once it's in, make the most of it. The biggest expense of 1000 HP is getting it to the road.

[unnatrl]

If you have the $, then it is that easy. Vorshlag makes all the BMW-specific parts you need to get it into a few different models according to your tastes. Once it's in, make the most of it. The biggest expense of 1000 HP is getting it to the road.

:-)

I'm aware of Vorschlag's products. There are other options as well. The parts you would use don't make much difference when shooting for that 1k mark.

My previous comment was based more on the idea that it sounds so easy "on paper." It's crazy how much work there really is between the idea phase and a completed car.

[734i]

To me the appeal of the LS1 version is that the Camaros were doing 31 MPG with 300 RWHP. Revvin' Evan J. Smith of Muscle Mustangs and Fast Fords magazine got an un-prepped, showroom-stock, nothing-special, non-Ss '98 Z28 to run a 12.89 @ 109.18 in the standing quarter mile, on Goodyear Eagle GS-C 245/50R16s at 28 psi. That verifies the subsequent dyno testing by Texas Speed that showed it actually made 400 HP at the flywheel. 4 seats, a/c, '02 emissions, 31 MPG, and 400 HP, with a warranty, nothing else on earth could touch that back then. And it'll hold 5 psi of boost with nothing more than a hair more premium fuel and a bottle of Super 104+ octane booster. That's about 533 HP. Not much even in 2018 cars that can rival all that in one package.

- - - Updated - - -

:-)

I'm aware of Vorschlag's products. There are other options as well. The parts you would use don't make much difference when shooting for that 1k mark.

My previous comment was based more on the idea that it sounds so easy "on paper." It's crazy how much work there really is between the idea phase and a completed car.

True that. Or pay to have it done.

[unnatrl]

To me the appeal of the LS1 version is that the Camaros were doing 31 MPG with 300 RWHP. Revvin' Evan J. Smith of Muscle Mustangs and Fast Fords magazine got an un-prepped, showroom-stock, nothing-special, non-Ss '98 Z28 to run a 12.89 @ 109.18 in the standing quarter mile, on Goodyear Eagle GS-C 245/50R16s at 28 psi. That verifies the subsequent dyno testing by Texas Speed that showed it actually made 400 HP at the flywheel. 4 seats, a/c, '02 emissions, 31 MPG, and 400 HP, with a warranty, nothing else on earth could touch that back then. And it'll hold 5 psi of boost with nothing more than a hair more premium fuel and a bottle of Super 104+ octane booster. That's about 533 HP. Not much even in 2018 cars that can rival all that in one package.

- - - Updated - - -



True that. Or pay to have it done.

You could go that route too.

I prefer to build my own. Albeit with some available parts. Making it all fit is the fun part. 14 psi on the stock bottom end was fun. Now fully forged on 6.5 psi, still gun shy.

[734i]

Of course bolting new speed parts together is fun, anyone with $ can do that. And that may even qualify as "Built, not bought", but it's not really custom-building, which is harder, and worthy of more respect. More glory. Especially if the results are at least functional, preferably beautiful also.
In a build like this, your best chance to show off, to represent yourself, to be expressive, is in the turbo. Choosing it, locating and orienting it, plumbing it. Most especially the plumbing.
By plumbing I mean getting fresh air into the compressor, routing boost from the compressor through an inter-cooler and into the engine, and routing the hot side, the exhaust gasses to and from the turbine. The BOV, and the Wastegate if not integral, are part of the plumbing. The above pic isn't bad, but it took the most work.
Speaking of which, why is the inlet into the compressor so small? That needs corrected.

[unnatrl]

Of course bolting new speed parts together is fun, anyone with $ can do that. And that may even qualify as "Built, not bought", but it's not really custom-building, which is harder, and worthy of more respect. More glory. Especially if the results are at least functional, preferably beautiful also.
In a build like this, your best chance to show off, to represent yourself, to be expressive, is in the turbo. Choosing it, locating and orienting it, plumbing it. Most especially the plumbing.
By plumbing I mean getting fresh air into the compressor, routing boost from the compressor through an inter-cooler and into the engine, and routing the hot side, the exhaust gasses to and from the turbine. The BOV, and the Wastegate if not integral, are part of the plumbing. The above pic isn't bad, but it took the most work.
Speaking of which, why is the inlet into the compressor so small? That needs corrected.

I'm not sure if that is a general statement or not.

Bolting speed parts together is a monkeys game. Anyone can do it. Making them all work together is entirely different. The plumbing of a turbo is actually quite simple. Making it all fit within a prescribed area isn't always as easy.

What you see at face value is a fraction of what it takes to make a car like this come together. One must consider integrating wiring- make it run, a/c functional, gauges functional, etc. Connecting the donor transmission to the original differential can be a chore as well. This part isn't a bolt together game. It takes skill and ingenuity.

In regard to the turbo inlet, the size is fine. An 80mm compressor wheel is roughly 3 1/4 inches in diameter, the inlet is 4". The inlet is necked from 5.5" to 4" to facilitate the installation of an air filter. Tubing size, headlight location, the inner fender apron and more come into play on what will fit.

[cobra30689]

I don't know why (maybe because of my age lol) but I dig that R4 AC compressor. How well does it work as opposed to a newer Sanden? I know they have gotten a bad rap over the years, but I personally never had a problem with them in any GM car I've owned. Was considering going the R4 route on my own swap....

[unnatrl]

I don't know why (maybe because of my age lol) but I dig that R4 AC compressor. How well does it work as opposed to a newer Sanden? I know they have gotten a bad rap over the years, but I personally never had a problem with them in any GM car I've owned. Was considering going the R4 route on my own swap....

I don't know how well it works yet. Discovered a home in on of the a/c lines. Once that's taken care of, I will post results on my build thread.