rt260, M Powered

[RTz]

A little history.... http://forums.hybridz.org/showthread.php?t=118747


Last summer, I installed a set of coilovers/HTS dampers from Beta Motorsports, and a fresh 3.36 NISMO Comp. LSD center section, along with a rear disc brake conversion (280zx). A stock L28E and 5 speed was dropped in as well.


Last week, BRAAP offered me a scorching deal on a BMW S52 drivetrain... http://forums.hybridz.org/showthread.php?t=150131

Why?... I've built/driven/campaigned a number of V8Z's. They're loads of fun. Fast, affordable, and effortless to maintain. However, the silkiness and refinement of the Z was lost in every case. I love the smoothness and aural qualities of the L6, but the L6 is so technologically challenged that it requires an incredible amount of money, time, and talent to build generous, street-able power. Some modern alternatives include the JZ and RB. Each has merit. So does the S52

Stock trim is 240HP, with a fat torque curve. 250-260HP is 'easy'. 300HP is not unreasonable with some effort. A street-friendly 9-10lbs/HP is looking feasible... N/A. And boosted results have been very respectable.

[RTz]

BRAAP and I weighed the S52 package this afternoon. On the same digital scale, a stock L24, fully dressed & dry, weighed in at 389.4 lbs. The S52, with equivalent components and oil, water, motor mount brackets, weighed in at 406.6. These two motors are within a handful of lbs of each other. A very welcome surprise.

The ZF trans weighed in at 83 lbs (wet), also very close to the L-series weight.

BRAAP will be posting the pictures in this thread, post 2 and 13... http://forums.hybridz.org/showthread.php?t=125246

The car will be weighed before and after to finalize the numbers.

[RTz]

An interesting discovery... we noticed, after removing the intake manifold, the backsides of all the valves are spotless. Absolutely no build up. Not representative of a 190K motor. I also noticed a non BMW tag on the block, "LKQ Corporation"... an automotive recycler. Maybe it runs like a low mileage motor because it is?

[RTz]

BRAAP and I poked this thing in a rotted old 77. Will it fit? Absolutely. Will it fit with the simplicity of a SBC.... not quite.

Motor mounts are 'on' the framerails.

Driver side...

Pass side...

Driver side TC bucket and oil pan conflict....

Heater lines...

ASC to Hood conflict (though I have no intentions of incorporating the ASC, I just removed it-problem solved)...

Until I get drive-line angles sorted, I won't know with certainty about the rack height. Also, tranny tunnel height is looking to be tight...

[RTz]

Turns out the '96 and later EFI is a nuisance. BMW incorporated a security system (EWS II), with a matching ECU (Siemens), and key w/embedded resistor & antenna. As I understand it, the matching ECU is a non-issue, but the rest of the system must remain functional. I'm not super excited about the extra complexity and cost of retrofitting the EWS system in the 260.

An alternate choice is to use an earlier harness and ECU. BMW did use an an earlier EWS system (EWS I), but Conforti makes an EWS delete chip that fits the older Bosch ECU, for $300. Much cleaner and not a bad price... until you start sourcing a harness, ECU, and schematic. Now we're sneaking up on the price of a midrange aftermarket ECU. There goes the budget

[RTz]

With the drivetrain sitting in the '77, it was clear the tranny needed to sit as high as possible. For giggles, I stuffed a stock Datsun mount under the trans, and found it to be a near perfect fit. Only needing to trim some of the flange off the front side, re-weld the flange at the cut, drill two holes for the fasteners, and a little massaging of the surrounding bolt hole area with a press (to provide enough flat area for the bottom washers to rest against). Took longer to clean and paint than to modify...

This location puts the tranny about as high as practical, with the height of the output shaft about 1/8" lower than stock, and the motor longitudinally within an 1/8" of of the pictures above. If the rest of the swap was this easy, I'd have it done in a couple of weeks

[RTz]

De-greased the slimy bugger...

BRAAP donated the only structurally straight parts car on the property, a '75 (thanks!). Dropped in the S52 and gearbox, and bolted up the trans mount. Fits well, mostly...

Heater lines look workable...

Oil pan is going to clear...

With the front of the motor sitting on the steering rack, I rigged up an adjustable mag-base and laser pointer. Spun the output shaft by hand and adjusted the base until the circle became small enough to be useful...

Prognoses?... The laser intersects the pinion flange about 1 5/8" too low, and the digital level says the diff and engine are within one-tenth of a degree of each other. Not only does the front of the motor need to come down, so does the nose of the diff.