This does not make $$$ sense now, but in a couple of years these will be in the junkyard. These cars are aimed at the young market and they will get totaled for sure. The 2008 BMW 135i weighs 3450 lbs. It has a twin turbo, inline six cylinder, DOHC, 3 liter engine, that produces 300 HP and 300 lbs torque, and it has a six speed manual transmission. It also has Brembo brakes.
I'm betting that this engine and transmission designed for your weight car would slide right in an '86 635 (the latest "simple" car) that you picked up in southern California. Don't know about the brakes, but it's worth a peek.
They would have computers and that would possibly be a problem, but then, maybe not. Even the gas mileage improves!

There is something to be said about the improvements in technology.

The sheer multitude of issues with the project would be enough to make most gearhead's toolboxes quake in terror.

Given how the engines are now, the only way you could get the thing to work would be to pretty much rip every bit of wiring and computer from the 135 and somehow shoehorn them into the E24. Or run a standalone.

Nice idea though.

The sheer multitude of issues with the project would be enough to make most gearhead's toolboxes quake in terror.

Given how the engines are now, the only way you could get the thing to work would be to pretty much rip every bit of wiring and computer from the 135 and somehow shoehorn them into the E24. Or run a standalone.

Nice idea though.

There is space under the hood, and I agree it sounds daunting, but you would only need keep your old battery and start the wiring there just as it comes from the 135. The engine layout, size and the weight of the car it was designed for seemed a fit, but the turbos would need space too. Modern engines with computers tend to be more compact. I had an '87 SAAB 9000 turbo that was an awesome car and that was my inspiration. The wiring to the instruments though would require someone who could read wiring diagrams and probably an EE degree!

The 2008 BMW 135i weighs 3450 lbs.

Holy crap! Will they never make a 2600lb car again? I thought the 1 series was supposed to make up for the ludicrous overgrowing of the 3 series, but I guess not, just another fat companion for it.

There is space under the hood, and I agree it sounds daunting, but you would only need keep your old battery and start the wiring there just as it comes from the 135. The engine layout, size and the weight of the car it was designed for seemed a fit, but the turbos would need space too. Modern engines with computers tend to be more compact. I had an '87 SAAB 9000 turbo that was an awesome car and that was my inspiration. The wiring to the instruments though would require someone who could read wiring diagrams and probably an EE degree!

The better solution would be to use a standalone EMS, like Motec or Haltec. I'm pretty sure MegaSquirt cannot run the N5X engines yet. Plus, then you could tune the engine to your heart's content.

The better solution would be to use a standalone EMS, like Motec or Haltec. I'm pretty sure MegaSquirt cannot run the N5X engines yet. Plus, then you could tune the engine to your heart's content.

Well, the Motec M800 would possibly do the job, but this is way above my technical level, and anything electrical on a race car usually has eye watering prices. I wonder what these EMS systems cost?
Years ago when I had an M6 I was always a bit leary of the engine because guys kept finding little things that were very important to longevity, and if you made a mistake it was really $$$ serious. (Still is, by the way) But the car was great because I never really found a speed where it was struggling or uncomfortable, so the basics were there, but the really reliable (in a confidence way) power wasn't. The drive line never caused anyone any trouble that I heard of so that's OK from the trans back, and the handling was fine too. I once followed a whaletail Porsche at speeds that were right at my limit and the car was very steady.
So an engine/trans swap to a higher HP standard BMW engine that fits in the space and is designed for the weight and performance envelope of the 635 seems a reasonable solution. Not unlike getting better brakes from a later model BMW. I live in the Chicago area and there are plenty of Porsche guys around who crunch numbers as well as twist a wrench, but I'm not sure, right now, who I would talk to about this 135 engine in a 635.
BMW turbo engines have somewhat of a checkered past too, so that would need a beer or two and some staring at the wall. That 2 liter four cylinder F1 engine from '81 did 1200 HP at least because that was the limit of their dyno: I assume BMW has a better dyno and develoment program now. The 135 engine should be very good right out of the box.

I'm also figuring the weight of the engine would be similar. A 3 liter engine with a lower end built to handle 300HP turbo power plus the turbo and intercooler weight would be similar in weight to the standard 635 engine. To keep the weight in the right place you could possibly move it longitudinally a bit, although the radiator space could be a problem forward.
The design of the 635 was eyeballed for aero so it has a nice greenhouse that is unavailable in the wind tunnel designs of today. Top speed is not a big consideration with me, not is the 0-60 number, and with the suspension options available plus the wheel and tire combos out there you should be comfortable at almost any speed even occsassionally possible here. That was/is the glory of the M6; it just didn't get ruffled, but the ride was a bit stiff for a dailly driver.

If you are going to do a swap then ORIGINAL is not your bag, sooooo,
do it right, forget the computer crap and drop in a Ford 302 cu.in (5.0) Fairly light at
500 lbs or so, tons of torque (302s can be taken up to 600 hp although 300-350 hp is common), cheap and plentiful, bullet proof, easy to modify, easy to work on. 600 cfm carburator and your ready to go. Lower center of gavity than an inline six, mounts farther back for better front to back weight ratio. Also one of the smallest in size V8s ever made, easily fit into a 635 with a T-5 worldclass 5-spd. Been thinking about it for a couple years. However, no BMW guy would ever talk to you, you would have to hang out at the local cruise ins with the Mustangs and Camareos and you would still be the weird guy and if you ever wanted to move on you would have to pay someone to take it off your hands.
Still...It would solve alot of problems.
Chris

Honestly, the swap seems like a lot of trouble when there are already several M30 turbo kits which get you to or exceed the current 335 setups. Boost does come on a tad later though. (~3000 RPM vs 1500)

Then you don't have to deal with swapping things or making a Frankenstein car.

Honestly, the swap seems like a lot of trouble when there are already several M30 turbo kits which get you to or exceed the current 335 setups. Boost does come on a tad later though. (~3000 RPM vs 1500)

Then you don't have to deal with swapping things or making a Frankenstein car.

Totally agree!! The M30 can take lots of abuse, there are tons of them out there, and the car stays basically original. I've done the transplant thing too many times, in the long run, it sucks. It's fun for awhile, but then problems start cropping up, soon you park it in the south 40 and it rusts away.