N47 Flip-Flop

[ClayW]

This is going to be fun. So much for me being the motor-swap trailblazer of the Ivy Street Red Car Gang.

One thing I noticed: If you use this motor, you can utilize the snorkel. Score.

[Swiftus]

I had looked at the snorkel... I thinking I may need to, in good ol' American fashion, supersize it!

Clay, I think that it was seeing your M42 in your car was the tipping point. Are you ready for a swap in a year?

[williamggruff]

TB is Throttle Body.

Or tuberculosis. One of the two.

[Swiftus]

I wasn't sure if this motor had one of those...

Turns out, it looks like it does...

Is it item 17 in the diagram?

http://realoem.com/bmw/showparts.do?model=UR31&mospid=50605&btnr=11_4101&hg=11&fg=40

[ClayW]

Clay, I think that it was seeing your M42 in your car was the tipping point. Are you ready for a swap in a year?

Your swap, yes. Mine, no.

If I swap motors next year, I'm going to have to move to Europe and find new friends to help me. I'm pretty sure that you were there when Dudley said in a Samuel-L.-Jackson-esque voice, "We aren't doing this again next year!"

Anyway, the M42 swap is meant, in part, to stop me from fiddling with tuning and get on to the rest of the car. As long as the engine stays reliable, powerful and fuel efficient, I'm leaving it in there!

[jgerock]

Don't modern diesel engines require urea injection to clean up the emissions?

Both MB and BMW have (I THINK) a reservoir that you need to keep filled with the liquid urea.

Diesel is great (the new 3 series is super quiet), but the new N20 4 cylinder gasoline might be a better candidate.

[Swiftus]

Don't modern diesel engines require urea injection to clean up the emissions?

EEEEEEEEEEEEEEEEEEEEEWWWWWWWWWWWW... Well there is an excuse to pee on your car...

IDK if this motor has a urea resevior. I briefly looked at the diagrams on RealOEM, but I didn't find anything with that quick search. It seems like the motor just does a lot of exhaust recirculation to clean up the emmissions.

Diesel is great (the new 3 series is super quiet), but the new N20 4 cylinder gasoline might be a better candidate.

I like the idea of the diesel because of it's Dr. Jeckyl / Mr Hyde routine when installed in a light car. Maybe we could start another thread looking in to the feasibility of an N20? powered 02?

[Guest]

This thought had occurred to me since most diesels have no throttle body. Fitting a hall effect sensor to a pedal is easy, and finding the proper accuracy should be as easy as looking up the diagnosis procedure in a shop manual.

I'm pretty sure a hall-effect sensor won't work for that, you'll need a type of degree sensor where as a hall-effect just measures how often it receives a certain magnetic field vs. how often it doesn't.

I think it's like this as the wheel spins around with the ..... being the missing tooth.

.:.:.:.:.:......:.:.:.:.:.

To gain the full advantage of this motor you'd need the original harness but standalone could do it. Modern standalone systems are just as advanced if not more advanced than what is on the car. You'd probably be looking at MoTec M400 to run it and that's going to cost another $5000+. It would be a nightmare to be the first person to do that, especially with no prior experience.

You should be able to pull the throttle sensor off any car with one(best if it's a BMW) and re-configure it to the '02's system. It will probably be easier to use hanging pedals, at least for the throttle.

[Swiftus]

I fully intended on using everything that came with the original car, short of the exhaust, AC, power steering, and any of the traction control or ABS stuff. This means using the original engine harness (I have built too many harnesses recently, I want to do something that is plug and play)

There are some rotational hall effect sensors. But using the sensor that came with the car is probably best if I were to end up using the original ECU. (Any rotary quadrature optical sensor would work too. I have some of those laying around... some with 12800 steps per rotation. If you work at a robotics company long enough, you end up collecting a bunch of what would otherwise be useless junk.)

I would much rather crack the original ECU than try to make an aftermarket one work for the car. That is a whole lot of work. I could probably wrangle a buddy who owns an engine shop into tuning the thing with me, but I would have to buy him a yaers worth of beer in order to convinvce him!

EDIT: I will complie my information from Metric Mechanic tonight and see what you think about it.

[Guest Anonymous]

Don't modern diesel engines require urea injection to clean up the emissions?

Both MB and BMW have (I THINK) a reservoir that you need to keep filled with the liquid urea.

Diesel is great (the new 3 series is super quiet), but the new N20 4 cylinder gasoline might be a better candidate.

Modern diesels have moved from the Diesel Particulate Filter to Urea Injection to ditch watercooled EGR's and DPF light off issues. Urea sucks. It freezes and is ridiculously expensive. The sensors inside the tank will go bad and if the tank runs dry the car will not start. (as it wouldn't be in compliance with emissions regulations)

I just perused and the one I saw was equipped with a DPF.

That high pressure pump better be on the motor, it's $940+ if it isn't.

Transmissions are rated at ft/lbs (torque rating) not by HP. Stabbing a diesel torque motor into a "older" transmission could be a recipe for trouble.

realoem and other sites will be helpfull for you to visualize. No the dealer can't code the anti-theft out of a motor. You'll need ignition and keys that are paired with the ECU. And steal the gaspedal out of the car your getting it from. Don't make one yourself. It's a free standing bolt in assembly.

[Guest Anonymous]

One more thing. Modern diesels are nothing like old ones. Every sensor, injector, kanoodler is now into the ridiculous range price wise. Don't think just because that person kept a sensor that it will be "no big deal". There are $300 sensors on these motors. The fuel must be more than clean. It must be spotless. Filter Filter Filter. DO NOT RUN THEM OUT OF GAS. Some motors have ECU programing that references the fuel level sensor and then once really really low but not out, it will shut off the motor. Some ECu's don't. When the fuel runs out, the injector tips hammer themselves into pieces. Important because those injectors will be between 200-450 each. Sometimes the manufacture IE ford will have the 2005's hammer the tips into oblivion and the 2006 models save the injectors. On a V8 you can see where this leaves owners with a bad taste in their mouths.

quick diagram so you can see how a common rail diesel system is setup.

[jgerock]

EEEEEEEEEEEEEEEEEEEEEWWWWWWWWWWWW... Well there is an excuse to pee on your car...

http://www.eurekalert.org/pub_releases/2008-11/i-uto111008.php

http://www.ehow.com/facts_6809075_urea-used-diesel-engines_.html

From this site: http://wardsauto.com/ar/bmw_diesel_us/

"Much like its competitors at Mercedes and Volkswagen, BMW’s technology additionally relies heavily on a sophisticated aftertreatment process, which injects small amounts of diluted, ammonia-based urea solution into the exhaust stream to convert toxic oxides of nitrogen emissions into a harmless mix of nitrogen and water."

Uh-oh - leaking urea tanks already & someone forgot to fill one of them??

http://www.bimmerfest.com/forums/showthread.php?t=349351

[Swiftus]

From what I read, the urea system has only been implemented on the 6 cylinder diesels in the US. The 4 cylinders are safe at the moment and overseas are not yet affected. They still use filters rather than urea. This is good. Ok, working on the Metric stuff now.

[02Coastie]

Just a thought: With all the issues with the integrated computers/electronics, you may be better suited looking at an earlier (mid 90's) engine. By doing so you'd also avoid dealing with the DPF/Urea. Of course, if you were looking for really easy, fab up some mounts for a VW TDi (pre-99), throw a rwd tranny on it (plenty of adaptors available) run a few wires and bob's your uncle. The nice thing about the VW's is that they are almost entirely mechanical, and can easily hit the power numbers you're looking for at a significantly reduced cost of sourcing a euro-only motor.

Secretly though, I hope you stick with the N47 and market a swap kit when you figure it all out ;-)

[Swiftus]

Yesterday I had a long and interesting conversation with some of the guys over at Metric Mechanic about this project. I forget the name of the first guy I spoke with (sorry, I'm horrible with names), but I eventually ended up speaking with Jim Rowe, the owner of Metric Mechanic.

He seemed pretty intrigued by the idea. He mentioned that he had thought about using a VW diesel in a E21 or E30 simply because of the motor's availability, but never a BMW diesel. Once I mentioned the BMW diesel, he was on board with the project. We ended up speaking for close to two hours about various specifics about this project, diesel theory, bio-diesel, tractor pulling (He talked about that, I just sort of gawked at what he was describing. Those diesels can run more than 200 psi of boost pressure!).

Before I go any further, please note that all of the 'According to Jim' comments have been interpreted through myself as I tried to understand what he was saying. If anything I mention happens to be wrong, I would not doubt that it is my fault for not understanding rather than Jim's lack of knowledge...

The Short:

The N47 is *probably* compatible with with the Getrag 240 and the Getrag 245 transmissions. I forget Jim's reasoning behind this, but I'll take it as the truth for now until someone proves otherwise. This is good because the '02 community knows that a 240 or a 245 will fit in the transmission tunnel of a stock 02 with very minor alterations.

Running the diesel through the small differential (168), means that the lowest final drive available is 3.25. With either of the previously mentioned transmissions, this is still too short a gear for the diesel to run optimally. Because of this issue, Jim suggested converting the car to a medium differential (188). These have gear ratios as low as 2.79. This lowers the diesel's highway rpm reasonably enough to be efficient.

The Long:

Jim has the opinion that modifying the transmission tunnel to allow the 6 speed transmission designed for the N47 is too much work for not enough benefit. The 02 is light enough that any efficiency loss from the missing gear would be negated by the car's relative lighter weight. If the 240 or 245 bolts to the N47, then apparently they should be able to handle the torque.

Jim's reasoning is as follows. The transmissions (and differentials) are rated for certain torques. The torque numbers generally seem low for a diesel application. The reason behind the seemingly low rating is that the torque rating is measured as a higher RPM. Because the bearings and gears have to move quickly, they have less ability to withstand a higher force (torque is a type of force... an angular force). Since diesels spin slower than gas engines, the connected gears should be able to withstand the higher forces. My analogy (I have to make an analogy for everything in order to understand it. I am an extremely visual person) is that the curiosity is like resting a heavy object on a flat piece of material versus hitting that material with a hammer. Even if the instantaneous force of the hammer were equal to the force exerted by the heavy object, the material would fatigue (dent, break, etc) much more rapidly with the hammer blow. The hammer blow is kin to a quickly rotating gear assembly and the resting load is similar to a slowly rotating assembly.

This may help explain (http://www.metricmechanic.com/pdfs/metric-mechanic-differential-booklet.pdf)

After having gained this knowledge, Jim summed up his gear force lecture by saying that I could choose any 5 speed and any differential and I would not have any problems from normal wear and tear (Jim and I agreed that normal meant daily driving during the week and spirited drives on the weekend. No auto-crossing, rallying, or racing.)

After doing more research, I have found that the GS6-53DZ (the 6 speed trans found with the N47), the Getrag 240 and the Getrag 245 all have very similar top gear ratios. All of them are about 0.85. The downside to the 5 speeds is that I would lose some ability to optimize the engine rpm, but that is about all that I can see. What I could gain, however, is the ability to one day install a modified 240 or 245 with a longer overdrive (0.77 is what I recall, but I can't be sure...my notes are a mess!). The 240 and 245 are also lighter (especially the 240) compared with the GS6.

Jim reassured me that a longer geared 168 differential would be able to handle the torque from the N47. Again, he mentioned that there is a 3.25 ratio diff available, but they were only found on 325i cars in Europe for a short amount of time. However rare, they do exist and it would mean no modification to the rear of the car. This is very good. If I were to get itchy and wanting of a drive after the motor were installed, a 3.64 could suffice briefly, but as I have come to find out, it far too short of a gearing for a diesel car.

To obtain the desired rear-end gearing, Jim said that I could convert the rear sub-frame from the 02 to accept the large 188 type differential. This would be a chore, but it has been done. Jim himself made a few of them and he laid down some very detailed guidelines about how to approach such an undertaking. The short of it is that you tack weld an 02 sub-frame to a welding table, then cut out the hanger for the 168, piece in the hanger for a 188 and weld it all back together. Apparently the alignment doesn't matter all that much since the driveshaft actually requires a bit of mis-alignment to function properly, and the rear axles are very rarely directly aligned with the differential anyways. After modifying the sub-frame, the underside of the car would need to be 'clearanced' for the larger differential.

The 188 allows a gear ratio as low as 2.79. This would put 75 mph cruising at around 2600 rpm. Still a little high, but way better than anything that could be achieved with the 168. With a 2.79 rear end and a modified transmission with a 0.77 top gear, 75 mph would be at 2400 rpm. This is almost right on what I believe to be a good cruising rpm. Far enough in to the torque curve to prevent any unintended lugging but not too far so as to stay efficient.

After all of that gearing talk, there is also always the option of a larger tire. Moving from a 15/205/50 tire to a 15/205/60 tire would increase the tire circumference 7%. This results in a cruising rpm decrease of close to 100 rpm in top gear. Pretty nifty.

Alright, there is more that I could write but this is most of the important stuff. I'll try to catch up on the comments posted today during the day tomorrow.