N47 Flip-Flop

[Swiftus]

First of all, I would like to welcome everyone to what will be a very exciting journey.

*Preface*

I don't exactly remember when this idea entered my mind, or who was the person who put it there, but I would like to thank the unnamed for their absolute brilliance. I would also like to thank the entire '02 community for putting up with an outsider for so long. I like to think that I have been a part of this community for close to 3 years now, even though for that entire time I never owned an '02. Because of the comradery and decorum that exists within this community, I grew to appreciate and adore 2002s.

Recently, I feel like my life became the 'Chronicle of Engine Swaps'. First, starting with the removal and installation of Clay's 2 liter into his 1602. Then there was was the installation of Grice's crazy 2.3l stroker that Blunt so graciously sold to him. Then Marshall decided that an M10 with dual 45s simply wasn't enough gusto, and is currently in mid-swap with a shiny S14. Then I luckily became a part of an awesome Lemon's 2002 team. This car's chassis needed a lot of work (again, a LOT of work), so out came the motor. And finally, almost like clockwork, Clay devises a scheme to wedge an M42 into his 1602.

I used to feel as if taking the motor out of the car was a massive obstacle that a half-wit like myself would never be able to accomplish. Not only have I now been able to participate in a bunch of motor swaps, but I have also been able to participate in nearly the entire scope of motor swaps commonly available to 2002s (The only one that I think I am missing is the infamous M20 . . . and I haven't actually worked on Marshall's car, which is probably good thinking on his part).

Because I have yet to actually own an '02, and because the spirit of the motor swap is fresh in my mind, and because I have gained the confidence that I can actually achieve what I would like to do, I have decided that it is time to officially begin my 2002 project. This thread will initially only be a research thread as I try to assemble my ideas in one place so that I can receive the most amount of assistance (although I have a feeling that it will be mostly ridicule and mockery with this crowd :-) ). Once I have fully gained enough confidence in the idea, I will turn it into the N47 project blog that I know everyone is dieing for!

Ok, on to the idea.

The Short:

I would like to swap BMW's newest 4 cylinder diesel motor, the N47, into a classic 2002.

The Long:

I would like to swap BMW's newest 4 cylinder diesel motor, the N47, into a classic 2002.

The initial idea was based on the theory that in order to achieve both better performance and better economy in an older car, one has to apply newer technology to the car. I also felt that the original lineup of 2002's had a good range of engine types that produced a decent spread of horsepower (~115hp to ~170hp). Having driven and ridden in 2002's across the spectrum (Dan's stock '02, Clay's freshened M10, Ian's M20, and Grice's stroker M10), I felt that a motor within that scope of power was the right choice. Those BMW designers actually knew a thing or two about how to design a balanced car.

On the performance side, I think that most would agree generally more power is better. Of course, one has to consider all of the variables, such as weight distribution and power distribution (torque / hp curves). A track racer can live with poor low-end performance from their engine because they can usually find a gear to keep themselves in the high-power, high side of the curve. An auto-crosser needs more low-end power than a track racer since they normally don't have as many options with the gear selection. A weekend driver is probably closer to an auto-crosser in the grand scope of things. Because of public roads populated by the public etc, the weekend driver cherishes the quick jaunts of speed that are so aptly provided by a 'torquey' motor.

On the economy side, most cars would actually benefit from smaller motors. When cruising on the highway, a 2002 needs approximately 9hp to do 60mph, 11hp to do 65mph, 13hp to do 70mph, and 15hp to do 75mph. Because of gearing, most 2002s can actually produce much more power than required. Actual potential power production is probably closer to 50hp at those speeds. This added 'potential' contributes to the inefficiencies that prevent the 2002 from being an econo-box. I know that most here are proud of the fact that their '02s are NOT econo-boxes, but I am willing to bet that if they could keep the current performance of their car and improve their gas mileage, most here would jump on the opportunity (assuming they only had to wave a wand and not actually perform any actual work).

This is where the N47 shines. It is a motor that actually had the capability to fulfill all of the previously mentioned requirements. The N47 comes in a horsepower range nearly identical to the original 2002 lineup. (~114hp to ~204hp in the N47). In my view, that 204hp figure is similar to the S14 hp figure, and since the S14 in the last of the M10s, I'll include it in my list of comparable motors. And in the new BMW's that are equipped with the N47, those cars can have fuel economy figures in the 55mpg to 65mpg range (A figure that will most likely be close to what a 2002 equipped with a N47 could achieve).

Now on to the catch. The N47 motor is a diesel. I don't know how most respond to the idea of installing a diesel in a 2002, but I like to think of it like this: "I always drive my car at Wide Open Throttle!!!" (Many diesels do not meter the air entering the engine, which means that they are essentially at WOT all of the time... hence the joke).

The good news about the N47 is that it produces a huge amount of torque (~295ft-lbs in some versions). It also has a red-line around 5000 rpm. This means that driving a N47 equipped 2002, performance wise, may actually feel quite similar to driving a more 'standard' 2002. Most of the N47 range produces full torque at 1700 rpm, which means that for the weekend driver there will almost always be a pass-the-plebe amount of torque available. Essentially, its the torque in a car that shoves you back into your seat, so having a lot of it is very, very good. I am also under the impression that the N47 range has a pretty flat torque curve.

Because the N47 produces such a large amount of torque at a low RPM, gearing the car to be fuel-efficient on the highway is much easier. This is because the engine can turn much slower than a gasoline engine and produce the same amount of power. The 6 speed manual transmission that is regularly mated with the N47 has two overdrive gears, at 0.8 and 0.6 ratios. With a 3.64 rear-end in an 02, 60mph cruising speed in 6th gear would be under 2000 rpm. 2500rpm would give an approximate speed of 79mph. This means that the entire range of 'normal' highway speeds would be below 2500 rpm. (The theoretical max speed of the car excluding wheels slip, etc, would be 157mph at 5000rpm). A 3.91 differential would give 73mph at 2500 rpm and a max speed of 146 mph at 5000rpm.

So that is the theory behind choosing the N47 as the next motor swap for a 2002. It has similar horsepower numbers as the original lineup of 2002s while providing the fun of huge torque and the joy of incredible gas mileage.

There is still much to sort out. Things like fuel delivery, engine bay fitment, transmission tunnel fitment, proper cooling, and hardest of all, digital to analog interfacing. I hope that many of you will join me on this adventure and with any luck, we will be able to produce a reasonable Franken-car.

In the future, I hope to use this thread at a location to discuss various aspects of the build in more focus and detail, but for now I would simply enjoy comments of any kind.

Wish me luck!

Soon-to-be-'02er

Jay Swift

[M3M3]

you need to start with this....

http://s397.photobucket.com/albums/pp59/mblytle/76%20shell%20project/?albumview=slideshow

[williamggruff]

Jay,

Have you set target dates for body acquisition, motor acquisition, and first start? Maybe a first drive by the time you're 21?

Yours in speed,

Grice

[williamggruff]

you need to start with this....

http://s397.photobucket.com/albums/pp59/mblytle/76%20shell%20project/?albumview=slideshow

Jay, the dates on those photos are from over a year ago, so this guy's been holding onto this shell for a while now. He's probably eager to get rid of it ;-)

Grice

[M3M3]

it is like a fine wine...getting better with age....;-)

[Swiftus]

As far as acquisitions are concerned, Marshall's shell would be a great starting point. Probably the best short of a shell that already had paint. I'm thinking that I could get a shell and much of the bodywork done this summer / fall. Hopefully I can import a motor by the winter so that I have all winter to fit the motor into the car. Then I could use the spring to finish / tune (tune as in listen to the wonderful tunes of diesel) the car so that I could drive it for my 21st (and to the next V). Sounds ambitious, right?

[Todd21]

Jay,

This is one of my current "If I could try something what would it be..." options for the 02. Budget $4,000 for the motor and brush up on your German.

Todd

[Guest Anonymous]

difficult swap..

Problems you'll encounter

3.64 is to high a rear gear. You'd want a 3.15 or something like that. To bad a 3.43 is about as low as I've seen and they're made of "turbo" gold.

modern bmw diesels are not standalone things. the ecu's are all interconnected and I'm surprised if it will start without all the other crap from the car. Can't standalone them.

Check to see if gastank is galvanized. If so diesel will remove the galvanization for you. I'd find that out before you hook up those expensive diesel injectors.

Many bmw diesels require a intank high pressure pump. a 300-400psi pump. Before the injectors, and other pumps bump that up for 20,000+psi.

[Swiftus]

Jay,

This is one of my current "If I could try something what would it be..." options for the 02. Budget $4,000 for the motor and brush up on your German.

Todd

Todd,

I am going through what I call the 'research stage' of the process publicly so that I can use all of the sources available to me. If one of those sources is a guy who can translate German, than I don't actually have learn German ;-). For me, learning another language would be very very difficult.

I have found semi-stripped N47's on Ebay for $2500, and doing my best working backwards through RealOEM, I believe that $4000 for the motor is about right. Then I can add $750 for the trans and I have what I think a pretty good ballpark figure of $5000 for the engine bay part of the drive train.

Here is the deal. I am willing to 'guinea pig' the idea for the community, but I want to be reasonably sure that it will work before I go spending 5 grand on a motor that I don't think is currently legal in the US.

Do you happen to know German? I am in the market for a translator...

[Swiftus]

difficult swap..

This I was expecting. Which is why, hopefully with the combined knowledge of this community and a few others, we will all be able to work through the difficulties that may arise.

3.64 is to high a rear gear. You'd want a 3.15 or something like that. To bad a 3.43 is about as low as I've seen and they're made of "turbo" gold.

I want to agree with you since it seems like whenever one drives a diesel, for efficiency one always looks to drop the engine rpms (to a point). However, here is my logic. Bear with me as I am quite often wrong. The 120d (The car that the motor comes in) has a top speed of 140mph. Doing this simple math, with a 3.64 differential a 2002 would have a top speed of 157 mph. That higher top speed means that it would have a lower highway cruising rpm than the stock car.

Would you care to elaborate even more on why a much lower differential ratio is required? My logic is in its infancy and I know is quite ignorant to many of the facts. Edjumucate me sir! (“Give a man a fish, and you’ll feed him for a day. Teach a man to fish, and you’ve fed him for a lifetime.”)

modern bmw diesels are not standalone things. the ecu's are all interconnected and I'm surprised if it will start without all the other crap from the car. Can't standalone them.

I have made a few posts in some aftermarket ECU tuning forums to address this issue. I basically knew that moving to an engine with a computer was going to be fraught with all sorts of computer-related issues. Luckily, I believe that there is a community that can give me the answers I need. After about 5 minutes of searching, I found the firmware for the N47 ECU in various applications (1 series, 3 series, X1 etc). Lets pray that whoever cracked that software knows how to make the ECU work outside of its original host car.

Check to see if gastank is galvanized. If so diesel will remove the galvanization for you. I'd find that out before you hook up those expensive diesel injectors.

This is the kind of thing I am looking for! I have no idea that diesel would destroy galvanized metals. Hopefully a stock type tank will work, but if not, manufacturing a tank is not out of the question. A guy on my Opel forum had a boat manufacturer build him a replacement tank for his GT for $450. The tank in a GT is an incredibly odd shape and it uses a lot of material to create very little volume (It is very flat). An '02 tank in much closer to a sphere than an Opel tank, so I'm going to assume for now that if I were to need a custom tank, it would be on the order of $500.

Many bmw diesels require a intank high pressure pump. a 300-400psi pump. Before the injectors, and other pumps bump that up for 20,000+psi.

I have read briefly about this in general. Most of the motors that I am finding come with the super-high pressure pumps. The in-tank pumps, however, are left in the tank. If the pressure is similar for the N47 as it is for some of the other diesel motors that we have in the states, then I don't see why I would be able to grab a pump out of a BMW diesel at a junkyard... Or have BLUNT SpecO me one from Germany.

I'm liking this discussion. Keep finding the holes! We want to seal this hull of an idea up tight!

Til Later,

Jay

[Todd21]

Jay,

One thing to keep in mind not all the N47's are 204 HP. See link for specific cars and coses for engines:

http://www.bmwheaven.com/database/engine.php?type=N47#/207

Todd

[Swiftus]

Yes, I was really focusing in on either the 163 or the 177 hp versions. I think having only one turbo at the moment is enough. lol. They are also a step cheaper than the 204.

Even the 116 hp version would work!

[Guest]

I think the swap would be awesome, but it's going to be a bitch to complete. As for the wiring, I'm no wiring expert(not even close), but you should be able to run the motor with it's wiring harness and computers and then build some sort of false triggers for anything else(say it needs to read something from the gauge cluster which is HIGHLY probable, you should plan on getting a gauge cluster and re-configuring the layout to match the '02 stock tach/speedo location)

Diesels make made torque, like big V8's. Big V8's break rear ends because of that loading. A lower gear ratio(turbo was 3.36, you'll never find one, some(/most?)Euro Tii's had 3.45 as did the E21 320i/6's iirc). That will help lower the torque lever arm and make your diff that much more likely to last. Metric mechanic used to have, maybe still has, a torque capacity chart for the medium case diffs. The 2.93's were able to hold over 100ft-lb more than the 4.11s. I think that's the only reason my friends LS1 E30 hasn't blown the diff when he drops the clutch(I thought the rear end of the car was going to tear off when he did that)

I think it would be a sweet swap, I would love a 2002 diesel. Modern diesels are awesome, most people wouldn't be able to tell listening to the exhaust note. Lining up the driveline/modifying the tranny tunnel will probably be the easiest part of the swap, fitting the oil pan around the subframe/block around the steering linkage and box may be troublesome. You'll have to make custom steel fuel lines to handle the pressure, or braided SS as long as the inner hose is compatible with diesel.

As far as BMW's go, the 2002 is pretty easy to swap all kinds of motors into as long as you're willing to cut up parts of it. The E21's might be the easiest of the bunch because of the rack/pinion, larger tranny tunnel, same size engine bay, but lacking the E30 challenges like PS/ABS.

Do it, but take your initial budget and bump it up at least 50% as well as your time budget. Unless you somehow are unemployed/non-student, have a garage full of tools, and tons of cash lying around, the project will take longer than expected. Since no one has done this swap before you won't have the experienced base to ask questions of, all of us will only be able to speculate on what may/may not work.

I 100% support the idea. I'd never do it to my 2002, but I'd love to have a 50+mpg 2002 to cruise around in.

[Guest Anonymous]

Check it. Yeah diesel eats galvanization. diesel tanks are either aluminum dipped or stainless.

In checking the diagrams for a 320d.. it looks like one normal supply pump and then a high pressure pump on motor..

As for exhaust. It does use a diesel particulate filter.. This is required to mount on 02 as eventually every so often it will light off the filter to clean it out. By light off, I mean dump fuel into exhaust until the EGT's go through the roof and ashen the soot trapped in it.

Any anti-theft system will need to be dealt with.

I assume you'll be using the n47 transmission with a custom driveshaft

The n47 uses a watercooled EGR.

The gas pedal on these unit's is drive by wire so the gas pedal doesn't connect to anything but a harness.

Some cars come with electric power steering. Some come with a pump. The issue is some will have a steering angle sensor or probably all will. You'll need that or the DSP traction control system will be spazzing. Speaking of ABS. How are you going to deal with the reluctor rings. Either the DSP will turn off and the computer will be kosher with it or all the abs craps gotta come over. It's a drive by wire car so not sure how it's TB will work with traction control and abs programming.

[Swiftus]

My head started spinning when I read this post! Many of these issues are the type of things that I simply don't know enough about at this time to answer in a definite manner. But, that is the reason for the thread. If everyone has some knowledge that they can contribute to this effort, then solutions will be found and the project will succeed.

I'm a ignorant schmuck with an idea, but I will try my best to answer what I can.

In checking the diagrams for a 320d.. it looks like one normal supply pump and then a high pressure pump on motor..

Hopefully the on-motor pump will come with whatever motor system I purchase. And the solution to the normal supply pump is find one in a junkyard.

As for exhaust. It does use a diesel particulate filter.. This is required to mount on 02 as eventually every so often it will light off the filter to clean it out. By light off, I mean dump fuel into exhaust until the EGT's go through the roof and ashen the soot trapped in it.

I am going to assume at this stage that a properly functioning ECU will deal with this process? If not, yet another issue that needs to be dealt with (I am making a list, so don't worry).

Any anti-theft system will need to be dealt with.

I wonder if a BMW dealer would be able to 'reset' the ECU so that it no longer would apply the anti-theft measures. I have read things about the proper VIN number from the car needing to be programmed into the ECU, but I didn't fully grasp what was being said. You know, not enough base knowledge to grasp a higher stage concept.

I assume you'll be using the n47 transmission with a custom driveshaft

This was the original plan. However, today I had a long conversation with a few of the folks over at Metric Mechanic and they seem to believe that the bolt pattern of the N47 transmission is the same as that of the transmissions that came with the M42, M44, and the M20 (the M20 has a different engine angle, but the pattern is the same). In that case, We, as a community, know that 240's and 245's fit in the 02 transmission tunnel. Yes, losing a gear would be a loss, but not having to modify the transmission tunnel would be a huge gain.

The n47 uses a watercooled EGR.

From what I obtained looking at the drawings of the motor, everything that the motor needs to operate is retained within its 'cubic' boundaries other than the inter-cooler and the radiator. I don't plan on modifying any of that. I probably would even keep the silly piece of plastic that goes on top of the thing.

The gas pedal on these unit's is drive by wire so the gas pedal doesn't connect to anything but a harness.

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.

Some cars come with electric power steering. Some come with a pump. The issue is some will have a steering angle sensor or probably all will. You'll need that or the DSP traction control system will be spazzing. Speaking of ABS. How are you going to deal with the reluctor rings. Either the DSP will turn off and the computer will be kosher with it or all the abs craps gotta come over. It's a drive by wire car so not sure how it's TB will work with traction control and abs programming.

Hopefully the aftermarket tuning community will have found solutions to some of these issues. If not, here is a theory. Make a signal generator that tells the ECU that the car is always going perfectly straight and that all of the wheels are turning at the same speed all of the time. The speed signal generator could be made to mimic the VSS in the trans so that no issues would occur.

I don't plan on using power steering in this 02. I realize that the 02 may be heavier up front, but at the moment I don't see how the benefit would outweigh the cost.

BTW, what does 'TB' mean in the context above?

Unless the signals are digital language signals, as in code, I am pretty confident that I would be able to create whatever ghost signals that would be required. For close to 2 years I had an internship designing haptic simulation robotics for the medical field. And recently I have been designing and building highly specialized computers for government purposes. Hopefully BMW spared the rocket science when it came to signaling the ABS system! ;-)

Keep em coming! My goal is to have the location of every bolt, hose, and electron sorted out before any further steps are taken in the development of the idea. I know this goal is unrealistic, but it should get across how thoroughly I am trying to approach this swap. I don't like not finishing a project and I hate half-assing in order to complete a project.

I will update with my conversation with Metric Mechanic tomorrow, but for now I am going to sleep!