I have a 1985 k100 with the 8v engine so from what I have been reading it would have the l-Jetronic fuel ECU.  I recently picked up a later modle 16v K100 engine from a 1991 K100RS.  Price was too good to pass up.  I have the Engine, with all connected sensors, the fuel rail, injectors, intake, airbox, radiator, and other connected bits,  I dont however have the fuel or ignition ECUs form the 16v bike.  What I am looking for is advice on how to do the engine swap,  IE, can I run the 16v engine with the 8v ECU's?

Thanks.

Dave

I don't see any reason that you couldn't use the L Jetronic injection just make sure you use the sensors (mainly the temp sensor) from the 8v engine and of course the air filter and air flow meter and injectors but with the 16v fuel rail.
The usual disclaimers go with this i.e. if your engine disintegrates because of thermonuclear combustion then don't blame me.  
If you do use the later motronic injection you will get better fuel consumption. you don't need an ignition module as it is all done in the ECU but you will need the ignition amplifier which is on the battery cradle and the 16v type coils

RicK G wrote:
If you do use the later motronic injection you will get better fuel consumption. you don't need an ignition module as it is all done in the ECU but you will need the ignition amplifier

Would like to add that the ignition amp is only used on the early Motronic (MA 2.1).

Inge K. wrote:

RicK G wrote:
If you do use the later motronic injection you will get better fuel consumption. you don't need an ignition module as it is all done in the ECU but you will need the ignition amplifier

Would like to add that the ignition amp is only used on the early Motronic (MA 2.1).

Which also needs to be mounted to an early 4V battery tray so serve as a heat sink.  If that is not done then the ignition amp will overheat and the bike will run like crap.

Thanks for the info.

Is it safe to assume that running the 16v engine with the 8v electronics will still gain me a little HP and Torque since it should breath better.

Thanks.

Totally seat of the pants crap that may or may not have merit:

1 - Given that you'd need to use a 2V mass airflow sensor I think that would restrict airflow more than using a 4V setup.  All of the air entering the MAF needs to flow through a relatively small square cross section.

2 - The Motronic is designed and fuel mapped to work with the 4V engine so I  imagine going that route would yield better results.

3 - Using the Motronic is a known quantity which doesn't require "shoe-horning" two dissimilar systems (and wiring harnesses) together.

JMHO but to ensure that things work well and "simplify" the project, I'd go the Motronic route.

Then again, it would also be interesting to see YOU go the L-Jet implementation and see how things work out.

And here's how the power curves compare. As you can see the 4V definitely out performs the 2V 1000 cc engine at higher RPMs.  How much of that is due to engine management vs. engine design is anybody's guess.

Interesting HP and Torque graphs.  Thanks.  Since I have all of the gear to go the L-Jet I will likely go that route first.  If all else fails I could always spend alot of money and go with this setup:

http://www.bskspeedworks.co.uk/engine-management-package.html

I got to give the engine a good solid once over however before I even start.  I believe the engine has 34k Km or possibly 34K Miles on it.  The bike was layed down on the crank case side.  Chewed up all of the fairing and some of the crankcase cover.  I suspect that is the better side to have on the ground form the engine survivability standpoint.  Other then the road rash on the crank case and a broken piece of aluminum from the starter stuck in the bell housing the engine looks solid.  It is fill of oil. Turns over well with a socket on the crank.

I will probably spend the next few weeks cleaning it up and taking all of the covers off.

Cheers

Dave.

Does anyone know if there is any difference between a motronic made for a K1100, and a K100 16v.

Thanks.

Dave.

Go to Real OEM http://realoem.com/bmw/ and check the part numbers.  That is a good reliable site for reference.

KafeRacer wrote:Does anyone know if there is any difference between a motronic made for a K1100, and a K100 16v.

Thanks.

Dave.

Yes, there is.  I can only speak from my experience with US bikes but the K100RS4V did not have a cat and O2 sensor while the K1100s did.

duck wrote:

KafeRacer wrote:Does anyone know if there is any difference between a motronic made for a K1100, and a K100 16v.

Thanks.

Dave.

Yes, there is.  I can only speak from my experience with US bikes but the K100RS4V did not have a cat and O2 sensor while the K1100s did.

Ok,  that makes sense. I certainly don't want to get into those emissions systems.

Thanks.

duck wrote:

KafeRacer wrote:Does anyone know if there is any difference between a motronic made for a K1100, and a K100 16v.

Thanks.

Dave.

Yes, there is.  I can only speak from my experience with US bikes but the K100RS4V did not have a cat and O2 sensor while the K1100s did.

Only from 1994 models on that have the Motronic 2.2, mine is a 1993 model with the Motronic 2.1 and does not have the O2 sensor. I have run a K100 16v motronic ECU in my K1100 and it works OK but I think they are a different part number and it stands to reason that they would be a bit different as there are also some differences from the K100 16v to the K1100.

RicK G wrote:

duck wrote:

KafeRacer wrote:Does anyone know if there is any difference between a motronic made for a K1100, and a K100 16v.

Thanks.

Dave.

Yes, there is.  I can only speak from my experience with US bikes but the K100RS4V did not have a cat and O2 sensor while the K1100s did.

Only from 1994 models on that have the Motronic 2.2, mine is a 1993 model with the Motronic 2.1 and does not have the O2 sensor. I have run a K100 16v motronic ECU in my K1100 and it works OK but I think they are a different part number and it stands to reason that they would be a bit different as there are also some differences from the K100 16v to the K1100.

A cat was available as an option for all 4V models from early -90, 2V's late -91.

According to the online manuals the same Motronic MA2.1 is used on all models.
(But I've seen different Bosch part numbers on them, during the years

I have done a very thorough examination on my 1993 K1100 and there is no way there is anywhere that an O2 sensor can be fitted and nowhere to plug it in. To the best of my knowledge there were no K1100s bought into Australia that had or were able to have O2 sensors fitted.  The first 16v that had an O2 sensor fitted in Australia was on the K1100 when the 1994 models came out which was when the K1100 RS was released and they all had them.

Pretty sure that it varied by country.  The marketing lit for 93 LTs in the US is very proud that it has a cat.  My 93 LT had (before I installed a Staintune) a cat and does have an O2 sensor.

I only said that a cat was available as an option from early -90.
I have no idea in which countries the importer choose to have it available.
I'll Guess that it didn't sell that good in the beginning, as it also was more expensive.

And of course you don't find any place to mount the O2 sensor, as long as
the bike is a non cat model from the beginning.

Real OEM show a different Exhaust for Australia. Gees they do some strange things. Why the hell remove the CAT and O2 from Australian bikes, in comparison to the rest of the world they sell bugger all here.

RicK G wrote:Real OEM show a different Exhaust for Australia.

Also on the 2V models, which I have mentioned earlier ....in a ekshaust thread.
As it's both 2V & 4V I would guess it has something to do with the noise regulations.


(and the reason to Caferacer62 found two different guts when moding a lot of silencers).

I would expect there to be somewhere on the exhaust to fit an O2 sensor if it were optional but we are talking about the strange ways of BMW. Mind it's not just BMW there were some odd things done to Hondas from country to country when I worked for them.

Why should you have the possibility to mount a O2 sensor as it's no cat inside exhauster from the beginning.

I didn't see post 17, for some reason it just passed me by.  Reading that I can see why you ask that.
I didnt realize that as an option it was exhaust and all and that is probably why I have no place to even plug an O2 sensor in to the harness.
As for the ECU I had often seen the later type referred to as a Motronic 2.2. The one I refer to is the one that sits on top of the ABS unit and has the plug into the flat top surface. I know that the people who make chips for them say only for one or the other and that they (the chip) is not interchangeable.