Going Stand Alone Management

Cyrus · 29th August 2006, 22:09

The thought is crossing my mind to ditch the motronic altogether in the 3.8 and fit something like MBE stand alone management.

The idea has been playing on my mind due to the experiences I am having with E30's.

Over the last year I have, with Bexley Motor Works converted quite a few customers' cars from running Air Flow Meter to MAF on various 2.7 and 2.5 E30's. The difference this makes is quite considerable over the nasty AFM.

Then we got hold of an Alpina C2 2.7 - quite a quick torquey machine to start with.

Owner decided to go a step further and went for MBE Stand Alone Management.

Now I thought the MAF conversion was good until I got to use this car over the last few months on a daily basis.

Bexley's took alot of care over the mapping and made sure it was extremely smooth, did good fuel economy and passed the MOT as far as emissions are concerned.

The car runs no MAF or AFM anymore. Everything is done on throttle position with a Barometric sensor and obvioulsy the crank sensor is also used.

The difference this made is simply phenominal. The throttle response is just brilliant, the driveability is so much better than before. Everything is so instant.

Getting back into the M5 - just feels so slow to respond, exactly like an M20 engine with a MAF on it (but much better than one equiped with an AFM).

MBE and many other good stand alone management systems can also have Lambda as an input and run ignition coils.

I think with a setup like this and skillfull mapping the S38 3.8 can really come alive just like the much more basic M20 engine has proven to do so.

The S38 being a much more advanced and power engine, I think the difference will be even bigger.

Has anyone ever tried this?

Also, does anyone know the resolution on the 3.8 ECU?

Sal

Yorldi · 29th August 2006, 23:39

The resolution? Sorry, I'm a dirty dago (thanks for the new word, wout! It's changed my whole life) and can't undersand... (really!!!)
Regarding the standalone, I've also been thinking about this for some time now. I've finally found someone to sell me the carbon intake manifold (at a reasonable price and it even seems like it works!) so the Standalone would be mandatory. I've played with these systems on Gr.A and heavily tuned E30 M3s, and difference is amazing. Better fuel consumption (at moderate speeds), sharper throttle response..., better control of the engine, to make it easy. After all, 10-15 years are a lot when it comes to electronic devices...

bobz · 30th August 2006, 07:05

I thought you could use the Alpha-N tuning, like in the E46 M3 CSL also one of the guys in Australia, has a 3.0 E36 M3 running an aftermarket CF inlet manifold with a Alpha-N chip and no AFM and standard EMS.

So there might be no need to change the computer.

BobZ

farrell · 30th August 2006, 09:30

Guys
I had deleted this post.
I now think it should stay
This is bolt on power to an existing engine that for all intents is ablack box item ?
You can bolt on whatever you like to the inlet.
Compared to std, you will lose low to midrange torque so the assumption is top end power ?
The exhaust manifold even now is a work of art.

So lets assume its an 80% efficient engine with conventional frictional & parasitic losses.

Fundementals here.
How much power your engine will make is purely a product of how much air & fuel it can consume.

So then, assuming the engine is a black box item...you have the following..
1. Increase efficiency but its already efficient so you infer that the original calibration is way too conservative..Bull$hit imho & gains are usually made at the expense of emissions & safety parameters.
So the likelyhood is that you will map fuel & spark even closer to detonation & not have the backdrop of a Knock sensor.
Ok, you could fit a knock sensor.

2.Reduce frictional losses..winded crank counterweights..but still involves a tear up of the engine.

3. Extend the rpm range..!
Is it not the only way to combust more air & fuel ?
Limitations..
Engine contruction, ie the bottom end bolts conrod to crank. Crank bearing load increased...are they a weak point already or not.
The physical restriction of the of the head ,valves / cam timing.
New cams & timing requirement...?

4.The cooling system...Is it efficient ?
Can it be improved easily to cope with power increase in any of the above.

In short, you appear so absorbed in the journey to get more power from an already stretched design concept, that you appeear to have have overlooked the fundemantals of why & for how long.

The how long part is very pertinent as currently, half the active part of this board in Europe are contemplating or actually undertaking rebuilds

One last thing is the dangerous drawing of comparisons of mods made to other engines as a good reason for the same thing to work on another engine.
Same configuration is it.
How efficient was that particular engine to start with ?

My Nissan is tuned...40% increase in power.
Two engine rebuilds in 65,000 kms !

This topic should be more about the straw that broke the Camels back !

Farrell

Yorldi · 30th August 2006, 12:42

Yes, you can use the Alpha-N. But the E34 M5 EMS is not a work of art, and upgradding to a more cappable unit will have great benefits on driveability over a stock engine

unesential · 30th August 2006, 17:11

Farrel,
I believe Cyrus was talking about an improvement in response time to change of state not as much as power gain, what little more you could squeeze out. There certainly have been vast improvements in this area with better EMS systems. The main determining factor would be value in making the changes. Now for instance if my MAF were to fail again @ $800 or a DME @ $950 to go to a newer stand alone EMS would not hurt so bad.
John

farrell · 30th August 2006, 20:18

Yes, I agree John
Sal was talking mainly about throttle response.
The wider topic included power increases mentioned.
Thats why I decided to expand on my topic as this type of management system is usually looking for power ,not just response.

Past threads on this topic & many recent failures prompted me to clarify that these systems appear to give on one front & take much more on other not so obvious aspects of the calibration.

Farrell

de Witt · 30th August 2006, 20:42

The benefits of a standalone ECU are not as noticable on the S38B36 as they are on the AFM S14/S38B35/M88. The difference with one of my E28 M5s and the Autronic ECU is quite impressive, but there reaches a point of tuning which requires an approach that Farrell mentions. I am happy with the MAF and ECU on the E34 M5, but I wish there was a way to get the coil packs like the 3.8 has.

I have toyed with a S38B38 swap into an old 528e, and for that project I would use a complete Autronic standalone ECU, no question.

unesential · 30th August 2006, 21:11

I had thought that the coil packs were prone to failure. If had the time and resources to dedicate that would be a project worth doing. I think that an E12 would perform wonderfully.

de Witt · 30th August 2006, 21:21

Quote:

Originally Posted by unesential

I had thought that the coil packs were prone to failure. If had the time and resources to dedicate that would be a project worth doing. I think that an E12 would perform wonderfully.

I have no idea about the 3.8 coil packs. I have not had a problem with the coils on the Autronic ECU.

An E12 with standalone managment and a stroked out M30 would be really sweet.