SimonExtreme

Pass the popcorn, this could take a while

I think that this is getting silly. An ECU is a data processor that takes data from a number of sources and converts that data into instructions that fuel and spark the engine. Different makes do it in different ways but, ultimately, all that matters is that it instructs the injectors to release the right amount of fuel, at the right time and for the spark to happen at the right time as well.

Both Motronics and MOTEC are fit for purpose and can get good results. The biggest downside to Motronics is that there simply aren't enough people around who know how to modify it. And to do so, one needs specialist equipment.

With MOTEC, or a number of other ECU's, all you need is a laptop and cable. There are a significant number of specialists throught the world and there are even courses that anybody acn go on to learn how to fit and map these systems. I could go on a course next week and be installing and mapping MOTEC straight after. My results might not be as good as Colin's, but they would be a lot better than I can achieve with Motronics.

If I am wrong with that assertion, please tell me how I can get into a position to map my Motronics as easily.

The market for tuning is so small that there just isn't the demand. Over here, every other tuner is a MOTEC "specialist"! Having said that, many of the high powered earlier cars (pre GT3) are run on ...............CARBS!!!! Yes, one tuner has suggested removing the Motronics and getting some nice big carbs instead.

Finally, where would I get more airflow from? Find me the extra fuel, I wilkl find the airflow Having said that, it is an interesting point. Where are the limits with standard heads and cams? I wonder if we really know. I have a feeling we are only just scratching the surface of this.

N51

Neil Bainbridge's name has been brought forth by some UK members. Does anyone know if his shop has the capability of mapping Motronics? Perhaps a viable solution to the OP. Checked out his exhaust for a 964. Looks like an SCARGO header, which looks like the C4LWT header. All nice and curious.

Noah

Red rooster

Simon,
I agree totally with what you are saying and yes , it is silly. I apologise for any offence I have caused and will shut up about Motronic.


Many years ago I re mapped a very simple aftermarket system for a friend and it took 45 mins to learn from a manual what everything was !
I do understand the attraction of Motec and all the very best to Motec mappers everywhere.


Geoff

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KS400200 , the oldest 964 on Rennlist , unless you know differently !

NineMeister

The 964 and 993 Motronic ecus run narrow band lambda control / sensors, the aim of which is to keep the mixture within a narrow band either side of stoichiometric (La = 1.0). Wide band lambda is used for race engines, typical LS11 sensors as used on the M48 measuring La from 0.75 to 1.2, so if you want to run your 964 flat out at La=0.90, using a wide band control you can programme trims to maintain this level and prevent the ecu from drifting away from the ideal mixture. Neither Motronic ecus support wide band lambda measurement or control, whereas all Motec ecus do provided they are enabled.

The Motec ecus also have datalogging and advanced tuning options which need to be enabled in order to run wide band lambda, again I don't believe that you can datalog or run traction control (for instance) on a 964 or 993 Motronic ecu. For the average Motec user cost is always a primary concern and most would not want to know how their engine is running, so these features are left as an option. To enable both of these features would cost £435 extra and a typical LS11 sensor is around £150.

NineMeister

I have known Neil for a very long time, he's a decent guy and my impression is that he runs a very professional race shop. To my knowledge he does not offer Motronic remapping and from my experience I think he should let me help him map their Motec conversions (I'll just leave it at that), in fact Autofarm down the road are now referring their difficult mapping jobs back to us (had a supercharged 993 of theirs on the dyno last week for remapping).

KirkF

Nobody even want to touch my question about wiring the knock link into one of the two spare digital inputs on the M48 to provide knock detection / retard?

Could the No2 retard/enrich be used for this somehow?

Autronic ECUs have knock detection capability.

http://www.autronic.com/page_files/sm4_kit.htm

Surely my question has to be more interesting than debating Motronic Vs Motec for the 400th time this year?



Kirk

NineMeister

If an engine is mapped correctly, knock control is only used as an extra safeguard, albeit one that could save your engine from damage if you run duff fuel. Christer's 964 on motec has now had a knocklink fitted, although as yet we have not linked it with the ecu. As you say there are many aftermarket ecus that claim to run knock control, but that does not mean that they are good enough to run a "noisy" 911 engine just below the edge of detonation - I already have one which will do the job but it retails at £4000+VAT so I don't think I'll get a steady queue of customers for this one just yet. Motec seem to have built some knock parameters into the new v33 software for the M400/600/800 ecus but I have not heard when the system will be enabled. After saying all that, I actually think knock control is fundamentally flawed because what you are listening for is a problem after it has occured, would it not be better to just prevent it from occuring in the first place?

As Jason hinted at in a previous post, the correct method of predicting the onset of detonation is to monitor the rate of cylinder pressure increase after the spark event, however until recently in-cylinder pressure measurement has been limited due to the lack of affordable transducers. Apparently Bosch (and probably others) now have production (affordable) sensors available, so it is no doubt that future aftermarket detonation prevention systems will adopt this strategy as a preference to listening for the wrong sound from the cylinder.

Red rooster

After saying all that, I actually think knock control is fundamentally flawed because what you are listening for is a problem after it has occured, would it not be better to just prevent it from occuring in the first place?


Colin,

Shall I call round Bosch etc and ask them to call you to see if you would correct their systems ?

Ever heard of variable fuel quality ? as a start . This looks like your systems need defensive BS .


Geoff
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KS400200 , the oldest 964 on Rennlist , unless you know differently !

NineMeister

Geoff,
Who is being defensive? Knock is just the sound of detonation/pre-ignition which is the direct result of an excessively fast rate of change of cylinder pressure - therefore if you can monitor the cylinder pressure rise in real time you can, in theory, control the ignition point to achieve the optimum rate of change of pressure without actually letting the engine knock. In contrast (as I understand it) most conventional systems listen for knock and when it occurs they pull out timing after the event. Can you tell me where the BS is? I'm definitely no system designer, but I do know what is possible on the cutting edge of technology and we all know that this will be on our road cars in a few years time.

KirkF

I have been reading about some of the upcoming knock detection tech thats coming out. Its pretty cool stuff. However I am most interested in the simplest route for our cars, using our existing knock sensors.

After my supercharger project is complete I might want to replace the Motronic setup & piggyback ECU with a single aftermarket ECU, but I would like to have knock detection because I never trust the gas I am going to get, etc.

I was thinking that something like this:

http://www.viatrack.ca/

Could be used to with the motec to tell it to retard the timing. 'Just in Case'

I respect the fact that a properly tuned car shouldnt need knock detection, but because of where I live, there is no one to tune it properly. So better safe than sorry!

Kirk

SimonExtreme

Life is never as black and white as we would like. I find such as "properly tuned cars shouldn't need knock detaction" and "knock detection is flawed because it is after the event", while being technically correct in sentiment, deflect attention away from real life.

I too have read some stuff on thge next generation knock protection which can anticipate knock. However, for most of us, knock is so rare that I really wonder how far it's worth going.

In the majority of cases, knock occurs because of either a fault with the car or poor fuel. What we really need is a simple system that warns us there is an issue, so we don't drive around and do any damage. As far as I know, nobody has destroyed their engine from a few moments of det and so long as one doesn't ignore the warning that is all we really need.

I have used Knock Link on cars and it is suprising how little it goes off and when it does, how easy it is to drive around the problem. The worst case was when we were mapping an Evo on the road, ran short of fuel and when we refilled, it was clear straight away that the fuel wasn't what it was meant to be (we suspect 95RON in the 98!! ) and we used the Knock Link to drive around safely until we had burnt off enough fuel.

It's great having a system that adjust when there is knock but it really isn't worth spending much money in getting such a thing. We are very lucky that our cars have, in the Motronics, good knock protection but many cars don't and if you fit a cheap devise like Knock Link, you will get all the protection you need.

Now, if you are the type to ignore the warning............

warmfuzzies

Simon has expressed my main concern, I would like more power, who wouldn't but I want that balanced with the variables outside of my control.
I was with Christer before he left Le Mans, it was all ok, later it wasn't. If there is an idiot proof way for the driver to know there's an issue, and then be responsible to acknowledging or not the issue, then it's on my list.
I do not have a preference as to Motec, or Motronic, its a side issue to me. I am interested in the debate, and haven't interjected yet because I hadn't felt it had run it's course again.
Now i feel it has and its time to speak. If the engine mapping is left out of the equation, and I do not want to SC the car, what then are my options? and having decided that there are a few, what then are the options, and then adding the mapping at a later date? Say like some offer the ability to map on a RR....

Thanks

Kevin.

Red rooster

Knock can be caused by octane drop, internal chamber temperature caused by a host of reasons etc,etc.
There are systems being developed to take chamber pressure as the major parameter and put the ones we know into control loops.
Non of that is 964 relevent !

The 964 M2.1 is a good knock control system which , in view of the motor compression falls into the " dont leave home without it ! " catergory .

An aftermarket system that doesnt have knock control will need to be very conservatively mapped , especially for timing .
That doesnt fit with an ambition to claim the most bhp on the block !

Another puzzle !!!

Geoff

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KS400200 , the oldest 964 on Rennlist , unless you know differently !

Superunknown

What sort of figures can be achieved with going for a 3.8 after and engine rebuilt and remap? That has to be a good option to release a few more horses surely?

SimonExtreme

Geoff

I am sorry to disagree with you. I have owned 2 cars with limited or no knock control on the ECU and on those cars I have used Knock Link as my safety net. In about 20,000 miles, I only had one real warning which was due to dodgy fuel. By watching the Knock link, I was able to drive around the problem. I also added some octaine booster, even though it doesn't make a huge amount of difference.

Both cars were mapped pretty aggressively. However, unless it's a race car, I believe that there should be a little left on the table. That, combined with clear instructions from the tuner meant that I should have been reasonable protected.

Now, I accept that in the UK we are pretty lucky with fuel quality and I don't know what its like in other countries. However, in the UK at least, I cannot see the point in spending a lot of money on automated knock control.

Ideally, if one can stay with Motronics, you keep the benefit of the knock control. But, as we have already discussed, that is not often possible for reasons already discussed. So for the rest of us, we should spend an amount on knock warning/control in accordance with the risk. IMO, that means fitting a Knock Link and learning what to do when it lights up like a Christmas tree!