NineMeister

You cannot piggy back a Motec with the Motronic, so it will have to be wired with an adapter box to the standard loom or preferably with a full custom wiring loom (which we much prefer for ITB set ups).

In any event, the Motronic will not be required at all once the Motec is running because the M84 has fully user programmable fuel & ignition tables for cranking, post start enrichment and engine temperature enrichment, all of which are more than capable of handling cold start and warm up performance.

Add in to the equation a fully configurable PID control circuit for a 2 or 3 wire idle valve and there is no reason why you cannot get an ITB equipped engine starting with zero throttle from cold and idling perfectly at 950rpm. As a case in point, the 4.0 litre 456hp 9m Race engine in my 993RS Clubsport would do exactly that, as well as running happily around the paddock at zero throttle in 2nd gear & accelerate happily with a gentle squeeze on the throttle.

The stock Motronic system will not do any of this on a modified ITB engine with a lightweight flywheel/clutch package, in fact it will struggle to work on a stock 3.6 engine with LWF unless you are lucky.

Hope this helps to clear up what is required?

kos11-12

I was going to sell my Motronic ECU but kept it to check for faults....in case....
my ECU still state condition of all the sensors and TPS,

ras62

Add in to the equation a fully configurable PID control circuit for a 2 or 3 wire idle valve and there is no reason why you cannot get an ITB equipped engine starting with zero throttle from cold and idling perfectly at 950rpm. As a case in point, the 4.0 litre 456hp 9m Race engine in my 993RS Clubsport would do exactly that, as well as running happily around the paddock at zero throttle in 2nd gear & accelerate happily with a gentle squeeze on the throttle.

The stock Motronic system will not do any of this on a modified ITB engine with a lightweight flywheel/clutch package, in fact it will struggle to work on a stock 3.6 engine with LWF unless you are lucky.

Hope this helps to clear up what is required?[/QUOTE]

Does this mean running ITB requires an additional idle control valve to run correctly from cold?
Given the power M84 unit why do PID parameters have to done manually, surely they could configure a self tuning loop for the purpose.

alexjc4

Thanks Colin,

Interesting you can't piggyback the Motronic - I've seen other Factory ECU's with Motec piggybacks (not the M84 though). It can speed up the tuning a bit if you don't need to care of some of that stuff and most notably it's nice to retain the knock control - admittedly that's a bigger deal with forced induction.

Now I think about, obviously Frank's build can't use the Motronic in any form - to start with it's not going to run off a MAP sensor is it!

Just to be clear, I'm only asking questions because I'm interested, not to pass judgement in anyway - Frank's in good hands.

Porsche964FP

NineMeister

No, you don't need to use an ISV but it will help if engineered correctly.

I agree that a self-tuning PID control loop would be desirable but it's not exactly rocket science to set one up manually. Always been this way with Motec (to date) so perhaps you should send your grievences to them to see if they will incorporate the option for the new M series ecus?

VR6-er

Motec is quite expensive; not for what it is but just the cost of it. Is there not a later Bosch unit that can be substituted for the 964 unit that can offer what the Motec does?

kos11-12

I have an Emerald ECU (no affiliation at all),
it's very important to have it mapped by someone who knows and have great experience mapping those cars... otherwise it could be a mess .....trust ....and cost you as much as the Motec...

ras62

Hardly a grievance, rather good sense if motec want a user friendly system surely they should incorporate the same. Likewise knock control, it is a hole that needs to be properly sorted. Spending big bucks on this system I expect it to cover all the bases, at the moment this does not seem to be the case.

NineMeister

These are good questions but (no ofence intended) you have to compare eggs with eggs, not eggs to an omelette.

There are many ecus on the market which claim all sorts of functionality, but when it gets down to the nitty gritty of the chip set coding, firmware or software you find that they are not as good as they claim. One of my associates specialises in writing software code to embed in the silicon and the operating firmware for ecu manufacturers. He has personally tested over 50 aftermarket ecus for reliability and accuracy. Motec scores midway of the top 10 units and is the cheapest product within that group. Of the other ones that he tested outside the top 10 he found several with running inaccuracies (ignition timing spreads of +/-4 degrees) and analysed one which spiked the ignition timing of a friends boosted engine to the point where it melted the motor. He eventually traced the problem to the firmware within the chipset. Are these the ecu's that you want to run on your $20k Porsche engines?

The answer to everyone's question is thus cost and performance: you simply get what you pay for. Myself, Geoffrey and others (along with Frank's chosen installer) simply chose to fit a rock solid ecu which does all the basic functions perfectly from the get-go, runs reliably for years on end and is also backed up by a long standing business with a World Wide dealer network. Motec have a knock system which will work with the M600/M800 ecu if you decide you need it (even though we think you don't) but it will cost to set it up correctly.


Sorry Frank, did not intend to hijack your engine thread, just seems that whenever you mention Motec we have to have the same discussions, which is slightly frustrating. I'm really looking forward to seeing how your motor turns out and wish you & Redtek success with the outcome.

Porsche964FP

Hi Colin,

True, having looked through threads about Motec - it seems it's always similar discussions.

Not at all. The whole point of my little threads are to help others. The more feedback from individuals the better in my view - thank you for your contributions.

Cheers,

ras62

I can understand why setting up knock control would be time consuming and therefore expensive, but for a road car I wouldn't agree it is unnecessary. This assumes octane ratings will be at least as good as that being used during mapping which is not a good assumption and it surely defeats to object of producing power gains no matter what fuel is used.

Porsche964FP

\/

Have a KitKat - enjoy your weekend

NineMeister

Well, I see your point, but why "nomatter what fuel is used"? Surely if your builder maps your new £25k engine on Shell V-Power you would do your utmost to always use the same or take extreme caution when not? I appreciate that occasionally you might not find a Shell station and have to use BP ultimate or Tesco 99 instead, but you would inevitably revert back to V-Power when going for a thrash at the track.

You pay yer money and you make a choice, so if you want to use any old fuel you are absolutely right, you need knock control for your standard engine.....

ras62

Yes Colin, absolutely right. Track is one thing, road is another and I have long been taught that Engineers should cater for the worst case scenario and assume nothing. You cannot guarantee its Stella coming out of the Stella tap in some places!
Btw nice display at Arley today